What is a Cruciate Ligament Injury?
Injury to the CCL, also referred to as the cranial cruciate ligament (or ACL), can induce lameness in dogs and ranks among the leading causes of hind leg lameness.
The role of this ligament is to prevent the femur (upper leg bone) and tibia (lower leg bone) from rubbing against each other.
When the cranial cruciate ligament is torn or ruptured, it compromises leg stability, leading to bone friction, inflammation, potential meniscal damage, and eventual arthritis.
In a healthy dog, the ACL experiences tension during activity, preventing the femur from pressing into the tibia and allowing for smooth fluid movement.
However, with a cruciate ligament tear, this tension diminishes, enabling unnatural bone movement, resulting in pain, lameness, and reluctance to use the affected leg.
It's akin to envisioning the ligament as a rubber band; when it snaps, the bones come into direct contact, eliminating the gliding joint and causing bone-on-bone interaction.
Distinguishing Between Acute and Chronic Cruciate Ligament Injury:
Acute injury typically arises from trauma, often involving improper knee rotation and hyperextension. This can occur through various incidents, such as missteps, jumping, or sudden movements to free oneself.
Conversely, chronic injury usually stems from disease, age-related ligament changes, excess weight, or knee joint conformation, particularly affecting certain large breed dogs.
Unfortunately, preventing chronic cruciate ligament injury is challenging.
Considerations Based on Size:
The outcome of an ACL injury differs between small and large dogs.
Research indicates that dogs weighing less than approximately 12kg may fully recover from ligament damage without surgery, unlike their larger counterparts. While larger dogs may show signs of improvement with conservative methods, full recovery is rare without surgical intervention. Although exceptions exist, smaller dogs generally fare better with conservative management approaches.
Symptoms of a Torn Cruciate Ligament:
The symptoms of a torn, ruptured, or injured CCL vary widely among dogs, depending on the injury's nature (acute or chronic), the dog's size, and whether other knee structures, such as the meniscus, are involved.
Common symptoms include decreased range of motion, the hind leg extending straight while sitting (known as the sit sign), crepitus (crackling noise of bones rubbing), pain when touching the knee joint, exercise intolerance, limited mobility, stiffness, swelling or warmth in the knee joint, and toe-touching while standing.
It's essential to consult a veterinarian if your dog exhibits any of these symptoms associated with a CCL tear, as other conditions may present similarly.