Os calcis refers to the heel bone. Astragalus is the talus bone of the ankle. Malunion refers to the imperfect union of a fractured bone.

Malunion of bones is caused by fractures that occur usually by direct trauma. Malunion may also be due to a lack of adequate blood supply at the fracture site; inadequate immobilization of the fracture; metabolic abnormalities; and infection.

The signs and symptoms of the condition may include: pain, weakness; callus formation; ulcers or skin breakdown; soft tissue injury; swelling; decreased circulation; instability of the deformity; and decreased mobility.

Tests for the condition may include: general physical and neurovascular examinations; range of motion; x-ray; bone scan; and computed tomography (CT) scan to assess the degree of injury.

Treatment may be conservative, and may include elevating the extremity; avoiding weight bearing until bone healing starts; and closed manipulation. Surgery and physical therapy may be indicated.

The outcome may depend on the type of fracture and its relationship to the articular surface. Chronic pain may last from six to twelve months. Deformity; residual weakness of the calf muscle; muscle wasting from immobilization; and antalgic gait may result. Degenerative arthritis; peroneal tendonitis; bone spurs; or entrapped nerves may also result. Depending on the severity of the injury, rehabilitation may be prolonged.

• 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.