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

Abstract

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 Schöttle point were also calculated.

Results: Fourteen patients underwent MPFLR revision by DDFO combined with MPFLR. The mean PLTA improved from 40.7° ± 11.9° to 20.5° ± 8.7° (P < 0.001). The mean FAA significantly decreased from 42.7° ± 12.0° to 14.1° ± 5.2° (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.

Level of evidence: IV.

Keywords: De-rotational distal femoral osteotomy; Medial patellofemoral ligament reconstruction; Recurrent patellar dislocation; Revision.