HETEROTOPIC OSSIFICATION: A PROSPECTIVE COMPARISON BETWEEN HIP RESURFACING AND TOTAL HIP REPLACEMENT

Abstract

Resurfacing arthroplasty of the hip is currently enjoying a resurgence in popularity. There are many reasons why resurfacing may be indicated, but one is that the absence of proximal femoral reaming at surgery may reduce the occurrence of heterotopic ossification (HO) after surgery. The objective of this study was to compare the prevalence of postoperative HO for patients undergoing two different types of hip surgery, resurfacing arthroplasty or total hip replacement. Data were gathered from 43 consecutive patients undergoing metal on metal hip resurfacing (MoM-R) and 37 consecutive patients undergoing metal on metal total hip replacement (MoM-THR) with a minimum of six months’ follow up. The Brooker classification was used to grade HO from postoperative radiographs1. We found that, when undergoing MoM-R, women had a lower chance of developing HO than men (p=0.04). In addition, women who received a MoM-R had a reduced incidence of developing HO than women who received a MoM-THR (p=0.04). There were no differences in the incidence of postoperative HO between men undergoing either MoM-R or MoM-THR. It can be concluded from this study that resurfacing does reduce the incidence of HO in women and that care must be taken when selecting women to undergo total hip replacement in preference to hip resurfacing. This study has highlighted the need to inform patients of HO as a common complication when consenting for hip arthroplasty, and has established an 18% rate of postoperative HO for hip resurfacing arthroplasty.