What Is Mosaicplasty for Osteochondral Lesions of the Talus?
Osteochondral lesions of the talus (OLT) are ankle joint injuries involving damage to the joint surface (cartilage) and/or underlying ankle bone (talus). A normal, healthy ankle joint is made up of smooth cartilage supported by strong bone underneath. Sometimes an ankle injury leads to damaged, rough areas of cartilage and bone underneath. Foot and ankle orthopaedic specialists call this type of injury an OLT. Since the ankle joint moves while walking, the rough spots may cause pain, swelling, stiffness, and decreased motion. It is kind of like having a pothole in the joint surface.
One way to treat the damaged ankle cartilage is through surgery. One type of surgery is called mosaicplasty (MP), which is the transplant of small amounts of bone and cartilage. The primary goal of this procedure is to smooth out the surface of the ankle joint by replacing the unhealthy spots with healthy, smooth cartilage. By reconstructing the surface, pain and other symptoms should decrease or stop all together.
MP might be considered if you continue to have symptoms after non-surgical treatment. Surgery also might be considered if an OLT completely detaches from the ankle bone and/or begins to move around in the joint space, causing locking and catching. Also, if an OLT is too large to heal on its own but small enough to allow for the transplantation of new tissue, surgery might be an option.
You should not have MP if the size of the OLT is too large for this technique, there is infection of the ankle joint or underlying bone, or your ankle is unstable. Young patients with a skeleton that is not yet mature typically do not have this surgery, nor should elderly patients with medical problems that would complicate recovery. Advanced arthritis throughout the ankle joint is another reason to avoid surgery.
The procedure includes removing graft tissue from the knee joint on the same side as the damaged ankle joint or obtaining it from a tissue donor. The orthopaedic surgeon makes incisions on the ankle to access the injured area. Once the unhealthy tissue is found, it is removed with a large drill to leave healthy bone underneath. The healthy tissue is transplanted into holes in the ankle joint until it forms a smooth surface. It may require multiple plugs to fill the gaps in the ankle surface. This gives the repaired surface the appearance of a mosaic. It is important to place the transplant tissue so that it produces a smooth surface. Once the procedure is finished, the surgeon closes the openings with stitches. A bandage is placed around the incision sites.
Patients are advised to keep all weight off the operated leg for four to six weeks after surgery. After this, the patient can begin physical therapy to regain strength and motion of the ankle. There may be pain and swelling after surgery, but the swelling usually subsides after one to two weeks. Stitches will be removed once the swelling has decreased to a safe level, typically two to three weeks after surgery. More than 90 percent of individuals undergoing this procedure have good to excellent results.
Risks and Complications
All surgeries come with possible complications, including the risks associated with anesthesia, infection, damage to nerves and blood vessels, and bleeding or blood clots.
MP generally is safe but there are potential complications that can occur during and after treatment for an OLT. Typical risks include pain that does not go away after the surgery (in the donor joint or the ankle), swelling, numbness, tingling, stiffness, non-healing of the transplanted tissue, and poor healing of the area from where the transplant was taken. The risk of infection and poor healing are much higher for patients who have uncontrolled diabetes or those who smoke.
During recovery, you should call your foot and ankle orthopaedic surgeon if you experience excessive bleeding, fever or chills, redness that expands from the incision site, continuous severe pain, new numbness of the foot or nausea, and vomiting that do not resolve with medication.
Will I have to stay overnight in the hospital after the surgery?
Most healthy patients will be able to leave the hospital after surgery as long as they can take medication by mouth and their pain is under control. Patients with other health problems may stay in the hospital for a longer period of time.
How much will this procedure hurt?
This procedure can cause some discomfort. Your physician will provide you with the appropriate pain medication. Other ways to decrease pain and swelling include resting, icing and elevating the affected limb above the level of the heart, especially during the first two weeks.
Will I regain all of my original function in my ankle joint?
After your ankle has had time to heal you will start physical therapy for ankle range of motion and strength to regain the function you had prior to surgery.
Where will the healthy cartilage transplant come from?
There are two sources of graft. The first comes from a healthy site in the patient’s own body. This is known as an autograft. The second comes from a deceased donor’s body. This is called an allograft.
Will taking cartilage from other joints in my body cause long-term problems?
The graft that is harvested is removed from a place in the healthy joint that has little weight bearing. This reduces the chance that problems will occur.
When can I go back to exercising or sports?
Although returning to activity is based on the individual patient’s progress as well as the surgeon’s expert opinion, most people can begin to increase activity as tolerated by 10-12 weeks.
When will I be able to drive?
You will be permitted to return to driving once you can walk without crutches and are able to react appropriately without pain of the ankle. You cannot drive if you are taking narcotic pain medications.
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