Abstract
Hip resurfacing procedures have gained increasing popularity for younger, higher demand patients with degenerative hip pathologies. However, with concerns regarding revision rates and possible adverse metal hypersensitivity reactions with metal-on-metal articulations, some authors have questioned the hypothesised superiority of hip resurfacing over total hip arthroplasty. The purpose of this meta-analysis was to compare the clinical and radiological outcomes and complication rates of these two procedures.
A systematic review was undertaken of all published and unpublished research up to January 2010. The primary search was of the databases Medline, CINAHL, AMED and EMBASE, searched via Ovid using MeSH terms and Boolian operators ‘hip’ AND ‘replacement’ OR ‘arthroplasty’ AND ‘resurfacing’. A secondary search of unpublished literature was conducted using the databases SIGLE, the National Technical Information Service, the National Research Register (UK), the British Library's Integrated Catalogue and Current Controlled Trials databases using the same search terms as the primary search. All included studies were critically appraised with the CASP appraisal tool.
In total, 46 studies were identified from 1124 citations. These included 3799 hip resurfacings and 3282 total hip arthroplasties. On meta-analysis, functional outcomes for subjects following hip resurfacing were better than or the same as subjects with a total hip arthroplasty, with significantly higher WOMAC score (Mean Difference (MD)=−2.41; 95% Confidence Interval (CI): −3.88, −0.94; p=0.001), and significantly better Harris Hip Score (range of motion component) (MD=−0.05; 95% CI: (−0.07, −0.03; p<0.0001) and overall Harris Hip Score (MD=2.51; 95% CI: 1.24, 3.77; p=0.0001) in the hip resurfacing compared to total hip arthroplasty cohorts. However, there were significantly greater incidences of heterotopic ossification (Risk Ratio (RR)=1.62; 95% CI: 1.23, 2.14; p=0.006), aseptic loosening (RR=3.07; 95% CI:1.11, 8.50;p=0.03) and revision surgery (RR=1.72; 95% CI: 1.20, 2.45; p=0.003) with hip resurfacing compared to total hip arthroplasty. The evidence-base presented with a number of methodological inadequacies such as the limited use of power calculations and poor or absent blinding of both patients and assessors, potentially giving rise to assessor bias. In respect to these factors, the current evidence-base, whilst substantial in its size, may be questioned in respect to its quality in determining superiority of hip resurfacing over total hip arthroplasty.
