Modified trapdoor procedures using autogenous tricortical iliac graft without preserving the broken cartilage for treatment of osteonecrosis of the femoral head: a prospective cohort study with historical controls

The aim of the present study was to investigate clinical and radiological outcomes of autologous tricortical iliac grafting performed through a window created at the femoral head without suturing the opened articular cartilage for the treatment of osteonecrosis of the femoral head (ONFH), called modified trapdoor procedures. A total of 59 consecutive patients (67 hips; 36 males and 23 females) with ONFH were included in this study, which was conducted from April 2009 to March 2012. Patients’ age ranged from 27 to 46 years old, with a 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 assess 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 between March 2007 and April 2009. 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-year follow-up examination (P < 0.001). At the 6-year follow-up, for modified trapdoor procedures, five hips (8.5%) were classified as clinical failure, and three 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 compared to 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; however, better clinical and radiographic results were observed in modified trapdoor procedures with size C and the ARCO stage III. The present study demonstrated superior midterm 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 femoral head-preserving procedure was superior compared to the “light bulb” procedure treatment in patients with postcollapse osteonecrosis and large lesion.