Cruciate ligament injury in the knee or stifle joint causes acute lameness in the dog.
The stifle joint opens and closes like a hinge. The cruciate ligament prevents the two bones of the hinge from sliding back and forth.
The ligament and joint deteriorate with age. A sudden stop or twist tears the weakened ligament. The dog cries and cannot bear weight. Some dogs remain unable to put the leg down, others improve to varying degrees.
The vet diagnoses rupture of the cruciate ligament by demonstrating instability or a drawer sign of the stifle joint. If the joint is very painful or the dog has strong leg muscles then a sedative or anaesthetic might be necessary to examine the joint thoroughly.
Most dogs require surgery to relieve the pain and prevent future arthritis. Inspection of the joint for cartilage damage, removal of the torn ligament and stabilisation of the joint with figure 8 sutures improves joint stability, reduces the development of arthritis and eliminates pain in small to medium sized dogs.
Restriction of activity for 3 months together with anti-inflammatory drugs may be adequate for smaller and lighter dogs. If the lameness does not improve significantly then the cartilage is probably damaged as well and surgery is necessary.
Referral to a specialist surgeon for a more complicated procedure is best for bigger or more active dogs.
Full recovery from cruciate ligament surgery takes at least 3 months and the repaired knee will never be as good as new.
Recovery time is longer and the chance of rupture of the cruciate ligament in the other leg is increased in overweight dogs. Please discuss about strategies for weight reduction with your vet or vet nurse.