Orthopedic problems can certainly affect our dog’s quality of life, but can they affect quantity of life, or lifespan? Cranial cruciate ligament disease and rupture are among the most common orthopedic conditions in dogs, especially large and giant dogs. Approximately 10 years ago, a study suggested that cranial cruciate ligament rupture in dogs was a $1.4 billion per year condition in the US alone! Yet despite many studies that have evaluated identification and treatment of cruciate disease, we still do not know exactly what causes it. Sure, many things are risk factors, such as breed, biomechanical influences, gender, body condition score, etc., and most of the studies regarding treatment have focused on short term outcomes (less than 6 months after surgery) and surgical complications. A few studies have evaluated conservative management. Regardless of treatment, all dogs have progressive osteoarthritis, although clinically, function appears to be better with surgery than without surgery.
More people are seeking nonsurgical methods of treating cranial cruciate ligament rupture. Social media and list serves are full of ideas – braces, kinesiology taping, exercises, various modalities, reparative therapies, and the list goes on and on. The reality is that there seem to be “copers” and “noncopers”. What does this mean? For whatever reason, some dogs seem to function with conservative therapy, albeit at a low level. Our research of conservatively managed cases of cruciate ligament disease suggests that 20% will have acceptable house pet function and have reasonable use of the limb at a walk, and the more therapies that are combined seem to result in a more favorable outcome. But when you add the costs up, it quickly approaches and may supersede the cost of surgery. But what about the other 80%? Unfortunately, these dogs have progressive osteoarthritis, develop meniscal tears, and overload the other three limbs. This is especially concerning because many dogs develop cruciate ligament disease in the other pelvic limb, and some have forelimb conditions, such as elbow dysplasia or shoulder conditions which may be exacerbated by shifting weight to the forelimbs. Of course, there are reasons why conservative treatment of cruciate disease may be elected, including severe liver, kidney, or heart disease that may make anesthesia risky or life threatening; the presence of a terminal disease, such as cancer; or financial limitations. But conservative management may result in more arthritis, loss of mobility, lameness, and chronic pain.
But does conservative management of cruciate disease affect lifespan?
A recent study from Norway and Sweden examined this question. Cases were evaluated over a 5 year period, and survival was assessed 2 years later. Treatment groups of the 333 dogs in the study included conservative management (65, 20%), lateral fabella-tibial suture (125, 38%), or an osteotomy procedure, such as tibial plateau leveling osteotomy or tibial tuberosity advancement (143, 43%). At the follow-up, 49.3% of the dogs were still alive, and 50.7% had died or were euthanized; 18% died or were euthanized for cruciate-related reasons. The type of treatment had an effect on disease and overall survival. Surgical treatment resulted in fewer deaths at follow-up than conservative treatment. For comparison, 29.2% of dogs in the conservatively treated group died due to disease-related causes, while 15.2% died in the lateral fabella-tibial suture group and 16.1% died in the osteotomy group. The most common cause for disease-related euthanasia was lameness.
Survival of dogs with cruciate ligament rupture was influenced by treatment method, the presence of co-morbidities, age, and weight. Although surgical treatment was associated with a lower risk of death than conservative treatment, one aspect of this study was that it was conducted in Norway and Sweden, which have stringent animal welfare laws. Because lameness is considered a welfare issue, it is possible that euthanasia was recommended at an earlier stage of disease than other countries. Additionally, a number of other factors may enter into the decision to euthanize a patient. Nevertheless, the quality of life is indirectly supported by this study when considering conservative vs surgical treatment of cruciate ligament rupture.
Another valid point that was made is that weight was one of the risk factors for death, with conservative treatment of cranial cruciate ligament rupture in smaller dogs less of a factor regarding death than larger dogs. The literature regarding conservative treatment of cruciate ligament rupture in smaller dogs was reviewed and provided some support for this finding. Also, smaller dogs tend to have longer life spans than larger dogs, so this could have also skewed this finding.
Additionally, orthopedic comorbidities also affected lifespan. This makes sense because if a dog has elbow dysplasia in addition to cranial cruciate ligament rupture, additional forces may be placed on affected limbs, resulting in additional pain, lameness, and mobility issues. Other non-orthopedic comorbidities also affect lifespan. Veterinarians may wish to alter the prognosis of large dogs with cranial cruciate ligament rupture that have other affected joints or medical comorbidities.
Because this was a retrospective study and the treatments were not randomized, the decision for treatment selection may have been biased by such factors as cost of treatment, and also for ongoing management of cruciate ligament rupture and any comorbidities. People that select less expensive forms of treatment may not wish to continue treating dogs with lameness, pain and other comorbidities.
Overall, this article provides somewhat sobering information regarding the long-term outcome of dogs with cranial cruciate ligament rupture. The fact that 18% of dogs died or were euthanized within 5 years of treatment suggests that owners should be counseled regarding long-term expectations when dogs are diagnosed with cruciate ligament rupture. Further, this study strongly suggests that lifelong management of cranial cruciate ligament rupture should be instituted to help alleviate lameness, pain and mobility disorders. In other words, treatment does not end as the patient exits the operating room - it’s only beginning!
Gudrun S. Bogea, Karolina Engdahlb, Annika Bergströmb, et al. Disease-related and overall survival in dogs with cranial cruciate ligament disease: a historical cohort study. Preventive Veterinary Medicine 1181 (2020) 105057 http://doi.org/10.1016/j.prevetmed.2020.105057