Anatomical and Clinical Concepts in Distal Radius Volar Ulnar Corner fractures.

Background Volar ulnar corner fractures are a subset of distal radius fractures that can have disastrous complications if not appreciated, recognized, and appropriately managed. The volar ulnar corner of the distal radius is the "critical corner" between the radial calcar, distal ulna, and carpus and is responsible for maintaining stability while transferring force from the carpus. Description Force transmitted from the carpus to the radial diaphysis is via the radial calcar. A breach in this area of thickened cortex may result in the collapse of the critical corner. The watershed ridge (line) is clinically important in these injuries and must be appreciated during planning and fixation. Fractures distal to the watershed ridge create an added level of complexity and associated injuries must be managed. An osteoligamentous unit comprises bone-ligament-bone construct. Volar ulnar corner fractures represent a spectrum of osteoligamentous injuries each with their own associated injuries and management techniques. The force from the initial volar ulnar corner fracture can propagate along the volar rim resulting in an occult volar ligament injury, which is a larger zone of injury than appreciated on radiographs and computerized tomography scan. These lesions are often underestimated at the time of fixation, and for this reason, we refer to them as sleeper lesions. Unfortunately, they may become unmasked once the wrist is mobilized or loaded. Conclusions Management requires careful planning due to a relatively high rate of complications after fixation. A systematic approach to plate positioning, utilizing several fixation techniques beyond the standard volar rim plate, and utilizing fluoroscopy and/or arthroscopy is the key strategy to assist with management. In this article, we take a different view of the volar ulnar corner anatomy, applied anatomy of the region, associated injuries, and management options.

Arthroscopic Resection of Lunotriquetral Coalition.

Carpal coalition is a rare condition caused by a failure in the process of apoptosis. It is often incidentally diagnosed and seldomly symptomatic. The lunotriquetral joint is the most commonly affected joint, accounting for 90% of carpal coalitions. Minnaar classified the lunotriquetral coalitions into 4 types based on their type, extent, and associated abnormalities. Accurately classifying the coalition requires advanced imaging, and we show an example that includes 2-dimensional and 4-dimensional computed tomography and magnetic resonance imaging. Management of carpal coalitions include nonoperative and operative management. Splinting, anti-inflammatory drugs, hand therapy, activity modification, and steroid injections are all examples of nonoperative management. Operative management of coalitions in the carpus has historically been an arthrodesis whereas in the tarsal bones the gold standard is resection. Arthrodesis has a high complication rate and reduces wrist range of motion, whereas resection retains range of motion and allows the patient to return to activity sooner. We present 2 techniques of treating symptomatic carpal lunotriquetral coalition with arthroscopic resection.