Derotational distal femoral osteotomy yields satisfactory clinical outcomes in pathological femoral rotation with failed medial patellofemoral ligament reconstruction

Purpose The purpose of this study was to evaluate the clinical outcomes of de-rotational distal femoral osteotomy (DDFO) in patients who underwent primary medial patellofemoral ligament reconstruction (MPFLR) failure with increased femoral anteversion along with high-grade J sign. Methods Between 2011 and 2019, 14 patients underwent DDFO revision surgery due to failed MPFLR. The pre- and postoperative J sign grade, Caton-Deschamps index (CDI), tibial tuberosity-trochlear groove (TT-TG) distance, femoral anteversion angle (FAA), patellar lateral tilt angle (PLTA), MPFL graft laxity, and patient-reported outcomes (Kujala, Lysholm, Tegner, and International Knee Documentation Committee (IKDC) subjective scores) were collected. The anterior-posterior and proximal-distal distances between the actual point and the Schottle point were also calculated. Results Fourteen patients underwent MPFLR revision by DDFO combined with MPFLR. The mean PLTA improved from 40.7 degrees +/- 11.9 degrees to 20.5 degrees +/- 8.7 degrees (P < 0.001). The mean FAA significantly decreased from 42.7 degrees +/- 12.0 degrees to 14.1 degrees +/- 5.2 degrees (P < 0.001). The mean patellar laxity index (PLI) decreased from 82.4% preoperatively to 15.1% postoperatively (P < 0.001). None of these patients experienced subluxation or re-dislocation during follow-up of 29.7 +/- 5.0 months after revision surgery. Meanwhile, the Tegner score at the last follow-up ranged from 3 to 6, with a median of 5. The Kujala, Lysholm, and IKDC subjective scores showed significant improvements, from a mean of 51.0 +/- 6.8 preoperatively to 75.4 +/- 5.1 postoperatively (P < 0.001), 49.2 +/- 7.9 to 75.2 +/- 7.2 (P < 0.001), and 42.9 +/- 6.2 to 76.8 +/- 6.0 (P < 0.001), respectively. The proportion of patients with a high-grade J sign was significantly lower postoperatively than preoperatively (100% vs. 14%). Four out of 14 patients (29%) showed femoral tunnel mal-positioning. Conclusion MPFLR revision by DDFO combined with MPFLR achieved favorable clinical outcomes in patients with increased femoral anteversion along with high-grade J sign.