Osteochondral lesions (OCLs) are also referred to as Osteochondritis dissecans (OCD) or Osteochondral fractures. They are areas of localised damage to either a small area of the joint surface, the bone underlying the joint surface or both.
OCLs most commonly occur on the surface of the talus bone in the ankle joint. Sometimes they occur on the underside of the tibia (the lower end of the shin bone, known as the tibial plafond). They can occasionally occur in the subtalar joint (the joint below the ankle which is responsible for side to side movement of the foot).
It is not known how OCLs arise. Sometimes they are a form of fracture and result directly from an injury. They may occur after a severe ankle sprain. Sometimes they arise as a result of long term laxity of the ankle ligaments – the recurrent episodes of the ankle giving way cause abnormal loading of the joint leading to localised damage.
Sometimes OCLs can be seen on an ordinary x-ray. A MRI scan is the most useful way of establishing the extent of the problem. In some people a OCL might be found as an incidental finding when looking for other conditions in the ankle – not all OCLs cause pain and not all require treatment.
Smaller OCLs can be treated with keyhole (arthroscopic) surgery of the ankle. The “debridement, curettage and microfracture” technique carried out by arthroscopic surgery is effective in about 75% of people.
Treatment of larger OCLS or OCLs that do not improve with arthroscopic surgery is more complex. One innovative and reliable technique is known as AMIC (Autologous Matrix-Induced Chondrogenesis). This involves replacement of the damaged area of cartilage with a collagen membrane implant which protects the cells of the joint surface and stimulates formation of cartilage repair tissue.
Unlike some treatments for OCLs, the AMIC procedure only involves one operation. If there is an area of damaged bone this can be replaced by grafting a bit of bone from elsewhere in the leg (usually from the heel bone). Sometimes the OCLs can be difficult to reach at surgery and it can be necessary to cut and reset the bone on the inner aspect of the ankle to gain access (known as a medial malleolar osteotomy). The bone and cartilage need time to heel which usually means you wold have to keep your weight off the leg for six weeks. During this time you would use crutches or a knee walker – a knee walker is a scooter type trolley device which allows you to keep the weight off the operated foot without having to use crutches. You can read more about use of crutches in our FAQs section.