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Focus on Canine Cranial Cruciate Ligament Disease

Cranial cruciate disease is the most common cause of lameness in the dog and is the most frequently encountered orthopedic injury in veterinary medicine. Over the past 40 years, numerous techniques have been developed to overcome the instability created by the ruptured cranial cruciate ligament (CCL) and the subsequent osteoarthritis that develops. However, no "perfect" procedure has been created that works in every animal or that halts the development of degenerative joint disease over time.

Pathogenesis of cruciate disease is multi-factorial and includes trauma, abnormal stifle biomechanics, as well as biological factors. A recent review of causes of CCL rupture in the April 2010 issue of Veterinary Surgery suggests that only a small percentage of animals with CCL rupture are as a result of a single traumatic episode. In fact, abnormal stifle biomechanics and biological changes within the joint both play significant roles in the deterioration of the CCL and ultimate rupture of the ligament. Current thought has focused on the conformation of the proximal aspect of the tibia (i.e. excessive tibial plateau angle and patellar tendon-tibial plateau angle) as primary underlying causes for cruciate ligament rupture, but there has been no definitive evidence that these changes significantly increase the risk for cruciate disease. Others have suggested that there is a dysfunction of the passive and active stifle stabilizers (ligaments, menisci, joint capsule, muscular support), that metabolic/endocrine causes, or the inflammatory cascade perpetuate ligament deterioration. It seems clear that cruciate ligament disease is caused by contributions of each of the aforementioned causes. With stifle incongruency, repetitive trauma, muscle weakness, and abnormal biology the inflammatory cascade is activated intra-articularly, perpetuating the deterioration of the cruciate ligament fibers, eventually causing a complete tear.

Numerous procedures have been developed over the years to address cruciate ligament deficiency in companion animals, each with their own subset of benefits, risks, and successful outcomes. However, the goal of each of these procedures remains the same- to return stability to the stifle and to return the pet to a pain-free, active lifestyle. When evaluating surgical options to stabilize a cruciate deficient stifle, all of these factors must be considered in order to attempt to select the ideal surgical technique for each individual patient.

Currently at Metropolitan Veterinary Associates, we offer our clients two different techniques for the treatment of cruciate ligament rupture, 1) the lateral fabellar suture (LS) and 2) the tibial plateau leveling osteotomy (TPLO). The lateral fabellar suture technique is an extra-articular stabilization that removes cranial drawer of the tibia by placing nylon across the joint in a position that mimics the orientation of the cranial cruciate ligament. The TPLO stabilizes the stifle by rotating the tibial plateau to approximately 6 degrees relative to the weightbearing axis. This changes cranial tibial thrust into caudal tibial thrust and this is counteracted by the caudal cruciate ligament.

Both procedures are reported to have an 85%-90% good to excellent prognosis for full return to function with few complications, however, heated debates continue at all veterinary surgery conferences as to which is the best procedure to perform. In the literature, there has been no evidencebased proof of the superiority of one procedure over the other. A comparison of the short- and long-term function and development of osteoarthritis in dogs having either TPLO or LS was published in the February 2010 Veterinary Surgery. This study revealed there was no significant difference in ground reaction forces or development of osteoarthritis in dogs receiving either surgical technique. However, these animals also received post-operative physical therapy.

When evaluating animals with cruciate ligament disease at Metropolitan Veterinary Associates, we evaluate each animal as an individual, taking into account conformation, breed, activity level, and biological factors. Our goal is always to address abnormal biology and biomechanics, decrease pain, restore function, and slow the progression of degenerative joint disease. Pre-operative radiographs are evaluated closely to determine if one procedure would produce better long-term outcomes over another. We find it important to educate owners on each procedure and work with them to decide on the best surgical option for their pet. Other factors taken into consideration when choosing a surgical technique include the weight and temperament of the dog, its expected activity level, owner finances and the presence or absence of cruciate ligament disease in the contra-lateral stifle. It is import to remind owners that even if their dog is currently sound in the other stifle, they have a 40-50% chance that their dog will develop cruciate ligament rupture in the other stifle within 1-2 years of the first side becoming clinical.

Post-operatively, animals are monitored closely and recommendations are made to help them achieve a full recovery. We have found that post-operative physical therapy plays an important role in rapid recovery, improved weight bearing, and full range of motion and each client is encouraged to have their pet participate in a program near them. Owners are also advised to maintain their dogs at an ideal body weight and consider starting their pet on a glucosamine/chondroitin joint supplement if they have not already done so.

Regardless of the surgical technique used, most animals are able to return to normal pre-operative activity levels around 12 weeks post-operatively. Dogs that still have a degree of residual lameness at 12 weeks post-operatively often continue to improve for 6-8 months post-operatively. Due to the subsequent development of osteoarthritis, many dogs will require the tactical use of non-steroidal anti-inflammatory drugs (NSAID's) if they have periods of mild lameness or stiffness, particularly associated with heavier than normal activity levels or cold, damp weather.

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