Revision of osteointegrated acetabular cup prostheses in nine dogs.

Objective: To describe the surgical technique and clinical outcome following revision of osteointegrated acetabular cups.

Study design: Retrospective case series.

Animals: Nine client-owned dogs undergoing revision surgery for total hip replacement (THR) with an osteointegrated cup.

Methods: Cases were recruited retrospectively from a single referral hospital for dogs undergoing revision surgery following THR. Cups were explanted using a combination of an osteotome and air burr and new cups were implanted. Owners were contacted to determine the medium- to long-term outcome.

Results: Surgery was performed at a median of 587 days (range 97-994 days) after initial surgery. Indication for revision was luxation (7), stem fracture (1), and stem loosening (1). All cups (8 BFX, BioMedtrix, 1 Helica) were successfully explanted and replaced with a BFX, BioMedtrix cup. Seven revisions required replacement with a larger cup than the primary cup size. Eight cases had minimal lameness 6 weeks postoperatively; one dog experienced repeat luxation, which resolved after open reduction and hobble placement. One dog presented with septic cup loosening 540 days postoperatively. Radiographically, all cups were stable at short-term follow up (median 45 days, range 35-618 days). Medium- to long-term functional outcome (median 621 days, range 251-1903 days) for the 6 dogs available was graded as good to excellent.

Conclusion: Cup revision of stable, osteointegrated cups can be successfully performed with the BFX BioMedtrix cup but often requires use of a larger sized implant compared to that used for the primary procedure.

Clinical significance: Revision of osteointegrated acetabular cups is a viable technique, with minimal complications encountered.