title: Medial Patellofemoral Ligament Reconstruction Femoral Tunnel Accuracy: Relationship to Disease-Specific Quality of Life.
abstract: BACKGROUND
  Medial patellofemoral ligament (MPFL) reconstruction is a procedure aimed to reestablish the checkrein to lateral patellar translation in patients with symptomatic patellofemoral instability. Correct femoral tunnel position is thought to be crucial to successful MPFL reconstruction, but the accuracy of this statement in terms of patient outcomes has not been tested.
  
  
  OBJECTIVE
  To assess the accuracy of femoral tunnel placement in an MPFL reconstruction cohort and to determine the correlation between tunnel accuracy and a validated disease-specific, patient-reported quality-of-life outcome measure.
  
  
  METHODS
  Case series; Level of evidence, 4.
  
  
  METHODS
  Between June 2008 and February 2014, a total of 206 subjects underwent an MPFL reconstruction. Lateral radiographs were measured to determine the accuracy of the femoral tunnel by measuring the distance from the center of the femoral tunnel to the Schöttle point. Banff Patella Instability Instrument (BPII) scores were collected a mean 24 months postoperatively.
  
  
  RESULTS
  A total of 155 (79.5%) subjects had adequate postoperative lateral radiographs and complete BPII scores. The mean duration of follow-up (±SD) was 24.4 ± 8.2 months (range, 12-74 months). Measurement from the center of the femoral tunnel to the Schöttle point resulted in 143 (92.3%) tunnels being categorized as "good" or "ideal." There were 8 failures in the cohort, none of which occurred in malpositioned tunnels. The mean distance from the center of the MPFL tunnel to the center of the Schöttle point was 5.9 ± 4.2 mm (range, 0.5-25.9 mm). The mean postoperative BPII score was 65.2 ± 22.5 (range, 9.2-100). Pearsonrcorrelation demonstrated no statistically significant relationship between accuracy of femoral tunnel position and BPII score (r= -0.08; 95% CI, -0.24 to 0.08).
  
  
  CONCLUSIONS
  There was no evidence of a correlation between the accuracy of MPFL reconstruction femoral tunnel in relation to the Schöttle point and disease-specific quality-of-life scores. Graft failure was not related to femoral tunnel placement. The patellofemoral instability population is complex, and patients present with multiple risk factors that, in addition to the accuracy of femoral tunnel position, contribute to quality of life and warrant further investigation.
authors.affiliation: Banff Sport Medicine, Banff, Alberta, Canada.; Department of Surgery, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Laurie A
authors.initials: LA
authors.lastname: Hiemstra
authors.affiliation: Banff Sport Medicine, Banff, Alberta, Canada.; Department of Physical Therapy, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Sarah
authors.initials: S
authors.lastname: Kerslake
authors.affiliation: Department of Health & Physical Education, Mount Royal University, Calgary, Alberta, Canada.
authors.forename: Mark
authors.initials: M
authors.lastname: Lafave
keywords: MPFL reconstruction; patellar dislocation; patellar instability; patellofemoral instability; patellofemoral stabilization; quality of life