[Bilateral SLAC (scapholunate advanced collapse) wrist: an unusual entity. Apropos of a 7000-year-old prehistoric case]

Abstract

SLAC (Scapho-Lunate Advanced Collapse) wrist is the most common form of osteoarthritis of the wrist. The main aetiology is ligamentous rotary subluxation of the scaphoid. The authors report on a case of bilateral SLAC wrist, identified on a prehistoric skeleton derived from the Hassi-el-Abiod site in the malian Sahara (Dutour, 1989). The paleopathological study consisted of macroscopic examination and radiological examination. Radiocarbon dating situated this human occupation to 7 thousand years ago. The diseases observed included bilateral radiocarpal lesions in an adult male individual. The degree of preservation of the carpal skeleton was 90%. Lesions were bilateral, but predominantly affected the right side. The radial styloid processes presented a lateral osteophytic cuff, giving a tapered "pen-nib" appearance. The scaphoid has a normal shape, but presented posterior and lateral osteophytes. The scaphoid surfaces of the two distal extremities of the radius and the corresponding parts of the scaphoid showed characteristic polishing. X-rays showed a band of condensation corresponding to the ivory region on the articular surfaces. In this case, the bilateral nature and the absence of any obvious macrotraumatic aetiology suggest that the only aetiology was progressive and bilateral ligamentous distension, due to repeated microtrauma analogous to that observed in sports disease (volley-ball) or in occupational diseases (jackhammer). The manufacture of stone tools (carved or polished) can be incriminated in the pathogenesis of these lesions. These lesions are therefore useful markers of repeated microtraumatic activities or "activity markers". The is the first paleopathological description and the oldest known case of bilateral SLAC wrist.