Long-Term Outcome of Zürich Cementless Total Hip Arthroplasty in 439 Cases.

Abstract

To review complications in dogs with the Zürich cementless total hip arthroplasty (Z-THA) with ≥ 2 year followup, and compare complications between juvenile and adult dogs classified by age (≤ 11 and > 11 months) at the time of original surgery. Retrospective case series. Three hundred and twenty-one dogs with 439 total hip arthroplasties. Medical records were reviewed from January 2002 to December 2007. Signalment, body weight and body condition score, implant size and positioning, and any complications were recorded. A step-up logistic regression analysis was performed for an outcome of any complication (yes/no). Predictors included were implant size, implant position, weight and body condition score before surgery, weight and body condition score change after surgery, breed, sex, and age. Four hundred and thirty-nine Z-THA were performed in 321 dogs. Mean (standard deviation) age was 8.5 (1.5) months, range 4.5-11 and 53.3 (31.2) months, range 12-132, for juvenile and adult dogs, respectively. Followup extended for a mean 47.8 (20.0) and 42.0 (13.5) months for juvenile and adults dogs, respectively, with complications recorded in 20% and 13% of Z-THA, respectively. All hips were successfully revised except for 2 explants in juvenile dogs and 2 in adult dogs. There were no statistical differences in the frequency of complications between juveniles or adult dogs, but the type of complication did appear to be different. From the logistic model, the probability of a complication increased with an increase in body condition score after surgery (P < .0001) and with an increase in the pre-surgery body condition score (P = .05), and decreased with an increase in weight after surgery (P = .05). The frequency of complications was less than 20% in juvenile and adult dogs and the frequency was not different across age groups. Complications were primarily related to the change (increase) in body condition score after surgery. Revision was successful in almost all dogs.