Introduction: Medial Patellofemoral Ligament (MPFL) reconstruction is an accepted treatment for recurrent patellofemoral instability when patients have normal alignment and deficient proximal medial restraints. There are several reports of malpositioned femoral tunnels leading to poor outcomes. The purpose of this study was to analyze femoral tunnel placement after MPFL reconstruction and correlate this with outcomes.
Methods: We performed a retrospective review of MPFL reconstructions done at our institution from 2006-2010. We then evaluated lateral radiographs and measured the distance between the radiographic femoral MPFL isometric point and the center of the femoral tunnel. We also evaluated post-operative KOOS scores.
Results: The average distance from the femoral tunnel to the MPFL isometric point was 13.25 mm. Sixty-four percent of tunnels were placed greater than nine millimeters from our isometric point and deemed to be malpositioned. There was no statistically significant difference in outcomes scores in patients with anatomically placed MPFL tunnels when compared to those placed non-anatomically.
Conclusion: Sixty-four percent of MPFL reconstruction femoral tunnels were placed non-anatomically, but this did not correlate with a worse outcome. Graft tension, trochlear groove anatomy, patellar height, and dynamic restraints all play important roles in outcomes after MPFL reconstruction. Even though non-anatomic tunnel placement does not guarantee a poor result, we believe an anatomic tunnel placement will give the best chance to maximize graft function and outcome.