Knee Surg Sports Traumatol Arthrosc (2014) 22:2286–2294 DOI 10.1007/s00167-014-3150-y
KNEE
Anterior knee pain: an update of physical therapy Suzanne Werner
Received: 16 January 2014 / Accepted: 19 June 2014 / Published online: 6 July 2014 Springer-Verlag Berlin Heidelberg 2014
Abstract Anterior knee pain is one of the most common knee problems in physically active individuals. The reason for anterior knee pain has been suggested to be multifactorial with patella abnormalities or extensor mechanism disorder leading to patellar malalignment during flexion and extension of the knee joint. Some patients complain mostly of non-specific knee pain, while others report patellar instability problems. The patients present with a variety of symptoms and clinical findings, meaning that a thorough clinical examination is the key for optimal treatment. Weakness of the quadriceps muscle, especially during eccentric contractions, is usually present in the majority of anterior knee pain patients. However, irrespective of whether pain or instability is the major problem, hypotrophy and reduced activity of the vastus medialis are often found, which result in an imbalance between vastus medialis and vastus lateralis. This imbalance needs to be corrected before quadriceps exercises are started. The non-operative rehabilitation protocol should be divided into different phases based on the patient’s progress. The goal of the first phase is to reduce pain and swelling, improve the balance between vastus medialis and vastus lateralis, restore normal gait, and decrease loading of the patello-femoral joint. The second phase should include improvement of postural control and coordination of the lower extremity, increase of quadriceps strength and when needed hip muscle strength, and restore S. Werner Stockholm Sports Trauma Research Center, Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden S. Werner (&) SSTRC/Capio Artro Clinic, Sophiahemmet, Box 5605, 11486 Stockholm, Sweden e-mail: [email protected]
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good knee function. The patient should be encouraged to return to or to start with a suitable regular physical exercise. Therefore, the third phase should include functional exercises. Towards the end of the treatment, single-leg functional tests and functional knee scores should be used for evaluating clinical outcome. A non-operative treatment of patients with anterior knee pain should be tried for at least 3 months before considering other treatment options. Keywords Electrical muscle stimulation Functional anterior knee pain score Patello-femoral pain Patellar hypermobility Patellar stabilizing brace Patellar taping Quadriceps weakness Vastus medialis–vastus lateralis imbalance Introduction Anterior knee pain is one of the most common knee complaints in physically active individuals [20, 56]. The reason for anterior knee pain is still unclear and suggested to be multifactorial [29], including anatomical patella abnormalities [30] or being an extensor mechanism disorder, resulting in patellar malalignment during knee flexion and knee extension [31]. Why this extensor mechanism disorder has developed is, however, not reported. Furthermore, some authors maintain that anterior knee pain could be due to overuse, especially in adolescents [20]. Clinical examination Symptoms and findings Since patients with anterior knee pain present with a myriad of symptoms and complaints, a thorough clinical
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Patellar position
examination is the key for optimal treatment. The clinical examination should consist of a careful control of the entire lower extremity [45]. Possible prevalence of increased internal femoral rotation that can be observed clinically often causes a squinting of the patella. Compensatory external tibial torsion should be noted, as well as genu recurvatum, genu valgum, and hyperpronation of the subtalar joint [10, 36, 47, 64]. Furthermore, it is important to control the patient’s foot position during weight-bearing and check how his/her shoes, especially sport shoes, are worn. Foot orthotics to control excessive pronation of the subtalar joint has been advocated in order to improve patellar tracking and lead to decreased anterior knee pain [67]. In addition, paying attention to an accurate history from the patient will greatly aid the physical therapist in making an accurate assessment of the patient’s condition and thereby design an appropriate treatment programme [3, 10].
Assessing the orientation of the patella relative to the femur and controlling the patellar position within the patellofemoral joint should be done. An optimal patellar position is when the patella is parallel to the femur in the frontal and the sagittal planes and when the patella is midway between the two condyles during 20 of knee flexion [47]. Possible anatomical variations such as patella alta, patella infera, tilted patella, and rotated patella should be checked for. One should be aware of that a high-riding patella (patella alta) is reported to be a risk factor for patellar subluxation or dislocation [34], while patients with patella infera rather seem to complain of patellar pain at the area of apex patellae. Tilted patella with a medial ‘‘opening’’ (a lateral tilt) seems to be relatively common in patients with anterior knee pain. The reason for this usually depends on tightness of the lateral retinaculum, which will tilt the patella so that the medial border of the patella is higher than the lateral border [47]. Furthermore, a hypotrophy of the vastus medialis obliquus (VMO) may aid in creating lateral patellar tilt. Some patients present with an externally rotated patella, when the inferior pole of the patella is lateral to the long axis of the femur, indicating tightness of the lateral retinaculum. Very few patients present with the opposite, an internally rotated patella. The ideal patellar position is when the long axis of the femur is parallel to the long axis of the patella [47]. A number of patients with anterior knee pain complaining mostly of patellar instability [1, 24, 27] often show a hypermobile patella and an observable tracking disorder [71]. Therefore, patellar mobility should be checked [10, 27, 36]. This can be done with the ‘‘patellar tracking test’’ by clinically observing patellar movement with manual resistance against concentric and eccentric knee extension during open kinetic chain and closed kinetic chain in knee loading conditions such as single-leg squat, for instance. Another way of revealing a possible patellar hypermobility
Pain versus patellar instability problems Patients with anterior knee pain mostly complain of nonspecific knee pain localized peripatellarly, often anteromedially and/or retropatellarly [1, 24, 35]. Others complain of a feeling of patellar instability [1, 24, 27]. Patients that mostly complain of pain usually have normal patellar mobility, and they mainly report the symptoms to occur after physical activity. Those with patellar instability often present with a patellar hypermobility with noticeable tracking problems, and they rather complain of knee problems during physical activity [36]. This means that patients with anterior knee pain should be divided into two treatment groups: one based on pain limitation and one on patella stabilization. Witvrouw et al. [77] developed a clinical classification system that provides the clinician with guidelines to classify and treat patients with anterior knee pain (Fig. 1).
Anterior Knee Pain
Muscular dysfunction
Malalignment
Malalignment of entire leg
Malalignment PF joint
Non-muscular origin
Muscular origin
Strength deficit
VMO
Quadriceps
Neuromuscular dysfunction
VMO/VL timing dysfunction
Flexibility
Hamstrings Quadriceps Gastrocnemius Iliotibial band
Fig. 1 Clinical classification of anterior knee pain
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is to manually perform a passive deviation both laterally and medially with the patient in supine position with the knee joint slightly flexed [50]. A deviation of 10 mm as well laterally as medially should be regarded as normal patellar mobility [50]. Weakness of knee extensors The knee extensors are often weakened in patients with anterior knee pain [72]. Isokinetic testing is the most optimal way for measuring muscle torques. However, isokinetic testing must be carried out cautiously [26]. Patients with patellar hypermobility should not be measured eccentrically during fast angular velocities ([90/s) due to risk of subluxation or even dislocation [70]. Imbalance between the knee extensors and knee flexors is frequently shown in patients with anterior knee pain. This usually depends on muscle weakness of the knee extensors and a normal strength of the knee flexors. This subsequently results in a higher hamstring/quadriceps ratio compared with healthy subjects [72]. Besides increased muscle torque, isokinetic training has been reported to lead to improved proprioception in patients with anterior knee pain [32], which most likely will improve knee function. Vastus medialis versus vastus lateralis Electromyography (EMG) recordings have been suggested to be important when evaluating the activity of the vasti muscles in order to diagnose anterior knee pain [21, 22]. Hypotrophy of the vastus medialis (VM) is common in anterior knee pain patients (30). VM also has a low activity and is the weakest and most vulnerable muscle of the extensor mechanism [24]. Vastus lateralis (VL) that usually has a considerably higher activity comprises the largest muscle mass and extensor power of the knee extensors. The lower activity of VM and the higher activity of VL could lead to an imbalance between VM and VL [43, 58]. It has also been reported that the onset of the VL contraction occurs before that of the VMO, indicating a difference in motor control in anterior knee pain patients compared with asymptomatic controls [15]. Owings and Grabiner [51] reported that the activation amplitude of VMO and VL in anterior knee pain patients was mostly altered during eccentric contractions and differed significantly from that of a control group. The authors conclude that the activation amplitudes of the VMO and VL in anterior knee pain patients are consistent with a lateral tracking of the patella during eccentric contractions [75]. Furthermore, some authors have found that the time to activation often is disturbed in patients with anterior knee pain [68, 74]. Therefore, it is important to improve the onset of muscle activity of the VMO in many anterior knee pain patients. Several
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authors maintain that the primary role of VMO is to enhance patellar stabilization within the patello-femoral joint and to prevent lateral patellar subluxation by pulling the patella medially during knee extension and flexion [24, 43, 46, 58]. More than 50 years ago, Brewerton [8], followed by Lieb and Perry [40], Martin and Londeree [44], and Bose et al. [7], reported VMO to be active during the full range of knee extension. Mariani et al. [43] found the EMG activity of both VM and VL to be of similar degree and mostly pronounced during the last 30 of knee extension in healthy subjects. It is important to check the muscle activity pattern between VM and VL, as well the patient’s asymptomatic leg as his/her symptomatic leg when designing an optimal treatment protocol for patients with anterior knee pain. When bilateral problems exist, I suggest that one relies on the EMG activity pattern of the less symptomatic leg. The need for strengthening the hip muscles in patients with anterior knee pain has been discussed during recent years [61]. Delayed onset of the activation of the hip abductors has recently been reported [16], but hitherto, no consensus exists about training the hip abductors. Muscle flexibility Soft tissue or muscle length is essential for musculoskeletal evaluation and has specific implications in patients with anterior knee pain. Smith et al. [63] found poor flexibility of the knee extensors and knee flexors to be correlated with anterior knee pain. Tightness of the tensor fascia lata and iliotibial band is associated with anterior knee pain [18]. Furthermore, a tight iliotibial band will result in a lateral deviation of the patella and lateral tracking, as well as lateral tilting and usually also weakening of the medial retinaculum [67]. Anterior knee pain patients sometimes also show tightness of the lateral retinaculum, which might lead to an ‘‘opening’’ of the patella on the medial side, a lateral patellar tilt. Piva et al. [57] reported tightness of both knee extensors and knee flexors to be correlated with anterior knee pain.
Rehabilitation programme Recent research has been reported that the lower the frequency of pain before treatment, the greater the quadriceps muscle size, and the smaller the eccentric torque at a low angular velocity—the better the functional outcome after a short period of physical therapy [55]. When designing a treatment programme, it is important to realize that each patient is unique and will present with different symptoms and clinical signs. This necessitates a flexible treatment approach [3]. The treatment protocol should therefore be based on findings from the patient’s
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history, clinical examination, and functional assessment [77]. To be aware of those factors that determine the functional outcome after a rehabilitation period is important for the patient as well as for the physical therapist, the physician, and the sport coach [55]. A fast pain relief should be specifically targeted during the rehabilitation of patients with anterior knee pain together with avoidance of painprovoking activities [55]. The use of the pain monitoring system developed by Thomee´ could aid in the rehabilitation when it comes to pain control [66]. This pain monitoring system is based on pain ratings according to the visual analogue scale (0–10 cm). Pain reported up to a level of 2 is considered to be ‘‘safe’’, pain up to a level of 5 to be ‘‘acceptable’’ (if pain had subsided by the next morning), and pain above level 5 is ‘‘high risk’’. A thorough clinical examination based on control of patellar mobility, muscle function, and each patient’s specific functional problem is of utmost importance for a successful clinical outcome. Moreover, patient education is one of the key factors in the management of anterior knee pain. The patient must have a clear understanding of why the symptoms have occurred and what needs to be done to reduce the symptoms. Training of the vastus medialis At the start of the rehabilitation, the main objective for the majority of patients with anterior knee pain is to strengthen the VM [12]. This is due to that appropriate timing and intensity of VMO activation relative to VL has been promoted as a key aspect in patients with anterior knee pain [74]. Therefore, the balance between VMO and VL should be restored before starting to train the entire group of knee extensors. Muscular hypotrophy and a reduced and/or delayed EMG activity of the VM are common in patients with anterior knee pain, resulting in an imbalance between VM and VL [12, 43]. Therefore, the initial treatment should consist of restoring the function of VM in an attempt to enhance patellar stabilization [6, 11, 24, 43, 46]. In the literature, several types of exercises have been suggested to increase the activity of VM over that of VL [38], but with no great success. Transcutaneous electrical muscle stimulation is the optimal way proven to selectively contract and improve the function of VM [69]. Steadman proposed electrical muscle stimulation of VM in order to keep the patella in a proper position within the patellofemoral joint [64]. With the help of computer tomography, Werner et al. [69] reported a significantly increased area of the VM after transcutaneous electrical stimulation of this muscle, while the VL was unchanged. Two-thirds of those patients also improved from a functional point of view directly after 10 weeks of daily electrical stimulation. At the follow-ups, 1 and 3.5 years later, the same patients were still improved [69].
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Knee extensor strengthening Several authors have emphasized the importance of knee extensor training in patients with anterior knee pain in order to improve the extensor mechanism [27, 35, 55, 64] and functional ability [59]. The greater the eccentric knee extensor torque at a low angular velocity, the greater the functional capacity and the lower knee pain has been reported by anterior knee pain patients [48]. Stability of the hip joint by strengthening of the hip muscles is important in order to absorb the appropriate load. This is due to that load is transmitted to other joints of the lower extremity, particularly the knee joint [45]. Strengthening of the knee extensors in combination with strengthening the abductors and the external rotators of the hip have been reported to reduce knee pain while descending stairs [25]. The knee extensors can be strengthened with as well closed kinetic chain (CKC) as open kinetic chain (OKC) exercises. Palmitier et al. [52] suggest that rehabilitation in a weight-bearing position such as during CKC exercises may have a greater carry-over to functional activities, as lower extremity function in daily weight-bearing activities involves multiple muscle groups acting in synergy. However, for optimal knee function, my suggestion is to strengthen the knee extensors during both CKC and OKC, which is in agreement with other authors [33, 76]. In order to reduce the patello-femoral joint reaction forces CKC exercises, such as leg press and step exercises, earlier research has suggested the training to be within the last 30 of knee extension [19]. Later, Bizzini et al. [5] have advocated a somewhat extended range of motion when it comes to squat and leg press. Contrarily, OKC exercises, such as sitting knee extension, have been suggested to rather be trained between 90 and 40 of knee flexion [65]. Isokinetic training is the most optimal way for muscle strengthening when it comes to OKC [70]. Isokinetic training provides optimal loading of the muscles and allows muscular performance at different velocities [2]. High angular velocities should be used in order to reduce compressive forces on the joint surfaces. This means that isokinetic training at high angular velocity (C120/s) should be preferred when strengthening the knee extensors in anterior knee pain patients during concentric actions. However, eccentric actions are more difficult to perform due to unfamiliarity with the decelerating type of movement and to coordinate the different muscles of the knee extensors [70, 72]. My suggestion is therefore that patients with anterior knee pain should perform isokinetic eccentric contractions at B90/s. The advantage with isokinetic training in anterior knee pain patients is, except for rapid muscular effect, that the training can be adjusted to possible knee pain and therefore diminish the risk for overload.
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Patellar stabilization If patellar hypermobility exists, the patella could initially be supported by a patellar stabilizing brace or patellar taping during the physical therapy treatment. However, it is of utmost importance to check in what direction the patella is hypermobile, laterally, medially, or both. I recommend either taping or bracing in patients with a lateral or a medial hypermobility and bracing in patients with both a lateral and medial hypermobility. When the patient improves and symptoms are reduced, the external patella support should be gradually removed. Recent research has shown that a 2-week period of patellar taping followed by an exercise programme for another 10 weeks to improve the activity of VMO led to a long-lasting (12 months) pain control in anterior knee pain patients with muscle imbalance between VMO and VL [54]. Supportive devices such as patellar stabilizing braces and patellar taping are aimed to improve patellar tracking problems [21, 42, 53]. Some authors have suggested that anterior knee pain patients should be treated with patellar stabilizing orthoses [35, 42], although there is no evidence of any major alteration of patellar tracking [26]. Palumbo reported decreased symptoms in 92 % when a patella stabilizing brace was used in anterior knee pain patients [53]. Sega et al. [62] reported that an orthosis with a medial support gave a good pain reduction in patients with patellar instability. Other authors recommend an elastic strap or taping in order to improve patellar tracking and thereby reduce patellar instability problems [46, 56]. McConnell [46] reported a success rate of 92 % maintaining that patellar taping with a medial glide technique can modify patellar tracking and therefore act as pain relief. During step-up and step-down tasks, Gilleard et al. [28] found that the onset of VMO activity occurred earlier, when the patella was taped compared with untaped. The activity of VL was unchanged during the step-up task and delayed during the step-down task with taping [28]. Ng and Wong [49] reported no improvement of VM activity with patellar taping. Powers et al. [60] studied the effect of patellar taping according to McConnell on functional outcomes and reported an average pain reduction of 78 % using the visual analogue scale. Kowall et al. [37] performed a prospective intervention study comparing two groups that followed the same physical therapy programme, one group with the patella taped and the other without taping. Both groups improved, irrespective of the addition of taping or not [37]. In contrast, Whittingham et al. [73] reported that a combination of patellar taping and exercise was superior to exercise alone in terms of reduction of knee pain and improved knee function. Christou [14] reported increased VM activity and decreased VL activity in anterior knee pain patients when
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the patella was taped medially. The benefits of patellar taping are probably not due to a change in patellar position, but rather due to enhanced support of the patello-femoral ligaments and/or pain modulation via cutaneous stimulation [14]. Werner et al. [71] reported that patients with patellar hypermobility (C15 mm deviation laterally or medially) improved their knee extension torque and agonist EMG activity during isokinetic knee extensions, when the patella was stabilized by taping, while patients with a normal patellar mobility did not benefit from taping. However, they also found that in order to optimize the treatment for supporting the patella with tape, it is important to check the direction of the patient’s patellar hypermobility, which can be laterally, medially, or both [71]. Furthermore, in order to control whether the patient needs a patellar support, orthosis, or taping, it is important to check patellar tracking within the patello-femoral joint during both concentric and eccentric knee extension (‘‘patellar tracking’’-test). In my opinion, patellar taping can be recommended only if patellar hypermobility exists and as a temporary treatment to facilitate physical therapy exercises, especially strengthening of the knee extensors. Stretching A number of patients with anterior knee pain shows tightness mostly of the iliotibial band and other lateral muscle structures, the quadriceps muscle, and sometimes also of the hamstrings and the gastrocnemius. Most of the stretching procedures could be performed by the patients themselves, and therefore, they should be instructed in how to stretch their tight muscle structures. The lateral retinaculum might also be tight, which could interfere with a normal patellar tracking, and should therefore be treated with medial patellar glide. Balance and coordination training Physical training causes changes within the nervous system that leads to improved coordination between muscle groups, and practice will result in automatics, which indicate a change and improvement in the motor programme [58, 62]. When the activity and the function of VM have improved, balance and coordination training of the lower extremity should be started. Balance and coordination exercises should preferably be performed during knee loading conditions and with slightly flexed knees in order to try to direct the training to the knee joint. Functional and sport-specific training When the quadriceps muscle has improved and a good balance exists within the extensor mechanism, functional
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training with gradual increase of knee loading exercises could begin. The patient should practice slowly stepping on and off a step with adequate pelvic control. Initially, a small step height should be used, and the patient is recommended to train in front of a mirror to be able to observe muscle function of the knee extensors. The pelvis must remain parallel with the floor, and the hip, knee, and foot should be aligned [47]. There is a wide variation of functional knee loading exercises that make different heavy demands upon the knee, for instance walking, jogging, running, stair-climbing, jumping, and bicycling. Those athletic patients that have improved and have a good knee extensor strength, good muscle flexibility, and a proper movement pattern during functional heavy knee loading activities performed without pain or swelling are encouraged to start sport-specific training.
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scoring system, the Samsung Medical Center (SMC) scoring system, based on both pain and function. Their SMC scoring system shows excellent test–retest and internal consistency, as well as acceptable ceiling and floor effects [39]. Regime Towards the end of the treatment period, it is recommended to stimulate the patient either to return to some kind of sport/physical activity or to start with a suitable regular physical exercise, where long walks could be one alternative [69, 70]. The reason for this is that the improved muscle function and balance that have been gained through the rehabilitation need to be maintained by performing physical exercise regularly. Psychological considerations
Evaluation Functional tests Dynamic evaluation with knee-related functional tests should be used in order to reproduce the patient’s symptoms and to make comparisons before and after a period of treatment. Examples of appropriate functional tests for anterior knee pain patients are stair-climbing (up and down), double-leg and single-leg squat, and raise from a chair and sit down using one leg. These tests could be used to evaluate knee pain using the visual analogue scale [13, 23], as well as the functional capacity of the knee extensors. The following four functional tests: anteromedial lunge, step-down, single-leg press, and balance and reach have been reported to be reliable [41]. Single-leg tests are very good indicators of controlling the extensor mechanism and thereby the patient’s symptoms. Future research is needed in order to evaluate intra-rater and inter-rater reliability as well as the validity and sensitivity of functional tests [17].
A poor correlation has been found between the patient’s clinical symptoms and the clinician’s objective findings [4]. Jacobson and Flandry [36] reported that some of the patients that came to visit the doctor for anterior knee pain problems at a Sport Medicine Clinic were having both chronic anterior knee pain and psychological problems. Carlsson et al. [9] used the Rorschach test and found elevations in psychological parameters such as hostility, dependency, and depression in patients with anterior knee pain compared with healthy controls, matched for gender and age, as well as with three other reference groups. However, these problems are not always evident for the patient himself or herself [9]. In such cases, a psychological evaluation is often advisable, and therefore, collaboration with a pain clinic with psychological expertise may be beneficial.
Rehabilitation protocol for anterior knee pain patients Phase 1 Goals
Functional knee score A knee score for functional evaluation of patients with anterior knee pain should consist of different categories of symptoms that are common in these patients. The Werner functional knee score has been modified from an earlier published version [69]. A test–retest of this score has revealed a very good reproducibility and sensitivity in patients with anterior knee pain. The score comprises 0–50 points and is provided with the following determinations in terms of anterior knee pain: C47 points = excellent, 42–46 points = good, 33–41 points = fair, and B32 points = poor. Recently, Lee et al. [39] have developed a new
Reduce pain and swelling, improve VMO:VL balance, and thereby patellar tracking, improve flexibility, restore normal gait, and decrease loading of the patello-femoral joint. Treatment •
•
Cryotherapy—after the physical therapy exercise and daily activities, that exacerbate symptoms to reduce pain and oedema. Transcutaneous electrical stimulation of VMO to restore the function of VMO and improve VMO:VL balance.
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•
•
• •
•
• •
Flexibility training: stretching of tight muscle structures, usually the tensor fascia lata and the iliotibial band, the quadriceps, in particular rectus femoris, the hamstrings, and the gastrocnemius. Tight lateral retinaculum can, except for stretching, be treated with medial patellar glide, friction and massage. If gait has been altered, the patient should be instructed in proper gait mechanics, which preferably could be done in front of a mirror. Instruct the patient to change postural habits such as standing in genu recurvatum, for instance. If patellar hypermobility exists, it is recommended to either tape the patella or to use a patellar stabilizing brace during the physical therapy exercises. However, patellar supporting devices should only be used temporarily until exercises and functional activities can be performed without knee pain. If increased pronation of the subtalar joint exists, treat the patient with foot orthotics or arch taping. Foot orthotics can be used temporarily or may be needed indefinitely to improve patellar tracking and alignment of the lower extremity. Check the patient’s shoe wear, in particular sport shoes, and if needed, suggest shock absorptive shoes. Modify daily activity level to temporarily reduce the load on the patello-femoral joint.
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•
•
•
compression forces within the patello-femoral joint. This type of exercise might improve both physical conditioning and thigh muscle strength. Functional knee exercises. Start with shallow squats and proceed with deeper ones. Squatting can initially be performed with addition of electrical stimulation of VMO to improve the VMO:VL balance. Stepping down exercises can also be started with addition of electrical muscle stimulation and gradually be performed without. Quadriceps strengthening is recommended to be started when a good balance between VMO and VL exists. Closed kinetic chain exercises are recommended to be performed between 40 and 30 and full knee extension, and open kinetic chain between 90 and 40 of knee flexion. Isokinetic training should preferably be performed at 120/s or higher during concentric actions and at 90/s or lower during eccentric actions. Strengthening of hip muscles when needed.
Phase 3 Goal Return to previous physical activity level.
Phase 2 Goals
Treatment •
Improve balance of the lower extremity, increase quadriceps strength and when needed hip muscle strength, and restore good knee function. Treatment •
•
Balance and coordination training with gradual increase of difficulty and loading on the patello-femoral joint. In order to try to mainly train the knee joint stabilizers, I suggest that these exercises should be performed in a standing position with a slightly flexed knee joint. Balance training on a balance board can initially be performed standing on one leg with addition of electrical stimulation of VMO to facilitate a proper balance between VMO and VL. When good muscle control is achieved, the patient can continue the balance exercise standing on one leg without electrical muscle stimulation or standing on both legs on two balance boards. Stationary bicycle training with a high seat aimed to reduce a big knee flexion angle and thereby
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•
•
•
Functional training with a gradual increase of knee loading activities can begin after improved quadriceps strength. Walking, jogging, and different types of jumping exercises are recommended during this phase. However, proceeding to a higher knee loading activity or exercise should only be allowed, if there is no knee pain and no swelling. Sport-specific exercises with a gradual increase of intensity can start as soon as the athletic patient is pain free, has a good muscle function, and a proper movement pattern during functional knee exercises. It is recommended to give the patient individual guidelines for physical activity and exercises in terms of, for instance number of repetitions, duration, intensity, and frequency. Patient education is also highly recommended in order to try to prevent recurrence of knee symptoms.
Non-operative treatment of patients with anterior knee pain should be tried for at least 3 months until both the physical therapist and the patient feel that pain and knee function have reached a plateau [45].
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References 1. Aglietti P, Buzzi R, Pisaneschi A (1990) Patella pain. J Sports Trauma Rel Res 12:131–150 2. Baltzopoulos V, Brodie DA (1989) Isokinetic dynamometry. Applications and limitations. Sports Med 8:101–116 3. Beckman M, Craig R, Lehman RC (1989) Rehabilitation of patellofemoral dysfunction in the athlete. Clin Sports Med 8(4):841–860 4. Bentley G, Dowd G (1984) Current concepts of etiology and treatment of chondromalacia patellae. Clin Orthop 189:209–228 5. Bizzini M, Biedert R, Maffiuletti N, Impellizzeri F (2008) Biomechanical issues in patellofemoral joint rehabilitation. Orthopade 37(9):864 (866–871) 6. Bockrath K, Wooden C, Worrel T, Ingersoll CD, Farr J (1993) Effects of patella taping on patella position and perceived pain. Med Sci Sports Exerc 25:989–992 7. Bose K, Kanagasuntherum R, Osman M (1980) Vastus medialis oblique: an anatomical and physiologic study. Orthopedics 3:880–883 8. Brewerton DA (1955) The function of the vastus medialis muscle. Ann Phys Med 2:164–168 9. Carlsson AM, Werner S, Mattlar C-E, Edman G, Puukka P, Eriksson E (1993) Personality in patients with long-term patellofemoral pain syndrome. Knee Surg Sports Traumatol Arthrosc 1:178–183 10. Carson WG (1985) Diagnosis of extensor mechanism disorders. Clin Sports Med 4:231–246 11. Cerny K (1995) Vastus medialis oblique/vastus lateralis muscle activity ratios for selected exercises in persons with and without patellofemoral pain syndrome. Phys Ther 75(8):672–683 12. Cesarelli M, Bifulco P, Bracale M (2000) Study of the control strategy of the quadriceps muscles in anterior knee pain. Trans Rehabil Eng 8(3):330–341 13. Chesworth BM, Culham EG, Tata GE, Peat M (1989) Validation of outcome measures in patients with patellofemoral syndrome. J Orthop Sports Phys Ther 10:302–309 14. Christou EA (2004) Patellar taping increases vastus medialis oblique activity in the presence of patellofemoral pain. J Electromyogr Kinesiol 14(4):495–504 15. Cowan SM, Bennell KL, Hodges PW, Crossley KM, McConnell J (2003) Simultaneous feedforward recruitment of the vasti in untrained postural tasks can be restored by physical therapy. J Orthop Res 21(3):553–558 16. Cowan SM, Crossley KM, Bennell KL (2008) Altered hip and trunk muscle function in individuals with patellofemoral pain. Br J Sports Med 43(8):584–588 17. Crossley KM, Bennell KL, Cowan SM, Green S (2004) Analysis of outcome measures for persons with patellofemoral pain: which are reliable and valid? Arch Phys Med Rehabil 85(5):815–822 18. Doucette SA, Goble EM (1992) The effect of exercise on patellar tracking in lateral patellar compression syndrome. Am J Sports Med 20(4):434–440 19. Doucette SA, Child DP (1996) The effect of open and closed chain exercise and knee joint position on patellar tracking in lateral patellar compression syndrome. J Orthop Sports Phys Ther 23(2):104–110 20. Fairbank J, Pynsent P, van Poortvliet J, Phillips H (1984) Mechanical factors in the incidence of knee pain in adolescents and young adults. J Bone Joint Surg Br 66:685–693 21. Felicio LR, Do Prado Baffa A, Liporacci RF, Saad MC, De Oliveira AS, Bevilaqua-Grossi D (2011) Analysis of patellar stabilizers muscles and patellar kinematics in anterior knee pain subjects. J Electromyogr Kinesiol 21:148–153 22. Ferrari D, Kuriki HU, Silva CR, Alves N, de Azevedo FM (2014) Diagnostic accuracy of the electromyography parameters
23.
24.
25.
26.
27. 28.
29. 30.
31.
32.
33.
34. 35. 36. 37.
38.
39.
40. 41.
42.
43.
associated with anterior knee pain in the diagnosis of patellofemoral pain syndrome. Arch Phys Med Rehabil 2–6 (in press) Flandry F, Hunt JP, Terry GC, Hughston JC (1991) Analysis of subjective knee complaints using visual analog scales. Am J Sports Med 19(2):112–118 Fox TA (1975) Dysplasia of the quadriceps mechanism, hypoplasia of the vastus medialis as related to the hypermobile patella syndrome. Surg Clin North Am 55:199–226 Fukuda TY, Rossetto FM, Magalha˜es E, Bryk FF, Lucareli PR, de Almeida Aparecida Carvalho N (2010) Short-term effects of hip abductors and lateral rotators strengthening in females with patellofemoral pain syndrome: a randomized controlled clinical trial. J Orthop Sports Phys Ther 40:736–742 Fulkerson JP, Hungerford DS (1990) Biomechanics of the patellofemoral joint. In: Fulkerson JP, Hungerford DS (eds) Disorders of the patellofemoral joint, 2nd edn. Williams & Wilkins, Baltimore, pp 25–41 Fulkerson JP, Shea KP (1990) Current concepts review disorders of patellofemoral alignment. J Bone Joint Surg Am 72:1424–1429 Gilleard W, McConnell J, Parsons D (1998) The effect of patellar taping on the onset of vastus medialis obliquus and vastus lateralis muscle activity in persons with patellofemoral pain. Phys Ther 78(1):25–32 Goldberg B (1991) Chronic anterior knee pain in adolescents. Pediatr Ann 20:186–193 Goodfellow J, Hungerford DS, Zindel M (1976) Patello-femoral joint mechanics and pathology: I. Functional anatomy of the patella-femoral joint. J Bone Joint Surg Br 58:287–290 Gunther KP, Thielemann F, Bottesi M (2003) Anterior knee pain in children and adolescents: diagnosis and conservative treatment. Orthopa¨de 32(2):110–118 Hazneci B, Yildiz Y, Sekir U, Aydin T, Kalyon TA (2005) Efficacy of isokinetic exercise on joint position sense and muscle strength in patellofemoral pain syndrome. Am J Phys Med Rehabil 84(7):521–527 Heintjes E, Berger MY, Bierma-Zeinstra SM, Bernsen RM, Verhaar JA, Koes BW (2003) Exercise therapy for patellofemoral pain syndrome. Cochrane Database Syst Rev (4):CD003472 Insall J, Goldberg V, Salvati E (1972) Recurrent dislocation and high-riding patella. Clin Orthop Relat Res 88:67–69 Insall J (1982) Current concepts review, patellar pain. J Bone Joint Surg Am 64:147–152 Jacobson KE, Flandry FC (1989) Diagnosis of anterior knee pain. Clin Sports Med 8:179–195 Kowall MG, Kolk G, Nuber GW, Cassisi JE, Stern SH (1996) Patellar taping in the treatment of patellofemoral pain: a prospective randomized study. Am J Sports Med 24(1):61–66 Laprade J, Culham E, Brouwer B (1998) Comparison of five isometric exercises in the recruitment of the vastus medialis oblique in persons with and without patella-femoral pain syndrome. J Orthop Sports Phys Ther 27(3):197–204 Lee C-H, Ha C-W, Kim S, Kim M, Song Y-J (2013) A novel patellofemoral scoring system for patellofemoral joint status. J Bone Joint Surg Am 95:620–626 Lieb F, Perry J (1968) Quadriceps function. J Bone Joint Surg Am 50:1535–1548 Loudon JK, Wiesner D, Goist-Foley HL, Asjes C, Loudon KL (2002) Intrarater reliability of functional performance tests for subjects with patellofemoral pain syndrome. J Athl Train 37(3):256–261 Lysholm J, Nordin M, Ekstrand J, Gillquist J (1984) The effect of a patella brace on performance in knee extension strength test in patients with patellar pain. Am J Sports Med 12:110–112 Mariani PP, Caruso I (1989) An electromyographic investigation of subluxation of the patella. J Bone Joint Surg Br 61:169–171
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2294 44. Martin JA, Londeree BR (1979) EMG comparison of quadriceps femoris activity during knee extension and straight leg raises. Am J Phys Med Rehabil 58:57–69 45. McCarthy MM, Strickland SM (2013) Patellofemoral pain: an update on diagnostic and treatment options. Curr Rev Musculoskelet Med 6:188–194 46. McConnell J (1986) The management of chondromalacia patellae: a long term solution. Austr J Physiother 32(4):215–223 47. McConnell J (1998) Examination of the patellofemoral joint: the physical therapist´s perspective. In: Grelsamer RP, McConnell J (eds) The patella. A team approach. Aspen Publishers, Gaithersburg, pp 109–118 48. Nakagawa TH, Muniz TB, Baldon RM, Maciel CD, Amorim C, Serra˜o F (2011) Electromyographic preactivation pattern of the gluteus medius during weight-bearing functional tasks in women with and without anterior knee pain. Rev Bras Fisioter 15(1):59–65 49. Ng GYF, Wong PYK (2009) Patellae taping affects vastus medialis obliquus activation in subjects with patellofemoral pain before and after quadriceps muscle fatigue. Clin Rehabil 23:705–713 50. Osborne AH, Farquharson-Roberts MA (1983) The aetiology of patella-femoral pain. J Roy Nav Med Serv 69:97–103 51. Owings TM, Grabiner MD (2002) Motor control of the vastus medialis oblique and vastus lateralis muscles is disrupted during eccentric contractions in subjects with patellofemoral pain. Am J Sports Med 30(4):483–487 52. Palmitier RA, An K-N, Scott SG, Chao EYS (1991) Kinetic chain exercise in knee rehabilitation. Sports Med 11(6):404–413 53. Palumbo PM (1981) Dynamic patellar brace: patellofemoral disorders. A preliminary report. Am J Sports Med 9:45–49 54. Paoloni M, Fratocchi G, Mangone M, Murgia M, Santilli V, Cacchio A (2012) Long-term efficacy of a short period of taping followed by an exercise program in a cohort of patients with patellofemoral pain syndrome. Clin Rheumatol 31:535–539 55. Pattyn E, Mahieu N, Selfe J, Verdonk P, Steyaert A, Witvrouw E (2012) What predicts functional outcome after treatment for patellofemoral pain? Med Sci Sports Exerc 1827–1833 56. Percy EC, Strother RT (1985) Patellalgia. Physician Sports Med 13:43–59 57. Piva SR, Goodnite EA, Childs JD (2005) Strength around the hip and flexibility of soft tissues in individuals with and without patellofemoral pain syndrome. J Orthop Sports Phys Ther 35:793–801 58. Portney LG, Sullivan PE, Daniell JL (1986) EMG activity of vastus medialis obliquus and vastus lateralis in normal and patients with patellofemoral arthralgia. Phys Ther 66:808 59. Powers CM, Perry J, Hislop HJ (1997) Are patellofemoral pain and quadriceps femoris muscle torque associated with locomotor function? Phys Ther 77(10):1063–1075 60. Powers CM, Landel E, Sosnick T, Kirby J, Mengel K, Cheney A, Perry J (1997) The effects of patellar taping on stride characteristics and joint motion in subjects with patellofemoral pain. J Orthop Sports Phys Ther 26(6):286–291 61. Robinson RL, Nee RJ (2007) Analysis of hip strength in females seeking physical therapy treatment for unilateral patellofemoral pain syndrome. J Orthop Sports Phys Ther 37(5):232–238
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Knee Surg Sports Traumatol Arthrosc (2014) 22:2286–2294 62. Sega L, Galante M, Fortina A, Squazzini Viscontini G, Bertolotti G, Benedetti MG (1988) Association of dynamic bandage with kinesitherapy in the treatment of patellar instability. Ital J Sports Traum 10:89–94 63. Smith AD, Stroud L, McQueen C (1991) Flexibility and anterior knee pain in adolescent elite figure skaters. J Pediatr Orthop 11:77–82 64. Steadman JR (1979) Nonoperative measures for patellofemoral problems. Am J Sports Med 7:374–375 65. Steinkamp LA, Dillingham MF, Markel MD, Hill JA, Kaufman KR (1993) Biomechanical considerations in patellofemoral joint rehabilitation. Am J Sports Med 21(3):438–444 66. Thomee´ R (1997) A comprehensive treatment approach for patellofemoral pain syndrome in young women. Phys Ther 77(12):1690–1703 67. Tiberio D (1987) The effect of excessive subtalar joint pronation on patellofemoral mechanics: a theoretical model. J Orthop Sports Phys Ther 9:160–165 68. Voight ML, Wieder DL (1991) Comparative reflex response times of vastus medialis obliquus and vastus lateralis in normal subjects and subjects with extensor mechanism dysfunction: an electromyographic study. Am J Sports Med 19:131–137 69. Werner S, Arvidsson H, Arvidsson I, Eriksson E (1993) Electrical stimulation of vastus medialis and stretching of lateral thigh muscles in patients with patello-femoral symptoms. Knee Surg Sports Traumatol Arthrosc 1:85–92 70. Werner S, Eriksson E (1993) Isokinetic quadriceps training in patients with patellofemoral pain syndrome. Knee Surg Sports Traumatol Arthrosc 1:162–168 71. Werner S, Knutsson E, Eriksson E (1993) Effect of taping the patella on concentric and eccentric torque and EMG of the knee extensor and flexor muscles in patients with patellofemoral pain syndrome. Knee Surg Sports Traumatol Arthrosc 1:169–177 72. Werner S (1995) An evaluation of knee extensor and knee flexor torques and EMGs in patients with patellofemoral pain syndrome in comparison with matched controls. Knee Surg Sports Traumatol Arthrosc 3:89–94 73. Whittingham M, Palmer S, Macmillan F (2004) Effects of taping on pain and function in patellofemoral pain syndrome: a randomized controlled trial. J Orthop Sports Phys Ther 34(9):504–510 74. Witvrouw E, Sneyers C, Lysens R, Victor J, Bellemans J (1996) Reflex response times of vastus medialis oblique and vastus lateralis in normal subjects and in subjects with patellofemoral pain syndrome. J Orthop Sports Phys Ther 24(3):160–165 75. Witvrouw E, Lysens R, Bellemans J, Cambier D, Vanderstraeten G (2000) Intrinsic risk factors for the development of anterior knee pain in an athletic population: a two year prospective study. Am J Sports Med 28(4):480–489 76. Witvrouw E, Danneels L, Van Tiggelen D, Willems TM, Cambier D (2004) Open versus closed kinetic chain exercises in patellofemoral pain: a 5-year prospective randomized study. Am J Sports Med 32(5):1122–1130 77. Witvrouw E, Werner S, Mikkelsen C, Van Tiggelen D, Vanden Berghe L, Cerulli G (2005) Clinical classification of patellofemoral pain syndrome: guidelines for non-operative treatment. Knee Surg Sports Traumatol Arthrosc 13:122–130
KNEE
Anterior knee pain: an update of physical therapy Suzanne Werner
Received: 16 January 2014 / Accepted: 19 June 2014 / Published online: 6 July 2014 Springer-Verlag Berlin Heidelberg 2014
Abstract Anterior knee pain is one of the most common knee problems in physically active individuals. The reason for anterior knee pain has been suggested to be multifactorial with patella abnormalities or extensor mechanism disorder leading to patellar malalignment during flexion and extension of the knee joint. Some patients complain mostly of non-specific knee pain, while others report patellar instability problems. The patients present with a variety of symptoms and clinical findings, meaning that a thorough clinical examination is the key for optimal treatment. Weakness of the quadriceps muscle, especially during eccentric contractions, is usually present in the majority of anterior knee pain patients. However, irrespective of whether pain or instability is the major problem, hypotrophy and reduced activity of the vastus medialis are often found, which result in an imbalance between vastus medialis and vastus lateralis. This imbalance needs to be corrected before quadriceps exercises are started. The non-operative rehabilitation protocol should be divided into different phases based on the patient’s progress. The goal of the first phase is to reduce pain and swelling, improve the balance between vastus medialis and vastus lateralis, restore normal gait, and decrease loading of the patello-femoral joint. The second phase should include improvement of postural control and coordination of the lower extremity, increase of quadriceps strength and when needed hip muscle strength, and restore S. Werner Stockholm Sports Trauma Research Center, Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden S. Werner (&) SSTRC/Capio Artro Clinic, Sophiahemmet, Box 5605, 11486 Stockholm, Sweden e-mail: [email protected]
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good knee function. The patient should be encouraged to return to or to start with a suitable regular physical exercise. Therefore, the third phase should include functional exercises. Towards the end of the treatment, single-leg functional tests and functional knee scores should be used for evaluating clinical outcome. A non-operative treatment of patients with anterior knee pain should be tried for at least 3 months before considering other treatment options. Keywords Electrical muscle stimulation Functional anterior knee pain score Patello-femoral pain Patellar hypermobility Patellar stabilizing brace Patellar taping Quadriceps weakness Vastus medialis–vastus lateralis imbalance Introduction Anterior knee pain is one of the most common knee complaints in physically active individuals [20, 56]. The reason for anterior knee pain is still unclear and suggested to be multifactorial [29], including anatomical patella abnormalities [30] or being an extensor mechanism disorder, resulting in patellar malalignment during knee flexion and knee extension [31]. Why this extensor mechanism disorder has developed is, however, not reported. Furthermore, some authors maintain that anterior knee pain could be due to overuse, especially in adolescents [20]. Clinical examination Symptoms and findings Since patients with anterior knee pain present with a myriad of symptoms and complaints, a thorough clinical
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Patellar position
examination is the key for optimal treatment. The clinical examination should consist of a careful control of the entire lower extremity [45]. Possible prevalence of increased internal femoral rotation that can be observed clinically often causes a squinting of the patella. Compensatory external tibial torsion should be noted, as well as genu recurvatum, genu valgum, and hyperpronation of the subtalar joint [10, 36, 47, 64]. Furthermore, it is important to control the patient’s foot position during weight-bearing and check how his/her shoes, especially sport shoes, are worn. Foot orthotics to control excessive pronation of the subtalar joint has been advocated in order to improve patellar tracking and lead to decreased anterior knee pain [67]. In addition, paying attention to an accurate history from the patient will greatly aid the physical therapist in making an accurate assessment of the patient’s condition and thereby design an appropriate treatment programme [3, 10].
Assessing the orientation of the patella relative to the femur and controlling the patellar position within the patellofemoral joint should be done. An optimal patellar position is when the patella is parallel to the femur in the frontal and the sagittal planes and when the patella is midway between the two condyles during 20 of knee flexion [47]. Possible anatomical variations such as patella alta, patella infera, tilted patella, and rotated patella should be checked for. One should be aware of that a high-riding patella (patella alta) is reported to be a risk factor for patellar subluxation or dislocation [34], while patients with patella infera rather seem to complain of patellar pain at the area of apex patellae. Tilted patella with a medial ‘‘opening’’ (a lateral tilt) seems to be relatively common in patients with anterior knee pain. The reason for this usually depends on tightness of the lateral retinaculum, which will tilt the patella so that the medial border of the patella is higher than the lateral border [47]. Furthermore, a hypotrophy of the vastus medialis obliquus (VMO) may aid in creating lateral patellar tilt. Some patients present with an externally rotated patella, when the inferior pole of the patella is lateral to the long axis of the femur, indicating tightness of the lateral retinaculum. Very few patients present with the opposite, an internally rotated patella. The ideal patellar position is when the long axis of the femur is parallel to the long axis of the patella [47]. A number of patients with anterior knee pain complaining mostly of patellar instability [1, 24, 27] often show a hypermobile patella and an observable tracking disorder [71]. Therefore, patellar mobility should be checked [10, 27, 36]. This can be done with the ‘‘patellar tracking test’’ by clinically observing patellar movement with manual resistance against concentric and eccentric knee extension during open kinetic chain and closed kinetic chain in knee loading conditions such as single-leg squat, for instance. Another way of revealing a possible patellar hypermobility
Pain versus patellar instability problems Patients with anterior knee pain mostly complain of nonspecific knee pain localized peripatellarly, often anteromedially and/or retropatellarly [1, 24, 35]. Others complain of a feeling of patellar instability [1, 24, 27]. Patients that mostly complain of pain usually have normal patellar mobility, and they mainly report the symptoms to occur after physical activity. Those with patellar instability often present with a patellar hypermobility with noticeable tracking problems, and they rather complain of knee problems during physical activity [36]. This means that patients with anterior knee pain should be divided into two treatment groups: one based on pain limitation and one on patella stabilization. Witvrouw et al. [77] developed a clinical classification system that provides the clinician with guidelines to classify and treat patients with anterior knee pain (Fig. 1).
Anterior Knee Pain
Muscular dysfunction
Malalignment
Malalignment of entire leg
Malalignment PF joint
Non-muscular origin
Muscular origin
Strength deficit
VMO
Quadriceps
Neuromuscular dysfunction
VMO/VL timing dysfunction
Flexibility
Hamstrings Quadriceps Gastrocnemius Iliotibial band
Fig. 1 Clinical classification of anterior knee pain
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is to manually perform a passive deviation both laterally and medially with the patient in supine position with the knee joint slightly flexed [50]. A deviation of 10 mm as well laterally as medially should be regarded as normal patellar mobility [50]. Weakness of knee extensors The knee extensors are often weakened in patients with anterior knee pain [72]. Isokinetic testing is the most optimal way for measuring muscle torques. However, isokinetic testing must be carried out cautiously [26]. Patients with patellar hypermobility should not be measured eccentrically during fast angular velocities ([90/s) due to risk of subluxation or even dislocation [70]. Imbalance between the knee extensors and knee flexors is frequently shown in patients with anterior knee pain. This usually depends on muscle weakness of the knee extensors and a normal strength of the knee flexors. This subsequently results in a higher hamstring/quadriceps ratio compared with healthy subjects [72]. Besides increased muscle torque, isokinetic training has been reported to lead to improved proprioception in patients with anterior knee pain [32], which most likely will improve knee function. Vastus medialis versus vastus lateralis Electromyography (EMG) recordings have been suggested to be important when evaluating the activity of the vasti muscles in order to diagnose anterior knee pain [21, 22]. Hypotrophy of the vastus medialis (VM) is common in anterior knee pain patients (30). VM also has a low activity and is the weakest and most vulnerable muscle of the extensor mechanism [24]. Vastus lateralis (VL) that usually has a considerably higher activity comprises the largest muscle mass and extensor power of the knee extensors. The lower activity of VM and the higher activity of VL could lead to an imbalance between VM and VL [43, 58]. It has also been reported that the onset of the VL contraction occurs before that of the VMO, indicating a difference in motor control in anterior knee pain patients compared with asymptomatic controls [15]. Owings and Grabiner [51] reported that the activation amplitude of VMO and VL in anterior knee pain patients was mostly altered during eccentric contractions and differed significantly from that of a control group. The authors conclude that the activation amplitudes of the VMO and VL in anterior knee pain patients are consistent with a lateral tracking of the patella during eccentric contractions [75]. Furthermore, some authors have found that the time to activation often is disturbed in patients with anterior knee pain [68, 74]. Therefore, it is important to improve the onset of muscle activity of the VMO in many anterior knee pain patients. Several
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authors maintain that the primary role of VMO is to enhance patellar stabilization within the patello-femoral joint and to prevent lateral patellar subluxation by pulling the patella medially during knee extension and flexion [24, 43, 46, 58]. More than 50 years ago, Brewerton [8], followed by Lieb and Perry [40], Martin and Londeree [44], and Bose et al. [7], reported VMO to be active during the full range of knee extension. Mariani et al. [43] found the EMG activity of both VM and VL to be of similar degree and mostly pronounced during the last 30 of knee extension in healthy subjects. It is important to check the muscle activity pattern between VM and VL, as well the patient’s asymptomatic leg as his/her symptomatic leg when designing an optimal treatment protocol for patients with anterior knee pain. When bilateral problems exist, I suggest that one relies on the EMG activity pattern of the less symptomatic leg. The need for strengthening the hip muscles in patients with anterior knee pain has been discussed during recent years [61]. Delayed onset of the activation of the hip abductors has recently been reported [16], but hitherto, no consensus exists about training the hip abductors. Muscle flexibility Soft tissue or muscle length is essential for musculoskeletal evaluation and has specific implications in patients with anterior knee pain. Smith et al. [63] found poor flexibility of the knee extensors and knee flexors to be correlated with anterior knee pain. Tightness of the tensor fascia lata and iliotibial band is associated with anterior knee pain [18]. Furthermore, a tight iliotibial band will result in a lateral deviation of the patella and lateral tracking, as well as lateral tilting and usually also weakening of the medial retinaculum [67]. Anterior knee pain patients sometimes also show tightness of the lateral retinaculum, which might lead to an ‘‘opening’’ of the patella on the medial side, a lateral patellar tilt. Piva et al. [57] reported tightness of both knee extensors and knee flexors to be correlated with anterior knee pain.
Rehabilitation programme Recent research has been reported that the lower the frequency of pain before treatment, the greater the quadriceps muscle size, and the smaller the eccentric torque at a low angular velocity—the better the functional outcome after a short period of physical therapy [55]. When designing a treatment programme, it is important to realize that each patient is unique and will present with different symptoms and clinical signs. This necessitates a flexible treatment approach [3]. The treatment protocol should therefore be based on findings from the patient’s
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history, clinical examination, and functional assessment [77]. To be aware of those factors that determine the functional outcome after a rehabilitation period is important for the patient as well as for the physical therapist, the physician, and the sport coach [55]. A fast pain relief should be specifically targeted during the rehabilitation of patients with anterior knee pain together with avoidance of painprovoking activities [55]. The use of the pain monitoring system developed by Thomee´ could aid in the rehabilitation when it comes to pain control [66]. This pain monitoring system is based on pain ratings according to the visual analogue scale (0–10 cm). Pain reported up to a level of 2 is considered to be ‘‘safe’’, pain up to a level of 5 to be ‘‘acceptable’’ (if pain had subsided by the next morning), and pain above level 5 is ‘‘high risk’’. A thorough clinical examination based on control of patellar mobility, muscle function, and each patient’s specific functional problem is of utmost importance for a successful clinical outcome. Moreover, patient education is one of the key factors in the management of anterior knee pain. The patient must have a clear understanding of why the symptoms have occurred and what needs to be done to reduce the symptoms. Training of the vastus medialis At the start of the rehabilitation, the main objective for the majority of patients with anterior knee pain is to strengthen the VM [12]. This is due to that appropriate timing and intensity of VMO activation relative to VL has been promoted as a key aspect in patients with anterior knee pain [74]. Therefore, the balance between VMO and VL should be restored before starting to train the entire group of knee extensors. Muscular hypotrophy and a reduced and/or delayed EMG activity of the VM are common in patients with anterior knee pain, resulting in an imbalance between VM and VL [12, 43]. Therefore, the initial treatment should consist of restoring the function of VM in an attempt to enhance patellar stabilization [6, 11, 24, 43, 46]. In the literature, several types of exercises have been suggested to increase the activity of VM over that of VL [38], but with no great success. Transcutaneous electrical muscle stimulation is the optimal way proven to selectively contract and improve the function of VM [69]. Steadman proposed electrical muscle stimulation of VM in order to keep the patella in a proper position within the patellofemoral joint [64]. With the help of computer tomography, Werner et al. [69] reported a significantly increased area of the VM after transcutaneous electrical stimulation of this muscle, while the VL was unchanged. Two-thirds of those patients also improved from a functional point of view directly after 10 weeks of daily electrical stimulation. At the follow-ups, 1 and 3.5 years later, the same patients were still improved [69].
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Knee extensor strengthening Several authors have emphasized the importance of knee extensor training in patients with anterior knee pain in order to improve the extensor mechanism [27, 35, 55, 64] and functional ability [59]. The greater the eccentric knee extensor torque at a low angular velocity, the greater the functional capacity and the lower knee pain has been reported by anterior knee pain patients [48]. Stability of the hip joint by strengthening of the hip muscles is important in order to absorb the appropriate load. This is due to that load is transmitted to other joints of the lower extremity, particularly the knee joint [45]. Strengthening of the knee extensors in combination with strengthening the abductors and the external rotators of the hip have been reported to reduce knee pain while descending stairs [25]. The knee extensors can be strengthened with as well closed kinetic chain (CKC) as open kinetic chain (OKC) exercises. Palmitier et al. [52] suggest that rehabilitation in a weight-bearing position such as during CKC exercises may have a greater carry-over to functional activities, as lower extremity function in daily weight-bearing activities involves multiple muscle groups acting in synergy. However, for optimal knee function, my suggestion is to strengthen the knee extensors during both CKC and OKC, which is in agreement with other authors [33, 76]. In order to reduce the patello-femoral joint reaction forces CKC exercises, such as leg press and step exercises, earlier research has suggested the training to be within the last 30 of knee extension [19]. Later, Bizzini et al. [5] have advocated a somewhat extended range of motion when it comes to squat and leg press. Contrarily, OKC exercises, such as sitting knee extension, have been suggested to rather be trained between 90 and 40 of knee flexion [65]. Isokinetic training is the most optimal way for muscle strengthening when it comes to OKC [70]. Isokinetic training provides optimal loading of the muscles and allows muscular performance at different velocities [2]. High angular velocities should be used in order to reduce compressive forces on the joint surfaces. This means that isokinetic training at high angular velocity (C120/s) should be preferred when strengthening the knee extensors in anterior knee pain patients during concentric actions. However, eccentric actions are more difficult to perform due to unfamiliarity with the decelerating type of movement and to coordinate the different muscles of the knee extensors [70, 72]. My suggestion is therefore that patients with anterior knee pain should perform isokinetic eccentric contractions at B90/s. The advantage with isokinetic training in anterior knee pain patients is, except for rapid muscular effect, that the training can be adjusted to possible knee pain and therefore diminish the risk for overload.
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Patellar stabilization If patellar hypermobility exists, the patella could initially be supported by a patellar stabilizing brace or patellar taping during the physical therapy treatment. However, it is of utmost importance to check in what direction the patella is hypermobile, laterally, medially, or both. I recommend either taping or bracing in patients with a lateral or a medial hypermobility and bracing in patients with both a lateral and medial hypermobility. When the patient improves and symptoms are reduced, the external patella support should be gradually removed. Recent research has shown that a 2-week period of patellar taping followed by an exercise programme for another 10 weeks to improve the activity of VMO led to a long-lasting (12 months) pain control in anterior knee pain patients with muscle imbalance between VMO and VL [54]. Supportive devices such as patellar stabilizing braces and patellar taping are aimed to improve patellar tracking problems [21, 42, 53]. Some authors have suggested that anterior knee pain patients should be treated with patellar stabilizing orthoses [35, 42], although there is no evidence of any major alteration of patellar tracking [26]. Palumbo reported decreased symptoms in 92 % when a patella stabilizing brace was used in anterior knee pain patients [53]. Sega et al. [62] reported that an orthosis with a medial support gave a good pain reduction in patients with patellar instability. Other authors recommend an elastic strap or taping in order to improve patellar tracking and thereby reduce patellar instability problems [46, 56]. McConnell [46] reported a success rate of 92 % maintaining that patellar taping with a medial glide technique can modify patellar tracking and therefore act as pain relief. During step-up and step-down tasks, Gilleard et al. [28] found that the onset of VMO activity occurred earlier, when the patella was taped compared with untaped. The activity of VL was unchanged during the step-up task and delayed during the step-down task with taping [28]. Ng and Wong [49] reported no improvement of VM activity with patellar taping. Powers et al. [60] studied the effect of patellar taping according to McConnell on functional outcomes and reported an average pain reduction of 78 % using the visual analogue scale. Kowall et al. [37] performed a prospective intervention study comparing two groups that followed the same physical therapy programme, one group with the patella taped and the other without taping. Both groups improved, irrespective of the addition of taping or not [37]. In contrast, Whittingham et al. [73] reported that a combination of patellar taping and exercise was superior to exercise alone in terms of reduction of knee pain and improved knee function. Christou [14] reported increased VM activity and decreased VL activity in anterior knee pain patients when
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the patella was taped medially. The benefits of patellar taping are probably not due to a change in patellar position, but rather due to enhanced support of the patello-femoral ligaments and/or pain modulation via cutaneous stimulation [14]. Werner et al. [71] reported that patients with patellar hypermobility (C15 mm deviation laterally or medially) improved their knee extension torque and agonist EMG activity during isokinetic knee extensions, when the patella was stabilized by taping, while patients with a normal patellar mobility did not benefit from taping. However, they also found that in order to optimize the treatment for supporting the patella with tape, it is important to check the direction of the patient’s patellar hypermobility, which can be laterally, medially, or both [71]. Furthermore, in order to control whether the patient needs a patellar support, orthosis, or taping, it is important to check patellar tracking within the patello-femoral joint during both concentric and eccentric knee extension (‘‘patellar tracking’’-test). In my opinion, patellar taping can be recommended only if patellar hypermobility exists and as a temporary treatment to facilitate physical therapy exercises, especially strengthening of the knee extensors. Stretching A number of patients with anterior knee pain shows tightness mostly of the iliotibial band and other lateral muscle structures, the quadriceps muscle, and sometimes also of the hamstrings and the gastrocnemius. Most of the stretching procedures could be performed by the patients themselves, and therefore, they should be instructed in how to stretch their tight muscle structures. The lateral retinaculum might also be tight, which could interfere with a normal patellar tracking, and should therefore be treated with medial patellar glide. Balance and coordination training Physical training causes changes within the nervous system that leads to improved coordination between muscle groups, and practice will result in automatics, which indicate a change and improvement in the motor programme [58, 62]. When the activity and the function of VM have improved, balance and coordination training of the lower extremity should be started. Balance and coordination exercises should preferably be performed during knee loading conditions and with slightly flexed knees in order to try to direct the training to the knee joint. Functional and sport-specific training When the quadriceps muscle has improved and a good balance exists within the extensor mechanism, functional
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training with gradual increase of knee loading exercises could begin. The patient should practice slowly stepping on and off a step with adequate pelvic control. Initially, a small step height should be used, and the patient is recommended to train in front of a mirror to be able to observe muscle function of the knee extensors. The pelvis must remain parallel with the floor, and the hip, knee, and foot should be aligned [47]. There is a wide variation of functional knee loading exercises that make different heavy demands upon the knee, for instance walking, jogging, running, stair-climbing, jumping, and bicycling. Those athletic patients that have improved and have a good knee extensor strength, good muscle flexibility, and a proper movement pattern during functional heavy knee loading activities performed without pain or swelling are encouraged to start sport-specific training.
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scoring system, the Samsung Medical Center (SMC) scoring system, based on both pain and function. Their SMC scoring system shows excellent test–retest and internal consistency, as well as acceptable ceiling and floor effects [39]. Regime Towards the end of the treatment period, it is recommended to stimulate the patient either to return to some kind of sport/physical activity or to start with a suitable regular physical exercise, where long walks could be one alternative [69, 70]. The reason for this is that the improved muscle function and balance that have been gained through the rehabilitation need to be maintained by performing physical exercise regularly. Psychological considerations
Evaluation Functional tests Dynamic evaluation with knee-related functional tests should be used in order to reproduce the patient’s symptoms and to make comparisons before and after a period of treatment. Examples of appropriate functional tests for anterior knee pain patients are stair-climbing (up and down), double-leg and single-leg squat, and raise from a chair and sit down using one leg. These tests could be used to evaluate knee pain using the visual analogue scale [13, 23], as well as the functional capacity of the knee extensors. The following four functional tests: anteromedial lunge, step-down, single-leg press, and balance and reach have been reported to be reliable [41]. Single-leg tests are very good indicators of controlling the extensor mechanism and thereby the patient’s symptoms. Future research is needed in order to evaluate intra-rater and inter-rater reliability as well as the validity and sensitivity of functional tests [17].
A poor correlation has been found between the patient’s clinical symptoms and the clinician’s objective findings [4]. Jacobson and Flandry [36] reported that some of the patients that came to visit the doctor for anterior knee pain problems at a Sport Medicine Clinic were having both chronic anterior knee pain and psychological problems. Carlsson et al. [9] used the Rorschach test and found elevations in psychological parameters such as hostility, dependency, and depression in patients with anterior knee pain compared with healthy controls, matched for gender and age, as well as with three other reference groups. However, these problems are not always evident for the patient himself or herself [9]. In such cases, a psychological evaluation is often advisable, and therefore, collaboration with a pain clinic with psychological expertise may be beneficial.
Rehabilitation protocol for anterior knee pain patients Phase 1 Goals
Functional knee score A knee score for functional evaluation of patients with anterior knee pain should consist of different categories of symptoms that are common in these patients. The Werner functional knee score has been modified from an earlier published version [69]. A test–retest of this score has revealed a very good reproducibility and sensitivity in patients with anterior knee pain. The score comprises 0–50 points and is provided with the following determinations in terms of anterior knee pain: C47 points = excellent, 42–46 points = good, 33–41 points = fair, and B32 points = poor. Recently, Lee et al. [39] have developed a new
Reduce pain and swelling, improve VMO:VL balance, and thereby patellar tracking, improve flexibility, restore normal gait, and decrease loading of the patello-femoral joint. Treatment •
•
Cryotherapy—after the physical therapy exercise and daily activities, that exacerbate symptoms to reduce pain and oedema. Transcutaneous electrical stimulation of VMO to restore the function of VMO and improve VMO:VL balance.
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•
•
• •
•
• •
Flexibility training: stretching of tight muscle structures, usually the tensor fascia lata and the iliotibial band, the quadriceps, in particular rectus femoris, the hamstrings, and the gastrocnemius. Tight lateral retinaculum can, except for stretching, be treated with medial patellar glide, friction and massage. If gait has been altered, the patient should be instructed in proper gait mechanics, which preferably could be done in front of a mirror. Instruct the patient to change postural habits such as standing in genu recurvatum, for instance. If patellar hypermobility exists, it is recommended to either tape the patella or to use a patellar stabilizing brace during the physical therapy exercises. However, patellar supporting devices should only be used temporarily until exercises and functional activities can be performed without knee pain. If increased pronation of the subtalar joint exists, treat the patient with foot orthotics or arch taping. Foot orthotics can be used temporarily or may be needed indefinitely to improve patellar tracking and alignment of the lower extremity. Check the patient’s shoe wear, in particular sport shoes, and if needed, suggest shock absorptive shoes. Modify daily activity level to temporarily reduce the load on the patello-femoral joint.
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•
•
•
compression forces within the patello-femoral joint. This type of exercise might improve both physical conditioning and thigh muscle strength. Functional knee exercises. Start with shallow squats and proceed with deeper ones. Squatting can initially be performed with addition of electrical stimulation of VMO to improve the VMO:VL balance. Stepping down exercises can also be started with addition of electrical muscle stimulation and gradually be performed without. Quadriceps strengthening is recommended to be started when a good balance between VMO and VL exists. Closed kinetic chain exercises are recommended to be performed between 40 and 30 and full knee extension, and open kinetic chain between 90 and 40 of knee flexion. Isokinetic training should preferably be performed at 120/s or higher during concentric actions and at 90/s or lower during eccentric actions. Strengthening of hip muscles when needed.
Phase 3 Goal Return to previous physical activity level.
Phase 2 Goals
Treatment •
Improve balance of the lower extremity, increase quadriceps strength and when needed hip muscle strength, and restore good knee function. Treatment •
•
Balance and coordination training with gradual increase of difficulty and loading on the patello-femoral joint. In order to try to mainly train the knee joint stabilizers, I suggest that these exercises should be performed in a standing position with a slightly flexed knee joint. Balance training on a balance board can initially be performed standing on one leg with addition of electrical stimulation of VMO to facilitate a proper balance between VMO and VL. When good muscle control is achieved, the patient can continue the balance exercise standing on one leg without electrical muscle stimulation or standing on both legs on two balance boards. Stationary bicycle training with a high seat aimed to reduce a big knee flexion angle and thereby
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•
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Functional training with a gradual increase of knee loading activities can begin after improved quadriceps strength. Walking, jogging, and different types of jumping exercises are recommended during this phase. However, proceeding to a higher knee loading activity or exercise should only be allowed, if there is no knee pain and no swelling. Sport-specific exercises with a gradual increase of intensity can start as soon as the athletic patient is pain free, has a good muscle function, and a proper movement pattern during functional knee exercises. It is recommended to give the patient individual guidelines for physical activity and exercises in terms of, for instance number of repetitions, duration, intensity, and frequency. Patient education is also highly recommended in order to try to prevent recurrence of knee symptoms.
Non-operative treatment of patients with anterior knee pain should be tried for at least 3 months until both the physical therapist and the patient feel that pain and knee function have reached a plateau [45].
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References 1. Aglietti P, Buzzi R, Pisaneschi A (1990) Patella pain. J Sports Trauma Rel Res 12:131–150 2. Baltzopoulos V, Brodie DA (1989) Isokinetic dynamometry. Applications and limitations. Sports Med 8:101–116 3. Beckman M, Craig R, Lehman RC (1989) Rehabilitation of patellofemoral dysfunction in the athlete. Clin Sports Med 8(4):841–860 4. Bentley G, Dowd G (1984) Current concepts of etiology and treatment of chondromalacia patellae. Clin Orthop 189:209–228 5. Bizzini M, Biedert R, Maffiuletti N, Impellizzeri F (2008) Biomechanical issues in patellofemoral joint rehabilitation. Orthopade 37(9):864 (866–871) 6. Bockrath K, Wooden C, Worrel T, Ingersoll CD, Farr J (1993) Effects of patella taping on patella position and perceived pain. Med Sci Sports Exerc 25:989–992 7. Bose K, Kanagasuntherum R, Osman M (1980) Vastus medialis oblique: an anatomical and physiologic study. Orthopedics 3:880–883 8. Brewerton DA (1955) The function of the vastus medialis muscle. Ann Phys Med 2:164–168 9. Carlsson AM, Werner S, Mattlar C-E, Edman G, Puukka P, Eriksson E (1993) Personality in patients with long-term patellofemoral pain syndrome. Knee Surg Sports Traumatol Arthrosc 1:178–183 10. Carson WG (1985) Diagnosis of extensor mechanism disorders. Clin Sports Med 4:231–246 11. Cerny K (1995) Vastus medialis oblique/vastus lateralis muscle activity ratios for selected exercises in persons with and without patellofemoral pain syndrome. Phys Ther 75(8):672–683 12. Cesarelli M, Bifulco P, Bracale M (2000) Study of the control strategy of the quadriceps muscles in anterior knee pain. Trans Rehabil Eng 8(3):330–341 13. Chesworth BM, Culham EG, Tata GE, Peat M (1989) Validation of outcome measures in patients with patellofemoral syndrome. J Orthop Sports Phys Ther 10:302–309 14. Christou EA (2004) Patellar taping increases vastus medialis oblique activity in the presence of patellofemoral pain. J Electromyogr Kinesiol 14(4):495–504 15. Cowan SM, Bennell KL, Hodges PW, Crossley KM, McConnell J (2003) Simultaneous feedforward recruitment of the vasti in untrained postural tasks can be restored by physical therapy. J Orthop Res 21(3):553–558 16. Cowan SM, Crossley KM, Bennell KL (2008) Altered hip and trunk muscle function in individuals with patellofemoral pain. Br J Sports Med 43(8):584–588 17. Crossley KM, Bennell KL, Cowan SM, Green S (2004) Analysis of outcome measures for persons with patellofemoral pain: which are reliable and valid? Arch Phys Med Rehabil 85(5):815–822 18. Doucette SA, Goble EM (1992) The effect of exercise on patellar tracking in lateral patellar compression syndrome. Am J Sports Med 20(4):434–440 19. Doucette SA, Child DP (1996) The effect of open and closed chain exercise and knee joint position on patellar tracking in lateral patellar compression syndrome. J Orthop Sports Phys Ther 23(2):104–110 20. Fairbank J, Pynsent P, van Poortvliet J, Phillips H (1984) Mechanical factors in the incidence of knee pain in adolescents and young adults. J Bone Joint Surg Br 66:685–693 21. Felicio LR, Do Prado Baffa A, Liporacci RF, Saad MC, De Oliveira AS, Bevilaqua-Grossi D (2011) Analysis of patellar stabilizers muscles and patellar kinematics in anterior knee pain subjects. J Electromyogr Kinesiol 21:148–153 22. Ferrari D, Kuriki HU, Silva CR, Alves N, de Azevedo FM (2014) Diagnostic accuracy of the electromyography parameters
23.
24.
25.
26.
27. 28.
29. 30.
31.
32.
33.
34. 35. 36. 37.
38.
39.
40. 41.
42.
43.
associated with anterior knee pain in the diagnosis of patellofemoral pain syndrome. Arch Phys Med Rehabil 2–6 (in press) Flandry F, Hunt JP, Terry GC, Hughston JC (1991) Analysis of subjective knee complaints using visual analog scales. Am J Sports Med 19(2):112–118 Fox TA (1975) Dysplasia of the quadriceps mechanism, hypoplasia of the vastus medialis as related to the hypermobile patella syndrome. Surg Clin North Am 55:199–226 Fukuda TY, Rossetto FM, Magalha˜es E, Bryk FF, Lucareli PR, de Almeida Aparecida Carvalho N (2010) Short-term effects of hip abductors and lateral rotators strengthening in females with patellofemoral pain syndrome: a randomized controlled clinical trial. J Orthop Sports Phys Ther 40:736–742 Fulkerson JP, Hungerford DS (1990) Biomechanics of the patellofemoral joint. In: Fulkerson JP, Hungerford DS (eds) Disorders of the patellofemoral joint, 2nd edn. Williams & Wilkins, Baltimore, pp 25–41 Fulkerson JP, Shea KP (1990) Current concepts review disorders of patellofemoral alignment. J Bone Joint Surg Am 72:1424–1429 Gilleard W, McConnell J, Parsons D (1998) The effect of patellar taping on the onset of vastus medialis obliquus and vastus lateralis muscle activity in persons with patellofemoral pain. Phys Ther 78(1):25–32 Goldberg B (1991) Chronic anterior knee pain in adolescents. Pediatr Ann 20:186–193 Goodfellow J, Hungerford DS, Zindel M (1976) Patello-femoral joint mechanics and pathology: I. Functional anatomy of the patella-femoral joint. J Bone Joint Surg Br 58:287–290 Gunther KP, Thielemann F, Bottesi M (2003) Anterior knee pain in children and adolescents: diagnosis and conservative treatment. Orthopa¨de 32(2):110–118 Hazneci B, Yildiz Y, Sekir U, Aydin T, Kalyon TA (2005) Efficacy of isokinetic exercise on joint position sense and muscle strength in patellofemoral pain syndrome. Am J Phys Med Rehabil 84(7):521–527 Heintjes E, Berger MY, Bierma-Zeinstra SM, Bernsen RM, Verhaar JA, Koes BW (2003) Exercise therapy for patellofemoral pain syndrome. Cochrane Database Syst Rev (4):CD003472 Insall J, Goldberg V, Salvati E (1972) Recurrent dislocation and high-riding patella. Clin Orthop Relat Res 88:67–69 Insall J (1982) Current concepts review, patellar pain. J Bone Joint Surg Am 64:147–152 Jacobson KE, Flandry FC (1989) Diagnosis of anterior knee pain. Clin Sports Med 8:179–195 Kowall MG, Kolk G, Nuber GW, Cassisi JE, Stern SH (1996) Patellar taping in the treatment of patellofemoral pain: a prospective randomized study. Am J Sports Med 24(1):61–66 Laprade J, Culham E, Brouwer B (1998) Comparison of five isometric exercises in the recruitment of the vastus medialis oblique in persons with and without patella-femoral pain syndrome. J Orthop Sports Phys Ther 27(3):197–204 Lee C-H, Ha C-W, Kim S, Kim M, Song Y-J (2013) A novel patellofemoral scoring system for patellofemoral joint status. J Bone Joint Surg Am 95:620–626 Lieb F, Perry J (1968) Quadriceps function. J Bone Joint Surg Am 50:1535–1548 Loudon JK, Wiesner D, Goist-Foley HL, Asjes C, Loudon KL (2002) Intrarater reliability of functional performance tests for subjects with patellofemoral pain syndrome. J Athl Train 37(3):256–261 Lysholm J, Nordin M, Ekstrand J, Gillquist J (1984) The effect of a patella brace on performance in knee extension strength test in patients with patellar pain. Am J Sports Med 12:110–112 Mariani PP, Caruso I (1989) An electromyographic investigation of subluxation of the patella. J Bone Joint Surg Br 61:169–171
123
2294 44. Martin JA, Londeree BR (1979) EMG comparison of quadriceps femoris activity during knee extension and straight leg raises. Am J Phys Med Rehabil 58:57–69 45. McCarthy MM, Strickland SM (2013) Patellofemoral pain: an update on diagnostic and treatment options. Curr Rev Musculoskelet Med 6:188–194 46. McConnell J (1986) The management of chondromalacia patellae: a long term solution. Austr J Physiother 32(4):215–223 47. McConnell J (1998) Examination of the patellofemoral joint: the physical therapist´s perspective. In: Grelsamer RP, McConnell J (eds) The patella. A team approach. Aspen Publishers, Gaithersburg, pp 109–118 48. Nakagawa TH, Muniz TB, Baldon RM, Maciel CD, Amorim C, Serra˜o F (2011) Electromyographic preactivation pattern of the gluteus medius during weight-bearing functional tasks in women with and without anterior knee pain. Rev Bras Fisioter 15(1):59–65 49. Ng GYF, Wong PYK (2009) Patellae taping affects vastus medialis obliquus activation in subjects with patellofemoral pain before and after quadriceps muscle fatigue. Clin Rehabil 23:705–713 50. Osborne AH, Farquharson-Roberts MA (1983) The aetiology of patella-femoral pain. J Roy Nav Med Serv 69:97–103 51. Owings TM, Grabiner MD (2002) Motor control of the vastus medialis oblique and vastus lateralis muscles is disrupted during eccentric contractions in subjects with patellofemoral pain. Am J Sports Med 30(4):483–487 52. Palmitier RA, An K-N, Scott SG, Chao EYS (1991) Kinetic chain exercise in knee rehabilitation. Sports Med 11(6):404–413 53. Palumbo PM (1981) Dynamic patellar brace: patellofemoral disorders. A preliminary report. Am J Sports Med 9:45–49 54. Paoloni M, Fratocchi G, Mangone M, Murgia M, Santilli V, Cacchio A (2012) Long-term efficacy of a short period of taping followed by an exercise program in a cohort of patients with patellofemoral pain syndrome. Clin Rheumatol 31:535–539 55. Pattyn E, Mahieu N, Selfe J, Verdonk P, Steyaert A, Witvrouw E (2012) What predicts functional outcome after treatment for patellofemoral pain? Med Sci Sports Exerc 1827–1833 56. Percy EC, Strother RT (1985) Patellalgia. Physician Sports Med 13:43–59 57. Piva SR, Goodnite EA, Childs JD (2005) Strength around the hip and flexibility of soft tissues in individuals with and without patellofemoral pain syndrome. J Orthop Sports Phys Ther 35:793–801 58. Portney LG, Sullivan PE, Daniell JL (1986) EMG activity of vastus medialis obliquus and vastus lateralis in normal and patients with patellofemoral arthralgia. Phys Ther 66:808 59. Powers CM, Perry J, Hislop HJ (1997) Are patellofemoral pain and quadriceps femoris muscle torque associated with locomotor function? Phys Ther 77(10):1063–1075 60. Powers CM, Landel E, Sosnick T, Kirby J, Mengel K, Cheney A, Perry J (1997) The effects of patellar taping on stride characteristics and joint motion in subjects with patellofemoral pain. J Orthop Sports Phys Ther 26(6):286–291 61. Robinson RL, Nee RJ (2007) Analysis of hip strength in females seeking physical therapy treatment for unilateral patellofemoral pain syndrome. J Orthop Sports Phys Ther 37(5):232–238
123
Knee Surg Sports Traumatol Arthrosc (2014) 22:2286–2294 62. Sega L, Galante M, Fortina A, Squazzini Viscontini G, Bertolotti G, Benedetti MG (1988) Association of dynamic bandage with kinesitherapy in the treatment of patellar instability. Ital J Sports Traum 10:89–94 63. Smith AD, Stroud L, McQueen C (1991) Flexibility and anterior knee pain in adolescent elite figure skaters. J Pediatr Orthop 11:77–82 64. Steadman JR (1979) Nonoperative measures for patellofemoral problems. Am J Sports Med 7:374–375 65. Steinkamp LA, Dillingham MF, Markel MD, Hill JA, Kaufman KR (1993) Biomechanical considerations in patellofemoral joint rehabilitation. Am J Sports Med 21(3):438–444 66. Thomee´ R (1997) A comprehensive treatment approach for patellofemoral pain syndrome in young women. Phys Ther 77(12):1690–1703 67. Tiberio D (1987) The effect of excessive subtalar joint pronation on patellofemoral mechanics: a theoretical model. J Orthop Sports Phys Ther 9:160–165 68. Voight ML, Wieder DL (1991) Comparative reflex response times of vastus medialis obliquus and vastus lateralis in normal subjects and subjects with extensor mechanism dysfunction: an electromyographic study. Am J Sports Med 19:131–137 69. Werner S, Arvidsson H, Arvidsson I, Eriksson E (1993) Electrical stimulation of vastus medialis and stretching of lateral thigh muscles in patients with patello-femoral symptoms. Knee Surg Sports Traumatol Arthrosc 1:85–92 70. Werner S, Eriksson E (1993) Isokinetic quadriceps training in patients with patellofemoral pain syndrome. Knee Surg Sports Traumatol Arthrosc 1:162–168 71. Werner S, Knutsson E, Eriksson E (1993) Effect of taping the patella on concentric and eccentric torque and EMG of the knee extensor and flexor muscles in patients with patellofemoral pain syndrome. Knee Surg Sports Traumatol Arthrosc 1:169–177 72. Werner S (1995) An evaluation of knee extensor and knee flexor torques and EMGs in patients with patellofemoral pain syndrome in comparison with matched controls. Knee Surg Sports Traumatol Arthrosc 3:89–94 73. Whittingham M, Palmer S, Macmillan F (2004) Effects of taping on pain and function in patellofemoral pain syndrome: a randomized controlled trial. J Orthop Sports Phys Ther 34(9):504–510 74. Witvrouw E, Sneyers C, Lysens R, Victor J, Bellemans J (1996) Reflex response times of vastus medialis oblique and vastus lateralis in normal subjects and in subjects with patellofemoral pain syndrome. J Orthop Sports Phys Ther 24(3):160–165 75. Witvrouw E, Lysens R, Bellemans J, Cambier D, Vanderstraeten G (2000) Intrinsic risk factors for the development of anterior knee pain in an athletic population: a two year prospective study. Am J Sports Med 28(4):480–489 76. Witvrouw E, Danneels L, Van Tiggelen D, Willems TM, Cambier D (2004) Open versus closed kinetic chain exercises in patellofemoral pain: a 5-year prospective randomized study. Am J Sports Med 32(5):1122–1130 77. Witvrouw E, Werner S, Mikkelsen C, Van Tiggelen D, Vanden Berghe L, Cerulli G (2005) Clinical classification of patellofemoral pain syndrome: guidelines for non-operative treatment. Knee Surg Sports Traumatol Arthrosc 13:122–130
