Zurich Cementless Total Hip Arthroplasty as a Treatment Option for Capital Physeal Fractures in Dogs: Complications in 47 Cases

Introduction: Capital physeal fractures (CPF) occur in skeletally immature animals. The viability of Zürich cementless total hip arthroplasty (Z-THA) for CPF repair is not reported. Our goal was to report the viability of Z-THA as the repair method of CPF. We hypothesized Z-THA complication rates as either the primary and definitive repair method of CPF (primary Z-THA), or as the definitive surgery after a failed initial repair (secondary Z-THA), would not differ.

Materials and Methods: Medical records of dogs undergoing Z-THA for CPF were reviewed. Identification of potential confounding variables associated with surgical treatment groups and incidence of complications was performed. Potential confounders were then tested in a binary regression model.

Results: Forty-seven CPF treated with Z-THA were included: 37 (78.7%) juveniles and 10 (21.3%) adults, 38 (80.9%) primary Z-THA, and 9 (19.1%) secondary Z-THA. According to age group, complications occurred in 8/37 (24.3%) juvenile and 3/10 (20%) adult dogs, and by treatment group complications occurred in 9/ 38 (23.7%) primary Z-THA and 2/ 9 (22.2%) secondary Z-THA. Complication rates did not differ between treatment or age groups (p > 0.5). Time from CPF to Z-THA was the only confounding variable identified (p = 0.01) and had no effect on the incidence of complications (p = 0.385).

Discussion/Conclusion: Complication rates were similar between treatment and age groups. We therefore did not have sufficient evidence to reject our null hypothesis, suggesting that Z-THA is a viable surgical option for CPF in juvenile and adult dogs, irrespective of having undergone a failed repair prior to Z-THA or not.

Acknowledgment: No proprietary interest or funding was provided.