[Ulnar nerve compression and pseudoarthrosis of the medial metacarpal bases].

A case of compression of the deep branch of the ulnar nerve associated with pseudarthrosis of the base of the fifth metacarpal and the upper shaft of the fourth metacarpal is reported. The delayed procedure consisted in volar decompression of the ulnar nerve by dividing the pisi-hamate ligament and plating and grafting of both fractures. The patient achieved marked improvement four weeks post-operatively and had complete functional recovery at follow-up of 16 years after injury without narrowing of the hamato-metacarpal joint despite synostosis of the bases of the medial metacarpals.