Professor Emeritus University of Georgia Athens, Georgia
Coxofemoral joint replacement (total hip replacement) in dogs has a long history of clinical success. Despite the robust clinical success of this procedure, complications do occur and remain a concern to surgeons and clients. Many risk factors in more challenging cases involve anatomical distortions of the pelvis or proximal femur. These distortions can be the result of trauma, end-stage osteoarthritis, or developmental issues (Luxoid Hips). Less common risk factors involve systemic problems (metabolic diseases) or age-related issues (inherent bone quantity and quality). Careful evaluation of the dog as well as the imaging modalities available can provide vital information to assist in lowering these risks. The following are some of the possible factors that need to be mitigated. The medialized greater trochanter - In these cases, routine preparation of the femoral canal can lead to implant malposition. Luxoid hips - The dorsal displacement of the femur is challenging. Consider downsizing the stem or using a cemented stem (with a shorter neck length). Saucerized cup with dorsal migration of the point of coxofemoral articulation - Minimal dorsal rim of the acetabulum. The use of a cementless cup is desirable as it can be medialized into the pelvic canal to some degree to improve dorsal coverage. Chronic dorsal luxation (with pseudoacetabulum) - Difficulty defining the original acetabular position. The use of a CT may be beneficial. Also, difficulty in exposing the correct acetabular bed is very common. Chronic femoral neck pathology (primarily medullary sclerosis) - Significant sclerosis in the medullary region of the proximal femur, there is less ability to differentiation between cancellous and cortical bone and femoral canal preparation must be done carefully. Conclusion- Clinicians/surgeons must account for many variables as part of their decision-making process and estimation of risks for complications in these challenging cases.