Patella Dislocation in Children and Adolescents

Summary

Introduction Patellar dislocation is one of the commonest knee injuries in adolescents. Although treatment usually leads to good results, the influence of anatomical and functional factors on therapeutic strategy has been underestimated, especially in cases of recurrence.

Patients and Methods The course of treatment has been analysed in 88 patients with 136 patellar dislocations. The importance of anatomical conditions was studied using X-ray and MRI findings. The treatment results were critically evaluated in comparison with current recommendations.

Results From 2000 to 2015, 109 patellar dislocations occurred in 88 patients; a further 27 previous dislocations were reported by the patients (mean age 14 years, 47 boys and 41 girls). About one-third of patients (35.2 %) suffered one or more recurrences. Almost half (48.6 %) of the dislocations occurred during physical exercise, particularly ball sports. Osteochondral flake fracture was found in 9 % of the patients, and a lesion of the medial patellofemoral ligament in 96 %. There was an anatomical predisposition to patellar dislocation in almost all cases. The sulcus angle, patellar and trochlear dysplasia, and patellar height were highly significantly different between the patient group and controls. The TT-TG distance was subsequently calculated, but had no impact on therapy. Seventy-seven patients were treated conservatively and 32 patients surgically. The conservative procedure included partial immobilisation for six weeks. Surgical reconstruction or tightening was performed in 27 cases; in five, in combination with other surgical procedures. Plasty of the medial patellofemoral ligament with a tendon graft was performed in five patients, and osteochondral or meniscal lesions were repaired in 10 patients. Recurrences occurred in 41.7 % of conservatively treated knees and in 29.6 % of surgically treated knees (without reconstruction with a tendon graft). No recurrence was seen after reconstruction of the medial patellofemoral ligament with a tendon graft. Fifty-four patients underwent a follow-up examination. Fourteen of these (25.9 %) had suffered a recurrence. The outcome 16 months after the end of treatment was mostly good, as were the results of self-assessment (Larson-Lauridsen Score).

Conclusion An anatomical predisposition is detectable in almost all cases of patellar dislocation, but frequently occurs with an accident event, e.g. in ball sports. Primary patellar dislocations without serious concomitant injuries may be treated conservatively. In the event of recurrence, the indication for surgery is given, even in young patients and in any patient with an osteochondral flake fracture. Tightening reconstruction of the MPFL used to be frequently performed, but is associated with a high rate of recurrence.

Key words

patellar dislocation - children - adolescents - MPFL - trochlear dysplasia

• References/Literatur

• 1 Stefancin JJ, Parker RD. First-time traumatic patellar dislocation: a systematic review. Clin Orthop Relat Res 2007; 455: 93-101
• 2 Atkin DM, Fithian DC, Marangi KS. et al. Characteristics of patients with primary acute lateral patellar dislocation and their recovery within the first 6 months of injury. Am J Sports Med 2000; 28: 472-479
• 3 Nikku R, Nietosvaara Y, Kallio PE. et al. Operative versus closed treatment of primary dislocation of the patella. Similar 2-year results in 125 randomized patients. Acta Orthop Scand 1997; 68: 419-423
• 4 Nikku R, Nietosvaara Y, Aalto K. et al. 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: 699-704
• 5 Mäenpää H, Huhtala H, Lehto MUK. Recurrence after patellar dislocation. Redislocation in 37/75 patients followed for 6–24 years. Acta Orthop Scand 1997; 68: 424-426
• 6 Armstrong BM, Hall M, Crawfurd E. et al. A feasibility study for a pragmatic randomised controlled trial comparing cast immobilisation versus no immobilisation for patients following first-time patellar dislocation. Knee 2012; 19: 696-702
• 7 Nietosvaara Y, Aalto K, Kallio PE. Acute patellar dislocation in children: incidence and associated osteochondral fractures. J Pediatr Orthop 1994; 14: 513-515
• 8 Lording T, Lustig S, Servien E. et al. Chondral Injury in Patellofemoral Instability. Cartilage 2014; 5: 136-144
• 9 Schneider F, Sperl M, Steinwender G. et al. Kindliche Kniebinnenverletzungen. Orthopade 2014; 43: 393-403
• 10 Duthon VB. Acute traumatic patellar dislocation. Orthop Traumatol Surg Res 2015; 101 (01) (Suppl.) S59-S67
• 11 Ji G, Wang F, Zhang Y. et al. Medial patella retinaculum plasty for treatment of habitual patellar dislocation in adolescents. Int Orthop 2012; 36: 1819-1825
• 12 Balcarek P, Oberthür S, Hopfensitz S. et al. Which patellae are likely to redislocate?. Knee Surg Sports Traumatol Arthrosc 2014; 22: 2308-2314
• 13 Steensen RN, Bentley JC, Trinh TQ. et al. The prevalence and combined prevalences of anatomic factors associated with recurrent patellar dislocation: a magnetic resonance imaging study. Am J Sports Med 2015; 43: 921-927
• 14 Hawkins RJ, Bell RH, Anisette G. Acute patellar dislocations: the natural history. Am J Sports Med 1986; 14: 117-120
• 15 Fithian DC, Paxton EW, Stone ML. et al. Epidemiology and natural history of acute patellar dislocation. Am J Sports Med 2004; 32: 1114-1121
• 16 Nomura E, Inoue M. Cartilage lesions of the patella in recurrent patellar dislocation. Am J Sports Med 2004; 32: 498-502
• 17 Inoue M, Nomura E, Sugiura H. et al. Histological findings of avulsion tear-type medial patellofemoral ligament injury in acute patellar dislocation. J Clin Pathol 2007; 60: 1068-1069
• 18 Drez D, Edwards TB, Williams CS. Results of medial patellofemoral ligament reconstruction in the treatment of patellar dislocation. Arthroscopy 2001; 17: 298-306
• 19 Ellera Gomes JL, Stigler Marczyk LR, César de César P. et al. Medial patellofemoral ligament reconstruction with semitendinosus autograft for chronic patella instability: a follow-up study. Arthroscopy 2004; 20: 147-151
• 20 Deie M, Ochi M, Sumen Y. et al. A long-term follow-up study after medial patellofemoral ligament reconstruction using the transferred semitendinosus tendon for patellar instability. Knee Surg Sports Traumatol Arthrosc 2005; 13: 522-528
• 21 Fernandez E, Sala D, Castejon M. Reconstruction of the medial patellofemoral ligament for patellar instability using a semitendinosus autograft. Acta Orthop Belg 2005; 71: 303-308
• 22 Nomura E, Motoyasu I. Hybrid medial patellofemoral ligament reconstruction using the semitendinous tendon for recurrent patellar dislocation: minimum 3 yearʼs follow-up. Arthroscopy 2006; 22: 787-793
• 23 Zhao J, Huangfu X, He Y. et al. Recurrent patellar dislocation in adolescents: medial retinaculum plication versus vastus medialis plasty. Am J Sports Med 2012; 40: 123-132
• 24 Iliadis AD, Jaiswal PK, Khan W. et al. The operative management of patella malalignment. Open Orthop J 2012; 6: 327-339
• 25 Neri T, Philippot R, Carnesecchi O. et al. Medial patellofemoral ligament reconstruction: clinical and radiographic results in a series of 90 cases. Orthop Traumatol Surg Res 2015; 101: 65-69
• 26 Dejour D, Lecoultre B. Douleur et instabilité rotulienne: essai de classification. Med Hyg 1998; 5: 1466-1470
• 27 Dejour D, Le Coultre B. Osteotomies in patello-femoral instabilities. Sports Med Arthrosc 2007; 15: 39-46
• 28 Tavernier T, Dejour D. Knee imaging: what is the best modality. J Radiol 2001; 82: 387-405 407–408
• 29 Dejour D, Saggin P. The sulcus deepening trochleoplasty – the Lyonʼs procedure. Int Orthop 2010; 34: 311-316
• 30 Smith TO, Donell ST, Chester R. et al. What activities do patients with patellar instability perceive makes their patella unstable?. Knee 2011; 18: 333-339
• 31 Nomura E. Classification of lesions of the medial patellofemoral ligament in patellar dislocation. Int Orthop 1999; 23: 260-263
• 32 Amis AA, Firer P, Mountney J. et al. Anatomy and biomechanics of the medial patellofemoral ligament. Knee 2003; 10: 215-220
• 33 Dejour H, Walch G, Nove-Josserand L. et al. Factors of patellar instability: an anatomic radiographic study. Knee Surg Sports Traumatol Arthrosc 1994; 2: 19-26
• 34 Van Haver A, De Roo K, De Beule M. et al. The effect of trochlear dysplasia on patellofemoral biomechanics: a cadaveric study with simulated trochlear deformities. Am J Sports Med 2015; 43: 1354
• 35 Alemparte J, Ekdahl M, Burnier L. et al. Patellofemoral evaluation with radiographs and computed tomography scans in 60 knees of asymptomatic subjects. Arthroscopy 2000; 23: 170-177
• 36 Schueda MA, Costa Astur D, Schueda Bier R. et al. Use of computed tomography to determine the risk of patellar dislocation in 921 patients with patellar instability. Open Access J Sports Med 2015; 6: 55-62
• 37 Dornacher D, Reichel H, Lippacher S. Measurement of tibial tuberosity – trochlear groove distance: evaluation of inter- and intraobserver correlation dependent on the severity of trochlear dysplasia. Knee Surg Sports Traumatol Arthrosc 2014; 22: 2382-2387
• 38 McNally EG, Osterle SJ, Pal C. Assessment of patellar maltracking using combined static and dynamic MRI. Eur Radiol 2000; 10: 1051-1055
• 39 Monk AP, Doll HA, Gibbons CL. et al. The patho-anatomy of patellofemoral subluxation. J Bone Joint Surg Br 2011; 93: 1341-1347
• 40 Balcarek P, Oberthür S, Frosch S. et al. Vastus medialis obliquus muscle morphology in primary and recurrent lateral patellar instability. Biomed Res Int 2014; 2014: 326586
• 41 Davies AP, Costa ML, Glasgow MM. et al. The sulcus angle and malalignment of the extensor mechanism of the knee. J Bone Joint Surg 2000; 82: 1162-1166
• 42 Brukner P, Khan K. Clinical Sports Medicine. 3rd ed.. London: McGraw-Hill Companies Inc.; 2009
• 43 Akeson WH, Amiel D, Abel MF. et al. Effects of immobilization on joints. Clin Orthop Relat Res 1987; 219: 28-37
• 44 Kannus P, Jozsa L, Renström P. et al. The effects of training, immobilization and remobilization on musculoskeletal tissue. Scand J Med Sci Sports 1992; 2: 100-118
• 45 Henriksson M, Rockborn P, Good L. Range of motion training in brace vs. plaster immobilization after anterior cruciate ligament reconstruction: a prospective randomized comparison with a 2-year follow-up. Scand J Med Sci Sports 2002; 12: 73-80
• 46 Brotzman SB, Wilk KE. Clinical orthopaedic rehabilitation. 2nd ed.. London: Mosby; 2003
• 47 Booth FW. Physiologic and biochemical effects of immobilization on muscle. Clin Orthop Relat Res 1987; 219: 15-20
• 48 Clark BC, Manini TM, Hoffman RL. et al. Restoration of voluntary muscle strength after 3 weeks of cast immobilization is suppressed in women compared with men. Arch Phys Med Rehabil 2009; 90: 178-180
• 49 Tesch PA, von Walden F, Gustafsson T. et al. Skeletal muscle proteolysis in response to short-term unloading in humans. J Appl Physiol 2008; 105: 902-906
• 50 Frank C, Akeson WH, Woo SL. et al. Physiology and therapeutic value of passive joint motion. Clin Orthop Relat Res 1984; 185: 113-125
• 51 Kannus P. Immobilisation or early mobilisation after an acute soft-tissue injury?. Phys Sportsmed 2000; 28: 1-8
• 52 Cash JD, Hughston JC. Treatment of acute patellar dislocation. Am J Sports Med 1988; 16: 244-249
• 53 Stein SBE, Ahmad CS. The management of patellar instability in the skeletally immature patient. Oper Techn Orthop 2007; 17: 250-256
• 54 Sillanpää PJ, Mäenpää HM, Mattila VM. et al. 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: 2301-2309
• 55 Lim AK, Chang HC, Hui JH. Recurrent patellar dislocation: reappraising our approach to surgery. Ann Acad Med Singapore 2008; 37: 320-323
• 56 Conlan T, Garth WP, Lemons J. Evaluation of the medial soft tissue restraints of the extensor mechanism of the knee. J Bone Joint Surg Am 1993; 75: 682-693
• 57 Sallay PI, Poggi J, Speer KP. et al. Acute dislocation of the patella. A correlative pathoanatomic study. Am J Sports Med 1996; 24: 52-60
• 58 Smith TO, Hunt NJ, Donell ST. Reliability and validity of the Q-angle: a systematic review. Knee Surg Sports Traumatol Arthrosc 2008; 16: 1068-1079
• 59 Seeley MA, Knesek M, Vanderhave KL. Osteochondral injury after acute patellar dislocation in children and adolescents. J Pediatr Orthop 2013; 33: 511-518
• 60 Koh JL, Stewart C. Patellar instability. Clin Sports Med 2014; 33: 461-476
• 61 Lind M, Enderlein D, Nielsen T. et al. Clinical outcome after reconstruction of the medial patellofemoral ligament in pediatric patients with recurrent patella instability. Knee Surg Sports Traumatol Arthrosc 2014; 24: 666-671
• 62 Haag C, Merkle K. Klinische und radiologische Ergebnisse der operativ behandelten Patellaluxation. Unfallchirurgie 1997; 23: 210-215
• 63 Jaquith BP, Parikh SN. Predictors of recurrent patellar instability in children and adolescents after first-time dislocation. J Pediatr Orthop 2015; [Epub ahead of print]
• 64 Lewallen L, McIntosh A, Dahm D. First-time patellofemoral dislocation: risk factors for recurrent instability. J Knee Surg 2015; 28: 303-309
• 65 Frosch KH, Schmeling A. A new classification system of patellar instability and patellar maltracking. Arch Orthop Trauma Surg 2016; 136: 485-497