Median nerve compression by volarly displaced fragments of the distal radius

Median nerve compression may occur acutely, subacutely, or late following fractures of the distal radius. Hematoma and swelling at the mouth of the carpal tunnel are the likely cause in acute cases. A contributing factor generally not recognized initially is a volarly displaced fragment of distal radius compressing the median nerve against the proximal edge of the flexor retinaculum. In nine such fractures, median nerve compression occurred in eight. Lack of recognition led to the delay in diagnosis and treatment of two patients. The volar fragment could always be seen on the first postreduction roentgenogram. Carpal tunnel release and removal or reduction of the displaced volar fragment should be carried out as early as possible to avoid the complications of reflex sympathetic dystrophy. Removal of the bony fragment alone, without carpal tunnel decompression, may be insufficient.