title: Medial patellofemoral ligament reconstruction for patellar maltracking following total knee arthroplasty is effective.
abstract: OBJECTIVE
  Maltracking of the patella after total knee arthroplasty (TKA) remains a well-recognized problem. The medial patellofemoral ligament (MPFL) has shown to be important for patellar stabilization and reconstructions of the MPFL have already shown excellent functional outcomes for patellar instability of the native knee. Nevertheless, there is only limited literature on using an MPFL reconstruction for correction of patellar maltracking after TKA. In this retrospective study, a consecutive case series was evaluated.
  
  
  METHODS
  Between 2007 and 2010, nine patients (nine knees) with anterior knee pain and symptomatic (sub)luxations of the patella after primary or revision TKA were treated by reconstruction of the MPFL in combination with a lateral release. In two cases, an additional tibial tuberosity transfer was performed, due to insufficient per-operative correction. Pre-operative work-up included a CT scan to rule out component malrotation and disorders in limb alignment. Pre- and post-operative patellar displacement and lateral patellar tilt were measured on axial radiographs. Clinical outcome was evaluated using the visual analogue scale (VAS) satisfaction, VAS pain, dislocation rate and Bartlett patella score.
  
  
  RESULTS
  Median patellar displacement improved from 29 mm (0-44) to 0 mm (0-9) post-operatively. Median lateral patellar tilt was 45° (23-62) pre-operative and changed to a median 15° (-3 to 21) post-operative. Median VAS satisfaction was 8 (5-9) and only one patient reported a subluxing feeling afterwards. The Bartlett patella score displayed a diverse picture.
  
  
  CONCLUSIONS
  Patellar maltracking after primary or revision TKA without malrotation can effectively be treated by MPFL reconstruction in combination with a lateral release. Only in limited cases, an additional tibial tuberosity transfer is needed.
  
  
  METHODS
  IV.
authors.affiliation: Orthopaedic Surgery, St. Maartenskliniek, Postbus 9011, 6500 GM, Nijmegen, The Netherlands, s.vangennip@maartenskliniek.nl.
authors.forename: Stijn
authors.initials: S
authors.lastname: van Gennip
authors.forename: Janneke J P
authors.initials: JJ
authors.lastname: Schimmel
authors.forename: Gijs G
authors.initials: GG
authors.lastname: van Hellemondt
authors.forename: Koen C
authors.initials: KC
authors.lastname: Defoort
authors.forename: Ate B
authors.initials: AB
authors.lastname: Wymenga
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000601:surgery; D007719:Knee Joint / Q000601:surgery; D008023:Ligaments, Articular / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D010329:Patella / Q000503:physiopathology* / Q000601:surgery; D057071:Patellofemoral Joint / Q000601:surgery*; D011183:Postoperative Complications / Q000601:surgery*; D019651:Plastic Surgery Procedures; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed