Mix and Match Use of Revision Universal Head-Neck Adapters in Hip Arthroplasty: A Complications and Survival Analysis of 306 Cases.

Background: Outcomes and safety of "mix and match" in total hip arthroplasty (THA) using universal head-neck adapters (UHNA) are a matter of ongoing discussion and concern due to legal affairs. This study aimed at analyzing the "mix and match" use of UHNA and evaluating complication and reoperation rates, possible risk factors, and the implant's survival.

Methods: A total of 306 patients treated with THA (94.1% revisions) using a UHNA at our institution between 2006 and 2022 were identified and included. Diagnoses, comorbidities, implants, and UHNA specifications were retrospectively recorded. Outcomes, complications, and survival analyses were evaluated, taking into account various possible risk factors.

Results: There were 19.9% of the 306 included cases (58.5% women; median age 74 years; median follow-up 57 months) that had at least 1 complication. There were 43 patients (14.1%) who had to receive ≥1 rerevision surgery. The most common complication was postoperative recurrent dislocation (n = 27, 8.8%). There was one case of a prosthetic stem-neck fracture that was registered. Statistically significant risk factors for postoperative recurrent dislocations and postoperative aseptic loosening were, respectively, dislocation as an indication for UHNA implantation (P < .001) and oversized neck lengths (≥2XL; P = .004). The overall revision-free survival was 92% after 1 year and 82% at ten years. Statistically significant better survival rates were registered in patients ≥60 years old, who had fewer comorbidities (<2), and normal neck lengths (S to XL).

Conclusions: The results of this study underline the overall safety of UHNA use in THA through "mix and match." Only one case of a stem-neck fracture was identified. The highlighted risk factors for failure must be kept in mind during the decision-making process with patients.