Downloaded from http://journals.lww.com/jbjscc by BhDMf5ePHKbH4TTImqenVGBWJMQ4hzAOL14yw8bREUQItle5M93G3Jo67tzZm7rh on 08/20/2020 Complex, Multidirectional Carpometacarpal Dislocations A Case Report Anil Dhal, MS, Saket Prakash, MBBS, and Pulkit Kalra, MBBS Investigation performed at Department of Orthopaedics, Maulana Azad Medical College & Lok Nayak Hospital, New Delhi, India Abstract Case: We present a rare combined convergent-divergent carpometacarpal (CMC) fracture dislocation with median nerve involvement in a young adult after a motorbike accident. Radiographs revealed a volar dislocation of the second and fifth metacarpals and dorsal dislocation of the third and fourth metacarpals with bases of the second and fifth metacarpals found to be converging in the coronal plane. Open reduction and fixation was performed with carpal tunnel release. Conclusion: Combined convergent-divergent CMC fracture dislocation should be kept as a differential while evaluating CMC dislocations. Metacarpal cascade line (posteroanterior view) and 2 lateral views (radial side up and ulnar side up) with computed tomography scan (3-dimensional reconstruction) prove to be vital in such high-energy trauma. C arpometacarpal (CMC) dislocations are uncommon injuries caused by high-energy trauma such as high- speed motorcycle accidents. Dorsal dislocations are more common than volar dislocations 1 . A few cases of diver- gent dislocations, in which a combination of dorsal and volar dislocation of metacarpal bases, have also been reported in the literature. Regarding the direction of the displacement of the base of the metacarpals, we present a rare case of combined convergent and divergent carpometacarpal fracture dislocation with median nerve injury hitherto unreported in the literature. The patient was informed that data concerning the case would be submitted for publication, and he provided consent. Case Report A 30-year-old man sustained a motorbike accident while pillion riding (in the seat behind the rider) and presented to us 4 days later with grossly swollen right dominant wrist and hand (Fig. 1). He informed that his knuckles (flexed meta- carpophalangeal [MP] joints) hit the road initially with his body subsequently falling on his wrist and hand. On exami- nation, the position of the MP joints seemed much more proximal and the metacarpals seemed shortened in com- parison to the left uninjured hand. Neurological examina- tion revealed sensory deficit in the radial 3 and a half digits suggesting median nerve compression. Motor function was grossly preserved. The x-rays (Figs. 2 and 3) and computed tomography (CT) scan (Figs. 4 and 5) revealed a volar dislocation of the second and fifth metacarpals with dorsal dislocation of the third and fourth metacarpals contributing to a divergent dis- location in the sagittal plane. There was concomitant fracture of the base of the second and third metacarpals. In coronal plane, the base of second and fifth metacarpals were found to be converging because of the radial dislocation of fifth CMC joint and ulnar deviation of the dislocated base of the second metacarpal. The swelling was brought down by hand elevation, ice application, active finger movements, and oral nonsteroidal anti-inflammatory medications over the next 1 week. An open reduction and K-wire fixation was performed 8 days after the injury, on appearance of wrinkling of skin on the dorsum of hand, using a 5 cm long dorsal midline incision centered on the base of the third metacarpal. The second, third, and fourth CMC dislocations were exposed. Under finger traction, the second metacarpal base was levered out dorsally, reduced under vison, and fixed with a 1.5 mm K-wire passing through the trapezoid. Subsequently, the third and fourth metacarpal bases were manipulated into reduced position and stabilized with an intermetacarpal K-wire (1.5 mm) between the second and third metacarpal. The fifth metacarpal was difficult to approach from the dorsal midline incision; there- fore, an ulnar incision centered over the fifth CMC joint was made. The base of the fifth metacarpal was reduced by pulling it toward the ulnar side with a small bone hook and fixed with a K-wire (1.5 mm) passing through the hamate. The fractured fragments from the base of the second and third metacarpals were additionally fixed with 1 mm K-wires. Disclosure: The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article ( http://links.lww.com/JBJSCC/B188). 1 COPYRIGHT Ó 2020 BY THE J OURNAL OF BONE AND J OINT SURGERY,I NCORPORATED JBJS Case Connect 2020;10:e19.00558 d http://dx.doi.org/10.2106/JBJS.CC.19.00558