Modified trapdoor procedures  using autogenous tricortical iliac graft  without preserving the broken cartilage to treat osteonecrosis of the femoral head: A Prospective Cohort Study With Historical Controls

Abstract

Background The aim of the present study was to investigate clinical and radiological outcomes of autologous tricortical iliac graft through a window created at the femoral head, without suturing the opened articular cartilage to treat osteonecrosis of the femoral head (ONFH), called modified trapdoor procedures.Methods A total of 59 consecutive patients (67 hips; 36 males and 23 females) with ONFH were included in this study, which was conducted during the period from April 2009 to March 2012. Patient age ranged from 27 to 46 years old, with mean age of 36.3 years. Harris hip scores (HHS) were used to evaluate hip function pre- and postoperatively. Anteroposterior and frog-position X-rays and magnetic resonance imaging (MRI) were conducted to evaluate lesion location, size, and ARCO stage. Clinical failure was defined as score < 80 points or treatment by total hip arthroplasty(THA). Radiographic failure was defined as a > 3 mm of collapse in the hip. This group was retrospectively matched according to the ARCO stage, extent, location, etiology of the lesion, average age, gender, and preoperative Harris hip score to a group of 59 patients (67 hips) who underwent the“light bulb”approach during March 2007 to April 2009. Results Mean follow-up was 91.2 ± 13.6 months (range, 75–115 months). Mean HHS was 91.3 ± 4.5, compared with 83.1± 4.5 in the “light bulb” cohort at the 6 years follow-up examination (P < 0.001). At the 6 years follow-up, for modified trapdoor procedures, five hips (8.5%) were classified as clinical failure, and 3 hips underwent total hip arthroplasty; Seven hips were classified as (10.4%) radiographic failure.The clinical and radiographic failure of the hips treated with the modified trapdoor procedure was significantly lower than that of the hips treated with the “light bulb” procedure (p < 0.05). Survival of the joint was not significantly related to the location of the femoral head lesion between two groups, but there was better clinical and radiographic results in modified trapdoor procedures with Size-C and the ARCO stage III.Conclusion The study demonstrated superior medterm clinical results in ONFH with the use of autologous tricortical iliac block graft through a femoral head window, without suturing the opened articular cartilage. The results of this femoral head-preserving procedure in patients with postcollapse osteonecrosis and large lesion are superior to those of the “light bulb” procedure treatment.