Carpal Flexural Deformity in Dogs

Also called knuckling over, carpal hyperextension, carpal hyperflexion or carpal laxity syndrome, carpal flexural deformity primarily affects puppies, particularly of medium and large breeds, when they are going through a growth spurt.

The condition is initially noticed in the growth plate of the dog’s front leg, either in the wrist or carpal area, occurring when the part of the dog’s body that bears weight is not able to support his entire body as a result of the muscle, tendon and ligaments lacking integrity.

A deformity in the growth plate of a dog’s front leg either in the wrist or carpal area, carpal flexural deformity occurs when the part of your dog’s body that bears weight cannot support his whole body.

A dog experiencing carpal flexural deformity will typically be under four months of age and their wrists will bulge forward or over flex. While a dog with this condition will not be in pain, he may show lameness and difficulty walking should the deformity be significant.

• Lameness
• Difficulty walking
• Over flexion

Types 

Carpal flexural deformity may occur when the muscle, tendon and ligaments are not strong enough to hold the weight of your dog. 

Should your dog experience an injury to his leg, the ligaments and fibrocartilage can tear and the carpal joint could collapse. Your dog can also experience degenerative carpal hyperextension, which will cause sudden hyperextension of the carpal joints.

Carpal flexural deformity is more likely to occur in large and medium breed puppies under the age of four months (though can be seen through seven months) as they go through a growth spurt, though the condition can occur in dogs of any size. The condition occurs more often in certain breeds, to include Shar-peis, Doberman Pinschers, German Shepherds and Great Danes. The 2007 study “Veterinary and Comparative Orthopaedics and Traumatology” noted a higher incidence among male puppies than female puppies. 

While the cause of the condition is not known, there are multiple theories that have not been confirmed. Some believe that the condition is a result of a temporary imbalance in the rate of growth between the bones and tendons of the dog’s front limbs. Other proposed causes, to include genetic influences, malnutrition, and an excess of vitamins and minerals, lack evidence to support them. Dogs who have the condition do not present signs of disease or other pathology.

Should you notice an apparent deformity in the front leg of your puppy, you will want to schedule an appointment with your veterinarian. You will be asked about when you first noticed the condition, as well as any other symptoms you have observed. Your veterinarian will conduct a physical examination of your dog (to include watching him walk) where he will look for excessive hyperextension or hyperflexion at the carpus. Depending on what is seen, your veterinarian may recommend conducting x-rays, where your dog will be sedated, and/or clinical pathologic testing.

As it is not clear what causes the condition, it is challenging to determine the ideal treatment for it. A study that was published in a 2007 issues of “Veterinary and Comparative Orthopaedics and Traumatology” provided evidence that a balanced diet and mild exercise may resolve the problem. This would include your veterinarian suggesting that you provide your puppy with adult dog food to decrease the rate of his growth in order to ensure the condition does not worsen.

Should your dog’s condition be severe, your veterinarian may recommend a soft wrap, like an ACE bandage, be used.  As hard splints restrict your dog’s ability to use his muscles, the use of one can worsen the condition. In the majority of cases of the condition, the wrist of the dog will straighten out on its own within a few weeks, with no treatment necessary.

Should your dog require treatment for carpal flexural deformity, it will typically be effective within a few weeks and a long-term impact is not seen in dogs that have experienced the condition. You will want to follow the recommendations of your veterinarian during your dog’s treatment and follow up as recommended, to ensure the best outcome for him.