Traumatic axial dislocation of the carpus: a case report of transscaphoid pericapitate transhamate axial dislocation

Traumatic axial dislocation of the carpus: a case report of transscaphoid pericapitate transhamate axial dislocation

J Orthop Sci (2002) 7:414–416 Traumatic axial dislocation of the carpus: a case report of transscaphoid pericapitate transhamate axial dislocation Yu...

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J Orthop Sci (2002) 7:414–416

Traumatic axial dislocation of the carpus: a case report of transscaphoid pericapitate transhamate axial dislocation Yuzo Tanaka, Toshihisa Ohshige, and Shiro Hanakawa Department of Orthopaedic Surgery, Okayama Rosai Hospital, 1-10-25 Chikkou Midori-machi, Okayama 702-8055, Japan

Abstract Traumatic axial dislocation of the carpus in a 20year-old man is described. This injury was accompanied by a crushing injury to the hand. The disruption pattern was different from those of previously reported cases. Despite the restoration of painless wrist motion postoperatively, grip strength remained below normal. Early accurate reduction, fixation, and range of motion (ROM) exercise are the treatment of choice in such complex injuries. Key words Axial dislocation · Carpus · Trauma

Introduction Traumatic axial disruptions of the carpus have been reported under a variety of different names.5,6 Most of these conditions were the result of severe trauma such as crush or blast injuries.1 These injuries have been recently classified into three groups: type AU (axialulnar), type AR (axial-radial), and type ARU (axialradial-ulnar, or combined) by Garcia-Elias et al.2 Our case, which was considered type ARU, had several unusual and interesting features. The onset mechanism of this injury is discussed.

Case report A 20-year-old right-handed man, employed as a heavy laborer, sustained a closed and crushing injury to his right hand when H-shaped steel materials fell on the lateral side of his clenched fist. The patient complained of severe pain in his right wrist. The wrist was moderately swollen, with marked limitation of range

of motion (ROM). There were no neurovascular disorders. Initial X-ray films of the wrist showed a scaphoid fracture at its waist, pericapitate dislocation (axial radial disruption), and the fourth and fifth metacarpal bases and hamate fracture dislocation (axial ulnar disruption) (Fig. 1). Closed reduction of the pericapitate dislocation was achieved with percutaneous Kirschner wire fixation between the third metacarpal and the capitate. Then, open reduction and internal fixation were performed for the scaphoid fracture with a Herbert Whipple bone screw through a volar approach. For the fourth and fifth metacarpal bases and hamate fracture dislocations, Kirschner wire fixation through an ulnar lateral approach was achieved (Fig. 2). The wrist was immobilized in a cast for 6 weeks. ROM exercise was then started. The Kirschner wires were removed 8 weeks after surgery. The scaphoid fracture was united 4 months after surgery (Fig. 3). The patient’s right/left wrist ROM 1 year after surgery was as follows: flexion, 75°/90°; extension, 50°/60°; radial deviation, 20°/25°; ulnar deviation, 50°/55°; pronation 90°/90°; and supination, 90°/90°. However, his grip strength was 70% of the contralateral normal value. A computed tomography (CT) scan showed that the diastasis remained (Fig. 4). The patient had no complaint, and was able to return to his original job without limitations. The clinical rating system that was devised by Green and O’Brien3 and modified by Cooney et al.1 was used to evaluate the degree to which function returned in this patient. The clinical score of this patient was good.

Discussion

Offprint requests to: Y. Tanaka Received: September 12, 2001 / Accepted: December 5, 2001

This case had several unusual and interesting features. The combination of transscaphoid pericapitate radial dislocation and transhamate ulnar dislocation is a rather

Y. Tanaka et al.: Traumatic axial dislocation of the carpus

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a,b Fig. 1a,b. Right wrist at presentation after injury. a Posteroanterior view, b oblique anteroposterior view. Radiographs show the scaphoid fracture, pericapitate dislocation (axial-radial disruption), and the fourth and fifth metacarpal bones and hamate fracture dislocation (axial-ulnar disruption)

Fig. 3. Follow-up posteroanterior view at 1 year. Radiograph confirms bony union

a,b Fig. 2a,b. Postoperative radiograph. a Posteroanterior view, b oblique posteroanterior view. The pericapitate dislocation was fixed with a Kirschner wire (K-wire) after reduction. The scaphoid fracture was fixed with a Herbert Whipple bone screw. The fourth and fifth metacarpal and hamate fracture dislocations were fixed with three K-wires in a reduced position

complex and a very unusual injury of the carpus. To our knowledge, this combination of injuries has not been reported previously. Axial disruption of the carpus appears to have been caused by an anteroposterior crushing force, because this force flattens the carpal arch and leads to longitu-

Fig. 4. Postoperative CT with view of normal left hand for comparison. The right carpal arch was flattened, and diastasis remained

dinal disruption of the carpus with the attached metacarpals.2 The injuring force usually causes disruption at the level of the midcarpal. The scaphoid, which acts as a stabilizing link between the proximal and distal carpal rows, fractures at its waist when the capitate exceeds the normal range of dorsiflexion in the capitate-lunate joint.3,4 In our case, which is one of type ARU, the severe radial-to-ulnar transverse compression force to the central portion between the first and

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the fourth–fifth metacarpals caused the combined axial radial/ulnar disruption, and the subsequent compression force exerted by the capitate caused scaphoid fracture. Our case could be adapted to the classifications proposed by Garcia-Elias et al.2 We consider that the direction of this injury force differed from those in the previous reports. This case involved soft tissue damage but not neurovascular injury. Judging from the X-ray films, this patient did not have major volar extrinsic and intrinsic ligament rupture, because carpal bone dissociation between the volar ligaments did not occur. This fact reveals the significance of the very strong volar ligament. Several authors suggest prophylactic carpal tunnel decompression for axial dislocation of the carpus when the proximal carpal arch is disrupted.5,6 In this case, because we believed that traumatic decompression was present, we did not perform carpal tunnel decompression. Also, carpal tunnel syndrome did not appear. The recovery of wrist ROM was sufficient, but the recovery of grip strength was not very good. This injury

Y. Tanaka et al.: Traumatic axial dislocation of the carpus

was caused by a crushing force. The osseous disruption and extensive soft tissue damage, including intrinsic muscles, caused collapse of the carpal arch. We believe the weakness of the grip strength is caused by residual diastasis and the flattened carpal arch. Accurate reduction is an essential part of the primary management of axial dislocation of the carpus. References 1. Cooney WP, Bussey R, Dobyns JH, et al. Difficult wrist fractures. Clin Orthop 1987;214:136–47. 2. Garcia-Elias M, Dobyns JH, Cooney WP, et al. Traumatic axial dislocation of the carpus. J Hand Surg Am 1989;14:446–57. 3. Green DP, O’Brien ET. Classification and management of carpal dislocations. Clin Orthop 1980;149:55–72. 4. Lowdon IMR, Simpson AHRW, Burge P. Recurrent dorsal trans-scaphoid perilunate dislocation. J Hand Surg Br 1984;9:307– 10. 5. Norbeck DE, Larson B, Blair SJ, et al. Traumatic longitudinal disruption of the carpus. J Hand Surg Am 1987;12:509–14. 6. Primiano GA, Reef TC. Disruption of the proximal carpal arch of the hand. J Bone Joint Surg Am 1974;56:328–32.