COMPLEX
CARPAL
DISLOCATION
L. R. IRWIN, R. PAUL, R. KUMAREN and T. K. BAGGA
From the Department of Orthopaedic Surgery, District GeneralHospital, Grimsby, Humberside, UK We present an unusual case of carpal dislocation which to our knowledge has not previously been described in any of the current classifications of such injuries. Despite the extensive damage sustained, the case was managed without difficulty and outcome has been very satisfactory.
Journal of Hand Surgery (British and European Volume, 1995) 20B." 6:746-749 X-rays showed that there was a marked carpal disruption but no significant fracture. The radial side of the carpus appeared to have been dorsally displaced and the ulnar side was displaced in a volar direction (Fig 1), both about an axis of rotation passing through the lunate and capitate. Detailed assessment showed an undisplaced crack fracture of the dorsal capitate and a minor degree of dorsal subluxation of the capitate with respect to the lunate, the latter appearing to be in normal alignment and orientation. On the ulnar side, there was a disruption of the intermetacarpal joint between the third and fourth metacarpals. The line of this disruption passed proximally through the capito-hamate joint and then between
CASE R E P O R T
A 58-year-old farmer presented 30 minutes after injury, having caught his dominant right hand in a rope which was being wound at speed onto an agricultural winch. He described clearly the mechanism of injury which was a combination of extension, internal rotation and supination. Examination of his hand revealed a closed injury with dorsal and ulnar deviation of his hand, and marked swelling of the distal quarter of his forearm and hand as far as the base of the digits. All movements of the wrist were severely restricted. The digits were well perfused and there was diminished sensation to the thumb and index finger.
Fig 1
( ~ d ) The initial findings on radiological assessment. The injuries sustained are described in detail in the text. 746
COMPLEX CARPAL DISLOCATION
Fig 1
747
(continued) Please see p. 746 for legend.
the hamate and triquetrum. The hamate and ulnar metacarpals were therefore dislocated ulnarwards en bloc. The triquetrum was subluxed under image intensifier screening, but was not obviously displaced on the pre-operative films. On the radial side, the scaphoid, trapezoid and trapezium were all subluxed dorsally with respect to the lunate and capitate, but again this was not entirely clear from the original films, showing up only under the image intensifier. The injury was therefore a variant of the combined axial radial/ulnar disruption described by Garcia-Elias et al (1989). Screening with an image intensifier under general anaesthetic 2.5 hours after the injury, confirmed and clarified the earlier X-ray findings. With gentle pressure and no traction, the mechanism of injury was reversed and all joints palpably reduced (Fig 2). X-ray screening and examination revealed a surprising degree of stability, which led to the decision not to undertake
further fixation. The carpal tunnel was decompressed, revealing a contused but macroscopically intact median nerve. Reduction was maintained in a plaster splint without postoperative complications and with early full recovery of median nerve function. Swelling dissipated within 2 weeks and the stab was converted to a full cast at this stage. The plaster was removed after 6 weeks and mobilization commenced under physiotherapy supervision. The patient regained full grip strength (35 kg) and function of the wrist 3.5 months after the injury, at which point he had 0 ° to 50 ° of extension, 0 ° to 65 ° of flexion, 90 ° of both pronation and supination, radial deviation of 15 ° and ulnar deviation of 25 ° . He complained of no pain, limitation, instability or complications from his scar. Perhaps most impressively, he had returned to his previous level of employment (farming) 2 weeks before this final assessment.
748
Fig 2
THE JOURNAL OF HAND SURGERY VOL. 20B No. 6 DECEMBER 1995
(a-c) The position following reduction and in an immobilizing plaster slab in the operating suite.
COMPLEX CARPAL DISLOCATION
DISCUSSION This is an unusual variant of a per-ilunate dislocation which fails to fit into any commonly used classification of carpal injuries (Green and O'Brien, 1980; Green, 1993). The closest approximation is to a grade 4c combined axial disruption in the Amadio/Green classification (Green, 1993). The accepted classifications concentrate on peri-lunate dislocations and scapho-peri-lunate fracture dislocations (Green, 1993; Herzberg et al, 1993), although many authors admit that our understanding of these injuries is incomplete (Green, 1993; Fisk, 1984; Mayfield, 1980). Subtle variations are recorded, and while accepting that there is no universally encompassing classification or understanding of the mechanics of injury, most authors are happy to add their own interpretation to the confusion (Vegter and Bessems, 1994; Lacour et al, 1993; Brunner and Spencer, 1992; Naam et al, 1992; Livesley and Compton, 1991; Lundkvist et al, 1991). Studies often conclude that the more severe injuries with serious ligamentous disruptions are associated with a very unsatisfactory outcome (Green, 1993; Herzberg et al, 1993; Fisk, 1984; Mayfield, 1980). The outcome is said to be particularly poor from severe carpal disruptions if treatment is delayed (Lacour et al, 1993; Weir, 1992). At least one study, however, has concluded that outcome is not influenced by the pattern of disruption (Inoue and Miura, t991). There is no consensus on the criteria for selecting different modes of treatment. Surgeons have widely differing views on the relative merits of closed and open reduction as well as the many variations of fixation and immobilization (Vegter and Bessems, 1994; Lacour et al, 1993; Pai et al, 1993; Naam et al, 1992; Inoue and Miura, 1991; Livesley and Compton, 1991; Green and O'Brien, 1980). Many authors make the self-evident point that stable reduction and adequate immobilization are prerequisites for a good outcome (Lacour et al, 1993; Pai et al, 1993; Naam et al, 1992). In view of the unusual nature of the injury presented here and its apparent severity, the initial prognosis was guarded. After a very short period of time however, it became clear that function and mobility were going to be much less impaired than was at first predicted. At last follow-up, the patient had regained all useful function in his hand and had returned to full time employ-
749
ment without any trace of hindrance or disability. He refused to attend for functional radiology or power testing as he considered that this was of no benefit to him, although it would have been useful to document these features for academic completeness. It is unclear whether the better outcome than was expected was due to a speedy operative intervention or lack of impaction because of the mechanism of injury. One case is insufficient to draw any conclusion. Acknowledgements The authors gratefully acknowledge the help and assistance of the staff of Grimsby Hospital Postgraduate Library.
References BRUNNER, W. G. and SPENCER, R. F. (1992). Combined radio-carpal and mid-carpal dislocation: A case report. Journal of Hand Surgery, t7B: 140 143. FISK, G. R. (1984). The wrist. Journal of Bone and Joint Surgery, 66B: 396-407. GARCIA-ELIAS, M., DOBYNS, J. H., COONEY, W. P. and LINSCHEID, R. L. (1989). Traumatic axial dislocations of the carpus. Journal of Hand Surgery, 14A: 446 457. GREEN, D. P. and O'BRIEN, E. T. (1980). Classification and management of carpal dislocations. Clinical Orthopaedics and Related Research, 149: 55-72. GREEN, D. P. Carpal Dislocations and Instabilities. In: Green D. (Ed). Operative Hand Surgery, 3rd Edn. New York, Churchill Livingstone, 1993: 861-928. HERZBERG, G., COMTET, J. J., LINSCHEID, R. L. et al. (1993). Perilunate dislocations and fracture dislocations: A multicenter study. Journal of Hand Surgery, 18A: 768-779. INOUE, G. and MIURA, T. (1991). Traumatic axial-ulnar disruption of the carpus. Orthopaedic Review, 20: 867-872. LACOUR, C., de PERETTI, F., BARRAUD, O. et al. (1993). Luxations p6rilunaires du carpe: Int6r6t du traitement chirurgical. Revue de Chirurgie Orthop6dique, 79:114-123. LIVESLEY, P. J. and COMPTON, E. H. (1991 ). An unusual type of perilunate dislocation: Case report. Journal of Trauma, 31: 429-430. LUNDKVIST, L., LARSEN, C. F. and JUUL, S. M. (1991). Dislocation of the lunate, triquetral and hamate bones: Case report. Scandinavian Journal of Plastic Reconstructive and Hand Surgery, 25:83 85. MAYFIELD, J. K. (t980). Mechanism of carpal injuries. Clinical Orthopaedics and Related Research, 149: 45-54. NAAM, N. H., SMITH, D. K. and GILULA, L. A. (1992). Transtriquetral perihamate ulnar axial dislocation and palmar lunate dislocation. Journal of Hand Surgery, 17A: 762-766. PAI, C-H., WEI, D-C. and HU, S-T. (1993). Carpal bone dislocations: An analysis of twenty cases with relative emphasis on the role of crushing mechanisms. Journal of Trauma, 35: 28-35. VEGTER, J. and BESSEMS, J. H. J. M. (1994). A new type of crush injury of the carpus. Journal of Bone and Joint Surgery, 76B: 330-331. WEIR, I. G. C. (1992). The late reduction of carpal dislocations. Journal of Hand Surgery, 17B: 137 139.
Accepted: 14 March 1995 L. R. Irwin, Department of Orthopaedic Surgery, St James' University Hospital, Beckett Street, Leeds LS9 7TF, UK. © 1995 The British Societyfor Surgery of the Hand