Surgical Treatment for Osteochondral Lesions of the Talus

Osteochondral lesions of the talus (OLT) are often associated with ankle pain and dysfunction. They can occur after ankle trauma, such as sprains or fractures, but they usually present as a continued ankle pain after the initial injury has resolved. Chronic ankle ligament instability and subsequent microtrauma may lead to insidious development of an OLT. Medial-sided lesions are more common (67%) than lateral-sided lesions. For acute lesions that are nondisplaced, nonoperative management is initially performed, with a 4-6 week period of immobilization and protected weight bearing. Symptomatic improvement results in more than 50% of patients by 3 months. Acute osteochondral talus fractures, which have a bone fragment thickness greater than 3 mm with displacement will benefit from early surgical intervention. These injuries should undergo primary repair via internal fixation with bioabsorbable compression screws 3.0 mm or smaller using at least 2 points of fixation. Acute lesions that are too small for fixation can be treated with morselization and reimplantation of the cartilage fragments. If OLTs are persistently symptomatic following an appropriate course of nonoperative treatment, various reparative and restorative surgical options may be considered on the basis of diameter, surface area, depth, and location of the lesion. A small subset of symptomatic osteochondral lesions of the talus involve subchondral pathology with intact overlying articular cartilage; in these cases, retrograde drilling into the cystic lesion can be employed to induce underlying bony healing. Cancellous bone graft augmentation may be used for subchondral cysts with volume greater than 100 mm3 or with those with a depth of more than 10 mm. Debridement, curettage, and bone marrow stimulation is a reparative technique that may be considered in lesions demonstrating a diameter less than 10 mm, with surface area less than 100 mm2, and a depth less than 5 mm. This technique is commonly performed arthroscopically using curettes and an arthroscopic shaver to remove surrounding unstable cartilage. A microfracture awl of 1 mm or less is used to puncture the subchondral bone with 3-4 mm of spacing between to induce punctate bleeding. Initial (<5 year) results are good to excellent in 80% of cases, with some deterioration of improvement over time. Factors contributing to poor results include surface area greater than 1.5 cm2, overall osteochondral lesion depth over 7.8 mm, smoking history, age over 40, and uncontained lesions. Lesions greater than 1.29 cm2, cystic lesions, and lesions that have failed prior treatment are potential candidates for osteochondral autograft transplantation. The autograft is typically harvested from the lateral femoral condyle of the ipsilateral knee with an optimal plug depth and diameter of 12-15 mm. Transplantation often involves open technique and may even require malleolar osteotomy for perpendicular access to the defect, as well as visualization of a flush, congruent graft fit. Good to excellent outcomes have been reported in up 87.4% of cases with the most common complication being donor site morbidity in up to 15% of cases. Failure rates increased significantly in lesions larger than 225 mm2. Scaffold-based therapies, such as matrix-associated chondrocyte implantation, can be employed in primary or revision settings in lesions larger than 1 cm2, including uncontained shoulder lesions with or without cysts. Lesions with greater than 4 mm of bone loss following debridement may require bone grafting to augment with the scaffold. This technique requires an initial procedure for chondrocyte harvest and a secondary procedure for transplantation of the scaffold. Outcomes have been good to excellent in up to 93% of cases; however, this technique requires a two-stage procedure and can be cost-prohibitive. Particulated juvenile cartilage is a restorative technique that employs cartilage allograft from juvenile donors. The cartilage is placed into the defect and secured with fibrin glue in a single-stage procedure. Studies have shown favorable outcomes in 92% of cases, with lesions between 10 and 15 mm in diameter, but increased failure rates and poorer outcomes in lesions larger than 15 mm. This may be an alternative option for contained lesions between 10 and 15 mm in diameter. Osteochondral allograft plugs are an option for larger contained lesions (>1.5 cm in diameter) and in patients with knee osteoarthritis (OA) and concern for donor site morbidity. Furthermore, bulk osteochondral allograft from a size-matched talus can also be used for even larger, unstable/uncontained shoulder lesions. An anterior approach is often employed and fixation is achieved via placement of countersunk headless compression screws. Failure of the aforementioned options associated with persistent pain or progressive OA would then lend consideration to ankle arthroplasty versus ankle arthrodesis.