The Application of Open and Closed KineDlatic Chain Exercises in Rehabilitation of the Lower ExtreDlity Bruce H. Greenfield, MMSc, PT Graduate Prolfram in Physical Therapy, Department of Rehabilitation Medicine, Emory University; and Physical Therapy Associates of Metro Atlanta

Brian J. lovin, PT, AlC Georgia Tech Athletic Association, Physical Therapy Associates of Metro Atlanta

The goal of rehabilitation is to return patients to their preinjury level of function. This task is achieved by restoring specific parameters of function that include joint range of motion (ROM), muscle performance (i.e., torque, work, power, time rate of tension development), soft tissue flexibility, proprioception/kinesthesia/balance, agility, and cardiovascular conditioning. Several methods are used by clinicians to restore function, including modalities and manual therapy. A key element, however, is the application of resistive exercises. The implementation and progression of exercises employed by the clinician may affect the final outcome. Exercises are used to isolate muscle action over one joint in a cardinal plane of movement. Other exercises incorporate synergistic action of muscle groups over multiple joints, using multiplanar movements. Ideally, treatment should incorporate a variety of exercises to achieve optimum rehabilitation. To facilitate this process, the rehabilitation specialist should understand basic concepts ofhuman kinesiology, as well as anatomy and the physiology of soft tissue healing. The purpose of this article is to: define terms associated with human movement; discuss kinematic-chain exercises; review rehabilitation principles and exercise progression; and incorporate this information into case studies.

TERMINOLOGY Kinematics is the term used to describe a body in motion irrespective of the forces that produce the motion. 1 Kinetics is the term applied to the forces acting on the body. When a body moves, it will do so in accordance with its kinematics, which in the human body takes place through arthrokinematic and osteokinematic movements. 2 Osteokinematics describes the movement of the bones relative to each other, such as movement of the tibia and the femur during knee joint flexion. Arthrokinematics describes the mechanics of an osteokinematic movement which takes place between the articulating surfaces of a joint. The arthrokinematic movements are described as roll, slide, and spin.2 A knowledge of the normal combination of roll, slide, and spin within a given joint allows the clinician to assess changes in arthrokinematics in the presence of joint dysfunction. The restoration of normal arthrokinematics, therefore, is a primary goal of rehabilitation. The relative direction of roll and slide is based on the shape of the corresponding articular surfaces. All synovial joints are either ovoid in a convex plane or ovoid in a concave plane. 3 A concave surface moving along a stationary convex surface results in a roll and slide occurring in the same direction. Conversely, a convex surface moving along a stationary concave surface results in roll and slide occurring in the opposite direction. The clinical implication of this information will be discussed in a forthcoming section. Human kinematics occurs as a result of synchronous movements of body parts. 4 Movement at one segment will induce movement at adjacent segments. Because

J Back Museuloskel Rehabil 1992; 2(4):38-51 Copyright © 1992 by Andover Medical.

Open and Closed Kinematic Chain Exercises in Rehabilitation of the Lower Extremity

the human body is multisegmental, it is often referred to as a kinematic chain. 5 Kinematic chain movements can occur through two mechanisms. The first, referred to as a closed kinematic chain (CKC), is operational when the distal segment is fixed and movement at one segment will move the other segments in a predictable pattern. 5 The second, referred to as an open kinematic chain (OKC), is operational when the distal segment moves freely. An example of a CKC movement is a simple squat, while an example of an OKC movement is throwing a baseball. With the exception of the swing phase of gait, most movements of the lower extremities, such as rising from a chair, occur as CKC movements. 4 Therefore, it is only logical that exercise progression during lower extremity rehabilitation incorporate CKC movements.

CLINICAL APPLICATION OF KINEMATIC CHAIN MOVEMENTS When choosing a mode of kinematic exercise, the variables of each type of exercise must be considered. The clinician should understand the principles of exercise application and the differences between OKC and CKC movements to accomplish a specific treatment goal. The following section reviews the biomechanical and neuromuscular differences that exist between these two modes of exercise during rehabilitation.

Biomechanical Comparison Significant differences occur in the internal dynamics of the lower extremities while performing weight bearing (CKC) and non-weight-bearing (OKC) exercises. These differences include kinematic movement of the bones and joints, the planes and axes of motion, and the joint reaction forces. Kinematics. CKC and OKC exercises result in different arthrokinematics in the joints of the lower extremities. This change can be exemplified by examining the ankle and the knee joints during a simple squat movement. During the squat, ankle joint dorsiflexion results from the tibiofibular mortise rolling forward along a stationary talus.

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The result is a concomitant anterior slide of the tibiofibular joint mortise. 6 Conversely, OKC ankle dorsiflexion results in a forward roll and backward slide of the talus within a stationary ankle joint mortise. During a squat, the femur rolls posteriorly and slides anteriorly along a stationary tibia to create knee flexion. There is also an initial external spin or rotation of the femur on the tibia. During knee flexion in an OKC, the tibia internally rotates and then precedes to roll and slide posteriorly along a stationary femur. A change in arthrokinematics in the lower extremities from an OKC to CKC exercises results in biomechanical differences that may affect rehabilitation. First, the arthrokinematic movement during CKC exercise may alter the instantaneous arc of motion in the ankle, knee, and hip joints, resulting in changes in stress patterns throughout the ROM. Second, during CKC activities, the joint is functioning within 3 degrees of freedom. 7 The result is increased stress on the ligaments, joint capsule and muscles to stabilize the joint compared to OKC exercise. Joint reaction forces. Increased stress to the joint during CKC exercises results partly from the change in arthrokinematics, but is largely due to the change in joint reaction force. For our purpose, joint reaction force is defined as stress per unit surface area within a joint. 8 "Ibe increase joint reaction force results from the summation of the ground reaction force through the center of the mass of the limb, the muscle activity around the joint, and the forces between the articulating surfaces. The actual joint reaction force will change throughout the ROM, as the angle of the joint changes in relation to the ground. 9 Joint reaction forces can result in compressive, shear or tensile forces. 10 Compression is the primary joint reaction force during CKC exercises, while shearing is the primary joint reaction force during OKC exercise. The types of forces produced during each exercise offer advantages and disadvantages during rehabilitation. For example, the shear forces produced during OKC exercises produces minimal irritation to the joint surfaces. This allows early implementation of OKC exercises in the presence of a reactive joint. This is particularly useful in

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BACK AND MUSCULOSKELETAL REHABILITATION / FALL 1992

cases such as chondromalacia or postoperative meniscus repairs. However, the shear forces produced during OKC exercises can potentially result in instability between joint surfaces, and may be harmful to post operative intraarticular ligament reconstructions or repairs. This phenomena is discussed in the second case study of a patient with an anterior cruciate ligament reconstruction. The compressive forces produced during CKC exercises may preclude early weight-bearing exercises in conditions involving articular cartilage damage. The compressive forces, however, provide joint stability and can be used early in rehabilitation to protect postsurgical ligament reconstructions or repairs. For example, terminal knee extension exercises performed in a CKC results in minimal anterior tibial shear compared to the same exercise performed in an OKC. ll

Neuromuscular Comparison The neuromuscular differences between OKC and CKC exercises can be attributed to the way the muscles are recruited. Generally, during most forms of OKC exercises, a single muscle group is selectively recruited over one joint and moves around a single joint axis in one plane. This type of training may be desired when a patient needs to emphasize one specific muscle group. Isolated training in an OKC, however, does not simulate functional movement patterns in the lower extremity.12 CKC exercises involve the recruitment of multiple muscle groups over multiple joints through a variety of patterns. Depending on the movement that is performed, muscles function as prime movers, synergists, stabilizers, and antagonists. For example, rising from a chair involves the hip extensors, knee extensors, and plantar flexors acting as prime movers; hip abductors and adductors, ankle evertors and inver tors acting as synergists and stabilizers; and hip flexors, knee flexors, and ankle dorsiflexors acting as antagonists. In addition, CKC exercises result in joint approximation that facilitates muscle co-contraction and mechanoreceptor activity within the joint. 13 This mechanism may be used clinically to in-

crease joint stability and improve proprioceptive feedback. For example, balance and proprioception following an ankle sprain may be facilitated by CKC exercises. Freeman and Wyke l4 concluded that apparent muscle "weakness" can be due to mechanoreceptor damage as opposed to true muscle weakness. CKC exercises are, therefore, an essential element in restoring neuromuscular reeducation. Summary. The previous section delineates influence of OKC and CKC exercises on the mechanical and neuromuscular responses of the lower extremity. The result is that each mode of exercise offers unique clinical advantages during rehabilitation. The advantages and disadvantages of each exercise mode are described in Table 1. OKC exercises in general impose less stress on the joint and isolate muscle activity without the influence of multiple forces imposed on the entire lower extremity during weight bearing. In most cases, therefore, OKC exercises are used initially in rehabilitation. CKC exercises offer the following advantages: produce a cocontraction around the joint; produce compression through the joint that enhances joint stability; facilitate joint mechanoreceptor activity that enhances joint proprioception and kinesthesia; and the patient can exercise using functional joint angular velocities.

REHABILITATION PRINCIPLES The objective of an individualized rehabilitation program is to progress the patient from less stressful OKC exercises, utilizing simple planar or diagonal patterns of movement, to more complex, eKC exercises that impose increased stress in multiple planes along lower extremity joints. By advancing from non-weight-bearing OKC exercises to full weight-bearing CKC exercise, rehabilitation follows a functional progression. This concept has been defined by Keggerreis l5 as an ordered sequence of activities enabling the acquisition or reacquisition of skills required for safe and effective performance for function or athletics.

Open and Closed Kinematic Chain Exercises in Rehabilitation of the Lower Extremity

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Table 1. CKC and OKC Exercises: Differential Features Exercise Mode Open kinematic chain

Characteristics 1. single muscle group 2. single axis and plane

3. emphasize concentric contraction 4. non-weight-bearing

Closed Kinematic Chain

I. multiple muscle groups 2. multiple axes and planes 3. balance of concentric and eccentric contractions 4. weight-bearing exercise

The functional progression is based on the SAID (Specific Adaptations to Imposed Demands) principle. 16 According to this principle, the body adapts to activities based on the type of stress experienced and is specific to the type of training performed. Functional exercises must, therefore, simulate the specific activity that the individual is required to perform. For example, CKC exercises for a basketball player should include a series of high ballistic plyometrics focusing on improving leaping ability, while exercises for a tennis player should include rapid cutting drills to restore lateral movement agility.

Exercise Progression As with any rehabilitation program, timely progression of exercise is critical to the outcome. Judicious implementation and monitoring of exercise advancement is crucial to the period of rehabilitation. The phases and time period of soft tissue healing must be considered in the presence of ligamentous disruption or following surgical intervention, as these phases dictate guidelines for exercise progression. In addition, the clinician should continuously monitor the patient's signs and symptoms in response to the exercise. Any

Advantages I. isolated recruitment 2. simple movement pattern 3. isolated recruitment 4. minimal joint compression 1. functional recruitment 2. functional movement patterns 3. functional contractions

4. increased proprioception, and joint stability

Disadvantages I. limited function 2. limited function 3. limited eccentrics 4. less proprioception and joint stability with increased joint shear forces I. difficult to isolate 2. more complex 3. loss of control of target joint 4. compressive forces on articular surfaces

significant increase in pain, tenderness, swelling, or loss of function indicates that the previous exercise session was either too rigorous or inappropriate, and therefore should be modified or discontinued. Table 2 is an example of a time-based exercise program that considers the phases of soft tissue healing and uses a functional exercise progression. These are general guidelines and should be modified based on each individual case. Open kinematic chain exercise progression. The three primary OKC exercise modes include isometrics, isotonics, and isokinetics Crable 3). Although each mode of exercise is designed to enhance muscle control performance, the application and progression of each mode of exercise is different. Isometric exercises require a muscle contraction in the absence of joint movement. Isometric muscle contractions are ideally suited as an initial mode of exercise because they can be performed in the painless portion ofthe ROM to avoid muscle inhibition and joint irritation. Patients can be progressed to multiple angle isometrics performed at every 20 degrees in the ROM, as research indicates that a 20 degree overflow of strengthening exists throughout each degree in ROM.17 Isometric

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BACK AND MUSCULOSKELETAL REHABILITATION / FALL 1992

Table 2. Time-based Exercise Progression Phase

Characteristics

Phase I

1. Inflammatory stage of healing 2. Maximum protection 3. Lasts 1 to 10 daysa 1. Fibroplasia stage of healing

Phase II

2. Protected mobilization 3. Lasts 10 days to 6 weeks 1. Maturation stage of healing

Phase III

2. Minimal protection 3. Lasts 6 to 12 weeks 1. Late maturation

Phase IV

2. Return to function 3. Lasts 12 to 16 weeks Table 3.

Goals

Treatment

1. Reduce pain

1. Ice

2. Decrease edema/effusion 3. Increase ROM 1. Restore ROM

2. Compression, elevation 3. Passive ROM 1. Whirlpool, PROM (mobilization and stretching), AROM 2. Multiple-angle isometrics, light-weight isotonics

2. Prevent muscle atrophy by initiating strengthening 1. Improve muscle

performance

2. Improve flexibility 3. Improve proprioception 1. Restore normal muscle performance 2. Restore normal flexibility 3. Return to function

1. Full-range isotonics

multiple speed isokinetics; CKC 2. Balance exercises 1. Advanced CKC exercises

Modes of Open Kinematic-Chain Exercise

Mode A. Isometrics

B. Isotonics 1. Concentrics 2. Eccentrics C. Isokinetics

Angular Velocity

Characteristics

Resistance

Muscle contracts without osteokinematic joint movement

Fixed at 0 degrees per second

Accommodating, but not quantified: dependent on amount of force applied

Dynamic contraction with muscle shortening Dynamic contraction with muscle lengthening Dynamic contraction

Accommodates to effort

Preset and quantified

Accommodates to effort

Preset and quantified

Preset and quantified in degrees per second

Accommodating to eft()rt and quantified in Newton-meters or f()ot-pounds.

muscle contractions aid in preventing early muscle atrophy, facilitating neuromuscular reeducation, and helping to reduce edema. Static muscle contractions, however, may not be effective in regaining dynamic strength. In addition, isometric exercises do not simulate functional activities and they become tedious for the patient, which may result in decreased compliance during a home program.

Isotonic exercises involve dynamic movements against a preset, quantified resistance. Because the resistance is quantified, progress can be objectively measured and the clinician can add or delete the amount of resistance based on patient performance. Isotonic exercises have functional implications because the movement allows the muscles to accelerate and decelerate through a ROM. Muscle length changes throughout the

Open and Closed Kinematic Chain Exercises in Rehabilitation of the Lower Extremity

ROM, which affects the ability of the muscle to generate tension. IS The resistance does not change during an isotonic exercise. The resistance, therefore, cannot accommodate to muscle length-tension changes through a full ROM. Changes in muscle length-tension during an isotonic contraction can occur through two different mechanisms: a concentric muscle contraction or an eccentric muscle contraction. Concentric muscle contractions involve external force applications with a resultant tension increase during physical shortening of a musculotendinous unit. 19 Eccentric muscle contractions involve external force applications with a resultant tension increase during physical lengthening of a musculotendinous unit. Eccentric contractions produce more tension in the musculotendinous unit with less metabolic energy than concentric contractions because most of the tension in an eccentric contraction is absorbed by the series elastic components of the muscle. Conversely, the tension in a concentric contraction is produced by the formation and release of protein cross-links between the actin and myosin fibers in the muscle, which requires energy from oxidative and glycolytic enzymes in the muscle fiber. Although both types of muscle contractions are part of an isotonic contraction, each is used for different training effects. Most muscles that function as prime movers during a CKC activity contract eccentrically and, therefore, eccentrics must be emphasized during the period of rehabilitation. For example, Bennett and Stauber 20 found that patients experiencing anterior knee pain exhibited normal quadriceps femoris concentric muscle control but demonstrated deficits in eccentric performance. Resolution of the anterior knee pain coincided with resolution of eccentric muscle deficits. Additionally, because eccentric muscle contractions incorporate the noncontractile element of the muscle, eccentric training has been shown to be effective in treating tendonitis conditions. 21 Isokinetic exercises involve dynamic movements at a fixed angular velocity, which is preset on the dynamometer. Isokinetic dynamometers test the ability of muscle groups to develop torque at a constant speed. 19 As the limb accelerates to

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the preset velocity, resistance is produced and torque is measured. Any changes in the angular velocity will affect the muscles' ability to generate tension. At slower speeds, the muscle has more time to generate tension and, therefore, can produce more torque. The advantage of isokinetic exercise is that a muscle group is permitted to generate maximum force production throughout a given ROM because the speed is held constant. 19 Isokinetic exercises can be implemented into the rehabilitation program when the patient is able to perform isotonic movements through a painfree ROM. Initially, the patient is instructed to perform a submaximal effort during the exercise, to reduce shear and compressive forces within the joint and recruit type I muscle fibers.22 As soft tissue healing progresses with improvement in signs and symptoms, the patient is instructed to increase his effort, thereby increasing resistance from the dynamometer. At the later stages of rehabilitation (see Table 2), patients are exercised through the full-velocity spectrum, allowing patients to train at various preset angular velocities. Some isokinetic dynamometers allow training up to 500 degrees per second,23 but this training does not simulate the speed required during most functional activities. 24 In addition to this disadvantage, isokinetics require presetting the angular velocities, which eliminates the functional elements of joint acceleration and deceleration throughout a ROM. A recent study indicated that the lack of accommodating velocity during isokinetics may actually preclude functional improvement. 25 Yet, isokinetic exercise is a reliable clinical measure of muscle force. Closed kinematic chain exercise modes. CKC exercises for the lower extremity restores muscle performance, proprioception and simulated functional activities. Specific treatment goals will dictate specific exercises during rehabilitation. Muscle strengthening can be initiated with partial weight-bearing exercises such as a leg press (Fig. 1) and advance to full weight-bearing exercises such as double-leg toe raises (Fig. 2) and squatting against a wall (Fig. 3) or on a squatting machine (Fig. 4). As the patient improves, the patient can be progressed from double-leg toe raises and wall squats to single-leg toe raises (Fig.

Figure 1.

Figure 2.

Leg press.

Figure 3.

Wall squatting.

Figure 4.

Machine squat.

Double-leg toe raise.

Open and Closed Kinematic Chain Exercises in Rehabilitation of the Lower Extremity

45

5), lateral dips (Fig. 6), step-ups (Fig. 7), and stepdowns (Fig. 8). Proprioception can be advanced from double-leg balance activities (Fig. 9) to singleleg balance activities (Fig. 10). Functional tasks such as dribbling a basketball can be incorporated into the proprioceptive exercise. Eventually, patients are advanced to functional eKC exercises, such as a stair climber (Fig. 11) or a slide board (Fig. 12). Although plyometric training for the lower extremity is a weight-bearing exercise, this mode of training is not a solely CKC activity. Plyometric activities involve a prestretching of the musculotendinous unit that activates the stretch-shortening cycle. 19 Prestretching is accomplished by repeated ballistic movements performed in a rapid manner. The purpose of plyometric exercise is to heighten neuromuscular excitability for improved reactive ability. This type of training is theoretically designed to bridge the gap between speed and strength. Plyometric exercises for the lower ex-

Figure 6.

Figure 5.

Single-leg toe raise.

Knee dips.

tremity can be progressed from in-place activities such as jumping rope or hopping on one leg to lateral movement activities and lateral jumping activities (Fig. 13). The key principle in plyometric training is to incorporate exercises that simulate the specific functional tasks that the patient needs to perform. Summary. Exercise selection and progression will depend on the nature of the injury and the needs of each patient. The first objective is to choose an exercise that will meet the goals of a treatment in a safe and effective manner. The second objective is to ensure that the exercises that are chosen are progressed in a manner that will allow a patient to return to a preinjury level of function . Although each individual's preinjury level of function will be different, each rehabilitation program should incorporate a combination of OKC and CKC exercises.

Figure 7.

Step-ups.

Figure 8.

Step-downs.

Figure 9.

Double-leg balance board.

Figure 10.

Single-leg balance board.

Open and Closed Kinematic Chain Exercises in Rehabilitation of the Lower Extremity

47

• Figure 11.

Stair climber.

Figure 13.

Lateral jumping.

Case 1: Inversion Ankle Sprain

Figure 12.

Slide board.

CASE STUDIES The following case studies demonstrate the clinical decision-making process when choosing a mode of exercise.

Subjective: A 22-year-old male recreational basketball player reported twisting his ankle during a game. He presented two days following the initial injury with a chief complaint of pain on the lateral aspect of his ankle, aggravated by ambulation. Past medical history was unremarkable. Objective: Swelling and ecchymosis was noted over the lateral aspect ofthe ankle, extending into the dorsum of the forefoot. Passive ROM revealed a limitation secondary to pain, with combined plantar flexion and inversion movements. Resisted testing for eversion reproduced the patients pain. Palpation revealed point tenderness over the anterior talofibular ligament and some tenderness over the calcaneal fibular ligament. An anterior drawer test revealed I + ligamentous laxity. Neurological testing and X-rays were negative. Assessment: First-degree lateral ankle sprain following an inversion-type injury.

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BACK AND MUSCULOSKELE1AL REHABILIlATION / fALL 1992

Problem list: 1. 2. 3. 4. 5.

Pain Swelling Decreased ROM Decreased strength Decreased functional use Goals:

1. 2. 3. 4. 5.

Decrease pain Eliminate swelling Restore painfree ROM Restore muscle strength Return to functional use

Plan: The first three goals were addressed immediately to facilitate a quick recovery. The PRICE principle was applied during this stage, which includes passive ROM (in a painfree range), rest from functional activities, ice, compression, and elevation. In addition, effleurage massage and other modalities such as electrical stimulation were used to reduce swelling. Although many clinicians would treat this injury with complete rest, immobilization, and no weight-bearing, current literature supports the use of early controlled mobilization and early weight bearing. 26 Mter the patient's initial symptoms and swelling decreased (after 4 days), strengthening commenced with OKC activities to avoid the joint irritation that commonly occurs with CKC exercises. Manual isometrics were initiated for plantarflexion, dorsiflexion, inversion, and eversion. At two weeks, the patient then progressed to isotonic resistance for all movements using surgical tubing. Isokinetic exercises and partial CKC exercises, using the leg press, were added at three weeks. The patient progressed to full CKC exercises for strengthening and proprioception by the fourth week. These exercises included toe raises, knee dips, step-ups, and step-downs. Functional exercises such as the slide board, jumping on the minitramp, using the stair climber, and straightahead running were initiated by the fifth week. The patient returned to basketball seven weeks after the initial injury.

Summary: This case study represents an accelerated rehabilitation program that involves minimal soft tissue healing so the patient was progressed as rapidly as tolerated. Additionally, both OKC and CKC exercises were introduced early in the rehabilitation program because these exercises have little adverse effects on this type of injury. However, rehabilitation of postsurgical cases, particularly ligament reconstructions, are significantly influenced by the neuromuscular and biomechanical differences between OKC and CKC exercises.

Case 2: ACL Reconstruction Subjective: An active, well-conditioned 32-yearold male sustained an injury to his left knee joint while rounding second base during a softball game. As he was accelerating, he heard a loud "pop" and had immediate knee joint pain and effusion. At the time, he was unable to bear weight on the injured extremity. He sought medical attention and was treated with ice, immobilization, and rest. The knee pain and effusion subsided after two weeks and he was able to continue activities of daily living. At six weeks following the initial injury, he attempted to return to an exercise program consisting of jogging, weight lifting, and bicycling. These activities caused further pain and resulted in knee joint effusion after exercise. He was unable to return to his preinjury active lifestyle and sought an orthopedic consultation approximately nine months after the initial injury. Objective: Upon examination by an orthopedist, the patient did not complain oflocking, popping, or giving way of the knee. His chief complaint was an inability to return to his preinjury level of activity without knee pain or effusion. Physical evaluation revealed a normal gait pattern without symptoms of the need for an assistive device. Functional testing revealed the patient was able to completely squat, hop on one leg, and turn in place without knee joint symptoms. Knee ROM was 0 to 135 degrees bilaterally. Examination of muscle function in the lower extremities revealed no atrophy of the thigh musculature and manual muscle testing failed to demonstrate a deficit between the right and left quadriceps femoris muscles. No intra-articular knee joint effusion or prepatellar swelling was present. Tracking of the

Open and Closed Kinematic Chain Exercises in Rehabilitation of the Lower Extremity

patellofemoral joint was normal without retropatellar grating or popping, and no tenderness was present in the quadriceps tendon or the patellar tendon. A positive McMurray test produced pain noted over the medial joint line of the knee. The patient had a positive (+ 3) anterior drawer, Lachman, and Pivot shift test. Knee joint arthrometry revealed a 12 mm anterior tibial translation with a 15 pound force, and 16 mm of anterior tibial translation with a 20 pound force. The uninvolved knee joint had 0 to 4 mm of anterior tibial translation in both tests, respectively. The remainder of the ligamentous examination was within normal limits. The objective examination revealed a well documented anterior cruciate ligament-deficient knee and a possible tear of the medial meniscus. This particular patient had a strong desire to return to his preinjury level of activity. The decision was, therefore, made to proceed with an anterior cruciate ligament reconstruction, using a patellar tendon autograft. Surgical treatment. The patient was examined under anesthesia prior to ACL reconstruction. Arthroscopic inspection revealed a bucket handle tear of the medial meniscus and a complete tear of the ACL. The patient also had severe articular cartilage damage. No synovitis or loose bodies were found. The bucket handle tear of the medial meniscus was trimmed, maintaining a well balanced meniscal rim. Isometric placement of a carefully prepared patellar tendon autograft was performed via arthroscopy and was fixated with an interference screw. Postsurgical arthrometric measurements confirmed adequate knee joint stability. Postoperative measurements were reduced from 12 mm on a 15 pound force, 16 mm on a 20 pound force, and 19 mm on a maximal force to 3 mm, 4 mm, and 5 mm, respectively. Clinical decision making for postoperative care. Unlike the first patient, this case involved surgical intervention using a biological tissue for a ligament reconstruction. The clinician, therefore, had to consider the effects of soft tissue healing (Table 2) and joint biomechanics on rehabilitation. Experimental evidence suggests that OKC exercises for knee extension causes excessive anterior tibial translation in the terminal 40 degrees of motion, which can be detrimental to the healing

49

graft. 27 In contrast, joint compression and cocontraction of the hamstrings which occurs during CKC knee extension increases knee stability and imposes only minimal stress on the ACL. 2H Following surgery, the patient remained in the hospital for three days. The patient was placed in a hinged knee brace locked in full extension for the first 10 postoperative days. The brace was removed to perform exercises including isometric contractions of the quadriceps femoris and hamstring muscles, straight leg raises, and passive ROM exercises. Emphasis at this stage was on decreasing pain and swelling and achieving full, passive knee joint extension. When the patient was able to perform leg raises independently, ambulation was initiated with the use of crutches and a hinged knee brace. Gait training continued, weight bearing as tolerated, until the patient left the hospital. Outpatient rehabilitation. Outpatient rehabilitation was initiated one week following surgery. The initial physical therapy visit included evaluation and treatment, which consisted of strengthening and ROM exercises. Passive knee joint ROM was - 2 degrees of knee joint extension to 73 degrees of knee flexion. The Lachman test revealed a solid end point. Moderate to severe knee joint effusion and mild soft tissue edema in the lower extremity was noted. Sensation was intact and the wounds showed no signs of infection. The patient was unable to voluntarily perform an isolated contraction of the quadriceps femoris muscle and had a 15 degree knee joint extension lag, when actively raising his lower extremity without assistance. Vastus medialis obliquis (VMO) contraction was poor. Passive gliding of the patella revealed mild restriction in the superior direction. Assessment: The patient is one week postarthroscopic-assisted autogenous patellar reconstruction. Problem List: 1. Decreased passive knee joint ROM and patellofemoral mobility 2. Knee joint effusion and lower extremity edema 3. Quadriceps femoris muscle inhibition, characterized by an extensor lag

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BACK AND MUSCULOSKELETAL REHABILITATION / FALL 1992

4. Atrophy and poor motor recruitment of the VMO resulting in lateral patellar tracking 5. Lack of independent ambulation

Initial Goals of Treatment: 1. Restore full passive tibiofemoral joint ROM and patellofemoral joint mobility 2. Resolve knee joint effusion and lowerextremity interstitial edema 3. Facilitate recruitment of VMO muscle and eliminate quadriceps muscle-extensor lag during straight leg raise 4. Restore independent ambulation without assistive devices

Long-Term Goals of Treatment: Restore muscle strength, power, endurance, joint proprioception, balance, and agility of involved lower extremity to the patient's preinjury level of function. Treatment Plan: The immediate treatment plan addressed the first two goals using various modalities and manual therapy techniques. This article will only discuss strengthening exercises as they relate to kinematic chain rehabilitation. This patient presented with considerable quadriceps femoris muscle inhibition causing poor muscular control and decreased ambulatory ability. Early strengthening exercises were, therefore, initiated to address these problems. Outpatient physical therapy was initiated with an emphasis on isometric exercises such as quadriceps and hamstring muscle setting, and straightleg raises. As ROM improved, multiple-angle isometric exercises were perfbrmed for the hamstrings and quadriceps (avoiding the final 40 degrees of knee extension). The patient was able to ambulate without the use of crutches by the end of the second week. Balance activities were initiated when the patient achieved a full weight-bearing status. Exercise progression for the first fbur months emphasized CKC activities fc)r strengthening, balance, and conditioning. Specific strengthening exercises progressed from toe raises, leg press, and wall squats to knee dips, step-ups, and step-downs. Weight shifting, one-legged bouncing, and bal-

ance board activities were added for proprioception, while a stair climber and a rowing ergometer were used for conditioning. The patient was able to ambulate without a flexed knee gait pattern by the sixth postoperative week and the use of the crutches was discontinued. By four months, full-range OKC exercises fbr the quadriceps femoris muscles were implemented using isotonic and isokinetic resistance. Initiation of these exercises was based on a tight graft (as evidenced by instrumented testing) and full, active knee joint extension. Emphasis during these exercises was on isolated strengthening of the quadriceps femoris muscles to prepare fbr the advanced functional strengthening exercises. During the fifth and sixth postoperative months, emphasis was placed on functional strengthening of the lower extremity. Activities included continued squatting with resistance, lunges,jumping rope, and slide board. A running program was also initiated during the fifth month. The patient returned to functional activities by the beginning of the seventh month. Summary. The patient represents an ideal case where rehabilitation following intraarticular ACL reconstruction progressed without difficulty. A reason for the success of the rehabilitation program was due to the careful integration of CKC and OKC exercises based on the biomechanical and soft tissue healing constraints. Clinicians must be aware that although eKC activities are more complex (due to the involvement of multiple muscle groups, multiple joints, and multiple planes of involvement) and impose large compressive forces, this mode of exercise is safe in specific populations. REFERENCES 1. Soderberg GS. Kinesiology. Appliwtion to pathological motion. Baltimore: Williams and Wilkins, 1986. 2. Williams PL, Warwick R, eds. Grais anatomy, 36th ed., British. Philadelphia: W.B. Saunders, 1980. 3. MacConaill MA. The movements of bones and joints: The significance of shape.j Bone joint Surg 1953; 35B: 290. 4. Norkin CC, Levangie PK. joint structure and function: A comprehensive analysis. Philadelphia: EA. Davis, 1992.

Open and Closed Kinematic Chain Exercises in Rehabilitation of the Lower Extremity

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