Core decompression combined with nano hydroxyapatite/polyamide 66 rod for the treatment of osteonecrosis of the femoral head

Abstract

Objective To investigate the effectiveness of core decompression in combination with a nano-hydroxyapatite/polyamide 66 (n-HA/PA66) rod and a porous bioglass bone graft for the treatment of osteonecrosis of the femoral head (ONFH). Methods A prospectively designed algorithm was applied retrospectively to a cohort of sixty-four patients (84 hips) with ONFH, which were treated from 2009 to 2013 in the Department of Orthopaedics, the Second Affiliated Hospital of Xi'an Jiaotong University. These hips were allocated to a program of either core decompression core decomp-copy in combination with a n-HA/PA66 rod and a porous bio-glass bone graft (treatment group, 29 patients with 38 hips) or core decompression with an autologous cancellous bone graft (control group, 35 patients with 46 hips). Clinical and radiographic retrospective follow-ups were performed on all patients with the prospectively collected data. The HHS, VAS and survival-rate of implants were compared respectively. Results No significant difference was observed between two groups on HHS and VAS scores(all P values>0.05). HHS and VAS scores of treatment group were significantly improved than those of control group(all P values 0.05). Significant difference in the VAS improvement was observed between the groups for ⅡB, ⅡC and ⅢA (t=2.933, 2.119, 3.513, all P values 0.05). Further analysis of Kaplan-Meier curves found that implants survival of treatment group was higher than that of control group, which was proved significantly different by Log-rank test(χ2=6.753, P<0.05). Imaging failure rate of treatment group was 21.05%(8/38), which was lower than that of control group (45.65%, 21/46), while clinical failure of treatment group was also lower than that of control group [23.68%(9/38) vs 52.17%(24/46)], and both difference had statistical significance (χ2=5.571, 7.081, all P values< 0.05). Conclusions Core decompression combined with the implantation of a n-HA/PA66 rod and a bioglass bone graft can significantly decrease hip pain, improve hip function, and prevent the collapse of the femoral head in patients with ONFH. As the effectiveness of this approach appears to vary with Steinberg stage, we suggest that this treatment procedure may be suitable for patients with early to middle stage ONFH. Key words: Femur head necrosis; Prostheses and implants; Hydroxyapatites; Core decompression; Biocompatible materials; Bone transplantation