The association of scapho-trapezio-trapezoid osteoarthrosis and scapholunate dissociation

There are two parts to this paper. In the first part we report 18 cases of bilateral scapho-trapezio-trapezoid osteoarthrosis associated with uni- or bilateral scapholunate dissociation. This case series was followed prospectively using repeat clinical assessments and radiographs. We were able to document the progression of both the clinical manifestations and radiographic features of the scapholunate dissociation in these patients. In the second part of the paper we compared the radiographic indices of scapholunate dissociation seen in our series, that is, the scapholunate angle and interval, with those of a control group over time, to determine if there was a significant difference. The control group differed from our series principally by being devoid of any clinical or radiographic evidence of scapho-trapezio-trapezoid osteoarthrosis. We found that our case series already had some radiographic evidence of scapholunate attrition at presentation and that at follow-up the scapholunate dissociation became more pronounced both clinically and radiographically relative to the controls. The authors propose a theory to explain the association and temporal relationship between the two conditions.