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Anterior Cruciate Ligament Injuries

Anterior cruciate injuries are the most common cause of acute lameness in dogs. Cats can develop ACL injuries but do so much less frequently. Large breed, and overweight dogs tend to be more predisposed. The anterior cruciate ligament is one of two ligaments that help stabilize the stifle or knee joint. Injury can occur in a young active dog, or an overweight dog that has abnormal stresses on the dynamics of the stifle. An injury typically occurs when a dog twists his leg, either running around a corner, or mis-stepping in a hole in the back yard. This is a common injury in professional athletes like football players and skiers.

The typical presentation is a dog that is presented three legged lame, and toe touching. There is usually no pain elicited and the knee may or not be swollen.

Diagnosis is made on clinical history and the presence of an anterior drawer sign. An anterior drawer is when the is abnormal forward movement of the tibia in relation to the femur. This sign can be difficult to elicit in a nervous dog because the tensing of the muscles could artificially stabilize the stifle. Sedation sometimes is required. ACL pull or tear is suspected in any dog that presents with acute, non painful, toe touching lameness. I normally recommend a series of therapeutic laser treatments in our office and send the dog home with glucosamine chondroitin sulfate/ MSM supplements, non steroidal pain medication, and orders for strict rest, leash walks only, and no running or jumping for at least two weeks. The rule of thumb is if the dog is still lame after two weeks, surgery is usually required to stabilize the joint. If this is not done degenerative joint disease or arthritis sets in very quickly.

There are several surgical options to stabilize the knee joint after an ACL tear:

Extracapsular repair- The stifle is opened and inspected and any remnants of the torn ligaments are removed. If the meniscus is damaged, it is removed, and any bone fragments are cleaned away. A large suture is placed around the back of the joint and inserted in the front of the stifle. This stabilizes the knee. This procedure is best used in smaller dogs that don’t have to support as much weight.

TPLO (Tibial Plateau Leveling Osteotomy)- This is considered by many, the best way to stabilize the stifle after acl rupture. It is a complex surgery requiring specialized equipment, and many radiographs. This is done by a surgical specialist.

TTA(Tibial Tuberosity Advancement)- This procedure is also complicated, but considered by many to be the preferred method of repair. It is less invasive than the TPLO, but also requires specialized equipment and expertise.

Rehabilitation is important to the ultimate success of any procedure. Rest, and leash walks are a must for 4-6 weeks post surgery. Icing the joint can reduce swelling. Passive range of motion exercises can be begun in 2-3 weeks. Light exercise can be introduced slowly. Full return to normal function can be expected in 2-3 months.

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