Osteochondral lesions of the talus (ankle cartilage injury)

What is an osteochondral lesion of the talus?

The ankle joint is lined with smooth cartilage. The top of the talus, the bone that sits in the ankle joint, is called the talar dome. An osteochondral lesion is an injury to the cartilage there and to the bone directly beneath it. The damaged area can be softened cartilage, or a flake or fragment that has come loose inside the joint.^[1,2] The terms “talar dome lesion,” “osteochondral defect” and “osteochondral lesion of the talus” (OLT) all describe the same kind of problem.

Symptoms

• deep ankle pain, especially when you put weight on the foot or play sports
• clicking or catching in the ankle while walking
• a locking feeling, or a sense that the ankle is unstable
• swelling when you are on your feet^[1]

These symptoms overlap with those of a sprain, a loose ligament and early arthritis, and they can go on for months after a sprain that seemed to have healed. See ankle pain and swelling.

What causes it?

Up to 75% of lesions are caused by trauma, such as an ankle sprain or fracture.^[2] If the injured cartilage doesn’t heal properly, it softens and breaks apart.^[1] An ankle that keeps giving way after a sprain can have a cartilage lesion as well as loose ligaments; see chronic ankle instability. A broken ankle can injure the cartilage as well as the bone; see ankle and foot fractures.

How it’s evaluated

We examine the ankle’s motion and where it hurts, and look at your history of injuries. X-rays are the first test, and MRI is often needed because it shows the cartilage and the bone beneath it. In some people an injection of numbing medicine into the joint helps confirm that the pain is coming from inside the joint.^[1,2] X-ray and ultrasound are available on site at our practice, and MRI is arranged with an imaging center; see foot and ankle imaging.

Non-surgical care

Treatment often begins without surgery: protection in a boot or cast, anti-inflammatory medicine, physical therapy for motion and strength, and a brace for stability.^[1]

The results are mixed. In a systematic review of 30 studies and 868 patients treated without surgery, about 45% had a good or excellent result. On X-rays, arthritis of the ankle progressed in about 9% of people, and scans showed the lesion itself worsening in roughly 11% to 12%.^[3] These figures suggest that non-surgical care is a reasonable first step for many people, and that a lesion that hasn’t improved deserves a fresh look.

When surgery is considered

Surgery is considered when non-surgical treatment doesn’t relieve symptoms.^[1] There isn’t one best operation: the choice is tailored to the lesion (its size, location and whether it is a first-time or repeat problem) and to the patient.^[2] The main approaches are:

• Removing loose fragments and stimulating healing (bone marrow stimulation, using tiny holes so the bone can bleed and form repair tissue), usually through the arthroscope^[1,4]
• Fixing a fragment back in place when the piece can be saved
• Replacing the damaged area with a plug of cartilage and bone (a graft), or with cultured cartilage cells^[4]

An older systematic review found similar success rates for bone marrow stimulation (85%), plug grafts (87%) and cell-based treatment (76%), and suggested starting with bone marrow stimulation for a first-time lesion, though it cautioned that the studies varied too much for firm conclusions.^[4] A later review found that the size of the lesion mattered: bone marrow stimulation may be best reserved for lesions smaller than about 107 mm² in area or about 10 mm across.^[5] In a study of 262 ankles followed for at least ten years, 82% of arthroscopic bone marrow stimulation procedures had not needed revision, and obesity was linked to a higher chance of revision.^[6]

For the operations, recovery and risks, see ankle cartilage repair and ankle arthroscopy. Untreated cartilage damage can contribute to arthritis over time; see ankle arthritis.

When to seek care

Consider an evaluation if ankle pain, clicking or swelling has lasted more than a few weeks after a sprain or fracture, or if the ankle catches or locks.