Extensor carpi ulnaris tendon instability - supination injury of the wrist
Presentation
Patient presenting after supination injury of the wrist tightening some industrial screws. Ulnar sided pain at the left wrist and forearm. Clinically unstable extensor carpi lunaris tendon with palmar subluxation when rotating the wrist.
Patient Data
The extensor carpi ulnaris tendon shows an intratendinous split lesion and mild palmar subluxation with slightly ill-defined subsheath radially to the tendon, indicative of possible subsheath injury. At the ulnar attachment of the volar (palmar) radioulnar ligament there is discontinuity with focal edema indicative of a tear. At the TFCC there is a partial tear of the styloid attachment (Palmer type Ib lesion), as well as central thinning. At the level of the prestyloid recess there is edema and thickening of the joint capsule. Partially ill-defined ulnotriquetral ligament indicative of probable partial tear. Incidental finding of a bifid median nerve in the carpal tunnel.
Case Discussion
Typical case of supination injury of the wrist, with traumatic lesions of several ulnar sided stabilizing structures and instability of the extensor carpi ulnaris tendon. The small intratendinous tear is probably chronic. The central thinning of the TFCC is also likely incidental, representing either a chronic Palmer type 2a lesion or a normal variant. In this case, the extensor carpi ulnaris tendon instability was judged to be clinically most consequential, and the patient underwent arthroscopic retinacular sling reconstruction.