350
Case report
Medial patellar subluxation without previous lateral release: a case report Michael G. Sapera,c and David A. Shneiderb,c Medial patellar subluxation (MPS) is normally described following a lateral release. We report on a 14-year-old girl with MPS without previous lateral release. Arthroscopic examination demonstrated MPS at 0 and 308 of flexion, and the patella was tight in flexion on the lateral side. A low lateral release with a tibial tubercle transfer was performed, followed by repair of the lateral release with an iliotibial band flap, and lateral patellofemoral ligament reconstruction. Excellent functional outcome was achieved. This type of patellar instability is often overlooked and a high index of suspicion is needed for appropriate diagnosis
c 2014 and treatment. J Pediatr Orthop B 23:350–353 Wolters Kluwer Health | Lippincott Williams & Wilkins.
Introduction
revealed a nondysplastic trochlea and a tendency towards patella baja (Figs 1 and 2).
Medial patellar instability can be a disabling condition that can limit daily functional activities because of apprehension and pain. The instability is influenced by a variety of factors that allow the patella to translate medially and ultimately subluxate or dislocate to the medial side. In patients with normal trochlear and patellar osseous anatomy and lower extremity alignment, the patellar instability results from insufficient passive soft-tissue stabilizers [1,2].
Journal of Pediatric Orthopaedics B 2014, 23:350–353 Keywords: knee, medial, patella, patellar subluxation a
Department of Osteopathic Surgical Specialties, Michigan State University, Mid-Michigan Orthopaedic Institute, East Lansing and cDepartment of Orthopaedic Surgery, McLaren Greater Lansing, Lansing, Michigan, USA
b
Correspondence to David A. Shneider, MD, Mid-Michigan Orthopaedic Institute, 830 W. Lake Lansing Rd, Suite 190, East Lansing, MI, 48823, USA Tel: + 1 517 333 3777; fax: + 1 517 203 3956; e-mail: [email protected]
Before surgery, the patient was examined under anesthesia to confirm the diagnosis of MPS. Passive medial patellar mobility testing at full knee extension revealed Fig. 1
Several reports are found in the literature describing this condition and its association with failed lateral retinacular release [3–8]. Surgical options to address the problem include repair of the lateral retinaculum with imbrication [6], reconstruction with local soft-tissue augmentation [3], and lateral patellofemoral ligament (LPFL) reconstruction [8]. However, there is limited literature describing medial patellar subluxation (MPS) in the absence of a previous lateral release. To the best of our knowledge, this study is the first report of a case of MPS without a previous lateral release treated with an LPFL reconstruction.
Case report A 14-year-old girl presented to the senior author for evaluation. She had steadily progressive lateral-sided knee pain for the past few years that had recently interfered with her quality of life. She had no history of previous surgery. The patient was also treated previously with a supervised physical therapy program and was provided with a lateral patellar stabilizing knee brace that aggravated her symptoms. Physical examination of the right knee demonstrated full extension and flexion limited to 1201 by pain. The patella subluxed medially with pain at 301 of flexion. Radiographs of her knee c 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins 1060-152X
Lateral radiograph of the right knee of the child with slight patella baja. DOI: 10.1097/BPB.0000000000000054
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
Isolated medial patellar subluxation Saper and Shneider 351
Fig. 2
Fig. 4
Lateral
Medial Patella
Femoral trochlea
Merchant radiographic view of both knees with a deep trochlea and slight lateral tilt on the right side. R, right.
Preoperative arthroscopic image of the patellofemoral compartment (right knee) viewed from the anterolateral portal showing medial patellar subluxation at 301 of knee flexion.
Fig. 3
Fig. 5
Lateral
Patella
Medial
Medial
Lateral Patella
Femoral condyle Preoperative arthroscopic image of the patellofemoral compartment (right knee) viewed from the anterolateral portal showing 2 + lateral patellar laxity at full knee extension.
medial subluxation of more than 50% of the patellar width, and nearly 100% of the patellar width at 301 of flexion. Diagnostic arthroscopy was then performed. There was no evidence of meniscal or chondral pathology. Patellar tracking was viewed from both the anterolateral and anteromedial portals. Lateral patellar laxity was present in full knee extension (Fig. 3), and MPS was observed at 0 and 301 of flexion (Fig. 4). The patella became captured in the trochlear groove beyond 401 of flexion. Also, the lateral retinaculum was tight in flexion,
Femoral condyle
Preoperative arthroscopic image of the patellofemoral compartment (right knee) viewed from the anteromedial portal showing compression of the patella over the margin of the lateral femoral condyle with the knee at 901 of flexion.
compressing the patella over the margin of the lateral femoral condyle (Fig. 5). The open portion of the case consisted of a midline skin incision centered over the patella. Skin flaps were developed to expose the patella and patellar mechanism from 5 cm above the patella to the tibial tubercle. A low lateral release was performed to relieve the lateral pressure in flexion. A tibial tubercle transfer was performed, to
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
352 Journal of Pediatric Orthopaedics B 2014, Vol 23 No 4
originates from the lateral femoral epicondyle and inserts onto the lateral aspect of the patella [10].
Fig. 6
Lateral
Medial Patella
Femoral trochlea
Postoperative arthroscopic image of the patellofemoral articulation, viewed from the lateral portal (right knee), demonstrating a stable patella, centered in the trochlea.
center the patella and address the patella baja. A wide strip of iliotibial band was mobilized proximally enough to allow the strip to be rotated up to the lateral side of the patella and allow reattachment to the patella to resist lateral side instability. A partial-thickness graft from the quadriceps tendon was used to reconstruct the LPFL to control lateral patellar laxity. The graft was 10 mm in width and was taken from the central third of the most superficial layer of the rectus femoris. It was turned 901 laterally and twisted 1801 and inserted at the LPFL attachment at the lateral epicondyle. After the reconstruction, the arthroscope was reintroduced into the knee joint to reassess the position and tracking of the patella. The lateral patellar laxity was corrected, and the patella was stable on both medial and lateral sides with no further MPS (Fig. 6). Postoperatively, the patient was instructed to be partial weight-bearing on crutches for 3–4 weeks. Her therapy was advanced to include range of motion exercises as well as progressive strengthening exercises. At last follow-up, the patient showed full quadriceps and hamstring strength. She denied instability symptoms and had complete resolution of her knee pain. This study was exempted by the local Institutional Review Board.
Medial subluxation of the patella, as described in the literature, is found either isolated or associated with a previous lateral release [3–8,11,12]. In the case of isolated MPS, only a few cases are described [11,12]. The recognition and treatment of isolated MPS may be difficult. Isolated MPS is identified clinically by increased passive medial patellar mobility, a positive medial patellar apprehension test, and demonstrable MPS or frank dislocation when manual pressure is applied to the lateral patella [4,5,7]. Patellar maltracking visualized from the anterolateral portal during diagnostic arthroscopy confirms the diagnosis. The patella sits medial to the trochlear groove until the knee is flexed to B401. At that point, the patella slides laterally into the trochlear groove and remains there through the remainder of knee flexion. Shellock et al. [13] evaluated patients with persistent symptoms after lateral release by kinetic MRI of the patellofemoral joint. They noted that MPS may be an unrecognized condition in patients with patellar maltracking. Seventeen of 40 patients (43%) who had a previous lateral release demonstrated MPS in the nonoperative knee. They suspect that MPS may have been present before the lateral retinacular release but was not recognized in these patients. There is a limited number of reported cases of medial patellar instability in patients without previous lateral release. Richman and Scheller [11] presented a case of a 17-year-old patient with persistent right patellofemoral joint complaints found to have isolated medial subluxation of the patella. Imbrication of the patient’s lateral patellar retinaculum centralized patella tracking and stabilized the patella. Shannon and Keene [12] reported two cases of recurrent medial subluxation of the patella that occurred spontaneously. Both cases were treated with arthroscopic medial retinacular release. At a mean follow-up of 2.7 years, both medial subluxation and knee pain were relieved. Teitge and Spak [8] described a technique for LPFL reconstruction using autogenous tissue as a salvage procedure for repair of medial iatrogenic instability. In their experience, direct repair or imbrication of the lateral retinaculum failed to provide long-term stability, as medial excursion usually appeared after 1 year. Their technique utilized the patient’s own quadriceps tendon to recreate the LPFL. They reported excellent results with no cases of recurrent instability. Conclusion
Discussion Several anatomic factors should be considered, although considerable variation exists. The quadriceps tendon includes contributions from the rectus femoris superficially, the vastus medialis and vastus lateralis intermediately, and the vastus intermedius deeply. The LPFL is located in the second layer of the lateral aspect of the knee [9]. The LPFL
There are a limited number of reported cases of isolated MPS. This case presented a 14-year-old girl with persistent right knee pain. Clinical examination showed increased medial patellar translation on manual stress. The patient had not undergone prior lateral retinacular release. Arthroscopic examination confirmed excessive medial patellar translation. A low lateral release with a tibial tubercle transfer was performed, followed by repair of the lateral release with an
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
Isolated medial patellar subluxation Saper and Shneider 353
iliotibial band flap and LPFL reconstruction. This centralized patella tracking and eliminated medial translation on stress testing as observed both arthroscopically and clinically. Excellent functional outcome was achieved. This type of patellar instability might not be as rare as previously thought. It can be a subtle problem, often overlooked, and difficult to diagnose. A high index of suspicion is needed for appropriate diagnosis and treatment.
Acknowledgements Conflicts of interest
4 5
6
7
8 9
There are no conflicts of interest. 10
References 1
2
3
Kramers-de Quervain IA, Biedert R, Stussi E. Quantitative gait analysis in patients with medial patellar instability following lateral retinacular release. Knee Surg Sports Traumatol Arthrosc 1997; 5:95–101. Sanchis-Alfonso V, Torga-Spak R, Cortes A. Gait pattern normalization after lateral retinaculum reconstruction for iatrogenic medial patellar instability. Knee 2007; 14:484–488. Abhaykumar S, Craig DM. Fascia lata sling reconstruction for recurrent medial dislocation of the patella. Knee 1999; 6:55–57.
11 12
13
Hughston JC, Deese M. Medial subluxation of the patella as a complication of lateral release. Am J Sports Med 1988; 16:383–388. Hughston JC, Flandry F, Brinker MR, Terry GC, Mills JC 3rd. Surgical correction of medial subluxation of the patella. Am J Sports Med 1996; 24:486–491. Johnson DP, Wakeley C. Reconstruction of the lateral patellar retinaculum following lateral release: a case report. Knee Surg Sports Traumatol Arthrosc 2002; 10:361–363. Nonweiler DE, DeLee JC. The diagnosis and treatment of medial subluxation of the patella after lateral retinacular release. Am J Sports Med 1994; 22:680–686. Teitge RA, Spak RT. Lateral patellofemoral ligament reconstruction. Arthroscopy 2004; 20:998–1002. Waligora AC, Johanson NA, Hirsch BE. Clinical anatomy of the quadriceps femoris and extensor apparatus of the knee. Clin Orthop Relat Res 2009; 467:3297–3306. Navarro MS, Navarro RD, Akita J Jr, Cohen M. Anatomical study of the lateral patellofemoral ligament in cadaver knees. Rev Bras Ortop 2008; 43:300–307. Richman N, Scheller A Jr. Medial subluxation of the patella without previous lateral retinacular release. Orthopedics 1998; 21:810–813. Shannon B, Keene J. Results of arthroscopic medial retinacular release for treatment of medial subluxation of the patella. Am J Sports Med 2007; 35:1180–1187. Shellock FG, Mink JH, Deutsch A, Fox JM, Ferkel RD. Evaluation of patients with persistent symptoms after lateral retinacular release by kinematic magnetic resonance imaging of the patellofemoral joint. Arthroscopy 1990; 6:226–234.
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
Case report
Medial patellar subluxation without previous lateral release: a case report Michael G. Sapera,c and David A. Shneiderb,c Medial patellar subluxation (MPS) is normally described following a lateral release. We report on a 14-year-old girl with MPS without previous lateral release. Arthroscopic examination demonstrated MPS at 0 and 308 of flexion, and the patella was tight in flexion on the lateral side. A low lateral release with a tibial tubercle transfer was performed, followed by repair of the lateral release with an iliotibial band flap, and lateral patellofemoral ligament reconstruction. Excellent functional outcome was achieved. This type of patellar instability is often overlooked and a high index of suspicion is needed for appropriate diagnosis
c 2014 and treatment. J Pediatr Orthop B 23:350–353 Wolters Kluwer Health | Lippincott Williams & Wilkins.
Introduction
revealed a nondysplastic trochlea and a tendency towards patella baja (Figs 1 and 2).
Medial patellar instability can be a disabling condition that can limit daily functional activities because of apprehension and pain. The instability is influenced by a variety of factors that allow the patella to translate medially and ultimately subluxate or dislocate to the medial side. In patients with normal trochlear and patellar osseous anatomy and lower extremity alignment, the patellar instability results from insufficient passive soft-tissue stabilizers [1,2].
Journal of Pediatric Orthopaedics B 2014, 23:350–353 Keywords: knee, medial, patella, patellar subluxation a
Department of Osteopathic Surgical Specialties, Michigan State University, Mid-Michigan Orthopaedic Institute, East Lansing and cDepartment of Orthopaedic Surgery, McLaren Greater Lansing, Lansing, Michigan, USA
b
Correspondence to David A. Shneider, MD, Mid-Michigan Orthopaedic Institute, 830 W. Lake Lansing Rd, Suite 190, East Lansing, MI, 48823, USA Tel: + 1 517 333 3777; fax: + 1 517 203 3956; e-mail: [email protected]
Before surgery, the patient was examined under anesthesia to confirm the diagnosis of MPS. Passive medial patellar mobility testing at full knee extension revealed Fig. 1
Several reports are found in the literature describing this condition and its association with failed lateral retinacular release [3–8]. Surgical options to address the problem include repair of the lateral retinaculum with imbrication [6], reconstruction with local soft-tissue augmentation [3], and lateral patellofemoral ligament (LPFL) reconstruction [8]. However, there is limited literature describing medial patellar subluxation (MPS) in the absence of a previous lateral release. To the best of our knowledge, this study is the first report of a case of MPS without a previous lateral release treated with an LPFL reconstruction.
Case report A 14-year-old girl presented to the senior author for evaluation. She had steadily progressive lateral-sided knee pain for the past few years that had recently interfered with her quality of life. She had no history of previous surgery. The patient was also treated previously with a supervised physical therapy program and was provided with a lateral patellar stabilizing knee brace that aggravated her symptoms. Physical examination of the right knee demonstrated full extension and flexion limited to 1201 by pain. The patella subluxed medially with pain at 301 of flexion. Radiographs of her knee c 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins 1060-152X
Lateral radiograph of the right knee of the child with slight patella baja. DOI: 10.1097/BPB.0000000000000054
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
Isolated medial patellar subluxation Saper and Shneider 351
Fig. 2
Fig. 4
Lateral
Medial Patella
Femoral trochlea
Merchant radiographic view of both knees with a deep trochlea and slight lateral tilt on the right side. R, right.
Preoperative arthroscopic image of the patellofemoral compartment (right knee) viewed from the anterolateral portal showing medial patellar subluxation at 301 of knee flexion.
Fig. 3
Fig. 5
Lateral
Patella
Medial
Medial
Lateral Patella
Femoral condyle Preoperative arthroscopic image of the patellofemoral compartment (right knee) viewed from the anterolateral portal showing 2 + lateral patellar laxity at full knee extension.
medial subluxation of more than 50% of the patellar width, and nearly 100% of the patellar width at 301 of flexion. Diagnostic arthroscopy was then performed. There was no evidence of meniscal or chondral pathology. Patellar tracking was viewed from both the anterolateral and anteromedial portals. Lateral patellar laxity was present in full knee extension (Fig. 3), and MPS was observed at 0 and 301 of flexion (Fig. 4). The patella became captured in the trochlear groove beyond 401 of flexion. Also, the lateral retinaculum was tight in flexion,
Femoral condyle
Preoperative arthroscopic image of the patellofemoral compartment (right knee) viewed from the anteromedial portal showing compression of the patella over the margin of the lateral femoral condyle with the knee at 901 of flexion.
compressing the patella over the margin of the lateral femoral condyle (Fig. 5). The open portion of the case consisted of a midline skin incision centered over the patella. Skin flaps were developed to expose the patella and patellar mechanism from 5 cm above the patella to the tibial tubercle. A low lateral release was performed to relieve the lateral pressure in flexion. A tibial tubercle transfer was performed, to
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
352 Journal of Pediatric Orthopaedics B 2014, Vol 23 No 4
originates from the lateral femoral epicondyle and inserts onto the lateral aspect of the patella [10].
Fig. 6
Lateral
Medial Patella
Femoral trochlea
Postoperative arthroscopic image of the patellofemoral articulation, viewed from the lateral portal (right knee), demonstrating a stable patella, centered in the trochlea.
center the patella and address the patella baja. A wide strip of iliotibial band was mobilized proximally enough to allow the strip to be rotated up to the lateral side of the patella and allow reattachment to the patella to resist lateral side instability. A partial-thickness graft from the quadriceps tendon was used to reconstruct the LPFL to control lateral patellar laxity. The graft was 10 mm in width and was taken from the central third of the most superficial layer of the rectus femoris. It was turned 901 laterally and twisted 1801 and inserted at the LPFL attachment at the lateral epicondyle. After the reconstruction, the arthroscope was reintroduced into the knee joint to reassess the position and tracking of the patella. The lateral patellar laxity was corrected, and the patella was stable on both medial and lateral sides with no further MPS (Fig. 6). Postoperatively, the patient was instructed to be partial weight-bearing on crutches for 3–4 weeks. Her therapy was advanced to include range of motion exercises as well as progressive strengthening exercises. At last follow-up, the patient showed full quadriceps and hamstring strength. She denied instability symptoms and had complete resolution of her knee pain. This study was exempted by the local Institutional Review Board.
Medial subluxation of the patella, as described in the literature, is found either isolated or associated with a previous lateral release [3–8,11,12]. In the case of isolated MPS, only a few cases are described [11,12]. The recognition and treatment of isolated MPS may be difficult. Isolated MPS is identified clinically by increased passive medial patellar mobility, a positive medial patellar apprehension test, and demonstrable MPS or frank dislocation when manual pressure is applied to the lateral patella [4,5,7]. Patellar maltracking visualized from the anterolateral portal during diagnostic arthroscopy confirms the diagnosis. The patella sits medial to the trochlear groove until the knee is flexed to B401. At that point, the patella slides laterally into the trochlear groove and remains there through the remainder of knee flexion. Shellock et al. [13] evaluated patients with persistent symptoms after lateral release by kinetic MRI of the patellofemoral joint. They noted that MPS may be an unrecognized condition in patients with patellar maltracking. Seventeen of 40 patients (43%) who had a previous lateral release demonstrated MPS in the nonoperative knee. They suspect that MPS may have been present before the lateral retinacular release but was not recognized in these patients. There is a limited number of reported cases of medial patellar instability in patients without previous lateral release. Richman and Scheller [11] presented a case of a 17-year-old patient with persistent right patellofemoral joint complaints found to have isolated medial subluxation of the patella. Imbrication of the patient’s lateral patellar retinaculum centralized patella tracking and stabilized the patella. Shannon and Keene [12] reported two cases of recurrent medial subluxation of the patella that occurred spontaneously. Both cases were treated with arthroscopic medial retinacular release. At a mean follow-up of 2.7 years, both medial subluxation and knee pain were relieved. Teitge and Spak [8] described a technique for LPFL reconstruction using autogenous tissue as a salvage procedure for repair of medial iatrogenic instability. In their experience, direct repair or imbrication of the lateral retinaculum failed to provide long-term stability, as medial excursion usually appeared after 1 year. Their technique utilized the patient’s own quadriceps tendon to recreate the LPFL. They reported excellent results with no cases of recurrent instability. Conclusion
Discussion Several anatomic factors should be considered, although considerable variation exists. The quadriceps tendon includes contributions from the rectus femoris superficially, the vastus medialis and vastus lateralis intermediately, and the vastus intermedius deeply. The LPFL is located in the second layer of the lateral aspect of the knee [9]. The LPFL
There are a limited number of reported cases of isolated MPS. This case presented a 14-year-old girl with persistent right knee pain. Clinical examination showed increased medial patellar translation on manual stress. The patient had not undergone prior lateral retinacular release. Arthroscopic examination confirmed excessive medial patellar translation. A low lateral release with a tibial tubercle transfer was performed, followed by repair of the lateral release with an
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
Isolated medial patellar subluxation Saper and Shneider 353
iliotibial band flap and LPFL reconstruction. This centralized patella tracking and eliminated medial translation on stress testing as observed both arthroscopically and clinically. Excellent functional outcome was achieved. This type of patellar instability might not be as rare as previously thought. It can be a subtle problem, often overlooked, and difficult to diagnose. A high index of suspicion is needed for appropriate diagnosis and treatment.
Acknowledgements Conflicts of interest
4 5
6
7
8 9
There are no conflicts of interest. 10
References 1
2
3
Kramers-de Quervain IA, Biedert R, Stussi E. Quantitative gait analysis in patients with medial patellar instability following lateral retinacular release. Knee Surg Sports Traumatol Arthrosc 1997; 5:95–101. Sanchis-Alfonso V, Torga-Spak R, Cortes A. Gait pattern normalization after lateral retinaculum reconstruction for iatrogenic medial patellar instability. Knee 2007; 14:484–488. Abhaykumar S, Craig DM. Fascia lata sling reconstruction for recurrent medial dislocation of the patella. Knee 1999; 6:55–57.
11 12
13
Hughston JC, Deese M. Medial subluxation of the patella as a complication of lateral release. Am J Sports Med 1988; 16:383–388. Hughston JC, Flandry F, Brinker MR, Terry GC, Mills JC 3rd. Surgical correction of medial subluxation of the patella. Am J Sports Med 1996; 24:486–491. Johnson DP, Wakeley C. Reconstruction of the lateral patellar retinaculum following lateral release: a case report. Knee Surg Sports Traumatol Arthrosc 2002; 10:361–363. Nonweiler DE, DeLee JC. The diagnosis and treatment of medial subluxation of the patella after lateral retinacular release. Am J Sports Med 1994; 22:680–686. Teitge RA, Spak RT. Lateral patellofemoral ligament reconstruction. Arthroscopy 2004; 20:998–1002. Waligora AC, Johanson NA, Hirsch BE. Clinical anatomy of the quadriceps femoris and extensor apparatus of the knee. Clin Orthop Relat Res 2009; 467:3297–3306. Navarro MS, Navarro RD, Akita J Jr, Cohen M. Anatomical study of the lateral patellofemoral ligament in cadaver knees. Rev Bras Ortop 2008; 43:300–307. Richman N, Scheller A Jr. Medial subluxation of the patella without previous lateral retinacular release. Orthopedics 1998; 21:810–813. Shannon B, Keene J. Results of arthroscopic medial retinacular release for treatment of medial subluxation of the patella. Am J Sports Med 2007; 35:1180–1187. Shellock FG, Mink JH, Deutsch A, Fox JM, Ferkel RD. Evaluation of patients with persistent symptoms after lateral retinacular release by kinematic magnetic resonance imaging of the patellofemoral joint. Arthroscopy 1990; 6:226–234.
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
