Carpal Hyperextension is a joint related condition that involves the supportive ligaments, or soft tissue in the wrist of the dog or cat. There are three main causes of this wrist malfunction.
Development: In cases where ligaments don’t grow to full strength while the pet is maturing into adulthood, both limbs will likely demonstrate the same severity of malfunction.
Typically an impact to the front limbs, a fall, stumble, or jumping from tall heights can cause injury leading to carpal hyperextension.
Degeneration: Signs usually develop in older animals and can appear very gradually. Sometimes both front limbs are affected and other times it’s just one limb. Normal wear and tear can result in weaker ligaments and cartilage surfaces in all major joints, which in turn can lead to the hyperextension.
Diagnosis will involve multiple approaches. In general, carpal hyperextension can be characterized by the observation of the pet’s gait in the front limbs. Often the paw appears collapsed at the wrist and the posture can resemble a duck’s foot. In the most severe cases, there is a right angle formed by the front leg and paw compared to the upright stance in the normal cat and dog limb. Since this injury involves the soft tissue around the joint, it is not easily identified using only radiographic imaging. You, your family veterinarian, and Dr. Jha will discuss utilizing computed tomography (CT) or magnetic resonance imaging (MRI) to analyze the injured area from a 3D image.
The best treatment is fusion of the carpus. This surgery involves placing a steel locking plate in the forelimb spanning the wrist joint, radius and the metacarpal bone. Typical rehabilitation period is 12 weeks. Most of the time, the patients go home with a bivalve cast bandage needing frequent (weekly or biweekly) changes. Prognosis is good and patients return to normal activity even with a fused carpus or wrist joint.