Computational contact analysis of joint congruency.

Joint contact analysis of the musculoskeletal system is an important biomedical research topic due to its significant clinical relevance. In this research, the finite element method was used to study the effect of joint congruencies (various radii, R1 and R2), contact area (angles theta), and contact stresses of articular joints (the far-field applied pressure, P = 10,000 Pa). In total, 12 joint congruency cases, ranging from R1/R2 = 100% (congruent) to R1/R2 = -100% (highly incongruent) were analyzed. The linear finite element (quasi-static/equilibrium) results show that peak contact stress delta r of a congruent joint (R1 = R2 theta = 90 degrees) is -13,068 Pa. However, with a slight change of joint congruency (R1/R2 = 99.7%), the contact area decreases dramatically (theta = 30 degrees) and leads to a much higher concentrated contact stress, delta r = -27,894 Pa. When R1/R2 = -100%, the finite element result shows that the contact region is only theta = 3 degrees and the associate peak contact stress delta r is -229,943 Pa.