Morphology of the scapholunate joint, lunate, and capitate in dorsal wrist ganglion: An MRI case-control study.

Abstract

BackgroundDorsal wrist ganglia (DWGs) are common, yet the contribution of carpal morphology to their formation is underexplored. We investigated whether scapholunate joint, lunate, and capitate morphology differ between DWG wrists and controls.MethodsRetrospective MRI case-control study of adults aged 18-60 years, comprising 70 DWG wrists and 70 controls. Categorical variables were lunate type (medial hamatolunate facet present or absent), scapholunate joint morphology (parallel, inverted-Y, point-like parallel), and capitate head shape (flat, round, V-shaped). Quantitative measures included capitate-triquetral distance, mid-joint scapholunate gap, and medial hamatolunate facet length, recorded only when a facet was present.ResultsInterobserver agreement was generally good across both categorical and quantitative measures (categorical κ range: 0.50-0.88; quantitative ICC range: 0.72-0.95). Capitate morphology differed between groups: round heads were more frequent in DWG (71.4%) than in controls (44.3%) (<i>p</i> < 0.05). The scapholunate gap was larger in DWG (mean 1.8 mm) than in controls (1.5 mm) (<i>p</i> < 0.05). No between-group differences were observed for lunate type (Type II: 51.4% vs 38.6%; <i>p</i> = 0.107), scapholunate joint type (<i>p</i> = 0.787), capitate-triquetral distance (<i>p</i> = 0.223), or medial hamatolunate facet length (<i>p</i> = 0.395).ConclusionDWG wrists more often exhibit a round capitate head and a larger scapholunate gap than matched controls, whereas lunate type, scapholunate joint configuration, capitate-triquetral distance, and medial hamatolunate facet length are similar. Capitate head shape may be associated with DWG; however, given the lower agreement for this parameter, this finding should be considered exploratory and requires further validation before any recommendation for routine reporting can be made. The scapholunate gap can be considered supportive context alongside clinical findings. Prospective multicenter studies with multiplanar/loaded MRI or arthroscopic correlation are warranted.