Modified vascularised posterior inter-trochanteric bone grafting technique for the treatment of femoral head necrosis: a technical note with 2-year follow-up based on cadaveric models

Osteonecrosis of the femoral head (ONFH) is a challenging orthopedic condition that often leads to progressive joint destruction and disability. This study aims to simplfy the surgical tehniques and idealize the position of bone grafting for the repair of ONFH, and its preliminary clinical results were reported.​ METHODS: Anatomical studies were first conducted on four fresh frozen cadaveric specimens (8 hips). Arterial perfusion was performed to precisely investigate the medial femoral circumferential vessels supplying to the posterior greater intertrochanter. Based on the anatomical findings, vascularised posterior inter-trochanteric bone graft and the corresponding surgical instruments were meticulously designed to ensure accurate creation of the decompression tunnel and precise fitting of the bone graft​From August 2018 to August 2021, a total of 20 patients (24 hips) underwent the medial femoral circumferential vascularized posterior intertrochanteric bone grafting procedure at our institution. Clinical data, imaging findings, ARCO staging, and Harris hip scores were systematically collected. Intraoperative parameters, including operative time and blood loss, were also recorded. Postoperatively, patients were followed up for at least two years. Hip preservation failure was defined as a decrease in the Harris score, radiographic progression of ONFH, or the necessity for THA.​ RESULTS: The cadaveric study revealed that the deep branch of the medial femoral circumflex artery (MFCA) consistently gave rise to 2-3 branches supplying the posterior intertrochanteric bone. The first branch originated from the superior margin of the quadratus femoris attachment, and the remaining two branches were located beneath the quadratus femoris. The branches supplying the posterior intertrochanteric bone are carefully dissected and preserved, a 4-5cm long, 1.5-16 cm thick and deep bone graft is cut, which is used to improve the vascularization and mechanical stability within the osteonecrosis.​There are 20 patients (24 hips) prospectively enrolled, including 15 male patients (19 hips). The average postoperative followup duration was 24.2 ± 5.6 months. Four patients had to undergo THA due to disease progression, while the remaining 20 hips continued to be monitored. The final mean postoperative Harris hip score (HHS) was 75.1 ± 13.7. Among the 24 hips, 20 did not require THA, resulting in a hip preservation rate of 83%. Based on comprehensive evaluations of clinical function, symptoms, and radiographic findings, 71% of the hips were considered to have achieved successful hip preservation.​ CONCLUSIONS: The modified vascularized posterior intertrochanteric bone grafting is a simple yet effective hip - preserving surgical technique. It enables precise placement of the vascularized bone graft directly under the subchondral bone, and the good blood supply of the graft significantly promotes bone repair. This technique provides a simple，reliable and ideal graft position to repair the ONFH, the clinical outcomes seem to be related to the degree of femoral head collapse, with less favorable results associated with more severe collapse, its long term efficacy needs studied further.