Clinical Review

Medial Patellar Subluxation: Diagnosis and Treatment

Am J Orthop. 2015 November;44(11):499-504

References

1. Marumoto JM, Jordan C, Akins R. A biomechanical comparison of lateral retinacular releases. Am J Sports Med. 1995;23(2):151-155.

2. Betz RR, Magill JT, Lonergan RP. The percutaneous lateral retinacular release. Am J Sports Med. 1987;15(5):477-482.

3. Shannon BD, Keene JS. Results of arthroscopic medial retinacular release for treatment of medial subluxation of the patella. Am J Sports Med. 2007;35(7):1180-1187.

4. Saper MG, Shneider DA. Medial patellar subluxation without previous lateral release: a case report. J Pediatr Orthop B. 2014;23(4):350-353.

5. Richman NM, Scheller AD Jr. Medial subluxation of the patella without previous lateral retinacular release. Orthopedics. 1998;21(7):810-813.

6. Nonweiler DE, DeLee JC. The diagnosis and treatment of medial subluxation of the patella after lateral retinacular release. Am J Sports Med. 1994;22(5):680-686.

7. Hughston JC, Deese M. Medial subluxation of the patella as a complication of lateral retinacular release. Am J Sports Med. 1988;16(4):383-388.

8. 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(4):486-491.

9. Abhaykumar S, Craig DM. Fascia lata sling reconstruction for recurrent medial dislocation of the patella. The Knee. 1999;6(1):55-57.

10. Teitge RA, Torga Spak R. Lateral patellofemoral ligament reconstruction. Arthroscopy. 2004;20(9):998-1002.

11. Kusano M, Horibe S, Tanaka Y, et al. Simultaneous MPFL and LPFL reconstruction for recurrent lateral patellar dislocation with medial patellofemoral instability. Asia-Pac J Sports Med Arthrosc Rehabil Technol. 2014;1:42-46.

12. Saper MG, Shneider DA. Simultaneous medial and lateral patellofemoral ligament reconstruction for combined medial and lateral patellar subluxation. Arthrosc Tech. 2014,3(2):e227-e231.

13. Udagawa K, Niki Y, Matsumoto H, et al. Lateral patellar retinaculum reconstruction for medial patellar instability following lateral retinacular release: a case report. Knee. 2014;21(1):336-339.

14. Sanchis-Alfonso V, Montesinos-Berry E, Monllau JC, Merchant AC. Results of isolated lateral retinacular reconstruction for iatrogenic medial patellar instability. Arthroscopy. 2015;31(3):422-427.

15. Borbas P, Koch PP, Fucentese SF. Lateral patellofemoral ligament reconstruction using a free gracilis autograft. Orthopedics. 2014;37(7):e665-e668.

16. Fulkerson JP, Gossling H. Anatomy of the knee joint lateral retinaculum. Clin Orthop Relat Res. 1980;153:183-188.

17. Kaplan E. Some aspects of functional anatomy of the human knee joint. Clin Orthop Relat Res. 1962;23:18-29.

18. Reider B, Marshall J, Koslin B, Ring B, Girgis F. The anterior aspect of the knee joint. J Bone Joint Surg Am. 1981;63(3):351-356.

19. Navarro MS, Navarro RD, Akita Junior J, Cohen M. Anatomical study of the lateral patellofemoral ligament in cadaver knees. Rev Bras Ortop. 2008;43(7):300-307.

20. Navarro MS, Beltrani Filho CA, Akita Junior J, Navarro RD, Cohen M. Relationship between the lateral patellofemoral ligament and the width of the lateral patellar facet. Acta Ortop Bras. 2010;18(1):19-22.

21. Salsich GB, Ward SR, Terk MR, Powers CM. In vivo assessment of patellofemoral joint contact area in individuals who are pain free. Clin Orthop Relat Res. 2003;417:277-284.

22. Merican AM, Kondo E, Amis AA. The effect on patellofemoral joint stability of selective cutting of lateral retinacular and capsular structures. J Biomech. 2009;42(3):291-296.

23. Vieira EL, Vieira EÁ, da Silva RT, Berlfein PA, Abdalla RJ, Cohen M. An anatomic study of the iliotibial tract. Arthroscopy. 2007;23(3):269-274.

24. Shneider DA. Lateral patellar laxity—identification, significance, treatment. Poster session presented at: Annual Meeting of the American Academy of Orthopaedic Surgeons; February 25-28, 2009; Las Vegas, NV.

25. 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(3):226-234.

26. Johnson DP, Wakeley C. Reconstruction of the lateral patellar retinaculum following lateral release: a case report. Knee Surg Sports Traumatol Arthrosc. 2002;10(6):361-363.

27. Saper MG, Shneider DA. Lateral patellofemoral ligament reconstruction using a quadriceps tendon graft. Arthrosc Tech. 2014;3(4):e445-e448.

28. Akşahin E, Yumrukçal F, Yüksel HY, Doğruyol D, Celebi L. Role of pathophysiology of patellofemoral instability in the treatment of spontaneous medial patellofemoral subluxation: a case report. J Med Case Rep. 2010;4:148.

LPFL Reconstruction. Before coming to our practice, most patients have tried several months of formal physical rehabilitation, medications, and bracing. Many have already had surgical procedures, including arthroscopy, lateral release, and tibial tubercle transfer. When the diagnosis of MPS is suspected after a thorough history and physical examination, LPFL reconstruction is offered. Management of MPS with LPFL reconstruction has yielded excellent and reliable clinical results. Teitge and Torga Spak¹⁰ described an LPFL reconstruction technique that is used as a salvage procedure in managing medial iatrogenic patellar instability (the patient’s own quadriceps tendon is used). In their experience, direct repair or imbrication of the lateral retinaculum failed to provide long-term stability because medial excursion usually appeared after 1 year. The 60 patients’ outcomes were excellent with respect to patellar stability, and there were no cases of recurrent subluxation. Borbas and colleagues¹⁵ reported a case of LPFL reconstruction in a symptomatic medial subluxated patella resulting from TKA and extended lateral release. Using a free gracilis autograft through patellar bone tunnels to reconstruct the LPFL, the patient was free of pain and very satisfied with the result at 1 year postoperatively. Our current strategy is anatomical reconstruction of the LPFL using a quadriceps tendon graft and no bone tunnels, screws, or anchors in the patella.²⁷ We previously reported a single case of isolated medial instability.⁴ At 2-year follow-up, there was no recurrent instability, and the functional outcome was excellent. This LPFL reconstruction method has been used in 10 patients with isolated MPS. There has been no residual medial subluxation on follow-up ranging from 3 months to 2 years. Outcome studies are in progress.

Rehabilitation. The initial goal of rehabilitation after surgical reconstruction of the lateral retinaculum or LPFL is to protect the healing soft tissues, restore normal knee ROM, and normalize gait. The knee is immobilized in a brace for weight-bearing activity for 4 to 6 weeks, until limb control is sufficient to prevent rotational stress on the knee. Gradual increase to full weight-bearing without bracing is permitted as quadriceps strength is restored. As motion is regained, strength, balance, and proprioception are emphasized for the entire lower extremity and core.

Functional limb training, including rotational activity, begins at 12 weeks. As strength and neuromuscular control progress, single-leg activity may be started with particular attention to proper alignment of the pelvis and the entire lower extremity. For competitive or recreational athletes, the final stages of rehabilitation focus on dynamic lower extremity control during sport-specific movements. Patients return to unrestricted activity by 6 months to 1 year after surgery.

Summary

MPS is a disabling condition that can limit daily functional activity because of apprehension and pain. Initially described as a complication of lateral retinacular release, isolated MPS can occur in the absence of a previous lateral release. Thorough physical examination and identification during arthroscopy are crucial for proper MPS diagnosis and management. When nonsurgical measures fail, LPFL reconstruction can provide patellofemoral stability and excellent functional outcomes.