What is Talar Osteochondritis Dissecans?
The ankle joint is formed by the articulation of the end of the tibia and fibula (shinbones) with the talus (heel bone). Osteochondritis dissecans of the talus or talar OCD is an injury characterised by damage to the talar bone as well as the cartilage covering it.
What are the Causes of Talar OCD?
Osteochondral injuries are most often caused by trauma to the ankle joint, such as with ankle sprains, overloading of the ankle due to instability, or poor alignment of the bones. The lower end of the tibia or shinbone may also be affected during an injury causing talar OCD. Some cases may not have any previous history of an ankle injury and may be caused by local osteonecrosis or a metabolic defect.
What are the Symptoms of Talar OCD?
A minor talar OCD where the cartilage is not displaced may be asymptomatic. Symptoms of severe talar OCD injury include:
- Localised pain of the ankle joint
- Tenderness and swelling of the ankle joint
- Difficulty in weight-bearing
- Locking of the ankle
- Popping or clicking sounds due to a loose osteochondral fragment
How are Talar OCD Injuries Diagnosed?
Your doctor will perform a physical examination and may order imaging studies such as X-rays, CT, and MRI scans. Plain X-ray images can reveal fractures of the talus as well as other ankle bones, bone spurs, and narrowing of the joint. A CT scan helps identify any bony fragments and cysts but is not very helpful to visualise bone oedema or cartilage defects. MRI is the best imaging modality to visualise cartilage and bone lesions as well as bone oedema.
What are the Treatment Options for Talar OCD?
Nonsurgical or surgical treatment may be recommended for the management of talar osteochondral injuries.
Nonsurgical treatment with immobilisation, restricted weight-bearing, and physical therapy may be ordered to help the bone and cartilage to heal while improving muscle strength, mobility, and coordination.
Surgical treatment is recommended for severe injuries and comprises debridement (removal) of the damaged cartilage and removal of any loose bodies. Some of the commonly used surgical techniques include:
- Arthroscopic debridement (removing loose tissue)
- Microfracture or drilling of the lesion
- Grafting of cartilage and bone
- Fixation of the fragments with the help of screws