Because the hand tolerates disuse so poorly, the beginning of early motion following fractures is important in achieving early restoration of function. This report concerns the use of a unique, expandable intramedullary device for internal fixation of metacarpal or phalangeal shaft fractures that renders enough intrinsic stability that motion may be started early without fear of loss of reduction. The device is applicable for transverse or short oblique fractures and consists of a cylindrical apparatus made of titanium that allows for collapse in the circumferential diameter. It is introduced into the medullary canal in its collapsed state, and then is released to allow reexpansion into its normal diameter in the canal with the fracture reduced over it. This gives excellent fixation and affords stability approaching that of normal bone. Minimal postoperative immobilization is needed and early restoration of motion is possible. The device may also be used to immobilize metacarpal bones or phalanges following osteotomies, and it appears to be excellent for fixation of the bone in digits to be replanted. No complications have occurred in the reported series.