# Isolated acetabular cup revision in Metal-on-Metal total hip arthroplasty: a low-complication strategy feasible in only half of cases

## TL;DR

The study finds that revising only the acetabular cup in metal-on-metal hip replacements has similar long-term outcomes to full revision in half of cases.

## Contribution

Demonstrates that isolated acetabular revision is a viable option with comparable outcomes to total revision in MoM THA.

## Key findings

- Isolated acetabular revision and total revision had similar 10-year survival rates (93.5% vs 79.5%).
- No significant differences in hip scores or metal ion levels between the two revision types.
- Isolated acetabular revision is feasible and advisable when indicated.

## Abstract

There is still a debate regarding the removal of the femoral stem due to the risk of trunnion. To answer this question, we conducted a study to compare long terms outcomes of isolated acetabular to total revision of MoM THA using an institutional arthroplasty registry.

From 1996 to 2019, 150 patients (12.5%) of the 1202 revision THAs (rTHA) recorded in Geneva Arthroplasty Registry (GAR) underwent a revision of a MoM THA. After matching the two groups,126 patients were finally included: 63 in each group. The mean age was 64.4 (SD 11.6) years, 48.4% (61/126) were women with a mean BMI of 27.2 (SD 5.5) Kg/m2.

The overall survival rate was 88.1% [79.9–97.2%] at ten years. 10-year survival rate was 93.5% [86.2–100.0%] after isolated acetabular rTHA and 79.5% [61.7–100.0%] after total rTHA (p = 0.16). Regarding Hip Harris score and Merle d’Aubigne score, no difference at last follow-up was observed between the two groups (respectively: p = 0.39; p = 0.33). Regarding the chrome, cobalt, and nickel level reduction, no difference was observed between the two groups (respectively, p = 0.38, 0.81 and 0.97).

No difference was observed between isolated acetabular and total revision of MoM THAs regarding survival rate and ions levels at long term. It seems advisable to perform an isolated acetabular revision of a MoM THA when it is indicated.

Level III, case control studies.

The online version contains supplementary material available at 10.1007/s00264-025-06534-z.