Distraction arthroplasty is a distraction (stretching out) of the ankle joint. The ankle is held in this distracted position for a period of time. This technique is used to unload the ankle joint and allow healing of the damaged joint. It may be recommended for a patient who has ankle arthritis.
The major goal of this treatment is healing of damaged tissue that occurs from arthritis. Distracting and unloading the ankle joint, along with the use of range of motion activity, is believed to help restore some of the damaged tissue in the ankle. With this restoration, a patient may be able to avoid or delay a more invasive procedure such as an ankle fusion or total ankle replacement. This allows patients to maintain motion of the ankle joint, which would be lost with an ankle fusion, and potentially avoid activity restrictions that may be necessary after an ankle replacement.
Appropriate candidates are young active patients with arthritis which is usually the result of an injury. Some joint space is visible on the X-rays, and no significant deformities are present.
If you are older or have non-injury arthritis (such as rheumatoid arthritis), complete loss of joint space or severe deformities, distraction arthroplasty is not right for you. Those with active infection or an inability to complete physical therapy treatments also should avoid distraction arthroplasty. Arthritis that is concentrated at the front of the joint does not respond as well.
There are two separate distraction arthroplasty procedures. The initial procedure is performed in the operating room under general anesthesia. An external frame is applied from the leg bone (tibia) down to the foot. The frame is attached to the bone by a combination of tensioned wires and/or pins.
The external fixator is entirely outside of the body. A hinge is built into the frame. The frame contains struts that allow the ankle joint to be slowly distracted over time. Additional procedures may be performed at the same time, such as the removal of bone spurs or the release of tight tissues.
At a second surgery approximately three months later, the external frame is removed under anesthesia. After frame removal a splint or cast dressing is applied.
Unless there are other related procedures, such as an ankle arthroscopy or a lengthening of the Achilles tendon, the only incisions will be very small stab incisions where the pins and wires are placed. The hinges allow for controlled range-of-motion, usually with guidance from a physical therapist after surgery. The external fixator that is applied is very strong and therefore the patient may be allowed to put weight on the foot and walk while in the frame.
The external fixator usually will allow for locking the ankle in a fixed position for walking and also allow the hinge to be unlocked with physical therapy for directed activities.
After the frame is applied, you will usually be asked to keep weight off the foot until you see your surgeon in a week to 10 days. Any incisions will be checked and sutures removed if needed. Your surgeon will also discuss how to take care of the frame and keep it clean. Your surgeon also may discuss physical therapy.
RISKS AND COMPLICATIONS
It’s very common to have irritation or minor infection at one of the pin sites, and this is usually treated with local wound care and occasionally oral antibiotics. Rarely, a pin or wire will have to be removed and replaced. Since the frame is designed to gently pull the ankle joint, some patients may experience some nerve pain while going through the stretching phase. Your surgeon will instruct you on how to improve these symptoms.
How do I take care of my frame?
Frame care is easy. Your surgeon will have some simple guidelines for keeping your frame clean. This involves you cleaning around the pins and wires once or twice daily.
Does ankle stretching hurt?
This process should not involve any significant pain. Your surgeon will carefully teach you how to slowly adjust the frame. This is done very gradually. If you have any significant increase in pain while stretching your ankle, you should notify your surgeon.
How long will I be in the frame?
This will vary based on your particular need, but the average time is about three months. Your doctor may have you begin walking or start physical therapy before the frame is removed.
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