A 17 year-old left hand dominant high school baseball player presents with severe, sharp pain in his right hand at the hypothenar eminence with associated numbness and tingling of his 4th and 5th digits. The pain and tingling began after he swung his bat and hit a ground ball. You obtain x-rays and see an abnormality. What is the most likely diagnosis, differential diagnosis, and management plan?
Figure 1. Carpal tunnel view of the right hand. Case courtesy of Dr Mohammad Taghi Niknejad, Radiopaedia.org
The athlete has sustained a hook of the hamate fracture. Hook of hamate fractures account for 2-4% of all carpal fractures in athletes and generally occur in baseball, golf, or racquet sport secondary to acute trauma . Always obtain “tunnel view” or carpal tunnel view if there is a concern for a hook of hamate fracture. Radiographs have been found to be only 41% sensitive for hamate fractures, so if suspicion remains after negative radiographs, consider CT imaging .
Figure 2. Carpal tunnel view of the right hand. Arrow indicates the location of fracture. Case courtesy of Dr Mohammad Taghi Niknejad, Radiopaedia.org
In an acute hook of hamate fracture, patients present with pain over the hook of the hamate and vague description of pain over the hypothenar eminence. They may have decreased grip strength and can endorse numbness and tingling in the 4th and 5th fingers as the deep branch of the ulnar nerve lies under the hook of the hamate (ulnar tunnel syndrome).
Refer the patient as an outpatient to a hand surgeon. Hook of hamate fractures can be managed conservatively with a short arm cast. However, there has been a trend to surgical excision of the fracture, especially in athletes, as this may provide an earlier return to play with limited complications .
Hook of hamate fractures are prone to non-union given its poor vascularity. These fractures may cause the above-mentioned ulnar tunnel syndrome, which requires operative decompression of the ulnar tunnel before excision of the fractured portion of the hamate.