Osteochondral Lesion Of Talus

An osteochondral lesion of the talus (OLT) is an area of abnormal, damaged cartilage and bone on the top of the talus bone (the lower bone of the ankle joint). This condition is also known as osteochondritis dissecans (OCD) of the talus or a talar osteochondral lesion (OCL). It is often associated with a traumatic injury such as a severe ankle sprain. However, it can also occur from chronic overload due to malalignment or instability of the ankle joint.

OCLs most commonly occur in two areas of the talus:
• The inside and top part of the lower bone of the ankle (the medial talar dome) or

• The outside and top part of the lower bone of the ankle (the antero-lateral talar dome)

SYMPTOMS

Many patients with talar OLTs are asymptomatic . OLTs can be an incidental finding on an MRI ordered to assess another problem. However, if the lesion is large enough, or the overlying cartilage is displaced, talar OLTs can be quite symptomatic. These symptoms could include localized ankle pain, as well as discomfort on either the inside (medial talar OLT) or outside (anterolateral talar OLT) of the ankle. The pain is often worse with activities, particularly running, walking and jumping. They may also complain of mechanical symptoms, such as clicking and popping sounds caused by a loose fragment of cartilage and/or bone associated with the OLT.

DAIGNOSIS

Plain x-rays can be used to help diagnose an osteochondral lesion. Areas of decreased density (i.e., darker areas) seen on the plain x-rays can be indicative of this condition.
The gold standard for diagnosis of talar OLTs is an MRI of the ankle. An MRI of the OLT may show that the cartilage and bone damage is displaced or non-displaced .

Treatment

Non-Operative Treatment Non-operative treatment can be successful for non-displaced talar OLTs, especially if the condition is recognized and treated early, and the lesion is relatively small.

• Cast immobilization: If the OLT occurs following an acute injury, initial immobilization in a cast for 4-6 weeks can help reduce stress on the OLT and allow healing.

• Physical therapy: working on strengthening the muscles around the ankle, range of motion of the ankle, and balancing (proprioception)

• Protective braces (ex. Ankle BRACE) to decrease stress can also be utilized

In younger patients, this condition has the potential to heal, making it possible to treat acute non-displaced talar OLTs with immobilization in a cast or CAM walker.

Operative Treatment Surgical treatment is indicated for displaced talar OLTs or lesions that have not improved with appropriate non-operative management. Surgical

treatment of talar OLTs includes:

• Arthroscopic debridement and microfracture of the talar OLT. This is the standard operative treatment and leads to good or excellent results in 75-80% of patients with typical talar OCLs

• Osteochondral Autologous Autograft Transfer (OATs Procedure) An OATs-type procedure is reserved for patients who have been treated with arthroscopic cleaning out (debridement) and microfracture and are still not doing well, or patients that have a very large talar OLT. This procedure may also be called a mosaicplasty. The theoretical advantage of this procedure is that it replaces the damaged cartilage with cartilage and bone harvested from the patient (autograft). The graft is usually harvested from the patient's knee on the same leg, from an area of that joint that does not bear any load.

• Osteochondral Allograft Transfer : A bone and cartilage plug may also be obtained from a cadaver and transplanted into the OLT

• Autologous chondrocyte transplantation (ACI): There has been an attempt to harvest a patient's own healthy cartilage, grow the cells in a lab, and then reimplant these cells back into the area where the cartilage has been lost