Revision Outcomes of Mixed Versus Matched Components in Primary Total Hip Arthroplasty: A Population-Based Study

Most manufacturers specify that surgeons should use all the components of their total hip arthroplasty (THA) system to avoid working "off-label." Despite this, studies show that mixing certain components in THA can produce comparable or even superior results to matched THA. Our primary aim was to compare all-cause revision rates for mixed and matched THA in Ontario, Canada.

We identified adults undergoing primary elective THA between 2012 and 2020 in Ontario, Canada, using administrative databases. We used propensity score matching to adjust for relevant confounding variables between groups. We used Chi-square and Fisher exact tests to compare dichotomous outcomes and Wilcoxon rank-sum tests to compare continuous outcomes between matched groups. We identified 906 patients who received mixed THA implants and 65,131 who received matched THA implants. Patients who received mixed implants were more likely to be women, have received THA at a teaching hospital, and be discharged home compared to those who received matched THA implants.

We found no significant difference in revision rate (mixed: 1.6%; matched: 1.7%, P = 0.797) or indications for revision. However, patients in the matched group had a significantly longer mean length of hospital stay (3.23 ± 2.29 days) than the mixed group (2.84 ± 2.25 days, P < 0.001).

Administrative data from Ontario, Canada, shows that mixing THA components appears to have no effect on all-cause revision when compared to matched THA.