Ankle pain when putting weight on the foot can come from a wide range of problems. One of those problems can be identified using an anesthetic injection into the joint. It's called osteochondral lesions of the talus (OLT).

In this article, orthopedic surgeons specializing in the treatment of OLT share their knowledge and expertise with other surgeons. Detailed descriptions of the lesions, the evaluation process, and management (both operative and nonoperative) are provided. Photos taken during surgery along with pearls (what to do) and pitfalls (what not to do) make this a very practical discussion of the problem.

What are osteochondral lesions of the talus? Well, first, the talus is a bone in the ankle. It is sandwiched between the lower leg bone (tibia) above and the calcaneus (heel bone) below.

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.

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 on the patient in order to make sure the real underlying problem is determined. Accurate diagnosis is important in planning treatment as well.

That's why the authors have developed their own decision-making process (algorithm) for the preoperative evaluation of osteochondral lesions of the talus (OLTs). As mentioned, the first step is to perform a diagnostic injection. Relief of symptoms 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.

The authors provide a step-by-step description of each implant procedure, including where to insert the arthroscope for surgeries on either side of the joint. Color photographs of the graft procedures, suture techniques, and results are included.

Results reported from various studies are reviewed. So far, it looks like the short- to mid-term results are good-to-excellent for each procedure when treatments are selected carefully for each patient.

The authors conclude that these reconstructive procedures are not 100 per cent guaranteed. When patients fail to recover after arthroscopic procedures, it may be necessary to perform a second operation -- this time with an open incision. Again, the selection of which approach to use depends on the type of lesion and stage. Some problems just can't be treated with the types of reconstructive procedures discussed in this article. That's when an ankle fusion or joint replacement might be more appropriate.

Reference: Mark E. Easley, MD, et al. Osteochondral Lesions of the Talus. In Journal of the American Academy of Orthopaedic Surgeons. October 2010. Vol. 18. No. 10. Pp. 616-630.