Scapholunate advanced collapse (SLAC)

Case contributed by Dr Dalia Ibrahim

Presentation

Right wrist pain, history of old wrist trauma.

Patient Data

Age: 55-year-old
Gender: Female

Extensive arthropathic changes of the radioscaphoid joint evident by severe narrowing of its joint space and subarticular sclerotic bony change and remodeling involving the scaphoid bone.

(Scapholunate dissociation) Scapholunate ligament interosseous tear resulting in increased distance (7mm) between the scaphoid and the lunate bones (Therry Thomas sign) (Normal distance < 4 mm). Proximal migration of the capitate bone.

Dorsally tilted lunate axis with increased scapholunate angle and capitolunate angles measuring 80°& 40°, (Normal >45° & > 30°)

Those findings are compatible with Dorsal intercalated segment instability (DISI).

Degenerative changes of the radioscaphoid and to less extent the intercarpal as well as the fifth carpometacarpal joints (most evident at the radioscaphoid joint) evident by  narrowing of the joint spaces, marrow degenerative changes, including subarticular sclerotic bony change and remodeling involving the scaphoid bone.

Those findings are impressive of Scapholunate advanced collapse (SLAC) (Stage IV)

Subluxation of extensor carpi ulnaris tendon.

Annotated image

1. (Scapholunate dissociation) with increased distance between the scaphoid and the lunate bones (Dashed line). Proximal migration of the capitate bone. (Red arrow)

2. Dorsal intercalated segment instability (DISI, with dorsally tilted lunate axis with increased scapholunate angle and capitolunate angles measuring 80°& 40°, (Normal <45° & <30°)

3. Degenerative changes of the radioscaphoid and to less extent the intercarpal joints.

Case Discussion

SLAC (scapholunate advanced collapse) is often a consequence of untreated chronic scapholunate dissociation or from chronic scaphoid non-union resulting in subluxation and a specific pattern of osteoarthritis. 

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Case information

rID: 32378
Case created: 24th Nov 2014
Last edited: 25th Sep 2016
Tag: wrist
Inclusion in quiz mode: Included

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