Missed Hand Injuries. The best insurance against missed diagnosis of hand injuries is an adequate history and physical examination.
History. Severe upper extremity injuries are frequently dramatic and attended by emotional factors. Because of this, it is usually best to obtain a history in a deliberate, orderly way. If possible, after hearing the story, the examiner should physically demonstrate the scenario of injury back to the patient to confirm the examiner's understanding of the details, including the position of the extremity at the time of injury. If an injury involves machinery, it should be described well enough to be visualized, in simple mechanical terms: was the mechanism sharp or dull? Did the mechanism involve rotating blades, belts, or chains? Was there exposure to heat, cold, or chemicals? Much of the nature of damage and extent of injury can be predicted before the examination. For example: Did the patient land on their palm with their wrist extended or on the dorsum of their wrist? Was the patient able to pull their hand out, or was it trapped, requiring extrication? Was the bleeding pulsatile? Even in what seems to be an obvious situation, clarification is important, and one should not assume that all problems with the hand developed as a consequence of a single reported injury: Did the pain start immediately after the event, or later? Did the numbness begin at the time of injury or later? Has the hand been injured previously? Recently? A long time ago? Before the injury, were there any problem with numbness, weakness or pain? Shoulder problems? Night time hand numbness? Attention to such details from the onset can avoid misguided treatment and false expectations. Additionally, hand injuries are a common starting point for personal injury litigation, and clear initial documentation of these points will prevent needless later aggravation at the hands of lawyers.
Examination. A working knowledge of anatomy usually allows much of the examination for an acute injury to be performed without touching the obvious site of injury. Sensory, motor and vascular examination distal to the injury can provide clues as to the status of more proximal wounds. This gentle approach is clearly preferable to attempting to define the injury by probing or instrumenting a wound in the emergency room.
Rapid survey of the hand. A focused, informative survey of the injured hand can be performed in about a minute. It is best to proceed with examination of the injured hand using a systems check list technique:
Vascular: Color of the skin and nail beds compared to the opposite side can indicate arterial (pale) or venous (dark or purple) insufficiency. Allen's test can be performed without patient participation by gently squeezing the palm while occluding radial and ulnar arteries at the wrist, then releasing one artery to assess patency of the two main arteries as well as the palmar arch. Digital Allen's test is performed in similar fashion, using the examiner's fingertips to exsanguinate a finger from distal to proximal, and then releasing one or the other side at the base of the finger (digitalallen.htm). Forearm compartment pressures can be measured with commercial kits or with materials available in any emergency room.
Muscle and Tendon: Posture of the fingers can indicate specific tendon injuries. Even if the patient is unconscious or under anesthesia, if the tendons and phalanges are intact, the fingers should assume a cascade position of progressively more flexion of both proximal and distal interphalangeal joints proceeding from the index to the small finger (survey.htm, cuttend.htm). Tenodesis motion of the fingers can be used to check relative finger posture during passive wrist flexion and extension (tenodesis2.htm, tenodesis4.htm). Squeezing the mid forearm will tighten the finger flexor tendons and mimic their active action.
Bone and Joint: Rotation of the fingers may be suspected if the tips overlap, but if the fingertips are not adjacent during flexion, it is normal for them all to converge toward a common target - the distal pole of the scaphoid, where the flexor carpi radialis tendon intersects the wrist flexion crease (point2.htm, 1432000s.htm). Contour abnormalities at joints or along long bones may indicate fractures or dislocations. Common contour changes due to displaced fractures include those due to distal radius fractures (1493502sx.htm), metacarpal neck fractures, and proximal phalanx fractures. Metacarpophalangeal or proximal interphalangeal joint dislocations alter flexor / extensor tendon tension balance and may present as unusual posture or positioning of joints distal to the injury (1437308x.htm). Bruising at a site away from an area of impact, such as dorsal wrist bruising after a fall on the outstretched palm, strongly suggests an underlying skeletal injury even with normal x-rays. Passive range of motion of the elbow, wrist and fingers can be used to assess crepitation (joint surface injury), resistance (swelling, subluxation, dislocation) and instability (ligament injury).
Nerve: Because the digital nerves are superficial to the digital arteries, an abnormal digital Allen test (digitalallen.htm) in the context of any palmar finger laceration strongly suggests an associated digital nerve injury, because the zone of external injury must pass through the nerve before reaching the artery . Tactile adherence is assessed by sliding an object with a smooth surface across the palmar skin. Compared to normal skin, a smooth surface such as a glass slide or the barrel of a shiny smooth plastic pen will slide with much less resistance ("adherence") over skin affected by nerve injury because recently denervated skin does not sweat. Normally, microscopic sweat droplets on the palmar skin confer some palpable resistance to this motion. The wrinkle test makes use of the finding that recently denervated skin does not wrinkle with prolonged water contact. In this this test, fingers are immersed in water (not saline or other salt solution) for five minutes, the inspected for wrinkling, which indicates denervation if absent (1491801s.htm). The mechanism of this test is unknown.
Missed problems elsewhere.
dramatic hand injury can divert the attention of both the surgeon and the
patient from a standard trauma systems evaluation. Complications from missed
injuries are most likely when a patient has sustained a traumatic amputation
in a blunt trauma scenario, such as a traffic accident or a fall.
Life threatening central nervous system or thoracoabdominal injuries may
be missed, as well as proximal skeletal and brachial plexus injuries. A
common occult medical condition accompanying hand injury is substance abuse:
in one report, nearly half of patients requiring emergency room treatment
for hand trauma tested positive for alcohol or other substance abuse (AA).