Overview
The talus is the bone that sits in the ankle mortise, and its rounded top, the talar dome, is covered by a layer of cartilage 1 to 2 mm thick. An osteochondral lesion is a patch of damage to that cartilage and the bone immediately beneath it, ranging from a bruise in the bone to a fragment of cartilage and bone that has cracked loose over a cyst. It matters because cartilage does not regrow, and a loose fragment catches between the joint surfaces.
Treatment is decided by whether the fragment is stable, how large the lesion is, and whether the bone underneath has formed a cyst. Small stable lesions are protected and become painless; unstable or persistently painful lesions are treated arthroscopically, and the size of the defect decides whether stimulating the bone to fill it is enough or a graft is needed.
Common Symptoms
- Deep, aching ankle pain with activity that lingers months after a sprain should have healed
- Pain felt inside the joint rather than over a ligament, often at the front inner or front outer corner of the ankle
- Catching, clicking or a momentary lock when the ankle is turned or loaded
- Recurrent swelling after sport or a long walk
An ankle that rolls repeatedly but does not ache deep inside is more likely chronic instability, and the two often coexist; the same twist that tears the ligaments drives the talus into the tibia. Pain that persists after an ankle fracture has healed is another common route to this diagnosis.
Causes & Risk Factors
Most lesions are traumatic. A hard inversion sprain shears the lateral shoulder of the talus against the fibula, producing a shallow, wafer-like lateral lesion; a fall from height or a twisting injury compresses the medial shoulder against the tibia, producing a deeper, cup-shaped medial lesion. A minority of medial lesions have no injury history and are attributed to a local loss of blood supply (osteochondritis dissecans), typically in teenagers. Most are diagnosed between 20 and 40, in court-sport athletes, dancers and skiers.
How It Is Diagnosed
The lesion is easy to miss because the ligaments have healed and the ankle looks normal. Dr. O'Donnell palpates the talar dome directly, with the foot pointed down to expose the front of the dome and pulled up to expose the back, and reproduces the pain at the medial or lateral corner. The anterior drawer and talar tilt tests check for associated instability.
Plain X-rays come first and show larger lesions, cysts and loose bodies, but a normal X-ray does not exclude the diagnosis. MRI is the key test: it shows the cartilage, the bone bruise beneath it, fluid tracking under a fragment (the sign that it is unstable) and any injury to the ligaments and peroneal tendons alongside. When surgery is planned, CT is added because it measures the bony defect and any cyst precisely, and that size decides the operation. Patients elsewhere can send their MRI through mymedicalimages.com.
Treatment Options
Non-operative care
Stable lesions without a loose fragment, bone bruises, and lesions in patients still growing are treated first without surgery: a walking boot for about 6 weeks, with weight bearing limited if the bone is edematous on MRI, followed by the motion, strength and balance program used for chronic instability, with no impact for 3 months. Non-operative care is given 3 to 6 months; a lesion still painful by then is unlikely to settle.
Arthroscopic debridement and microfracture
Lesions that remain painful, and any lesion with an unstable fragment, are treated by ankle arthroscopy. The loose cartilage and fragment are removed, the bone bed is cleaned, and small holes are made in the bone to release marrow cells that fill the defect with fibrocartilage. This is reliable for defects up to about 1.5 cm across without a significant cyst, and it is the operation most patients with this diagnosis need, done at Bayside Surgery Center in under an hour.
Osteochondral grafting for large or cystic lesions
Larger defects, lesions with a deep cyst, and lesions that have failed a previous microfracture are treated by replacing the lost bone and cartilage rather than filling it: a plug of bone and cartilage from the patient's own knee or a donor, or a bone graft topped with a cartilage scaffold. The choice is made from the CT.
Recovery & What to Expect
Repair cartilage matures slowly, so the joint is protected from impact well after the ankle feels normal. The timeline below is general, for arthroscopic microfracture; grafting adds 4 to 6 weeks to each phase and progression is individualized.
| Phase | Timing | What happens |
|---|---|---|
| Protection | Weeks 0–2 | Splint or boot; non-weight-bearing or touch-down weight on crutches; elevation; toe and knee motion |
| Motion | Weeks 2–6 | Daily ankle range of motion out of the boot to nourish the repair tissue; protected weight bearing; stationary bike without resistance |
| Weight bearing & strength | Weeks 6–12 | Progressive weight bearing to full; wean boot to shoe; band and calf strengthening; balance; swimming and cycling |
| Return to activity | Months 3–6 | Jogging from about month 3 to 4 if pain-free without swelling; agility and sport drills; cleared on symmetric strength and hop testing |
Desk work resumes within the first week; driving with a right-sided ankle waits for the boot to come off at about 6 weeks; running returns at 3 to 4 months and sport at 4 to 6 months.
Frequently Asked Questions
Can an osteochondral lesion of the talus heal on its own?
Bone bruises and small stable lesions with the cartilage intact can settle with 6 weeks of protection and 3 months without impact. A lesion with a loose fragment or a cyst underneath does not heal. If the ankle still aches after 3 to 6 months of protection, waiting longer rarely changes the outcome.
Why does my ankle still hurt months after a sprain?
The ligaments heal within weeks; deep aching, catching and swelling that persist beyond 6 to 8 weeks usually mean something else was injured in the same twist. An osteochondral lesion, a peroneal tendon tear or a small fracture are the usual causes, and MRI finds most.
What does surgery for an osteochondral lesion involve?
For most lesions, ankle arthroscopy through two small incisions: the loose cartilage is removed and the bone bed is microfractured so marrow cells form repair tissue. It takes under an hour as an outpatient. Large or cystic lesions are grafted with bone and cartilage instead, a bigger operation with a longer recovery. The CT scan decides which.
How long is recovery after ankle microfracture?
Crutches and a boot for about 6 weeks, full weight bearing and strengthening from weeks 6 to 12, jogging at 3 to 4 months and sport at 4 to 6 months, provided the ankle is not swelling. Grafting procedures add roughly a month to each stage. Desk work resumes within the first week.
Will an osteochondral lesion cause arthritis?
An untreated unstable lesion can, because the loose fragment and the crater wear on the opposing tibial cartilage. A treated lesion that fills with repair tissue, in a stable ankle, protects the rest of the joint well, and most patients return to full sport.
This page is for general education and is not a substitute for a medical evaluation. Treatment recommendations depend on your individual diagnosis and goals. Kevin O'Donnell, MD sees patients from Coral Gables, Miami, Brickell, Pinecrest and Coconut Grove at 475 Biltmore Way, and out-of-town patients by telemedicine.