Surgical versus Nonsurgical Treatments of Acute Primary Patellar Dislocation with Special Emphasis on the MPFL Injury Patterns

Abstract

The objective of the present study was to compare the clinical results of the surgical versus nonsurgical treatments of acute primary patellar dislocations with a medial patellofemoral ligament (MPFL) injury in the nonoverlap region with the vastus medialis oblique. In this study, 62 patients with an acute patellar dislocation and a concurrent MPFL injury in the nonoverlap region were randomly divided into two groups based on their birth years (even vs. odd years) and received either surgical or nonsurgical treatment. Of the 62 eligible patients, 30 were in the nonsurgical treatment group (Group 1) and 32 were in the surgical group (Group 2). Patellar stability tests and the Kujala knee questionnaire were performed, and radiographs were evaluated for patellar tilt and the lateral shift ratio by two blinded investigators. An osteochondral injury was noted in six (23.1%) patients from Group 1 and five (16.7%) patients from Group 2, with no statistical difference between the two groups. The mean Kujala score was 80.19 ± 5.07 and 93.57 ± 4.03 (p < 0.001) between the surgical and nonsurgical groups, respectively. The mean patellar tilt was 8.96 ± 1.64 and 6.83 ± 1.44 degrees (p < 0.001) and the lateral shift ratio was 11.08 ± 1.99 and 9.23 ± 1.96 (p = 0.001) between the surgical and nonsurgical groups, respectively. This study showed that the surgical treatment of MPFL injuries in the nonoverlap region achieved better clinical outcomes and improved subjective knee function compared with conservative therapy. Surgery should therefore be considered as the treatment of choice for these specific injuries.

Keywords

knee - acute primary patellar dislocation - MPFL injury patterns

• References

• 1 Palmu S, Kallio PE, Donell ST, Helenius I, Nietosvaara Y. Acute patellar dislocation in children and adolescents: a randomized clinical trial. J Bone Joint Surg Am 2008; 90 (3) 463-470
• 2 Amis AA, Firer P, Mountney J, Senavongse W, Thomas NP. Anatomy and biomechanics of the medial patellofemoral ligament. Knee 2003; 10 (3) 215-220
• 3 Nomura E, Inoue M. Injured medial patellofemoral ligament in acute patellar dislocation. J Knee Surg 2004; 17 (1) 40-46
• 4 Nomura E, Inoue M, Osada N. Anatomical analysis of the medial patellofemoral ligament of the knee, especially the femoral attachment. Knee Surg Sports Traumatol Arthrosc 2005; 13 (7) 510-515
• 5 Panagiotopoulos E, Strzelczyk P, Herrmann M, Scuderi G. Cadaveric study on static medial patellar stabilizers: the dynamizing role of the vastus medialis obliquus on medial patellofemoral ligament. Knee Surg Sports Traumatol Arthrosc 2006; 14 (1) 7-12
• 6 Tuxøe JI, Teir M, Winge S, Nielsen PL. The medial patellofemoral ligament: a dissection study. Knee Surg Sports Traumatol Arthrosc 2002; 10 (3) 138-140
• 7 Davis DK, Fithian DC. Techniques of medial retinacular repair and reconstruction. Clin Orthop Relat Res 2002; (402) 38-52
• 8 Desio SM, Burks RT, Bachus KN. Soft tissue restraints to lateral patellar translation in the human knee. Am J Sports Med 1998; 26 (1) 59-65
• 9 Apostolovic M, Vukomanovic B, Slavkovic N , et al. Acute patellar dislocation in adolescents: operative versus nonoperative treatment. Int Orthop 2011; 35 (10) 1483-1487
• 10 Sallay PI, Poggi J, Speer KP, Garrett WE. Acute dislocation of the patella. A correlative pathoanatomic study. Am J Sports Med 1996; 24 (1) 52-60
• 11 Stefancin JJ, Parker RD. First-time traumatic patellar dislocation: a systematic review. Clin Orthop Relat Res 2007; 455 (455) 93-101
• 12 Nikku R, Nietosvaara Y, Aalto K, Kallio PE. 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 2005; 76 (5) 699-704
• 13 Nikku R, Nietosvaara Y, Kallio PE, Aalto K, Michelsson JE. Operative versus closed treatment of primary dislocation of the patella. Similar 2-year results in 125 randomized patients. Acta Orthop Scand 1997; 68 (5) 419-423
• 14 Sillanpää PJ, Mäenpää HM, Mattila VM, Visuri T, Pihlajamäki H. 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 2008; 36 (12) 2301-2309
• 15 Christiansen SE, Jakobsen BW, Lund B, Lind M. Isolated repair of the medial patellofemoral ligament in primary dislocation of the patella: a prospective randomized study. Arthroscopy 2008; 24 (8) 881-887
• 16 Cofield RH, Bryan RS. Acute dislocation of the patella: results of conservative treatment. J Trauma 1977; 17 (7) 526-531
• 17 Camanho GL, Viegas AdeC, Bitar AC, Demange MK, Hernandez AJ. Conservative versus surgical treatment for repair of the medial patellofemoral ligament in acute dislocations of the patella. Arthroscopy 2009; 25 (6) 620-625
• 18 Bitar AC, Demange MK, D'Elia CO, Camanho GL. Traumatic patellar dislocation: nonoperative treatment compared with MPFL reconstruction using patellar tendon. Am J Sports Med 2012; 40 (1) 114-122
• 19 Balcarek P, Ammon J, Frosch S , et al. Magnetic resonance imaging characteristics of the medial patellofemoral ligament lesion in acute lateral patellar dislocations considering trochlear dysplasia, patella alta, and tibial tuberosity-trochlear groove distance. Arthroscopy 2010; 26 (7) 926-935
• 20 Fithian DC, Paxton EW, Stone ML , et al. Epidemiology and natural history of acute patellar dislocation. Am J Sports Med 2004; 32 (5) 1114-1121
• 21 Nomura E. Classification of lesions of the medial patello-femoral ligament in patellar dislocation. Int Orthop 1999; 23 (5) 260-263
• 22 Balcarek P, Walde TA, Frosch S , et al. Patellar dislocations in children, adolescents and adults: a comparative MRI study of medial patellofemoral ligament injury patterns and trochlear groove anatomy. Eur J Radiol 2011; 79 (3) 415-420
• 23 Weber-Spickschen TS, Spang J, Kohn L, Imhoff AB, Schottle PB. The relationship between trochlear dysplasia and medial patellofemoral ligament rupture location after patellar dislocation: an MRI evaluation. Knee 2011; 18 (3) 185-188
• 24 Kang HJ, Wang F, Chen BC, Zhang YZ, Ma L. Non-surgical treatment for acute patellar dislocation with special emphasis on the MPFL injury patterns. Knee Surg Sports Traumatol Arthrosc 2013; 21 (2) 325-331
• 25 Elias DA, White LM, Fithian DC. Acute lateral patellar dislocation at MR imaging: injury patterns of medial patellar soft-tissue restraints and osteochondral injuries of the inferomedial patella. Radiology 2002; 225 (3) 736-743
• 26 Paxton EW, Fithian DC, Stone ML, Silva P. The reliability and validity of knee-specific and general health instruments in assessing acute patellar dislocation outcomes. Am J Sports Med 2003; 31 (4) 487-492
• 27 Philippot R, Chouteau J, Wegrzyn J, Testa R, Fessy MH, Moyen B. Medial patellofemoral ligament anatomy: implications for its surgical reconstruction. Knee Surg Sports Traumatol Arthrosc 2009; 17 (5) 475-479
• 28 Ronga M, Oliva F, Longo UG, Testa V, Capasso G, Maffulli N. Isolated medial patellofemoral ligament reconstruction for recurrent patellar dislocation. Am J Sports Med 2009; 37 (9) 1735-1742
• 29 Sanders TG, Morrison WB, Singleton BA, Miller MD, Cornum KG. Medial patellofemoral ligament injury following acute transient dislocation of the patella: MR findings with surgical correlation in 14 patients. J Comput Assist Tomogr 2001; 25 (6) 957-962
• 30 Diederichs G, Issever AS, Scheffler S. MR imaging of patellar instability: injury patterns and assessment of risk factors. Radiographics 2010; 30 (4) 961-981
• 31 Guerrero P, Li X, Patel K, Brown M, Busconi B. Medial patellofemoral ligament injury patterns and associated pathology in lateral patella dislocation: an MRI study. Sports Med Arthrosc Rehabil Ther Technol 2009; 1 (1) 17
• 32 Elias DA, White LM, Fithian DC. Acute lateral patellar dislocation at MR imaging: injury patterns of medial patellar soft-tissue restraints and osteochondral injuries of the inferomedial patella. Radiology 2002; 225 (3) 736-743
• 33 Seeley M, Bowman KF, Walsh C, Sabb BJ, Vanderhave KL. Magnetic resonance imaging of acute patellar dislocation in children: patterns of injury and risk factors for recurrence. J Pediatr Orthop 2012; 32 (2) 145-155
• 34 Bedi H, Marzo J. The biomechanics of medial patellofemoral ligament repair followed by lateral retinacular release. Am J Sports Med 2010; 38 (7) 1462-1467
• 35 Mountney J, Senavongse W, Amis AA, Thomas NP. Tensile strength of the medial patellofemoral ligament before and after repair or reconstruction. J Bone Joint Surg Br 2005; 87 (1) 36-40
• 36 Steensen RN, Dopirak RM, McDonald III WG. The anatomy and isometry of the medial patellofemoral ligament: implications for reconstruction. Am J Sports Med 2004; 32 (6) 1509-1513