Finite Element Analysis of In Vivo Radiocarpal Contact Mechanics Resulting From Scapholunate Ligament Injury

Secondary osteoarthritis (OA) as a result of joint injury is a significant problem. For the wrist in particular, scapholunate dissociation, resulting from injury to the scapholunate interosseous ligament (SLIL), is a commonly occurring pathology. SLIL tears can lead to scapholunate joint instability due to abnormal motion and load transfer through multiple carpal joints. If left untreated, SLIL injury has been known to progress to scapholunate advanced collapse (or SLAC wrist) with radiocarpal OA [1]. While the pathomechanics leading to the onset of OA are not clearly understood, changes in kinematics and contact mechanics with injury are believed to be causative factors. Of particular importance are joint contact pressures and pressure distributions, which are considered to be important mechanical factors. Comparing changes in joint mechanics between normal and injured wrists may help us better understand the progression of OA and improve the efficacy of corrective measures. Several techniques exist to evaluate joint mechanics. Of these, 3D image-based computational modeling is very useful to determine in vivo joint mechanics. Finite element modeling (FEM) is the most common and widely used computational method because of the ability to obtain 3D stresses and strains, and due to software availability. Therefore the objective of this study was to compare radiocarpal joint mechanics (contact forces, contact areas, contact locations, peak and average contact pressures) from FEM between normal and injured wrists. We hypothesized that peak contact pressures and average contact pressures would be higher in the injured wrists.