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Dr. Daniel Low is a small animal surgery resident in Leeds, England. His latest study was published online (ahead of print) in December in Veterinary Surgery. He conducted a meta-analysis of 24 studies in which researchers evaluate if canine gonadectomy is associated with the risk for cranial cruciate ligament disease.
What is the most important takeaway from this study?
Dr. Low: Gonadectomy is associated with a twofold increase in risk for cranial cruciate ligament (CCL) disease in both female and male dogs, but the available data is imperfect.
After analyzing the 24 included studies (with data from more than 1.8 million dogs!), did anything surprise you?
Dr. Low: From the subgroup analysis, gonadectomy after 1 year of age in both male and female dogs actually resulted in a reduction of risk for CCL disease, although this was not statistically significant. This shows that the timing of gonadectomy matters when considering risk-reduction strategies.
What is the biggest limitation of this study?
Dr. Low: There are 2 major limitations to keep in mind. First, all the included studies were observational; and no controlled trials were available, so direct causation cannot be proven. Second, the risk for CCL disease is breed-dependent; these population-level results may not apply to certain breeds at very high or very low risk for the disease.
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Do you have any advice for primary care veterinarians on how to guide clients to make evidence-based decisions on gonadectomy for their dogs?
Dr. Low: The body of evidence suggests that waiting until musculoskeletal maturity to perform gonadectomy mitigates the risk of developing clinically significant orthopedic disease, which includes developmental conditions of the hip and elbow as well as knee. Maturity may be 12 months of age for small breed dogs and 24 months of age for giant breeds. However, gonadectomy also affects a dog’s risk for certain neoplastic diseases, female dog’s risk for urethral sphincter mechanism incompetence, and behavior. Therefore, outside of a shelter medicine setting, gonadectomy and timing of gonadectomy should be a personalized decision based on the individual animal and client.
Your study points out that the association between gonadectomy and CCL disease is complex and multifactorial. With that in mind, what would be the most beneficial focus of future research on this association?
Dr. Low: An interventional study on gonadectomy and CCL disease is almost impossible to conduct. The next best study would be an observational study with lifetime follow-up, which is lacking from most current studies.
The Study
The association between gonadectomy and timing of gonadectomy, and the risk of canine cranial cruciate ligament disease: A systematic review and meta-analysis
Low D, Costa L, Hawkesby J, Nardulli L, Proteasa A, Vallios V. Vet Surg. https://doi.org/10.1111/vsu.14197