Complete Compound Dislocation, Without Fracture, of the Distal Joint of the Ring Finger

Abstract

The following case of complete compound dislocation of the middle phalanx upon the terminal phalanx of the right ring finger is thought to be of sufficient rarity and interest to warrant its report, especially as there was no associated fracture. In reviewing the literature, in English, of the past five years, only 8 reports of compound dislocation unassociated with fracture have been found. Of the 8 cases recorded, only 1 involved a finger, in that case the thumb. The thumb is more susceptible to this type of injury because of its position away from the other fingers, which work together and act as a protection to one another. For this reason the ring finger is less liable to such an accident. Of the other cases reported in the recent literature, 6 involved the ankle and 1 the knee (1). Hermann (1), in his discussion of the management of compound dislocations and fracture-dislocations, mentioned that in 19,291 cases obtained from the Boston City Hospital records for the period 1928 to 1937, inclusive, only 117 were compound fracture-dislocations, an incidence of 0.6 per cent. None of these was reported as a pure compound dislocation without associated fracture. Of an additional 2,374 cases in the year 1937 reviewed by Hermann, only 13 were of the compound dislocation or compound fracture-dislocation type, an incidence of 0.5 per cent. While this latter series is not subdivided into dislocations with and without fracture, one may assume that the latter constitute only a small fraction of the total incidence. It has been suggested by Bell and Lock-wood (2), Conwell and Alldredge (3), Devine (4), Haines (5), North (6), and Penhallow (7) that these dislocations are produced by direct trauma, the direction of application of force being such that one articular surface of the joint is moved in a direction parallel with the other, which usually remains stationary. The resultant dislocation and compounding occur when the joint capsule ruptures without tearing away from its bony attachment and producing a chip fracture. If the capsule were torn away from its attachments to the cancellous bone, it would seem probable that chips of bone could be seen on the x-ray film. Case Report T. R., aged 25 years, white male, soldier, while playing soft ball was hit on the end of the ring finger of his right hand by the ball when he attempted to catch it. His finger was injured severely, the distal end of the middle phalanx protruding through the skin on the palmar surface of the finger, with ragged laceration of the skin edges. The patient did not show any evidence of shock and complained only of slight pain. Roentgenographic examination of the right ring finger (Fig. l) revealed a compound dislocation of the distal interphalangeal joint, with the distal head of the middle phalanx protruding beyond the palmar surface of the skin, with no break in the continuity of either bone entering into the formation of this joint.