This code refers to the surgical excision of the astragalus or talus bone. The talus is a tarsal bone that is formed by the joining of the tibula and fibula to form the ankle joint.

Surgery on this bone may result from fractures, trauma, and osteochondral lesions of the ankle.

Surgery may be a result of the underlying causes. Signs and symptoms relative to these causes may include: pain; swelling; inflammation; and difficulty in walking downhill.

Tests may be performed to determine the extent of the underlying cause and the need for surgical intervention. These tests may include: functional examination; range of motion testing (ROM); x-ray; magnetic resonance imaging (MRI); and computed tomography (CT) scan.

Depending on the cause, treatment may be conservative and aimed at preserving the articular surfaces, maintaining stability and mobility, as well as minimizing complications. Treatment measures include: cast immobilization; injection of anti-inflammatory and pain medications; no weight bearing; and rehabilitation. When preservation is unlikely, surgical stabilization by internal fixation and open reduction with or without bone grafting is the treatment. Osteochondral lesions may require removal of the bone and cartilage fragments. According to the American Orthopaedic Foot and Ankle Society, total ankle arthroplasty may be performed in certain locations around the country. Additional management may be focused on the postsurgical treatment which may include: antibiotic therapy, pain management, immobilization, and physical therapy.

Postoperatively, the residual level of mobility may depend on the amount of damage to the articular surfaces and may not be known for a prolonged period of time after the injury. There may be surgical ankylosis. Rehabilitation may be difficult and prolonged. Arthritis, degenerative disease of the tibia, fibula, and subtalar joints; chronic pain; and shortened limb with impaired gait may be long term complications. (See Diagnostic Code: 5003 Arthritis, degenerative, hypertrophic or osteoarthritis). There may also be a need for long-term anti-inflammatory and pain medications. Orthotic or assistive devices may be needed to aid walking. In the event of joint replacement, infection may develop postoperatively with associated symptoms, or there may be no symptoms for months or years. According to the American Orthopaedic Foot and Ankle Society, original ankle replacements performed in the 1970s and 1980s resulted in long-term failure rates. Infection, loosening, and collapse were complications of these earlier procedures which resulted in additional extensive surgery. At present, total ankle arthroplasty with new designs have encouraging short-term results. Long-term conditions are currently unknown.

• The rating schedule for musculoskeletal was updated on February 7, 2021. Protection still does apply and should be considered with existing evaluations (38 CFR 3.951(a)).

• None.