Ganz head reduction osteotomy for the treatment of femoral head deformities: radiological and functional outcomes

Ganz's studies made it possible to address joint deformities on both femoral and acetabular side brought by the Legg-Calvè-Perthes disease (LCPD). Femoral head reduction osteotomy (FHRO) was developed to improve joint congruency along with periacetabular osteotomy (PAO). The purpose of this study is to show the clinical and morphologic outcomes of the technique, and an implemented planning approach. From 2015 to 2023, 13 FHROs were performed on 11 patients for LCPD, in two centers. 11 of 13 hips had an associated PAO. A specific CT and MRI-based protocol for virtual simulation of the corrections was developed. Outcomes were assessed with radiographic parameters (sphericity index, extrusion index, integrity of the Shenton's line, LCE angle, Tonnis angle, CCD angle) and clinical parameters (ROM, VAS, Merle d'Aubigné-Postel score, modified-HHS, EQ5D-5L). Early and late complications were reported. The mean follow-up was 40 months. The mean age at surgery was 11,4 years. No major complications were recorded. One patient required a total hip arthroplasty. Femoral Head Sphericity increased from 45% to 70% (p < 0,001); LCE angle from 18° to 42,8° (p < 0,001); extrusion Index from 36,6 to 8 (p < 0,001); Tonnis Angle from 14,4° to 6,2° (p = 0.1); CCD Angle from 131,7 to 136,5° (p < 0,023). The VAS score improved from 3,25 to 0,75,(p = 0.06); Merle d'Aubigné-Postel score from 14.75 to 16 (p = 0,1); Modified-HHS from 65,6 to 89,05 (p = 0,02). The EQ 5D 5L showed significant improvements. ROM increased especially in abduction and extra-rotation. FHRO associated with periacetabular procedures is a safe technique that showed improved functional, clinical and morphologic outcomes in LCPD. The newly introduced simulation and planning algorithm may help to further refine the technique.