title: Results of medial patellofemoral ligament reconstruction compared with trochleoplasty plus individual extensor apparatus balancing in patellar instability caused by severe trochlear dysplasia: a systematic review and meta-analysis.
abstract: OBJECTIVE
  Many studies have reported satisfactory clinical outcomes and low redislocation rates after reconstruction of the medial patellofemoral ligament (MPFL) for the treatment of lateral patellar instability. Despite uncorrected severe trochlear dysplasia (Dejour type B to D) being acknowledged as a major reason for less favourable clinical outcomes and a higher incidence of patellar redislocations after an isolated MPFL reconstruction, the evidence for a deepening trochleoplasty procedure remains scarce in the current literature. The hypothesis of this systematic review and meta-analysis was that a deepening trochleoplasty in combination with an a la carte extensor apparatus balancing procedure provides lower redislocation rates and superior clinical outcomes than isolated MPFL reconstruction in patients with lateral patellar instability caused by severe trochlear dysplasia.
  
  
  METHODS
  A systematic review of the literature was conducted using specific inclusion and exclusion criteria for clinical studies reporting index operations (trochleoplasty and MPFL reconstruction) for the treatment of patellar instability caused by severe trochlear dysplasia. The Kujala score was analysed as the primary clinical outcome parameter in a random effects meta-analysis.
  
  
  RESULTS
  Ten uncontrolled studies with a total of 407 knees (374 patients) were included in this analysis. The MPFL group comprised 4 studies with a total of 221 knees (210 patients), and the trochleoplasty group comprised 6 studies with a total of 186 knees (164 patients). The mean preoperative Kujala score ranged between 50.4 and 70.5 in the MPFL group and between 44.8 and 75.1 in the trochleoplasty group. The pooled Kujala score increased significantly by 26.4 (95% CI 21.4, 31.3; P < 0.00001) points in the MPFL group and by 26.2 (95% CI 19.8, 32.7; P < 0.00001) points in the trochleoplasty group. The post-operative patellar redislocation/subluxation rate was 7% in the MPFL group and 2.1% in the trochleoplasty group.
  
  
  CONCLUSIONS
  This analysis found significant post-operative improvements in patient-reported outcomes for patients undergoing both an MPFL reconstruction and in those undergoing a trochleoplasty plus an individual extensor apparatus balancing procedure when assessed using the Kujala score. The likelihood of preventing the patella from subsequent post-operative redislocation/subluxation was, however, greater in patients who underwent trochleoplasty plus extensor balancing.
  
  
  METHODS
  IV.
authors: Arcus Sportklinik, Rastatter Str. 17-19, 75179, Pforzheim, Germany. balcarek@sportklinik.de.|Department of Trauma Surgery and Orthopaedics, University Medical Center Göttingen, Göttingen, Germany. balcarek@sportklinik.de.
authors: Peter
authors: P
authors: Balcarek
authors: Department of Trauma Surgery and Orthopaedics, University Medical Center Göttingen, Göttingen, Germany.
authors: Stephan
authors: S
authors: Rehn
authors: Avon Orthopaedic Centre, Bristol, England, UK.
authors: Nick R
authors: NR
authors: Howells
authors: Avon Orthopaedic Centre, Bristol, England, UK.
authors: Jonathan D
authors: JD
authors: Eldridge
authors: Department of Sports Orthopaedics, Osaka Rosai Hospital, Osaka, Japan.
authors: Keisuke
authors: K
authors: Kita
authors: Knee and Sportmedicine Department, Lyon-Ortho-Clinic, Lyon, France.
authors: David
authors: D
authors: Dejour
authors: MVZ Oberstdorf, Clinics Kempten-Oberallgäu, Oberstdorf, Germany.
authors: Manfred
authors: M
authors: Nelitz
authors: Department of Orthopedic Sports Surgery, Klinikum Rechts Der Isar, TU München, Munich, Germany.
authors: Ingo J
authors: IJ
authors: Banke
authors: Department of Orthopaedic Surgery and Traumatology, Ghent University Hospital, Ghent, Belgium.
authors: Delphine
authors: D
authors: Lambrecht
authors: Department of Medical Statistics, University Medical Center Göttingen, Göttingen, Germany.
authors: Markus
authors: M
authors: Harden
authors: Department of Medical Statistics, University Medical Center Göttingen, Göttingen, Germany.
authors: Tim
authors: T
authors: Friede
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D005269:Femur / Q000601:surgery*; D006801:Humans; D004204:Joint Dislocations / Q000150:complications; D007593:Joint Instability / Q000601:surgery*; D007719:Knee Joint / Q000601:surgery*; D008023:Ligaments, Articular / Q000601:surgery*; D008297:Male; D010329:Patella / Q000601:surgery*; D031222:Patellar Dislocation / Q000601:surgery; D057071:Patellofemoral Joint / Q000601:surgery; D019651:Plastic Surgery Procedures / Q000379:methods*; D055815:Young Adult
keywords: MPFL; MPFL reconstruction; Medial patellofemoral ligament; Patellar instability; Trochlear dysplasia; Trochleoplasty