Radiocarpal Contact Pressures Are Not Altered after Scapholunate Ligament Tears.

Background  The scapholunate interosseous ligament (SLIL) couples the scaphoid and lunate, preventing motion and instability. Prior studies suggest that damage to the SLIL may significantly alter contact pressures of the radiocarpal joint. Questions/Purposes  The purpose of this study was to investigate the contact pressure and contact area in the scaphoid and lunate fossae of the radius prior to and after sectioning the SLIL. Methods  Ten cadaveric forearms were dissected distal to 1-cm proximal to the radiocarpal joint and a Tekscan sensor was placed in the radiocarpal joint. The potted specimen was mounted and an axial load of 200 N was applied over 60 seconds. Results  Sectioning of the SLIL did neither significantly alter mean contact pressure at the lunate fossa ( p  = 0.842) nor scaphoid fossa ( p  = 0.760). Peak pressures were similar between both states at the lunate and scaphoid fossae ( p  = 0.301-0.959). Contact areas were similar at the lunate fossa ( p  = 0.508) but trended toward an increase in the SLIL sectioned state in the scaphoid fossa ( p  = 0.055). No significant differences in the distribution of contact pressure ( p  = 0.799), peak pressure ( p  = 0.445), and contact area ( p  = 0.203) between the scaphoid and lunate fossae after sectioning were observed. Conclusion  Complete sectioning of the SLIL in isolation may not be sufficient to alter the contact pressures of the wrist. Clinical Relevance  Injury to the secondary stabilizers of the SL joint, in addition to complete sectioning of the SLIL, may be needed to induce altered biomechanics and ultimately degenerative changes of the radiocarpal joint.