$comminuted fracture hand$

$comminuted fracture hand$

Conversely, the index and middles finger can tolerate only minimal apex dorsal angulation, and reduction should be attempted with greater than 10° of angulation. Mobility at the CMC joint allows the patient to adapt appropriately to 10°–15° of apex dorsal angulation in the ring and small fingers, respectively, without functional impairment. Metacarpal shaft fractures are less forgiving. However, more than 30° of dorsal angulation can lead to weakness of grip. Acceptable results can be expected for small finger metacarpal neck fractures with angulation as high as 70°. Most authors recommend nonoperative management for up to 40°–50° of apex dorsal angulation in the small finger, 30° at the ring finger, 20° at the middle finger, and 15° at the index finger. Most commonly, metacarpal fractures have apex dorsal angulation. As the MCP joints naturally hyperextend by about 20°, shortening of up to 6 mm is tolerable with neutral MCP extension.Īngulation is also best assessed radiographically. Every 2 mm of shortening will result in 7° of extension lag. Shortening is potentially problematic as the extensor mechanism is attached at the level of the metacarpal head, through the sagittal bands, and therefore, the shortening will create a tendon imbalance resulting in an extension lag. Shortening is more common at the border digits or with multiple fractures, as the intermetacarpal ligament helps to prevent shortening more than 3–4 mm in the central digits. Shortening is usually detected radiographically. On examination, there may be loss of knuckle contour from shortening and more proximal dorsal bony prominence secondary to excessive angulation. Metacarpal fractures tend to have apex dorsal angulation due to the force exerted by the intrinsic and extrinsic flexors on the distal fragment. Fracture lines may be oblique, transverse, spiral, or comminuted. They may be open or closed, and intra- or extra-articular. Metacarpal fractures follow the same descriptive classification patterns as other long bone fractures. These tendons exert deforming forces on fractured metacarpals. The ring finger is the only metacarpal without a proximal tendon attachment. Proximally, the extensor carpi ulnaris attaches to the base of the small finger metacarpal, while the extensor carpi radialis longus and brevis attach to the middle and index finger metacarpal bases, respectively. The dorsal and palmar interossei arise from the metacarpals and insert into the extensor expansion and proximal phalanx. The volar plate resists hyperextension and provides stability to the metcarpophalangeal (MCP) joint, while the intermetacarpal ligament stabilizes the fingers, minimizing proximal migration and rotation of the fractured bone. The increased stability in flexion allows for more effective lateral key-pinch and grip strength. In flexion, the cam structure puts the collateral ligaments under tension which stabilizes the joint allowing minimal motion to radial and ulnar directed forces. In extension, the collateral ligaments are lax and thus the joints may deviate radially and ulnarly. The metacarpal head is cam-shaped and forms a condyloid joint with the proximal phalanx.

$comminuted fracture hand$

The index and middle finger metacarpals are fixed relative to the carpus, while the ring and small finger metacarpals are mobile with a flexion-extension arc of motion of 15–25° at the carpometacarpal (CMC) joint. Taken together, they form a transverse arch supporting the palm. The four finger metacarpals are concave on the palmar aspect.

$comminuted fracture hand$

Comminuted fracture hand