Anterior Cruciate Ligament (ACL) injury can be a serious blow to the careers of professional athletes such as England Lioness’s captain Leah Williamson, NFL quarterback Tom Brady, and Brazilian footballer Neymar Júnior, but did you know dogs often suffer cruciate ligament injury too?

A new study from the Royal Veterinary College (RVC) has shown that surgery can support better recovery from CCL ruptures in dogs, just like your favourite footballer or professional sportsman. The study found surgery was more effective than non-surgical management of the injury, helping to reduce injured dogs’ short-term lameness by a quarter (25.7%) and long-term lameness by a third (31.7%).

This evidence will help vets recommend the best course of care and management for owners deciding on treatment for CCL ruptures in their dogs. Like human ACL injuries, CCL ruptures in dogs are a serious and common problem, but are usually caused by gradual degeneration of the cruciate ligament until it finally ruptures in dogs.

Previous RVC VetCompass research* had reported that CCL rupture affects approximately 1 in 180 dogs and that Rottweilers, Bichon Frise, West Highland White Terriers and Golden Retrievers are at greatest risk of CCL rupture, with dogs most commonly affected in middle-age.

Treating CCL rupture often requires owners to decide between surgical and non-surgical management. However, until now, the evidence comparing clinical outcomes between surgical versus non-surgical management in dogs has been limited. Most previous veterinary studies were limited to reporting associations rather than showing true causal links between treatment and outcome.

To fill these data gaps, this new study measured clinical outcomes following surgical vs non-surgical treatment for CCL rupture to report on short- and long-term lameness as well as the use of pain relief medication prescription. These data were analysed using novel causal inference methods and demonstrated a substantial causal link between receiving surgical management and better outcomes.

Led by the RVC’s VetCompass Programme and supported by an award from Dogs Trust, the study was based on anonymised clinical records from more than two million dogs under first opinion veterinary care in the UK in 2019.

This study applied causal inference methods to the analysis of random samples of 815 dogs with CCL rupture aged between 1.5- and 12-years-old to replicate a randomised clinical trial and explore the impact of the different treatment methods. Balancing the arms of the study for variables including age, breed and bodyweight, the researchers compared the outcomes for the dogs who received surgical management for CCL ruptures to those that were managed non-surgically.  

The results showed that dogs managed surgically were 25.7% less likely to show short-term lameness at 3 months post-diagnosis and 31.7% less likely to show long-term lameness at 12 months post-diagnosis than dogs managed non-surgically.

Surgically managed dogs were 38.9% less likely to have a pain relief prescription at 3 months post-diagnosis, 34.1% less likely at 6 months and 32.7% less likely at 12 months than dogs managed non-surgically. These findings also similarly demonstrate lower longer term pain in surgically managed dogs.

Camilla Pegram, VetCompass PhD student at the RVC and lead author of the paper, said: “This study used an exciting new approach that allowed us to determine ‘cause’ rather than being limited to ‘association’. Surgical management for CCL rupture is often considered as providing better outcomes than non-surgical management, but this study now provides an evidence base to support this. Whilst surgical management might not always be feasible for some dogs, the findings allow vets to quantify the benefit in their discussions with owners.”

Dr Dan O’Neill, Associate Professor in Companion Animal Epidemiology at the RVC and co-author of the paper, said: “Uncertainty when deciding on the best treatment option for their ill dog is one of the hardest challenges for any owner. This new VetCompass research uses Big Data analyses from millions of dogs to give owners of dogs with cruciate rupture the best evidence to support the best possible treatment decisions. Good science should be caring as well as scientific.”

Paula Boyden, Veterinary Director at Dogs Trust, said: “We’re delighted that Dogs Trust can support a wide range of groundbreaking studies through its Canine Welfare Grants. This study has revealed useful data that can help vets guide owners to make the most appropriate decision to deliver the best outcome for their dog. We hope this new insight will lead to improved dog welfare.”