There are five metatarsal bones (first, second, third, fourth, and fifth) that make up the forefoot or area from mid-foot to the toes. The digits of the foot are identified as first or great toe, second, third, fourth, and fifth. Each digit (except the great toe) includes three phalanges: proximal phalanx (closest to the ankle), middle phalanx, and distal phalanx (closest to the tip of the toe). Malunion or nonunion of the tarsal refers to the failure of a bone to unite after a fracture or imperfection in the healing position of a bone or bones. The condition involves the ankle. Tarsal is a collective name of the seven bones of the ankle, hind foot and mid-foot (calcaneus, talus, cuboid, navicular, and first, second and third cuneiform bones).

The causes of nonunion or malunion may be due to a lack of adequate blood supply at the fracture site, inadequate stabilization of the fracture, metabolic abnormalities, and infection.

The signs and symptoms of nonunion or malunion of the tarsal may include: pain; weakness; callosities; ulcers or skin breakdown; soft tissue injury; swelling; decreased circulation; instability of the deformity; and reduced mobility.

Diagnostic measures may include: general physical and examinations of nerve and muscle functions; laboratory studies; x-ray; magnetic resonance imaging (MRI); bone scan; or computed tomography (CT) scan.

The treatment of choice for a nonunion with a false joint is surgical intervention. Other treatments may include: ankle arthroplasty; splinting; casting; traction; bone graft; range of motion exercises; and medication to treat infection or pain.

Outcome of function and motion may depend on the length of time the nonunion existed. Malunion without surgical intervention is possible. Osteomyelitis may develop. The need for physical therapy may be ongoing.

• 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)).

• When multiple foot disabilities are present, but the etiology of the symptoms cannot be separated, assign a single disability evaluation for the predominant symptoms. If the etiology of the symptoms can be delineated, separate disability evaluation may be assigned under multiple DCs for foot disabilities provided that the principles of 38 CFR 4.14 have not been violated.

• With actual loss of use of a foot, rate 40 percent.