Early subsidence of shape-closed hip arthroplasty stems is associated with late revision

Abstract

Background and purpose — Few studies have addressed the association between early migration of femoral stems and late aseptic revision in total hip arthroplasty. We performed a meta-regression analysis on 2 parallel systematic reviews and meta-analyses to determine the association between early migration and late aseptic revision of femoral stems.

Patients and methods — Of the 2 reviews, one covered early migration data obtained from radiostereometric analysis (RSA) studies and the other covered long-term aseptic revision rates obtained from survival studies with endpoint revision for aseptic loosening. Stems were stratified according to the design concept: cemented shape-closed, cemented force-closed, and uncemented. A weighted regression model was used to assess the association between early migration and late aseptic revision, and to correct for confounders. Thresholds for acceptable and unacceptable migration were determined in accordance with the national joint registries (≤ 5% revision at 10 years) and the NICE criteria (≤ 10% revision at 10 years).

Results — 24 studies (731 stems) were included in the RSA review and 56 studies (20,599 stems) were included in the survival analysis review. Combining both reviews for the 3 design concepts showed that for every 0.1-mm increase in 2-year subsidence, as measured with RSA, there was a 4% increase in revision rate for the shape-closed stem designs. This association remained after correction for age, sex, diagnosis, hospital type, continent, and study quality. The threshold for acceptable migration of shape-closed designs was defined at 0.15 mm; stems subsiding less than 0.15 mm in 2 years had revision rates of less than 5% at 10 years, while stems exceeding 0.15 mm subsidence had revision rates of more than 5%.

Interpretation — There was a clinically relevant association between early subsidence of shape-closed femoral stems and late revision for aseptic loosening. This association can be used to assess the safety of shape-closed stem designs. The published research is not sufficient to allow us to make any conclusions regarding such an association for the force-closed and uncemented stems.

RGN, BGP, and ERV conceived the study. SM provided methodological input and MF provided statistical input during the conceptual phase of the study. JWP designed the search strategy for the literature search. PV, BGP, MJN, and JJ performed the study selection and matching procedure. PV and JJ appraised the quality of the literature and performed the data extraction. MF and BGP analyzed the data. PV, BGP, ERV, and RGN wrote the initial draft of the manuscript. MF and SM ensured the accuracy of the data and analysis. BGP and MF wrote the Appendix. Critical revision of the manuscript was done by all the authors.

We thank the Atlantic Innovation Fund (Atlantic Canada Opportunities Agency; contract number 191933), the Dutch Arthritis Association (project number LLP13; 08-1-300), and the European Information and Communication Technologies Community Seventh Framework Programme (FP7/2007-2013; grant agreement number 248693) for providing funding for this study. The Atlantic Innovation Fund, the Dutch Arthritis Association, and the European Information and Communication Technologies Community Seventh Framework Programme did not take part in the design or performance of the study; in the collection, management, analysis, or interpretation of the data; or in preparation, review, or approval of the manuscript.

Statistical code and dataset are available from the corresponding author upon request. R code for the analysis described in the Appendix is available from one of the authors (e-mail [email protected]).