title: Medial patellofemoral ligament repair for recurrent patellar dislocation.
abstract: BACKGROUND
  The medial patellofemoral ligament (MPFL) is the primary restraint to extreme lateral displacement and is typically disrupted with an acute lateral patellar dislocation. Patients who fail a comprehensive nonoperative program and experience recurrent lateral patellar instability episodes are candidates for surgical treatment. Current surgical procedures include a variety of proximal realignment techniques, including repair or reconstruction of the MPFL along with distal realignment of the tibial tubercle when indicated.
  
  
  OBJECTIVE
  The objective of this study was to review the clinical, functional, and radiographic outcomes of isolated MPFL repair for recurrent lateral patellar dislocation.
  
  
  METHODS
  Case series; Level of evidence, 4.
  
  
  METHODS
  The records of all patients undergoing MPFL repair for recurrent patellar dislocation at the Mayo Clinic from 2001 to 2006 were retrospectively reviewed. Twenty-seven patients (29 knees) with an average age of 19 years (range, 11-32 years) were included in this study. Clinical, functional, and radiographic outcomes were assessed at an average of 4 years after surgery (range, 2-7 years), using recurrent instability as the primary end point.
  
  
  RESULTS
  The success rate of MPFL repair for preventing recurrent dislocations was 72% (21 of 29 knees). Eight patients (28%) experienced a recurrent lateral patellar dislocation. Five of these patients required a reoperation, including two MPFL reconstructions, 1 tibial tubercle osteotomy with MPFL reconstruction, 1 tibial tubercle osteotomy with revision MPFL repair, and 1 revision MPFL repair. At final follow-up, the mean Lysholm and Kujala scores were 86 (range, 42-100) and 92 (range, 57-105), respectively. Postoperative radiographs revealed a mean patellofemoral congruence angle improvement of 27° (range, 5°-44°). The only statistically significant risk factor for failure was nonanatomical MPFL repair at the medial femoral condyle (P = .004).
  
  
  CONCLUSIONS
  Isolated repair of the MPFL for recurrent patellar instability is associated with a relatively high failure rate, but remains a viable surgical option if surgical technique principles are followed. The clinical success of this operation depends on restoration of the anatomical origin of the MPFL and careful patient selection.
authors: Michael J. Stuart, Mayo Clinic, 200 First St, SW, Rochester, MN 55905, USA.
authors: Christopher L
authors: CL
authors: Camp
authors: Aaron J
authors: AJ
authors: Krych
authors: Diane L
authors: DL
authors: Dahm
authors: Bruce A
authors: BA
authors: Levy
authors: Michael J
authors: MJ
authors: Stuart
mesh_terms: D000293:Adolescent; D000328:Adult; D001265:Athletic Injuries / Q000000981:diagnostic imaging / Q000601:surgery*; D002648:Child; D005260:Female; D006305:Health Status Indicators; D006801:Humans; D008297:Male; D017888:Medial Collateral Ligament, Knee / Q000293:injuries / Q000601:surgery*; D019637:Orthopedic Procedures / Q000379:methods*; D031222:Patellar Dislocation / Q000000981:diagnostic imaging / Q000601:surgery*; D057071:Patellofemoral Joint / Q000293:injuries / Q000601:surgery*; D011859:Radiography; D012008:Recurrence; D012189:Retrospective Studies; D012307:Risk Factors; D018709:Statistics, Nonparametric; D016896:Treatment Outcome; D055815:Young Adult