PREDICTING PALMAR RADIO-CARPAL LIGAMENT DISRUPTION IN FRACTURES OF THE DISTAL ARTICULAR SURFACE OF THE RADIUS INVOLVING THE PALMAR CORTEX

12 adult cadaver wrists were dissected to identify the regions of orig in of the four palmar radio-carpal ligaments. A non-dimensionalized va lue, called the radio-carpal ligament ratio (RLR), was defined as the width of ligament origin from the radius divided by the length of the capitate. Both values were measured directly from radiographs of the c adaver specimens. The RLRs for the four palmar radio-carpal ligaments were found to be statistically consistent. We applied the RLR concept retrospectively to 20 wrists with intraarticular distal radius fractur es requiring open reduction. It was found that those fracture patterns in which the fracture fragment ratios (FFR: widths of the fracture fr agments divided by the length of the capitate) were outside the limits of corresponding RLRs had clear intra-operative evidence of palmar ra dio-carpal ligament disruption, while those with FFRs within the limit s of corresponding RLRs were noted to have no ligament disruption.