Cranial and Caudal Cruciate Ligament Injuries in Horses

Complete rupture of a cruciate ligament in a horse is usually a catastrophic injury resulting in severe lameness and joint instability. Strains and partial rupture of the cranial and caudal cruciate ligaments can result in variable lameness, depending on the severity of injury.

Partial tearing of the cranial cruciate ligament most commonly occurs at the midbody segment of the ligament. Effusions of the femoropatellar or femorotibial joints are sometimes present. Lameness is usually improved by intra-articular anesthesia of the femorotibial joints.

In some horses, radiographic changes associated with cruciate ligament injuries might be evident at the sites of attachment of the ligament, with enthesiophyte formation (particularly at the intercondylar eminence) or focal areas of radiolucency. Ultrasonography of the cruciate ligaments is difficult but can demonstrate some lesions. In most horses, however, arthroscopic examination is the only way to confirm diagnosis.

Conservative treatment involving rest, systemic NSAIDs, and intra-articular corticosteroids is indicated in horses with acute cranial or caudal cruciate ligament injuries. If a patient does not respond to conservative treatment, arthroscopic surgery is recommended to debride loose and torn ligament fibers, assess concurrent cartilage injury, and flush the joint.

The prognosis for a horse's return to athletic function after injury to the cranial or caudal cruciate ligament depends on the severity of the injury:

• For complete rupture, the prognosis is grave.

• For moderate to severe injuries, the prognosis is poor.

• For mild injuries, the prognosis is fair.