The goals of treating angular limb deformities are to prevent or correct the bone and joint abnormalities, reduce the dog’s discomfort and maintain as much leg length as possible.
The most commonly reported treatment for an angular limb deformity, caused by premature closure of a distal ulnar growth plate or otherwise, is surgical correction. The particular surgical approach will depend upon the age of the animal (whether its growth plates are still growing or are already closed), and on the nature and extent of the existing deformity. Young dogs with developing forelimb deformities may benefit from a procedure called an ostectomy; if the ulna is affected, the procedure is referred to as a distal ulnectomy. An ostectomy involves surgically removing a several centimeter section of the affected long bone (usually the ulna), to allow unrestrained growth of the other long bone (usually, the radius). Think of cutting a one inch piece out of the center of a chicken drumstick bone, leaving the two remaining end-pieces of the bone intact. That, essentially, is what is done with an ulnar ostectomy. Because the ulna and radius are so intimately connected, creating this surgical gap in the non-growing ulna allows the still growing radius to lengthen normally. The space created by this procedure typically is packed with a graft of fat collected from the dog’s flank area, to prevent premature union of the now two separate pieces of the affected bone. Hopefully, this will facilitate spontaneous correction of the distortion of the radial bone, by permitting it to continue growing normally because it is no longer restricted by a shortened, solid ulna.
Mature dogs with limb deformities that were not corrected during their youth may be candidates for a surgical procedure called a corrective closing radial wedge osteotomy. An osteotomy involves making a surgical cut (transection) through the entire width of the affected long bone, without removing a full-cut section of that bone. The transection can be stabilized with either internal or external fixative devices, such as metal pins, wires, screws and/or plates. If the elbow joint is severely affected, additional surgery can be performed to realign the bones forming that joint.
The affected limb will be bandaged for protection after surgery. The dog will be placed on cage rest and exercise restriction for at least 6 weeks. Physical therapy is also important to reduce the chances of post-operative complications. The dog should be reevaluated radiographically (with X-rays) every few weeks, until s/he has stopped growing. If bony bridges occur between the radius and ulna, or if the first surgery is not cosmetically or functionally successful by the time of skeletal maturity, the surgery may need to be repeated.
Of course, the selection of any specific surgical or other treatment will depend upon the particular growth plate affected, the extent of the limb deformity, the age of the dog, the professional assessment of the attending veterinary surgeon and the commitment and financial wherewithal of the owner.
The overall prognosis for young dogs with angular limb deformities is good to guarded. Puppies whose premature physeal closure is caught early have a good chance of complete recovery following surgical correction. Older dogs with severe leg deformities have a more guarded prognosis, even with attempted surgical correction.