RESUMO
Posttraumatic ulnar radiocarpal translation is a rare, often subtle, highly unstable, and potentially devastating manifestation of severe "proximal radiocarpal ligamentous instability. Radiocarpal dislocation should alert the treating physician to the risks of the spectrum of radiocarpal instabilities. Radiocarpal instability may initially be masked or unappreciated owing to presentation without radiocarpal dislocation, local pain and swelling, initially normal standard wrist radiographs, lack of recognition, or delay in the appearance of a static lesion. The specificity, sequence, and extent of extrinsic radiocarpal and ulnocarpal ligament traumatic disruptions are not fully understood, vary with injury severity, and may differ in instances of dorsal as opposed to palmar subluxation or dislocation. Multidirectional (global) wrist instability typically accompanies this ulnar radiocarpal instability in its most severe form and consequences may be dire. The carpus may be difficult to reduce or maintain owing to marked instability, compressive forces across the wrist, and soft tissue or bony fragment interposition. Additional local distal radioulnar joint or intercarpal injuries may further confound stability and require their own specific and simultaneous treatment. Radiocarpal reduction and repair of the radioscaphocapitate ligament and radiolunate ligaments may be sufficient treatment for acute isolated palmar radiocarpal instability. Temporary K-wire fixation may be added as a precaution to prevent palmar carpal subluxation during the time of ligament healing. Radiocarpal reduction, palmar and dorsal soft-tissue repair, and temporary K-wire fixation comprise one method of treatment for early recognized cases of post-traumatic ligamentous ulnar radiocarpal transposition. Halikis et al have recommended radiolunate arthrodesis. Rayhack et al have suggested that limited or complete wrist arthrodesis may be indicated for patients with delayed presentation or in acute cases with extreme instability. Wrist arthrodesis is one means of management for patients with severe radiocarpal instability confounded by distal radioulnar joint or intercarpal instability, as seen in our patient. Damaged ligaments may have a poor blood supply and often may not hold sutures or heal well. Bone anchor sutures or some type of ligament augmentation may help to restore joint stability in some patients. Loss of stability may occur later owing to ligamentous laxity or inadequate soft-tissue healing. Radiolunate, radiocarpal, or complete wrist arthrodesis may be necessary to relieve pain, restore wrist alignment and stability, and reestablish extremity function for patients with chronic radiocarpal instability. Wrist symptoms, age, general health, hand dominance, and occupation may be among the factors that influence the necessity for and timing of reconstruction. Rayhack et al have also postulated that negative ulnar variance may accommodate the occurrence of ulnar radiocarpal translocation and confound repair owing to lack of buttress at the ulnocarpal joint. They further speculated that a joint leveling procedure might improve the support for ligamentous repair or reconstruction in these cases. Permanent functional impairment must be anticipated in patients with ulnar radiocarpal instability. Impairment has typically been commensurate with the extent of the initial lesion, additional confounding local lesions, and length of follow-up.