Athletic Training and Sports Health Care

Team Physician 

Treatment of Athletes With Patellofemoral Instability

Brian Forsythe, MD; Rachel M. Frank, MD

Abstract

Patellofemoral instability is a challenging clinical problem. The objectives of non-operative treatment involve strengthening the athlete’s core, as well as muscles around the knee joint. With recurrent instability, surgical management restores adequate patellofemoral tracking through realignment of the extensor mechanism. Athletes requiring surgery may return to sports 4 months postoperatively.

Abstract

Patellofemoral instability is a challenging clinical problem. The objectives of non-operative treatment involve strengthening the athlete’s core, as well as muscles around the knee joint. With recurrent instability, surgical management restores adequate patellofemoral tracking through realignment of the extensor mechanism. Athletes requiring surgery may return to sports 4 months postoperatively.

The authors are from the Division of Sports Medicine, Midwest Orthopaedics at Rush, Rush University Medical Center, Chicago, Illinois.

The authors have no financial or proprietary interest in the materials presented herein.

Address correspondence to Brian Forsythe, MD, Central DuPage Hospital, 25 N Winfield Road, Suite 505, Winfield, IL 60190; e-mail: brian.forsythe@rushortho.com.

The knee consists of 2 primary articulations—the tibiofemoral joint and the patellofemoral (PF) joint. The PF joint is composed of the patella and the femoral trochlea. Throughout normal range of motion, the shape of the trochlea, as well as the surrounding soft tissues, including the medial patellofemoral ligament, medial retinaculum, and vastus medialis muscle, holds the patella within its groove. Occasionally, the PF joint becomes unstable, leading to the sensation of the patella slipping out of place. When a patient develops subluxation or dislocation, the condition is referred to as PF instability.

Treatment of the young (age 15 to 40 years) athletic patient with PF instability poses a significant challenge to orthopedic surgeons. Athletes place high demands on their PF joints, as demonstrated by studies showing peak PF joint compressive forces between 5 and 6 times the body weight during running activities.1,2 Treatment options for PF instability include both operative and nonoperative management. The majority of patients experiencing PF dislocation can be treated nonoperatively, with a 73% satisfaction rate following nonsurgical management, as reported by Garth et al.3 However, a minority of patients can develop persistent symptoms of instability following a 1-time dislocation event, resulting in inability to return to prior activity levels. Following dislocation, recurrent symptoms are typically due to laxity of medial restraints within the medial PF ligament (MPFL) and its deep capsular layer.4,5

The natural history of patellar dislocation following nonoperative management yields a recurrence rate between 15% and 44%.5–7 In the athletic population, the recurrence rate may be higher due to the demands placed on the PF joint during athletic competition. Athletes with valgus alignment of their knee are especially at high risk for PF instability. This type of alignment causes these athletes to have a wider Q angle than normal (usually 14° in men and 17° in women). With a Q angle >20°, the patella becomes malaligned laterally within the trochlear groove (PF maltracking), leading to subluxation and/or dislocation. The need for an effective and durable surgical intervention is essential in this population of athletes who are at higher risk of failing conservative treatment.

Physical examination of athletes presenting with suspected PF instability begins with a gait assessment and visual inspection of both knees. The examiner then performs palpation of the medial and lateral facets of the patella for tenderness. The apprehension test (manual subluxation of the patella laterally) is then performed with the knee in both full extension and 30° of flexion. Medial, lateral, superior, and inferior translation of the patella are likewise assessed. The examiner can then attempt to displace the patella in a distal lateral direction (by approximately 2 cm) with the knee flexed to 30° in an effort to detect for disruption of the MPFL.

Positive PF instability test criteria include ease of patellar translation and a softer end point compared with a normal knee.8 Following inspection, palpation, and stability testing, the knee should be brought through a range of motion while the physician assesses for crepitation. Crepitus of the PF joint can be of synovial or arthritic origin; the former is deemed present by a snapping sensation, whereas the latter is marked by a fine, grinding sensation. The PF compression test (performed with the patient flexing and extending the knee while the examiner manually compresses the patella) should be performed, and it is considered positive if the patient complains of pain or discomfort throughout the movement. The presence or absence of a J sign (proximal and lateral deviation of the patella with terminal knee extension) is also noted.

Athletes who have sustained a patellar dislocation or who experience recurrent instability without dislocation should initially undergo a prolonged course of nonoperative management. If aggressive functional rehabilitation, patellar bracing, or patellar taping are unsuccessful in improving joint stability, patients may require surgical intervention to facilitate return to their sport. A variety of studies have described surgical techniques for recurrent PF instability and associated patellar pathology.9–20

To determine candidacy for surgical realignment, all patients should undergo the following bilateral radiographs to assess patellar tilt and position: standing anteroposterior view, merchant (45°) view, standing anteroposterior 45° flexion view (Rosenberg view), and 30° flexed lateral view (Figures 1 and 2). Patella alta (high-riding patella) versus patella baja (low-riding patella), patellar tilt (lateral tilt associated with instability), and the presence of osteochondral fragments or arthritic changes are noted. Preoperative magnetic resonance imaging should be obtained on all patients to assess for associated meniscal and chondral injuries and to evaluate the status of the MPFL. For cases in which the MPFL is attenuated and persistent laxity is demonstrated, a medial reefing procedure (tightening of the soft tissue capsule and ligament medial to the patella) is performed to further enhance patellar stability.

Preoperative flexion lateral radiograph demonstrates patella alta, with the inferior pole of the patella significantly higher than Blumensatt’s line.

Figure 1. Preoperative flexion lateral radiograph demonstrates patella alta, with the inferior pole of the patella significantly higher than Blumensatt’s line.

Preoperative sunrise view of the knee demonstrating lateral patellar subluxation and lateral tilt.

Figure 2. Preoperative sunrise view of the knee demonstrating lateral patellar subluxation and lateral tilt.

If a patient is deemed appropriate for surgical repair of PF instability, several surgical options are available. The cornerstones of the surgical approach include: (1) correction of malalignment; (2) correction of patella alta; and (3) unloading of the PF joint. The authors’ procedure of choice involves a modified Fulkerson osteotomy with arthroscopic lateral release (Figures 3 and 4). The Fulkerson osteotomy involves cutting and moving the tibial tubercle from its native location to a more medial (inner) and anterior (forward) position. The tubercle is fixed to its new position with screws. Arthroscopic lateral release allows for a minimally invasive release of the tight tissues along the lateral (outer) aspect of the patella. Overall, this procedure allows for correction of patella alta and malalignment via distalization and medialization of the tubercle, respectively, while unloading the damaged or at-risk distal medial facet of the patella via anteriorization of the tubercle.

The osteotomy is directed postero-laterally while beginning along the medial border of the patellar tendon.

Figure 3. The osteotomy is directed postero-laterally while beginning along the medial border of the patellar tendon.

Postoperative radiograph demonstrates a healed osteotomy and correction of patella alta.

Figure 4. Postoperative radiograph demonstrates a healed osteotomy and correction of patella alta.

Following this procedure, patients are evaluated at regular intervals: 1 and 6 weeks, 3 and 6 months, and 1 year postoperatively. All patients are placed on a continuous passive motion machine for 7 to 10 days postoperatively, which is continued until 110° of flexion and full extension are achieved. For the first 6 weeks, patients are allowed to bear weight as tolerated, with a functional knee brace locked in extension. Goals during this first rehabilitation phase include quadriceps activation and acquiring range of motion from 0° to 90° of flexion. After 6 weeks, the brace is unlocked and closed-chain exercises and strengthening are initiated. The brace is discontinued after full range of motion and quadriceps control are achieved, typically approximately 8 weeks postoperatively. Return to full, unrestricted activity is usually allowed 4 to 5 months after surgery, given adequate quadriceps strength and restoration of full range of motion.

Recently, we reviewed a series of 34 athletes21 who presented with patellar instability and failed nonoperative management and ultimately underwent surgical correction via modified Fulkerson osteotomy and arthroscopic lateral release. As mentioned above, the osteotomy addresses the underlying malalignment predisposing the patient to PF instability. In this study, 97% of the athletes were successfully returned to their previous level of athletic competition.

An alternative procedure that has proven useful in the surgical management of PF instability is MPFL repair or reconstruction because this ligament is commonly disrupted in acute lateral PF dislocation events. The majority of MPFL injuries occur at the femoral site. In this procedure, following diagnostic arthroscopy, an incision is made between the patella and the medial epicondyle, and the MPFL is identified by its location deep to the vastus medialis (the most medial quadriceps muscle). The MPFL can then be repaired directly to the bone with suture anchors or can be reconstructed with autograft or allograft tissue augmentation.22–27

Conclusion

Patellofemoral instability is a complicated pathology that can be extremely frustrating for athletes, coaches, and physicians. The goals of treatment involve strengthening the muscles around the knee joint, particularly the quadriceps muscles. If nonoperative treatment fails, surgical approaches revolve around reestablishing the patient’s knee anatomy in such a way that allows adequate tracking of the patella within the trochlear grove. With proper surgical technique and strict compliance with postoperative rehabilitation, most athletes can expect a complete return to full activity.

References

  1. Flynn TW, Soutas-Little RW. Patellofemoral joint compressive forces in forward and backward running. J Orthop Sports Phys Ther. 1995;21(5):277–282.
  2. Kaufman KR, An KN, Litchy WJ, Morrey BF, Chao EY. Dynamic joint forces during knee isokinetic exercise. Am J Sports Med. 1991;19(3):305–316. doi:10.1177/036354659101900317 [CrossRef]
  3. Garth WP Jr, Pomphrey M Jr, Merrill K. Functional treatment of patellar dislocation in an athletic population. Am J Sports Med. 1996;24(6):785–791. doi:10.1177/036354659602400614 [CrossRef]
  4. Garth WP Jr, DiChristina DG, Holt G. Delayed proximal repair and distal realignment after patellar dislocation. Clin Orthop Relat Res. 2000;(377):132–144. doi:10.1097/00003086-200008000-00019 [CrossRef]
  5. Hawkins RJ, Bell RH, Anisette G. Acute patellar dislocations. The natural history. Am J Sports Med. 1986;14(2):117–120. doi:10.1177/036354658601400204 [CrossRef]
  6. Cofield RH, Bryan RS. Acute dislocation of the patella: results of conservative treatment. J Trauma. 1977;17(7):526–531. doi:10.1097/00005373-197707000-00007 [CrossRef]
  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. doi:10.1177/036354658801600413 [CrossRef]
  8. Tanner SM, Garth WP Jr, Soileau R, Lemons JE. A modified test for patellar instability: the biomechanical basis. Clin J Sport Med. 2003;13(6):327–338. doi:10.1097/00042752-200311000-00001 [CrossRef]
  9. Carney JR, Mologne TS, Muldoon M, Cox JS. Long-term evaluation of the Roux-Elmslie-Trillat procedure for patellar instability: a 26-year follow-up. Am J Sports Med. 2005;33(8):1220–1223. doi:10.1177/0363546504272686 [CrossRef]
  10. Chrisman OD, Snook GA, Wilson TC. A long-term prospective study of the Hauser and Roux-Goldthwait procedures for recurrent patellar dislocation. Clin Orthop Relat Res. 1979;(144):27–30.
  11. Fernandez E, Sala D, Castejon M. Reconstruction of the medial patellofemoral ligament for patellar instability using a semitendinosus autograft. Acta Orthop Belg. 2005;71(3):303–308.
  12. Fulkerson JP. Anteromedialization of the tibial tuberosity for patellofemoral malalignment. Clin Orthop Relat Res. 1983;(177):176–181.
  13. Marcacci M, Zaffagnini S, Lo Presti M, Vascellari A, Iacono F, Russo A. Treatment of chronic patellar dislocation with a modified Elmslie-Trillat procedure. Arch Orthop Trauma Surg. 2004;124(4):250–257. doi:10.1007/s00402-003-0511-2 [CrossRef]
  14. Marsh JS, Daigneault JP, Sethi P, Polzhofer GK. Treatment of recurrent patellar instability with a modification of the Roux-Goldthwait technique. J Pediatr Orthop. 2006;26(4):461–465. doi:10.1097/01.bpo.0000217711.34492.48 [CrossRef]
  15. Mikashima Y, Kimura M, Kobayashi Y, Miyawaki M, Tomatsu T. Clinical results of isolated reconstruction of the medial patellofemoral ligament for recurrent dislocation and subluxation of the patella. Acta Orthop Belg. 2006;72(1):65–71.
  16. Nam EK, Karzel RP. Mini-open medial reefing and arthroscopic lateral release for the treatment of recurrent patellar dislocation: a medium-term follow-up. Am J Sports Med. 2005;33(2):220–230. doi:10.1177/0363546504267803 [CrossRef]
  17. Nomura E, Inoue M. Hybrid medial patellofemoral ligament reconstruction using the semitendinous tendon for recurrent patellar dislocation: minimum 3 years’ follow-up. Arthroscopy. 2006;22(7):787–793. doi:10.1016/j.arthro.2006.04.078 [CrossRef]
  18. Panni AS, Tartarone M, Patricola A, Paxton EW, Fithian DC. Long-term results of lateral retinacular release. Arthroscopy. 2005;21(5):526–531. doi:10.1016/j.arthro.2005.01.007 [CrossRef]
  19. Schottle PB, Scheffler SU, Schwarck A, Weiler A. Arthroscopic medial retinacular repair after patellar dislocation with and without underlying trochlear dysplasia: a preliminary report. Arthroscopy. 2006;22(11):1192–1198. doi:10.1016/j.arthro.2006.07.002 [CrossRef]
  20. von Knoch F, Bohm T, Burgi ML, von Knoch M, Bereiter H. Trochleaplasty for recurrent patellar dislocation in association with trochlear dysplasia. A 4- to 14-year follow-up study. J Bone Joint Surg Br. 2006;88(10):1331–1335. doi:10.1302/0301-620X.88B10.17834 [CrossRef]
  21. Tjoumakaris FP, Forsythe B, Bradley JP. Patellofemoral instability in athletes: treatment via modified Fulkerson osteotomy and lateral release. Am J Sports Med. 2010;38(5):992–999. doi:10.1177/0363546509357682 [CrossRef]
  22. Fisher B, Nyland J, Brand E, Curtin B. Medial patellofemoral ligament reconstruction for recurrent patellar dislocation: a systematic review including rehabilitation and return-to-sports efficacy. Arthroscopy. 2010;26(10):1384–1394. doi:10.1016/j.arthro.2010.04.005 [CrossRef]
  23. Camp CL, Krych AJ, Dahm DL, Levy BA, Stuart MJ. Medial patellofemoral ligament repair for recurrent patellar dislocation. Am J Sports Med. 2010;38(11):2248–2254. doi:10.1177/0363546510376230 [CrossRef]
  24. Panagopoulos A, van Niekerk L, Triantafillopoulos IK. MPFL reconstruction for recurrent patella dislocation: a new surgical technique and review of the literature. Int J Sports Med. 2008;29(5):359–365. doi:10.1055/s-2007-965360 [CrossRef]
  25. Tom A, Fulkerson JP. Restoration of native medial patellofemoral ligament support after patella dislocation. Sports Med Arthrosc. 2007;15(2):68–71. doi:10.1097/JSA.0b013e31803035d3 [CrossRef]
  26. Smith TO, Walker J, Russell N. Outcomes of medial patellofemoral ligament reconstruction for patellar instability: a systematic review. Knee Surg Sports Traumatol Arthrosc. 2007;15(11):1301–1314. doi:10.1007/s00167-007-0390-0 [CrossRef]
  27. LeGrand AB, Greis PE, Dobbs RE, Burks RT. MPFL reconstruction. Sports Med Arthrosc. 2007;15(2):72–77. doi:10.1097/JSA.0b013e31803bb513 [CrossRef]
Authors

The authors are from the Division of Sports Medicine, Midwest Orthopaedics at Rush, Rush University Medical Center, Chicago, Illinois.

The authors have no financial or proprietary interest in the materials presented herein.

Address correspondence to Brian Forsythe, MD, Central DuPage Hospital, 25 N Winfield Road, Suite 505, Winfield, IL 60190; e-mail: brian.forsythe@rushortho.com

10.3928/19425864-20120629-03

Sign up to receive

Journal E-contents