Osteochondral lesions refer to defects in the joint surface, specifically the articular cartilage that lines the joint. Chondral refers to cartilage. Osteo- tells us that the damage goes clear down to the first layer of bone.
You have an osteochondral lesion of the talus. The talus is a bone in the ankle that is sandwiched between the lower leg bone (tibia) above and the calcaneus (heel bone) below. Treatment for this problem ranges from rest and immobilization to surgery.
Surgeons have been grappling for years how to repair painful, debilitating osteochondral lesions of the knee. Now the same techniques (debridement, microfracture, osteochondral autograft transfer or OAT, autologous chondrocyte implantation or ACI) are being used on the ankle.
But osteochondral repair on the ankle is more difficult than on the knee because there is limited access to the ankle joint. The surgeon must do a thorough and extensive work-up in order to make sure the real underlying problem is determined. Accurate diagnosis is important in planning treatment as well.
The first step is to perform a diagnostic injection. It sounds like you may have already gotten a diagnosis. When using an injection of a numbing agent like Novocaine, relief of symptoms points to an osteochonral defect and requires a CT scan to stage the lesion.
Staging is a way of determining the location, extent, depth, and overall severity of the defect. With mild (early stage) disease, it may be possible to treat the patient conservatively with nonoperative care (rest, immobilization in cast or splint). Deep fissures or displaced fragments require more extensive surgical procedures.
If the OLT is free of cysts, then a simple debridement (smooth the area, remove frayed edges) may be all that’s needed. Another treatment option early on is called microfracture — after debridement, the surgeon drills tiny holes in the area of the defect down into the bone. This stimulates bleeding and a healing response.
For larger defects (or for any size defect that doesn’t respond to a more conservative approach), the lesion is filled with graft material. The donor graft may come from a bank (allograft) or from the patient (autograft).
Many of these procedures can be done arthroscopically, which avoids an open incision and disruption of the soft tissues around the ankle. Another advantage of an arthroscopic approach is the pre-procedure diagnostic information it provides.
Before setting to work with the osteochondral repair or reconstruction, the surgeon uses the scope to look the joint over carefully. Every aspect of the lesion is reviewed and measured in preparation for the surgery. In fact, the diagnostic arthroscopic exam really helps the surgeon make the final treatment decision as to which procedure should be used.