Background: Causality has not been formally demonstrated between carpal tunnel syndrome and osteoarthritis of the wrist or at the base of the thumb. The purpose of this study was to assess the relationship between carpal tunnel syndrome and concomitant degenerative osteoarthritis of the wrist or basal thumb joint. We hypothesised that wrist osteoarthritis by reducing the free volume of the carpal tunnel would be associated with carpal tunnel syndrome, while basal thumb osteoarthritis would show no direct correlation with carpal tunnel syndrome.
Methods: A case-control study including 95 cases and 99 control subjects, has been carried out. Sixty-eight per group were matched for age and sex. Posterior-anterior and lateral plain wrist radiographs for the two matched groups were analysed.
Results: Except for scaphotrapeziotrapezoid location, degenerative osteoarthritis of the wrist was significantly linked with carpal tunnel syndrome, whereas there was no significant difference between case and control groups for prevalence of basal osteoarthritis of the thumb.
Conclusions: These results suggest that basal osteoarthritis of the thumb is not a causal factor in carpal tunnel syndrome. In contrast, degenerative osteoarthritis of the wrist was strongly associated with carpal tunnel syndrome, suggesting a causal relation.
Keywords: Carpal tunnel syndrome; Case control studies; Osteoarthritis; Wrist.