CCL Rupture – In dogs and cats the stifle (knee) is in a constant state of partial flexion, unlike a human knee. It is stabilized by several ligaments but the most common ligament that becomes injured is the cranial cruciate ligament (CCL), which correlates to the anterior cruciate ligament (ACL) in humans. If the CCL ruptures completely, it will be diagnosed during a physical exam. It is common that during the complete tear of the CCL, damage also occurs to the medial meniscus. The medial meniscus is a cartilage stabilizing cushion that the bottom of thigh bone rests on primarily. Dr. Brown performs CBLO’s to stabilize full and partial CCL tears. Rehabilitation therapy following CBLO, TPLO, TTA and lateral suture repair surgeries can improve return to function 20% more than without rehab therapy.
Partial Knee Ligament (CCL) Tear – Full CCL tears are straightforward to diagnose. Partial tears are a bit more difficult to diagnose definitively. There are five symptoms of CCL instability:
1. Positive Sit Test – When sitting, a dog will displace the injured pelvic limb either externally or internally because it’s painful to place in the normal position.
2. Joint Effusion – A cruciate tear will cause a buildup of fluid in the joint. This is determined by palpation of the patellar tendon compared to the normal other knee. A normal joint easily allows for palpation of the tendon. Joint effusion won’t allow this.
3. Extension/hyperextension of the knee is painful.
4. Tibial transtation/drawer sign will be noted during the exam
5. X-rray evidence – infrapatellar fat pad sign +/- osteoarthritis and joint effusion.
An informal study of over 100 dogs who had partial CCL tears repaired by TPLO or the newer CBLO procedure showed complete healing of the CCL one year post op. Therefore, repairing a partial tear before it becomes a full tear will greatly reduce post operative morbidity.