Rare old distal carpal row dislocation: wait don’t reduce or operate
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Abstract
Post-traumatic carpal dislocations are rare entities most frequently resulting from high-energy axial loading of the forearm with the wrist extended (1). Several variants of carpal dislocations exist. The most commonly observed are those involving lunate wrist trauma (1, 2). If clinicians do not employ a high index of suspicion, they readily miss the diagnosis of carpal dislocations in the emergency department. These injuries can result in persistent pain and stiffness if left untreated. X-rays are the imaging modality of choice in the early post-traumatic situation, where carpal dislocations frequently appear with only mild anomalies. If there is a difference between clinical and radiological findings, a CT scan should be used as a problem-solving tool. The eight carpal bones form a complex structure (two horizontal rows) that enables the wrist to move in three dimensions. In order to maintain wrist stability, The proximal row is an intercalated section between the radius and the distal carpal row (trapezium, trapezoid, capitate, and hamate) (3). Treatment in the acute setting should always include closure reduction and immobilization to relieve pressure on the nearby structures. K-wire may be used in conjunction with immobilization to give the wrist more stability after reduction. This used to be the previously recommended treatment. However, new research has revealed a high incidence of recurrent instability and arthritis. Open reduction is now the accepted standard approach since it has produced superior results for most injuries compared to closed reduction (1).
We report a case of complex carpal injury in a 46-year-old policeman involving dislocation of the entire distal carpal row. He presented to the emergency department complaining of tolerable right wrist pain. He allegedly fell on his extended right hand while trying to catch a thief, at which point he started feeling a mildly tolerable pain at the wrist joint. What brought him to the emergency department was not a pain, but he recalls that the exact mechanism of trauma happened ten years ago while he tried to catch a thief. At that time, he complained of mild pain but never sought medical advice. After the recent trauma, he decided to get a doctor's opinion regarding both traumas. On examination, the right hand showed a bit of extension limitation with a mild bulging during hand extension and a pain score of 3/10. A right-hand x-ray was requested and revealed overlapped carpal bones, as shown in Figure 1. A CT scan was requested to get more details regarding the carpal bones. Figure 2 shows a CT scan that confirmed a total distal carpal row dislocation. Both carpal bone rows were shown to be on top of each other in cross-sectional CT at the carpal bone level, representing the distal row, which overlapped the proximal row, as shown in Figure 3.
In this case, we can emphasize that those stable, chronic dislocations with patient adaptation did not require any reduction or operation and were not considered emergencies that needed urgent reduction or manipulation. In conclusion, even if the patient presented to the emergency department with a trauma of the exact mechanism without new findings, we may choose to wait rather than reduce or operate.
