Trapeziometacarpal Joint Laxity in Pre- and Post-Menopausal Females by Dynamic Ultrasound

Author(s): Kendra Coleman, Vivian Li, Hui Zhang, C. Kent Kwoh, Zong-Ming Li

The trapeziometacarpal joint is critical for thumb functionality and a common site for osteoarthritis, especially in post-menopausal females. Joint laxity has been identified as a contributing factor to joint instability and osteoarthritis. The purpose of this study was to investigate the difference in trapeziometacarpal joint laxity between pre- and postmenopausal females using dynamic ultrasound imaging. The thumb was placed under traction at varying force levels with ultrasound evaluation of in vivo changes in joint distance. The subjects remained relaxed throughout the traction experiment. Joint distance change was calculated as the joint separation under traction with respect to no traction force. Joint laxity was quantified by the slope of the regression line of joint distance change as a function of traction force. Two-way ANOVAs showed that the joint distance changes were significantly affected by group (p < 0.05) and force level (p < 0.001). Joint laxity for the post-menopausal group (0.0709 ± 0.0202 mm/N) was 44.1% greater than the pre-menopausal group (0.0492 ± 0.0065 mm/N; p < 0.05). This increase in trapeziometacarpal joint laxity in the post-menopausal women suggests that menopause may affect the structural integrity of joint stabilizing tissues. This study highlights the application of dynamic ultrasound imaging to assess joint integrity of the trapeziometacarpal joint and sets the stage for future research on the pathomechanics of trapeziometacarpal joint osteoarthritis.