Radiographic and Computed Tomography Correlation of Kienböck's Disease: Is There a Need to Revisit Staging with Improved Imaging?

Abstract

Carpal height ratio and ulnar variance on plain X-ray were measured and compared to the width/height ratio of the lunate as measured on a computed tomography (CT) scan in 50 patients with Kienböck's disease. Width/height ratio of the lunate was also measured in a series of 50 controls. No correlation between ulnar variance and fractures was found. Conversely, the correlation between carpal height ratio on X-ray and width/height ratio on a CT scan was statistically significant. Similarly, the correlation between ulnar variance and width/height ratio was statistically significant. We have concluded that width/height ratio while correlating with carpal height is a better measure of lunate collapse. It also appeared that lunate collapse precedes carpal collapse, specifically most if not all lunates have collapsed prior to reduction in carpal height ratio. Finally, while we are unable to conclude the level at which the width/height ratio of lunate becomes unreconstructable, it does appear that in all Litchman stage 3b and most if not all of 3a the shape of the lunate has altered significantly.

Diagnostic performance of traditional radiographic indices in detection of carpal collapse in Kienböck’s disease

“…The authors concluded that the lunate W/H ratio measured on CT, while significantly correlating with CHR, is a better measure of the lunate collapse. Furthermore, they found a significant correlation between the CHR on radiographs, and the W/H ratio on CT scans in delineating advanced collapse (Mohan et al., 2020). Thus, the primary objective of previous studies was to establish specific cut-off values of radiographic indices.…”

“…(2004) showed that the Bouman index (height of the capitate divided by the carpal height) had higher applicability and sensitivity for a carpal collapse than the CHR, wherefore they recommended using the Bouman index, especially in rheumatoid arthritis patients (Bouman et al, 1994). Mohan et al. (2020) measured the CHR and ulnar variance on radiographs and compared it with the width/height (W/H) ratio of the lunate as measured on CT scans in 50 patients with Kienböck’s disease.…”

“…Patients with stages IIIa or less can be considered for surgical reconstruction techniques. In contrast, individuals with stages IIIb and IV are candidates for salvage procedures and have a worse prognosis (Mohan et al., 2020).…”