Canine TAR is a surgical procedure in which the damaged surfaces of an unhealthy ankle joint are replaced with a prosthetic device. The BioMedtrix TATE Ankle was developed as an alternative to fusion for ankles with severe osteoarthritis. The prosthesis is designed to replicate the joint articular surfaces accurately after these have been carefully removed, and eliminate the pain associated with end stage osteoarthritis of the joint.
For cases in which moderate to severe pain affects the ankle, and those not responsive to medical management, a fusion will alleviate pain but eliminates the joint’s range of motion. A successful Total Ankle Replacement is intended to alleviate pain and fully restore range of motion to the joint.
The TATE Ankle prosthesis is currently in clinical evaluation at a limited number of centers around the world.
Ankle dysplasia is an abnormal condition involving multiple developmental abnormalities of the ankle joint. These abnormalities initially induce localized lesions where the healthy joint cartilage surfaces have eroded.
SIGNS of ankle dysplasia may be subtle early in the disease’s progression, but become much clearer as it develops. Early on, they can include a subtle limp after a bout of exercise. Dogs generally become less active and playful, choosing to lie down more often in an effort to take the weight off their ankles. At a level described as “end stage,” a dog may be reluctant to get up and walk a short distance. At this stage, joint manipulation is usually quite painful and the range of motion of the ankle is considerably limited.
Patients are screened before surgery to make sure they do not have problems in other joints of the affected hind limb such as the knee or the hip. Your veterinary surgeon will also ensure that your dog is healthy, does not have any neurological or medical conditions including chronic infection such as pyoderma.
Once preoperative examinations are completed, radiographs (x-rays) are taken to assess the severity of the ankle problem. If TAR is indicated, surgery can be scheduled.
The surgery entails the removal of the damaged articular surface of the tibia and talus at the ankle.
The Total Ankle Replacement requires special training to be performed reliably. To find a surgeon participating in the TATE Ankle clinical evaluation, use the Practice Locator.
Most veterinarians keep dogs for one to three days following surgery.
Dogs often regain limited use of their operated limb on the day of surgery.
Activity should be supervised and limited to leash walks for approximately eight weeks after surgery.
Two months after the surgery, radiographs are retaken to see how the implant is doing. If the implant looks good, full unrestricted activity can be resumed.
The TATE Ankle prosthesis is currently in clinical trials at a limited number of centers around the world.
The TATE Ankle implant replicates the natural articular surfaces of the ankle, and utilizes the latest in biomedical manufacturing and material technologies.
• The titanium components are manufactured through additive manufacturing, which facilitates integrated bone ingrowth porosity.
• Patented expanding post technology simplifies implant insertion and locks the implant to the bone, greatly improving implant stability in the critical weeks following surgery.
• Patented ‘cartridge implant’ design minimizes the amount of bone that is removed for implantation and greatly reduces damage to surrounding soft tissues.
• Hydroxyapatite (HA) coatings help jumpstart bone ingrowth into the implant.
• The bearing, made from a cross-linked polyethylene impregnated with vitamin E, is designed to last the life of the patient.
Through a thorough diagnostic procedure, your veterinarian has concluded that your dog has severe osteoarthritis of the ankle. After a physical examination was performed, concluding that the ankle is abnormal, a radiograph was taken in order for a detailed look at the joint and the surrounding bones. The joint space appears irregular, showing a lack of cartilage and possibly abnormal bone growth surrounding the joint.
The current method of treatment for end-stage osteoarthritis of the ankle is fusion. Unfortunately, ankle fusions have a very high complication rate and, as the name implies, result in the ankle being fixed at one specific angle. Another option, which is less favorable, is amputation.
There are five key steps to the TATE Ankle Surgery. The TATE Ankle surgery starts with a long incision along the medial or “inside” of the dog’s ankle. This allows the surgeon access to the medial malleolus, a bony feature covering the ankle joint, which will be removed in order to access the joint surfaces. Once removed, the surgeon will use a proprietary milling and drilling technique in order to remove the damaged joint surfaces. After the damaged joint surfaces have been carefully removed, the implant components are pressed into the joint and locked in place. The surgeon will then reattach the medial malleolus using a bone plate and a series of screws then proceed with closing the surrounding soft tissue and skin with sutures.
As with any joint replacement, there is always the possibility that complications may arise. These can include, but are not limited to, infection, an unstable implant, and conflicts with the surrounding soft tissue. If the patient were to over-stress the joint in the early stages after surgery, the implant could become unstable, which would inhibit bone from growing into the implant. The implant would then remain loose within the joint and be a possible source of pain. If the implant is not entirely encapsulated in bone, the implant could irritate the surrounding soft tissue structures. In the worst-case scenario resulting from these possible complications, the surgeon would remove the implant and proceed with a joint fusion.
Like any joint replacement surgery, the patient needs to be managed carefully after the surgery and remain on leash walks for at least 2 months. Although the patient may be feeling better and wish to do more, it takes time for the bone to grow into the implant. As such, it is important that excessive movement and exercise are avoided, as subjecting the implant to any unnecessary stress could prevent the bone from growing into the implant.
Around two months after the surgery, your doctor will request to see your dog again in order to take radiographs and see how the implant is doing. If the implant looks good, then your dog can return to full unrestricted activity.
As with all surgical procedures, patient-owners should consult with their veterinary orthopedic surgeon prior to surgery concerning any potential risks associated with surgery.