Avascular necrosis and vascular anatomy of the metacarpals.

Aseptic necrosis of the metacarpal head is extremely rare and has been described in association with systemic lupus erythematosus, steroid use, trauma, and other sites of bone infarction. The long metacarpal is the most commonly involved. The extrinsic and intrinsic vascular anatomy of the metacarpal is described in fifty metacarpal specimens. No definite conclusions can be drawn about anatomic variations in blood supply between the different metacarpals. However, in 35% of the specimens, a main arteriole in the distal epiphysis was absent, making these metacarpal heads solely dependent on small circumferential pericapsular arterioles. This group of metacarpals, when associated with other risk factors, such as trauma, systemic lupus erythematosus, or steroid use, may be at increased risk for the development of aseptic necrosis.