Objective:

To present the case of a male tennis player, with wrist pain and ulnar neuropathy in the Guyon's canal, without known trauma history.

Method:

The assessment included clinical data, imaging and nerve function study. The neurophysiological study confirmed ulnar neuropathy, but neither conventional radiology nor ultrasound provided an etiologic diagnosis, achieved only with the use of computed tomography scan.

The patient was operated via volar approach, Guyon's canal opening and osteosynthesis with two 1.5 mm diameter screws.

Results:

The clinical recovery and the consolidation of the pseudoarthrosis occurred at four months after the procedure.

Conclusions:

Pain in the ulnar border of the hand in association with flexor tenosynovitis of the fourth and fifth fingers and/or signs of distal ulnar neuropathy, in patients practicing sports that involves hand grip, forces to perform computed tomography scan, and if it shows a pseudoarthrosis of the hook of the hamate, osteosynthesis should be tried.