Tibial Tuberosity Transposition in Dogs

Tibial tuberosity transposition is a corrective surgery to secure the patellar tendon into the trochlear groove. Many dogs develop an issue where this tendon and the small kneecap-like bone attached to it become displaced, or dislocated. The issue ranges in severity, with some dogs only experiencing episodes of patellar displacement and others having the tendon and knee cap out of place at all times. Dogs with this issue often present as bow-legged, with up to 50% of dogs with this ailment being affected in two legs at once.

This is a very common problem in dogs that can be diagnosed as early as a few weeks into the dog's life. Non-invasive techniques are often attempted first to see if the kneecap will resume its place in the femoral groove with rest and anti-inflammatory drugs. If this fails, or the problem becomes chronic, surgical intervention is required. A tibial tuberosity transposition uses metal implants to transplant a bone fragment to secure the tendons and ligaments in place. It should only be performed by an ACVS board-certified veterinary surgeon.

Dislocation may be identified during a physical examination. X-rays will be taken to assess the severity of the issue. Blood work will have to be run to determine if the dog is healthy enough to undergo general anesthesia. If surgery is deemed appropriate, the dog will need to fast for several hours prior to the operation. A sedative will be given to the animal, and the affected limb will be clipped and cleaned. An IV will be administered and general anesthesia will be administered.

The dog should be placed on its back with its legs apart. The leg can then be incised laterally. The joint capsule, once visible, will be opened. Then, the connective band holding the tendon groups can be released to allow the kneecap to go back into the femoral groove. The tibial tuberosity (elevated portion of the tibia) will then be cut using an osteotome. It will be placed towards the center of the body. Wire is then used to secure this fragment in place and either a lag screw or two pins will be added for extra stabilization. It is important that the wire not be too tight so as not to dislocate the knee cap the other way. The joint capsule can then be shut and the incision sutured closed.

This surgical procedure has been found to have a decent success rate in most dogs. Good reports have been made following the recovery of both small and large breeds of dog, although more small dogs are affected by this ailment. The prognosis after surgery is often good in mild to medium cases of patellar luxation. Up to 90% of dogs resume some functionality in the limb that has been operated on. 

For dogs with extreme cases, the effectiveness of this surgery may not be so pronounced. If the operation must be done in a very young dog, this indicates that the condition is very severe and prognosis may be guarded. One of every two dogs receiving this surgery will go on to experience another luxation. Many procedures exist to treat this problem, but if a tibial tuberosity transposition is not performed along with these techniques, the operation is likely to fail. 

The dog should be closely monitored during the hours that follow the surgery. All vital functions will be watched to ensure that they resume with no issues. The surgical wound will be bandaged and the dog will be given pain medication. A prescription for non-steroidal anti-inflammatory drugs and a course of antibiotics will also be administered to the dog. An Elizabethan collar can be used if the dog begins to bite or lick at its incision. 

All exercise should be decreased during the healing period, although physiotherapy can be started immediately. A follow-up appointment will be needed two weeks post-surgery for suture removal. By six weeks, the dog should be fully recovered. X-rays will be taken at this time to assess how well the leg has healed.

The cost of surgery to repair a patellar luxation can range from $1,000 to $3,000. This is because blood work, x-rays, medication and general anesthesia are all needed in addition to the actual procedure. Using a specialist as opposed to a standard veterinary surgeon will also increase costs. If physiotherapy is used, it may cost up to $75 per treatment. The dog will likely require non-steroidal anti-inflammatory drugs on and off once recovered from surgery to manage the affected limb.

Various complications may arise during the treatment of a luxation. If the bone fragment is not secured correctly, it can break after the dog begins to be active again. It is also not uncommon for an infection to develop in the surgical area. A seroma (pooling liquid) may form where the fragment has been placed. The dog may also suffer from periods of lameness after it has recovered from the operation. The metal pins used in the procedure may irritate the dog, causing the need for a second surgery to remove them. All of the surgical treatments for a patellar luxation vary in their long-term success. Surgery does not prevent the development of degenerative joint disease. In medium and mild cases, rest and medication may be attempted in lieu of surgery. Unless the dog is experiencing significant pain, surgery may not be necessary.

As patellar luxation is generally a congenital defect, dogs presenting with this problem should not be bred, so that the affected genes do not pass on. When obtaining a dog, request for the full family health history to help identify potential health problems that may arise during your dog's life. Traumatic luxation may be prevented by reduce the chance of a major injury. Preventions may include keeping your dog leashed while on walks and discouraging rough play or fighting.