The Mix and Match Approach in Primary Total Hip Arthroplasty Reveals Comparable or Lower Revision Rates to Matched Components: A Systematic Review.

Introduction: The mix and match (stem and cup from different manufacturers/systems, MM) approach in primary total hip arthroplasty (THA) involves combining components from different manufacturers. Despite various configurations discussed in literature and evidence supporting the safety of MM, controversy persists regarding safety and long term outcomes compared to matched components. Our study aimed to compare the revision rates of MM versus matched components. Materials and Methods: Two databases were searched for English full-text articles published until January, 2024 that evaluated revision rates after primary MM THA. Additionally, MM revision rates data was extracted from the German Arthroplasty Registry (EPRD). The Newcastle-Ottawa Scale (NOS) for cohort studies was used for quality assessment. Results: Three national and one hospital registry studies were included, of which three demonstrate MM as a common practice (19-24%). All studies found comparable revision rates for MM cohorts, or even slightly improved survival rates in MM cohorts concerning revision rate and PROMs, mostly lacking clinical relevance. These findings align with the data reported in the EPRD, with revision rates of approximately 3.6% after 6 years in both MM and matched THA. Conclusions: Employing MM in primary THA presents a feasible and safe approach, capable of providing custom fit tailored to individual patients with revision rates comparable to those of matched THA.