Emergency Department Evaluation: Hand Injuries
patient history should include the position of the hand at the time of
injury, mechanism of injury, previous hand injuries, occupation, and
hand-dominance. Physical examination should assess for tenderness,
tendon integrity, joint stability, range of motion, two-point
sensation, capillary refill, and motor function.31
Mallet finger (also known as baseball finger) is a rupture of the extensor tendon that attaches to the dorsal side of the distal phalanx of the finger. This tendinous injury occurs when there is a forced flexion of a fully extended finger, commonly involving a baseball or volleyball striking the tip. This forced flexion can cause a rupture of the extensor tendon or an avulsion of the bone at the tendon insertion. With the extensor mechanism disrupted, the patient will be unable to fully extend the distal phalanx, although passive extension will be possible.
While the physical examination will be diagnostic, a radiograph
should be obtained to rule out an associated avulsion fracture of the
distal phalanx. Treatment is conservative and involves immobilizing the
joint in an extension splint in a neutral position (some recommend
slight hyperextension) for 6-8 weeks. The patient should be referred to
a hand specialist for follow-up.
Jersey finger, or a tear of the flexor digitorum profundus, is essentially the opposite of mallet finger, as there is a forced extension of the finger during an effort to actively flex the digit. The classic description is that of a football player trying to grab his opponent's jersey as the opponent is running downfield. The physical examination, again, is diagnostic, as the patient is unable to flex the distal phalanx at the distal interphalangeal joint. Radiographs should be obtained to rule out an associated avulsion fracture of the distal phalanx.
Jersey finger is usually managed operatively within 14 days of the
injury. The finger should be splinted with the finger and wrist flexed
and urgently referred to a hand specialist.
Gamekeeper's thumb, also known as skier's thumb (sinceskiing is now more common than twisting off the heads of rabbits), refers to injury of the ulnar collateral ligament (UCL) of the thumb's metacarpal phalangeal joint. On examination, there is tenderness over the ulnar side of the joint and weakness of pinch. Valgus stress testing of the thumb UCL should be done both in full extension and in 30° of flexion. Greater than 35º of joint laxity or 15º more laxity than the contralateral side UCL indicates a complete UCL rupture.4,32
Radiographs should be obtained before stressing the joint to exclude associated avulsion or condylar fractures. Treatment of a partial UCL rupture involves immobilization in a thumb spica cast for four weeks. Complete tears require surgery. All patients suspected of this injury should be immobilized and referred to an orthopedist, as underdiagnosis can lead to chronic disability.4