Cruciate Ligament Injuries: A New Therapeutic Approach

By Dr. Ed Mapes
Stonebridge Animal Hospital
McKinney, TX

Anterior Cruciate Ligament (ACL) disorders are very commonly seen in our canine patients; less so in felines. The ACL combines with the Posterior Cruciate Ligament to hold the femur in proper alignment with the tibia bone within the knee joint. Many factors are involved in damage to this important structure, and all of these must be taken into account when assessing an animal and the most appropriate treatment at your animal hospital McKinney.


animal hospital McKinneyPartial or complete tears of the ACL can happen to any dog if acute trauma occurs. This usually involves making a sharp turn or stepping in a depression in the ground while running. The femur bone continues forward motion while the bottom of the leg is prevented from the same motion, thus putting abnormal stress on the ligament.

When the ACL is damaged, there is usually swelling noted at the medial aspect of the knee joint and the dog will resist using the leg initially. Partial tears can actually be more painful than complete ruptures.
Along with the injured ACL, there can be damage to the collateral ligaments, meniscus, joint capsule, and bony structures within the joint. These are complicating factors that must be dealt with to bring around a suitable therapeutic outcome by your animal hospital McKinney.

Age is of course a factor in ACL injuries, since ligaments and tendons can become less elastic and more susceptible to tearing in older animals. Overweight dogs are also far more susceptible to injury.

Some dogs are thought to genetically inherit ligaments that are prone to tearing; we often see patients that rupture the opposite ACL after a previous injury. Approximately 70% of dogs will injure the other ligament at some point in time.

Many of the cases I’ve operated on show varying degrees of arthritis within the joint, leading to the suspicion that a previous incomplete tear had caused instability in the joint. That increased motion results in arthritic changes seen when treating a subsequent complete tear of the ligament.

All animals that are acutely lame in a rear leg should have thorough examinations by a veterinarian familiar with these types of injuries. The leg should be examined from toe to hip since many structures can be damaged – finding one problem doesn’t mean there’s not trouble somewhere else in the leg.

Sedation is commonly used to provide muscular relaxation so that joints can be manipulated freely. This also helps us to be thorough in our testing without causing undue pain for the patient. Radiographs are also a part of the diagnostic efforts at our animal hospital McKinney.

Once we’ve ruled out pathology in any other structures, we can concentrate on the knee joint to elucidate what tissues are damaged. We check for “popping” in the joint during flexion-extension and assess for integrity of structures throughout the joint.

Damaged anterior cruciate ligaments demonstrate a positive “drawer movement sign” in which the tibia can be moved cranially in relation to the femur. Experience in this maneuver allows us to postulate complete vs. partial tears; there is often a noticeable difference in the motion when comparing the two injuries.

Radiographs do not distinguish between complete vs partial tears; CT scans, MRI, or arthroscopy are needed to diagnose with greater certainty. This distinction is important in our therapeutic approach because total ruptures generally require surgical repair while partial ruptures can be treated non-surgically; rest and time can allow a return to leg function albeit with a far greater chance for torn menisci and arthritis.

Our newest approach to the healing of partially torn ligaments is with stem cell therapy. Stem cells, derived from the animal’s own fat tissue, are injected directly into the affected joint(s) and are also delivered into the bloodstream by intravenous injection. There is no chance of rejection because the cells are derived from the animal’s own fat tissue.

A great additional result of stem cell use is that other damaged ligaments or tendons, or arthritic joints anywhere in the body, derive benefit from this treatment. A dog, for example, that has a cruciate injury but also suffers from arthritis in a hip or shoulder joint will get added relief from pain control in those locations. Dogs with an undiagnosed partial tear of the opposite ACL will also experience healing of that ligament.

We are taking advantage of this technology to help patients in new ways. Those who previously were automatically scheduled for surgery are now able to regain function of their legs without invasive surgical procedures. Those that do need surgery for complete ruptures or where other damage exists are also candidates for stem cell therapy to aid in healing and to protect/heal other structures in the body.

We now have access to exciting new technology and advances in medicine; so why not take advantage of them at our animal hospital McKinney?

animal hospital McKinney
Stonebridge Animal Hospital
5913 Virginia Parkway
McKinney, Texas 75071
214-856-7005

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