The cruciate ligament is located in the knee, where it helps to stabilize the joint. Injury to the ligament leads to instability in the knee joint. This triggers pain, swelling, and limping. Injury to the cruciate ligament usually is caused by trauma to the knee.
Injury to the cruciate ligament may lead to partial or complete disruption (tearing) of the ligament. Partial cruciate ligament tears sometimes heal with activity restriction. Complete tears of the cruciate ligament usually require surgical correction. Partial tears often progress to complete tears. Both types of cruciate ligament injury may lead to arthritis and chronic limping later in life.
- Sudden, severe limping on one rear leg is the most common symptom of cruciate ligament damage. In some cases, the limping will occur after visible trauma. Some dogs vocalize at the time of the injury. In most cases, the dog bears no weight on the leg after the injury.
- Dogs with partial cruciate ligament tears may experience milder or intermittent limping.
- Notable swelling of the knee may occur in conjunction with limping.
Risk Factors and Prevention
- Large and giant breeds of dogs suffer higher rates of cruciate ligament injury than small breeds.
- Young, active dogs are more likely to experience cruciate ligament injury because they are more likely to engage in the sort of vigorous activities (such as jumping for balls) that can lead to cruciate ligament trauma.
- Overweight dogs suffer higher levels of stress on their joints, and consequently higher rates of cruciate ligament injury.
- Dogs that are hit by cars, attacked by other dogs, or that suffer other forms of trauma may incur a cruciate ligament injury during the traumatic event.
- Dogs that have previously injured a cruciate ligament in one knee are at increased risk of injuring the ligament in the other knee at a later date.
- Dogs with relatively long legs are at increased risk of cruciate ligament injury.
- Dogs that are spayed or neutered at a very young age may be at relatively higher risk of cruciate ligament injury.
Even with proper treatment, arthritis often develops in the affected knee as a result of cruciate ligament injury.
Partial cruciate ligament injuries may progress to complete tears over time. Dogs that suffer cruciate ligament injury in one knee may suffer a cruciate tear on the other knee in the future.
Diagnosis is based on physical examination, often in combination with X-rays of the knee. Sedation may aid in diagnosis. Complete cruciate ligament tears often result in instability in the knee that can be detected by a veterinarian.
Partial cruciate ligament tears may be managed with activity restriction in combination with anti-inflammatory medications. Prolonged periods of activity restriction (up to six weeks) may be needed. This can challenge owners of extremely energetic or active dogs. This conservative form of treatment often fails, leading to a recommendation of surgery.
Surgical correction is required for most complete cruciate ligament tears as well as many partial injuries. A very large number of surgical procedures has been developed to correct cruciate ligament injuries. All are relatively expensive, and all have relatively long recovery times (six weeks or more in many cases). The method that is currently preferred by most experts is called TPLO (short for tibeal plateau leveling osteotomy).
Physical therapy may be beneficial to dogs recovering from cruciate repair surgery.
Overweight dogs with cruciate injuries will benefit from weight loss.
All dogs with cruciate ligament injuries may benefit from supplementation of the diet with glucosamine-chondroitin combinations. Some may require long-term anti-inflammatory medications.
The goal of treatment is resolution of limping and the ability to return to normal activity. Even with appropriate treatment, some dogs may experience chronic limping or restrictions to activity.
In dogs, the full name of the cruciate ligament that is most commonly injured is the cranial cruciate ligament. It is anatomically similar to the anterior cruciate ligament in humans. Humans often suffer anterior cruciate ligament damage as a result of sports injuries.
Some evidence suggests that large male dogs who are neutered at less than six months of age may be anatomically predisposed to cruciate ligament injury. However, more studies will be required to determine whether early neutering is in fact a risk factor for cruciate ligament injury.
Copyright © Eric Barchas, DVM All rights reserved.
The contents of this page are provided for general informational purposes only. Under no circumstances should this page be substituted for professional consultation with a veterinarian.