Abstract
Purpose
To define medial patellofemoral ligament (MPFL) injury characteristics at the patellar attachment and clinical outcome in patients with primary traumatic patellar dislocation and MPFL avulsion injury at the patella.
Methods
Magnetic resonance imaging (MRI) was used to assess patients with primary (first-time) patellar dislocation and MPFL injury at the medial margin of the patella. Fifty-six patients with patellar attachment MPFL injury were enrolled in the study. Thirteen patients underwent surgical fixation of the avulsed MPFL and patellar medial margin osteochondral fracture, and the remaining patellar MPFL injures were treated nonoperatively. Forty-four patients were evaluated clinically at median four (range 1–10) years after patellar dislocation. The follow-up included evaluation of recurrent patellar instability, subjective symptoms, and functional limitations.
Results
Three types of patellar MPFL injuries were found; type P0 with ligamentous disruption at the patellar attachment, type P1 with bony avulsion fracture from the medial margin of the patella, and type P2 with bony avulsion involving articular cartilage from the medial facet of the patella. Of the patellar MPFL avulsion injuries that underwent initial surgical fixation, two patients (2/13) reported an unstable patella at follow-up. Fifty-five per cent (17/31) of patellar MPFL avulsion injuries that were treated nonoperatively had recurrent patellar instability (n.s.). The median Kujala score was 90 for patellar avulsion with surgical fixation and 86 for patellar avulsion without surgical fixation (n.s.).
Conclusion
Patellar attachment MPFL injury showed three different patterns, classified as types P0, P1, and P2. MRI can be used to assess the injury pattern. Patellar MPFL avulsion injuries do not benefit from acute surgical repair compared with nonsurgical treatment. Type P2 patellar MPFL avulsion includes an osteochondral fracture that may require surgical fixation.
Level of evidence
Prognostic study, Level III.
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References
Avikainen VJ, Nikku RK, Seppänen-Lehmonen TK (1993) Adductor magnus tenodesis for patellar dislocation. Technique and preliminary results. Clin Orthop Relat Res 297:12–16
Burks RT, Desio SM, Bachus KN, Tyson L, Springer K (1998) Biomechanical evaluation of lateral patellar dislocations. Am J Knee Surg 11(1):24–31
Camanho GL, Viegas Ade C, Bitar AC, Demange MK, Hernandez AJ (2009) Conservative versus surgical treatment for repair of the medial patellofemoral ligament in acute dislocations of the patella. Arthroscopy 25(6):620–625
Conlan T, Garth WP Jr, Lemons JE (1993) Evaluation of the medial soft-tissue restraints of the extensor mechanism of the knee. J Bone Joint Surg Am 75(5):682–693
Dejour H, Walch G, Nove-Josserand L, Guier C (1994) Factors of patellar instability: an anatomic radiographic study. Knee Surg Sports Traumatol Arthrosc 2(1):19–26
Desio SM, Burks RT, Bachus KN (1998) Soft tissue restraints to lateral patellar translation in the human knee. Am J Sports Med 26(1):59–65
Elias DA, White LM, Fithian DC (2002) Acute lateral patellar dislocation at MR imaging: injury patterns of medial patellar soft-tissue restraints and osteochondral injuries of the inferomedial patella. Radiology 225(3):736–743
Fucentese SF, von Roll A, Koch PP, Epari DR, Fuchs B, Schottle PB (2006) The patella morphology in trochlear dysplasia—a comparative MRI study. Knee 13:145–150
Guerrero P, Li X, Patel K, Brown M, Busconi B (2009) Medial patellofemoral ligament injury patterns and associated pathology in lateral patella dislocation: an MRI study. Sports Med Arthrosc Rehabil Ther Technol 1:17
Hensler D, Sillanpää PJ, Schoettle PB (2014) Medial patellofemoral ligament: anatomy, injury and treatment in the adolescent knee. Curr Opin Pediatr. doi:10.1097/MOP.0000000000000055
Kepler CK, Bogner EA, Hammoud S, Malcolmson G, Potter HG, Green DW (2011) Zone of injury of the medial patellofemoral ligament after acute patellar dislocation in children and adolescents. Am J Sports Med 39:1444–1449
Kujala UM, Jaakkola LH, Koskinen SK, Taimela S, Hurme M, Nelimarkka O (1993) Scoring of patellofemoral disorders. Arthroscopy 9(2):159–163
LaPrade RF, Engebretsen AH, Ly TV, Johansen S, Wentorf FA, Engebretsen L (2007) The anatomy of the medial part of the knee. J Bone Joint Surg Am 89(9):2000–2010
Matic GT, Magnussen RA, Kolovich GP, Flanigan DC (2014) Return to activity after medial patellofemoral ligament repair or reconstruction. Arthroscop. doi:10.1016/j.arthro.2014.02.044
Nikku R, Nietosvaara Y, Aalto K, Kallio PE (2005) Operative treatment of primary patellar dislocation does not improve medium-term outcome: a 7-year follow-up report and risk analysis of 127 randomized patients. Acta Orthop 76(5):699–704
Nomura E (1999) Classification of lesions of the medial patello-femoral ligament in patellar dislocation. Int Orthop 23(5):260–263
Palmu S, Kallio PE, Donell ST, Helenius I, Nietosvaara Y (2008) Acute patellar dislocation in children and adolescents: a randomized clinical trial. J Bone Joint Surg Am 90(3):463–470
Sillanpaa PJ, Maenpaa H, Mattila VM, Visuri T, Pihlajamaki H (2008) Arthroscopic surgery for primary traumatic patellar dislocation: a prospective, nonrandomized study comparing patients treated with and without acute arthroscopic stabilization with a median 7-year follow-up. Am J Sports Med 36(12):2301–2319
Sillanpaa PJ, Mattila VM, Maenpaa H, Kiuru M, Visuri T, Pihlajamaki H (2009) Treatment with and without initial stabilizing surgery for primary traumatic patellar dislocation. A prospective randomized study. J Bone Joint Surg Am 91(2):263–273
Sillanpaa PJ, Peltola E, Mattila VM, Kiuru M, Visuri T, Pihlajamaki H (2009) Femoral avulsion of the medial patellofemoral ligament after primary traumatic patellar dislocation predicts subsequent instability in men: a mean 7-year nonoperative follow- up study. Am J Sports Med 37(8):1513–1521
Stefancin JJ, Parker RD (2007) First-time traumatic patellar dislocation: a systematic review. Clin Orthop Relat Res 455:93–101
Tecklenburg K, Dejour D, Hoser C, Fink C (2006) Bony and cartilaginous anatomy of the patellofemoral joint. Knee Surg Sports Traumatol Arthrosc 14:235–240
Tegner Y, Lysholm J (1985) Rating systems in the evaluation of knee ligament injuries. Clin Orthop Relat Res 198:43–49
Teitge RA (2008) Patellofemoral syndrome a paradigm for current surgical strategies. Orthop Clin North Am 39(3):287–311
Vainionpää S, Laasonen E, Silvennoinen T, Vasenius J, Rokkanen P (1990) Acute dislocation of the patella. A prospective review of operative treatment. J Bone Joint Surg Br 72(3):366–369
Weber-Spickschen TS, Spang J, Kohn L, Imhoff AB, Schottle PB (2011) The relationship between trochlear dysplasia and medial patellofemoral ligament rupture location after patellar dislocation: an MRI evaluation. Knee 18(3):185–188
Zaidi A, Babyn P, Astori I, White L, Doria A, Cole W (2006) MRI of traumatic patellar dislocation in children. Pediatr Radiol 36(11):1163–1170
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Sillanpää, P.J., Salonen, E., Pihlajamäki, H. et al. Medial patellofemoral ligament avulsion injury at the patella: classification and clinical outcome. Knee Surg Sports Traumatol Arthrosc 22, 2414–2418 (2014). https://doi.org/10.1007/s00167-014-3174-3
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DOI: https://doi.org/10.1007/s00167-014-3174-3