Pyramido-lunar fusion in black Africans. Apropos of 32 cases

Lunotriquetral coalition is a congenital carpal anomaly rarely discovered in a white population. In the black population, most cases have concerned blacks in America, Australia and South Africa. In the Sub-Saharia area, in Senegal, the authors, after 8 incidental cases, report 32 lunotriquetral coalitions collected in 20 patients. This retrospective study comparatively analysed 361 X-rays of the wrist performed between February 1989 and July 1992 in the Orthopaedic and Traumatologic Center (CTO) in Dakar. The bony coalition was bilateral in 12 patients and unilateral in the other 8 cases. The complete form (type III) was the most frequent (46.8%). In the bilateral forms, 5 patients presented this complete form. Lunotriquetral coalition was associated, in absence of congenital abnormalities, with a synovial cyst of the wrist (2 cases), scaphoid fracture (1 case), non-union of a scaphoid fracture (1 case) and osteoarthritis of the wrist (2 cases). After review of the literature, the authors discuss racial factors, anatomo-radiographic forms and associated injuries.