The canine knee or stifle as it is called in veterinary terms is identical to the human knee in terms of it basic anatomical structures. But after that the mechanics and the diseases differ. There are many conditions of the canine stifle that require surgical intervention. Two of the most common conditions are cranial cruciate rupture and patellar luxation, which in human terms would be anterior cruciate rupture and slipping kneecap.
In contrast to the rupture of the human cruciate ligament which is usually a traumatic episode on the football pitch; the dog usually infrequently suffers a true traumatic full rupture of the cruciate but more of a progressive breakdown of the fibrils. The progressive breakdown of the fibrils can occur over hours, days or sometimes even longer to the point that the function of the ligament is impaired. Once the ligament can no longer work the stifle becomes unstable and lameness occurs.
Osteoarthritis begins to set in within 7 days microscopically, and is progressive. Concomitant meniscus damage is common. Surgical stabilisation can be achieved by static repair or dynamic repair. TPLO or TTA are examples of dynamic repair and would be considered the best option, especially for bigger dogs.
Static repair using nylon or similar to try to mimic the ligament can be used as well but is more suited to smaller dogs. Successful outcome following surgery is highly likely but no matter how good the repair there will always be some osteoarthritis present which will need some management.
Luxating patella is common also and surgical correction is the only way to resolve the problem. Corrective surgical techniques such as sulcoplasty, osteotomy, and desmotomy will be needed to realign the quadriceps mechanism and counteract the muscular forces pulling the patella in the wrong direction. Correction is possible in approximately 95% of cases.
Other conditions that necessitate surgery are fractures, dislocations, OCD, LDE avulsion, patella ligament rupture, septic arthritis and miscellaneous conditions. All of these require surgical intervention to correct the problem. If the problem is not correctable or is beyond salvage then a total knee replacement or stifle arthrodesis can be performed to allow continued function.