We hypothesise that after isolated cup revision most unrevised stems do not need subsequent revision, and that most do not exhibit evidence of radiographic loosening.
A retrospective analysis of all patients who underwent revision of the acetabular component only during revision hip arthroplasty between March 1970 and July 2013 was carried out. We assessed survival of the unrevised stem, reasons for subsequent revision, plus radiographic analysis for stem loosening.
Two hundred and twenty-seven hips were included (215 patients with an average age at the time of primary surgery was 47 [13–70] years). The Charnley stem was used in 161 cases; C-Stem 65, Howse 1. Average time between primary surgery and cup revision was 15.9 (1.6–33.4) years. Average follow-up for all stems post isolated cup revision was 6.1 (0.1–30.7) years. Twenty-eight stems (12.3%) were subsequently revised 5.1 (0.1–12.6) years after the isolated cup revision. Reasons for subsequent revision were: aseptic loosening (10); infection (8); dislocation (6); unreconstructible joint post-loose cup removal (2); fracture (2). Radiographic review was possible on 140 cases. Five femoral stems were revised and 2 others showed evidence of possible radiological loosening but were not revised.
To our knowledge, this is the largest series showing that isolated cup revision in the place of a well-fixed cemented stem is safe and is associated with ongoing good long-term survival of the stem.
Level IV, retrospective case series.