Cranial cruciate ligament disease in dogs

The cranial cruciate ligament (CCL) is the primary ligament that stabilizes the stifle (knee). CCL disease is a chronic process whereby the CCL degenerates and causes pain, instability, and osteoarthritis. Eventually the ligament ruptures, further increasing instability and pain in the joint. Usually, clinical signs of lameness are not readily appreciated until the ligament ruptures. CCL disease most commonly affects middle-aged, large and giant-breed dogs, but it occurs somewhat frequently in smaller dogs and occasionally in cats. The disease usually occurs in one leg, but rupture of the CCL in the other leg is common within 6-12 months following the first ligament tear.
Clinical Signs
Although CCL disease is a chronic, progressive condition, in many cases sudden onset of lameness occurs in association with activity. If not immediately treated, the lameness often improves to some degree but does not completely resolve. Signs typical of arthritis (lameness that is worse with rest and improves with mild exercise, stiffness, and muscle wasting) are usually present and worsen with time.
Treatment Options
The best treatment for CCL disease is greatly debated. Medium, large- and giant-breed dogs recover quicker and regain the best function with surgery. Small dogs and cats are often treated initially with restricted exercise and medical therapy. In these latter animals, surgery is reserved for those that do not respond to medical therapy. Numerous techniques are available for stabilizing the stifle. Keep in mind that the phrase "cruciate repair" is inaccurate, because in CCL disease the ligament is always beyond repair. Surgery is actually designed to improve stability of the joint. Currently, no single technique has been proven to be superior.
Follow-up Care
Regardless of which technique is chosen, strict restriction of activity for at least 8-10 weeks after surgery is critical for ultimate success. Physical rehabilitation and/or exercises at home also greatly improve the outcome of surgery.
Dogs with osteoarthritis may require continued medical therapy if the signs do not completely resolve with surgery.