Contracted flexor tendons occur in the carpal or wrist joints of the front legs. The condition is variously called as knuckling, carpal hyperflexion, carpal flexural deformity or carpal laxity syndrome. An affected dog’s front legs look as though they are bending in half; the dog may struggle to support his weight. With treatment, a contracted flexor tendon is generally easy to correct, with no lasting symptoms.
This condition typically appears in puppies between the ages of 6 and 12 weeks, though it can occur as late as 7 months. You may notice a mild turn in the wrist area. In a severe case, the wrist area might be completely bent, preventing your dog from standing on his feet at all. He may look as though he is kneeling over to stand. While the condition may look painful, it does not cause pain to your pup.
The exact cause of contracted flexor tendons is unknown, though it usually occurs in large-breed or overweight puppies that experience rapid growth. Often the bones develop faster than the surrounding muscles and tendons. Other possible causes include genetic predisposition, malnutrition or overfeeding.
A 2006 study in Veterinarni Medicina looked at 31 puppies with carpal flexural deformity. Affected breeds included Anatolian sheepdogs, rottweilers, English setters, German shepherds, Irish setters, Italian pointers, Dobermans, Staffordshire bull terriers and pit bull terriers. All affected puppies showed symptoms shortly after being separated from their nursing mother. All were treated with splints and dietary changes. This treatment resulted in full recovery. Researchers determined that, in these cases, nutritional factors played a role in the condition.
Treatments for contracted flexor tendons include basic splints to support the legs, as well as a change in diet. Puppy food specifically for large-breed dogs is recommended to slow the growth rate. Because your puppy may have difficulty walking, providing a living area with good footing is essential to recovery. If your flooring is hardwood or tile, consider throw rugs or rubber mats to provide traction and help strengthen the legs. Typically, the tendons and deformity will return to normal within seven to 10 days of splint use.