M Mutschler, A Massazza, M Palazzuolo, A Antoniadis, J Wegrzyn
(Lausanne, Suisse)
Background:
Along with the advent of newer bearings, hip resurfacing (HR) is gaining renewed interest as a bone sparing alternative to conventional total hip arthroplasty (THA) in young patients. However, the outcome of conversion of failed HR to THA (HRc) remains sparsely described. This study aimed to compare the outcomes and complication rates of HRc to the those of primary (pTHA) and revision THA (rTHA).
Methods:
Between 2001 and 2011, a continuous series of 207 HR were prospectively included in our institutional total joint registry and retrospectively analyzed. Out of them, 17 HR (8%) were converted to THA. Propensity scores were used to match patients in the HRc group to the pTHA and the rTHA groups using a greedy 1:3 matching procedure (51 pTHA and 51 rTHA). Clinical and radiographic outcomes, perioperative data and complications were analyzed and compared between the three groups.
Results:
No significant difference between HRc and pTHA was observed in terms of clinical and functional outcomes, length of surgery, acetabular component diameter and length of hospital stay (p=0.13 to 0.94). Perioperative blood loss was significantly lower for pTHA than for HRc (p=0.01). HRc demonstrated significantly higher HHS and HOOS scores than for rTHA (p=0.03 and p<0.01, respectively). Length of surgery was significantly lower in HRc compared to rTHA (p=0.02) while length of hospital stay was similar (p=0.84). Complication rate was significantly higher in the rTHA group, while it was significantly lower in the HRc and pTHA groups (37.3 vs 29.4 vs 11.8%, p=0.01).
Discussion & conclusion:
This comparative propensity-matching study demonstrated that HRc yielded clinical and functional outcomes similar to those of pTHA, and higher to those of rTHA, with lower complication than for rTHA. As such and particularly with the recent advance in bearing for HR such as ceramic-on-ceramic, this study tended to favor HR as a safe and reliable alternative to conventional THA, especially in young and active patients who will potentially require revision during their lifetime. Interestingly, the intraoperative blood loss during HRc was similar to that observed during rTHA and was significantly higher than during pTHA despite an operative time similar to that of pTHA. Further studies with longer follow-up and larger cohort of patients are needed to assess long-term outcome and survivorship of HRc, thereby enabling a more accurate evaluation of its similarity to either primary or revision THA.