Management of non-traumatic avascular necrosis of the femoral head—a comparative analysis of the outcome of multiple small diameter drilling and core decompression with fibular grafting

Background: The purpose of this study was to compare the clinical and radiological outcomes of multiple small diameter drilling and core decompression with fibular strut grafting in the management of non-traumatic avascular necrosis (AVN) of the femoral head. Materials and methods: Outcomes of patients with AVN treated by multiple small diameter drilling (group 1) were compared retrospectively with patients treated by core decompression and fibular grafting (group 2). Harris hip score (HHS) was used to assess the clinical status pre- and postoperatively. Modified Ficat and Arlet classification was used to assess the radiological stage pre- and postoperatively. Results: Forty-six patients (68 hips) were included in this study. Group 1 consisted of 33 hips, and group 2 consisted of 35 hips. In stages I and IIB, there was no statistically significant difference in the final HHS between the two groups. However, in stages IIA and III, hips in group 2 had a better final HHS (P < 0.05). In terms of radiographic progression, there was no statistical difference between hips in stages I, IIA and stage IIB. However, in stage III, hips belonging to group 2 had better results (P < 0.05). Kaplan–Meier survivorship analysis showed better outcome in group 2 in stage III (P < 0.05). Conclusions: Hips with AVN in the precollapse stage can be salvaged by core decompression with or without fibular grafting. Multiple small diameter drilling is relatively simple and carries less morbidity and hence preferred in stages I and II. However, in stage III disease, core decompression with fibular strut grafting gives better results.