Patellar tilt correction magnitude, rather than residual tilt, predicts functional outcome after isolated medial femoropatellar ligament reconstruction
Ella George, Pierre‐Henri Vermorel, Frédéric Farizon, Rémi Philippot, Thomas NeriAbstract
Purpose
Patellar tilt is considered a key factor in patellofemoral instability, with a commonly accepted pathological threshold of 20° on computed tomography (CT) scan assessment. However, the clinical relevance of correcting tilt below this threshold remains unclear. This study aimed to determine whether functional improvement after isolated medial patellofemoral ligament (MPFL) reconstruction is better associated with achieving a postoperative tilt <20° or with the magnitude of tilt correction.
Methods
A retrospective study was conducted on 182 patients who underwent isolated MPFL reconstruction. Functional outcomes, including International Knee Documentation Committee (IKDC) and Kujala scores, were collected preoperatively and at final follow‐up. Patellar tilt was measured on CT scan preoperatively and at 6 months postoperatively, with both contracted and relaxed quadriceps. Patients were analysed according to postoperative tilt thresholds and correction differentials (diffQC and diffQR). Statistical analysis included group comparisons, correlation analyses, analysis of variance across correction categories and generalized linear models.
Results
Patellar tilt on CT scan was significantly reduced postoperatively in both contracted and relaxed quadriceps across all groups ( p < 0.001), with significant improvements in IKDC and Kujala scores at last follow‐up ( p < 0.001). No significant differences in IKDC or Kujala scores were observed between patients with postoperative tilt <20° and >20° (all p > 0.05). No correlation was found between functional outcomes and isolated preoperative or postoperative tilt values. In contrast, greater correction magnitude was significantly associated with improved functional outcomes. A progressive increase in IKDC and Kujala scores was observed with increasing correction, with maximal gains for corrections ≥20°. This relationship was consistent for both contracted and relaxed quadriceps (all p < 0.001).
Conclusion
Functional improvement after isolated MPFL reconstruction was more strongly associated with the magnitude of patellar tilt correction than with achieving a specific postoperative tilt threshold. Corrections exceeding 15° in patellar tilt yielded the greatest clinical benefit. These results support an individualized correction‐based strategy based on preoperative patellar tilt.
Level of Evidence
Level III, retrospective comparative study.