Osteochondral lesions are injuries to the talus that involve both the bone and the overlying cartilage.
These injuries are also called osteochondritis dessicans or osteochondral fractures. Osteochondral lesions to the talus (OLT) may include softening of the cartilage layers, cyst-like lesions within the bone below the cartilage, or fracture of the cartilage and bone layers.
Because the blood supply to the talus is not as rich as many other bones in the body, injuries to the talus are often more difficult to heal than similar injuries in other bones.
How do I know if I have an OLT?
OLTs usually occur after an injury to the ankle, either a single traumatic injury (85%) or as a result of repeated trauma. Common symptoms include:
Instability of the ankle joint
(Unfortunately, these symptoms are also very similar to a typical ankle sprain).
Nb. Symptoms can be vagueand are best addressed by a qualified podiatrist!
How is an OLT be treated?
Non-surgical treatment (typically type I and II)
Goal of non-surgical treatment is to allow the injured cartilage and bone to heal
Immobilisation and restricted weight bearing for 6 weeks followed by gradual progression of weightbearing and physical/podiatric therapy
After the injury, the patient should follow RICER principles (Rest, Ice, Compression, Elevation, Referral (to health practitoner such as a podiatrist). Persistent pain after several months despite the appropriate treatment can be a sign an OLT has developed.
How is an OLT diagnosed:
History taking and physical examination is always key but imaging is necessary to confirm the diagnosis.
X-Ray can show an OLT but normally additional imaging is needed such as a CT scan or an MRI to examine the integrity of the cartilage.
Classification of OLTs (see figure adjacent):
OLT’s can be classified into these categories:
Stage I: subchondral bone compression (marrow oedema)
Stage IIa: subchondral cyst
Stage IIb: incomplete separation of fragment
Stage III: complete separation but no displacement
Stage IV: displaced fragment
Surgical treatment (typically type III and IV)
Goal is to restore the normal shape and gliding surface of the talus in order to decrease pain, catching and swelling, with the long-term goal of limiting the risk of developing arthritis
Arthroscopy or large incision
Removing injured cartilage and bone
Fixing the injured fragment in place with pins or screws
Microfracture or drilling of the lesion (to create channels for blood and bone marrow to help heal)
Bone grafting the bone cyst below the cartilage
Transfer or grafting of bone and cartilage
Recovery can range from several weeks to several months.
The results of non-surgical treatment of OLTs have been disappointing. Most studies show that full resolution of the pain from an OLT occurs in less than half of cases. Studies examining the outcomes after surgical debridement and microfracture (drilling) of OLTs have show than more than 70% of patients have a good or excellent outcome.