Estimation of joint contact pressure in the index finger using a hybrid finite element musculoskeletal approach

Abstract

The knowledge of local stress distribution in hand joints is crucial to understand injuries and osteoarthritis occurrence. However, determining cartilage contact stresses remains a challenge, requiring numerical models including both accurate anatomical components and realistic tendon force actuation. Contact forces in finger joints have frequently been calculated but little data is available on joint contact pressures. This study aimed to develop and assess a hybrid biomechanical model of the index finger to estimate in-vivo joint contact pressure during a static maximal strength pinch grip task. A finite element model including bones, cartilage, tendons, and ligaments was developed, with tendon force transmission based on a tendon-pulley system. This model was driven by realistic tendon forces estimated from a musculoskeletal model and motion capture data for six subjects. The hybrid model outputs agreed well with the experimental measurement of fingertip forces and literature data on the physiological distribution of tendon forces through the index finger. Mean contact pressures were 6.9 ± 2.7 MPa, 6.2 ± 1.0 MPa and 7.2 ± 1.3 MPa for distal, proximal interphalangeal and metacarpophalangeal joints, respectively. Two subjects had higher mean contact pressure in the distal joint than in the other two joints, suggesting a mechanical cause for the prevalence of osteoarthritis in the index distal joint. The inter-subject variability in joint contact pressure could be explained by different neuromuscular strategies employed for the task. This first application of an effective hybrid model to the index finger is promising for estimating hand joint stresses under daily grip tasks and simulating surgical procedures.

The effect of index finger distal interphalangeal joint arthrodesis on muscle forces and adjacent joint contact pressures

“…Joint contact pressure levels estimated by the finite element model ranged between 2 and 8 MPa which is consistent with the findings of Faudot et al [14]. The largest effect of fusion angle on adjacent loading was observed for participant P4, especially for PIP where the difference in joint contact pressure between control condition and a fusion of 0° is 1.9 MPa (Fig.…”

“…This result is not surprising as this participant also showed the largest variations of finger posture and muscle force. It confirms results from previous studies showing an intricate link between abilities (applied force and finger posture), muscle forces, and joint loading [14,17] and justifying the need for more studies to understand the outcomes of such surgical acts. By combining all these measurements and results, this study showed that arthrodesis simulation can lead to participant specific adaptations of index finger posture, inducing an increase in muscle forces ultimately resulting in higher contact pressure on the joint's cartilage.…”

“…The finite element (FE) model of the index finger was developed in a previous study by our group [14]. Basically, this mechanical model reproduces the three-dimensional structure of the osteoarticular system including bones, cartilage, ligaments, tendons, and pulleys (Fig.…”

“…The latter was driven by the Abaqus/Explicit analyzer (SIMULIA, Dassault System®). All the finite element model parameters, except muscle forces, such as mesh size, interaction, and boundary conditions, were the same as in the previous study [14]. For the simulated arthrodesis condition, the DIP joint angle was modified by rotating the distal phalanx around the DIP rotation axis (Fig.…”

“…The effect of arthrodesis on grip force and joint position influences muscle forces, as their production and transmission capacity also depend on joint position, through the force-length relationship and moment arm values [17,26]. Ultimately, such changes at the muscle level could also influence joint contact pressures [14]. The DIP fusion angle could thus affect the biomechanics of adjacent non-operated joints altering finger kinematics, muscle forces, and joint contact pressures.…”