Proximal Dynamic Ulnar Osteotomy in Dogs

What is proximal dynamic ulnar osteotomy?

Proximal dynamic ulnar osteotomy (PDUO) is a surgery used to correct an angular limb deformity (ALD) in growing dogs. An ALD is an abnormal alignment in one or more bones of the leg. It occurs when the radius and ulna (the two bones of the lower front leg) do not grow at the same rate. 

The radius and ulna are attached to each other by ligaments and connect the elbow joint to the wrist joint. If one bone stops growing while the other continues to grow, it causes deformities in one or both bones. The misalignment may cause the leg to curve, twist, or become shortened. 

ALDs are usually caused by damage to the bones’ growth centers, called growth plates or physes. PDUO treats deformities caused by damage to the growth center of the ulna. This damage causes premature closure and discontinuation of bone growth from that area. PDUO can also be used to treat dogs with elbow dysplasia, a painful condition in which the elbow bones do not fit together normally. This procedure is most effective in younger puppies whose bones are still growing.

What happens in a PDUO?

In PDUO surgery, the ulna is completely cut near the elbow, which allows the radius to resume growing in a straight line. The ulna is left to heal slowly on its own, allowing it to grow longer and match the growth in the radius. Before the ulna heals, the surrounding muscles and ligaments gently pull and hold the upper part of the ulna into a position that better matches the radius. This position can improve how the elbow joint fits together and can help correct elbow dysplasia. During a PDUO, your dog’s surgeon may perform other procedures to address specific types of elbow dysplasia.

What follow-up care is needed after a PDUO?

After the surgery, it’s important to follow all your surgeon’s instructions closely to reduce complications. 

• Your dog may have a bandage on their leg to reduce swelling and protect the incision. Keep the bandage clean and dry and monitor for swelling and discomfort. 
• Restrict your dog’s activity for at least four to six weeks unless your surgeon says otherwise. Jumping must be prevented and your dog must be on a short leash when outside for bathroom breaks. 
• Your dog may need to wear an Elizabethan collar to keep them from licking their incision. 

Follow your surgeon’s recommendations for recheck exams, bandage changes, and X-rays. Physical therapy is often recommended to help restore strength, manage pain, and improve movement, once it is safe to do so. 

What complications can occur after surgery? 

Complications include:

• Reduced or non-healing of the surgical bone correction
• Infection
• Bending, breaking, or loosening of metal implants
• Recurrence of the deformity in growing puppies that may require additional surgery

What is the prognosis?

Bone growth can be difficult to predict, so achieving perfect bone alignment is not always possible. In rare cases, some dogs may require follow-up surgery. Overall, most dogs that have PDUO are more comfortable and have improved limb function afterward, but they may still develop some degree of arthritis.