Osteochondral defects of the ankle have been described with several names, including osteochondral lesions, osteochondral fractures, dome fractures, and osteochondritis dessicans. Osteochondral defects typically occur at the bottom bone of the ankle joint, named the talus. They typically result from previous ankle trauma, such as a sprain or ankle fracture.
The talus has limited capacity to repair itself, and patients with chronic pain should be evaluated for these focal areas of cartilage and/or bone loss. X-rays may show injuries at the talar dome, but are limited insofar as bone damage also must be present to detect these injuries radiographically. Magnetic resonance imaging provides more detailed information regarding cartilage injury and other pathologies around the ankle joint.
CT-Scans of Osteochondral Defect of the Talus
Nonsurgical Treatment for Osteochondral Defects
Generally, nonsurgical treatment involves an initial period of no weight bearing with cast immobilization, followed by progressive weight bearing and mobilization to full ambulation by 12 to 16 weeks. A meta-analysis of 14 studies with a total of 201 patients followed for approximately two years showed only a 45% success rate of nonsurgical treatment of grade I, grade II, and medial grade III talar osteochondral lesions.
Surgical Treatment for Osteochondral Defects
Surgical management is reserved for unstable fragments or for failure of nonsurgical treatment. The first line of surgical treatment is performed with ankle arthroscopy and consists of the microfracture technique or drilling, in which multiple holes spaced 2-3 mm apart are placed into the cartilage defect to stimulate cartilage healing.
Results of microfracture or drilling have been encouraging compared with those of nonsurgical treatment. In a review of 16 studies with a total of 165 patients, Tol et al found these bone marrow stimulating techniques to have had “good-to-excellent” results in 88% of patients with grade III and higher lesions.
As a second and more invasive line of treatment, osteochondral grafting may be performed to reconstruct the talar dome, also leading to high success rates with pain relief and functional improvement.
Internal fixation of osteochondral lesions may be done using a variety of methods, including screws, Kirschner wires, and bioabsorbable devices. If sufficient healthy bone forms part of the osteochondral defect, fixating the osteochondral lesion may lead to significant healing.
Postsurgical Recovery for Osteochondral Defects
Following ankle surgery for osteochondral defects, patients typically are instructed to remain nonweight-bearing for 6 weeks. Ankle range-of-motion is begun at the time of suture removal, typically at two weeks. Patients are placed into CAM boots and are instructed to perform range of motion exercises at least 3 times per day.