Determining Isolated Thumb Forces in Osteoarthritic and Healthy Persons

Psychometric properties of body structures and functions measures in non-surgical thumb carpometacarpal osteoarthritis: A systematic review

BACKGROUND

Measurement of treatment outcomes and change in health status over time is a critical component of clinical practice and research for people with osteoarthritis. Numerous clinical tools are used to assess the structures and function of the thumb in persons with thumb carpometacarpal osteoarthritis however their psychometrics have not yet been systematically explored.

PURPOSE

The purpose of this study was to explore the psychometric properties of clinical tools used in persons with non-surgical thumb carpometacarpal osteoarthritis to objectively measure thumb structures and function, evaluate the quality of such studies, and subsequently make clinical and future research recommendations.

STUDY DESIGN

Systematic review.

METHODS

A systematic search and screening was conducted across nine databases. Original research published between 2002 and 2022 that involved the assessment of psychometric properties (validity, reliability, precision, responsiveness, sensitivity, specificity, and minimal clinically important difference) of clinical tools were included. Sample characteristics, methods, and psychometric findings from each study were compiled. The methodological quality of included studies was evaluated using the COnsensus-based Standards for the selection of health Measurement Instruments' checklist. Two independent researchers screened articles and assessed methodological quality and when not in agreement, a third party was consulted.

RESULTS

Eleven studies were included in the review. The mean age of all participants in the studies was 69 years of age. The study designs included prospective case-control, prospective cohort, and cross-sectional to determine the psychometric properties of the measurements and tools. The included studies examined techniques to assess range of motion, strength, and pain-pressure thresholds, and screen for arthritis (ie, provocative tests). The intermetacarpal distance method, Kapandji index, pain-pressure threshold test, and pain-free grip and pinch dynamometry demonstrate excellent reliability and acceptable precision. Metacarpal extension, adduction, and pressure-shear provocative tests have superior sensitivity and specificity and the extension and adduction tests have excellent reliability. Other assessments included in the review yielded less robust psychometric properties. Studies were of variable methodological quality spanning from inadequate to very good.

CONCLUSIONS

Based on the available literature on the psychometric properties of assessments of body structures and functions in persons with non-operative thumb carpometacarpal osteoarthritis, we offer a limited set of recommendations for use when screening for arthritis symptomology and measuring hand strength, thumb mobility, and pain thresholds. Additional psychometric research is needed in these domains as well as in dexterity, sensation, and objective measures of hand function. Future research should employ best practices in psychometric research.

Complex motions embedded in a hand exercise regimen - effects on thumb function in participants with carpometacarpal osteoarthritis: A pilot study

Objective

The goal of this pilot study was to identify changes associated with completion of a unique six-week hand exercise program in persons with carpometacarpal osteoarthritis.

Methods

Twenty-four individuals, aged 55-80, with doctor-diagnosed carpometacarpal osteoarthritis participated in the study. Movement data from standard clinical motions and complex multi-planar motions were obtained using a motion capture system at three-time points: an initial visit, after two weeks of hand exercises, and after completion of the six-week exercise program.

Results

This exercise program produced trends of improvement in complex multi-planar motions. Specifically, joint angle changes were seen during opposition and the formation of an "okay sign" that was included as part of the exercise program.

Conclusion

Through the use of motion capture, changes were identified in thumb joint function after exercise. Specifically, motions associated with the more complex multi-planar tasks showed changes in individual joint contributions following the six-week exercise intervention. The results suggest that further exploration of this exercise program, particularly the inclusion of complex multi-planar tasks during osteoarthritis treatment and associated evaluations, should be considered in future clinical studies.

Simulating finger-tip force using two common contact models: Hunt-Crossley and elastic foundation

Musculoskeletal models of the hand rarely include fingerpad contact mechanics, thereby limiting our ability to simulate and examine hand-object interactions. The objective of this study was to evaluate whether two common contact models (Hunt-Crossley and Elastic Foundation) can accurately represent the fingerpad. Two musculoskeletal models of the index finger were created by adding fingerpad contact geometry using either the Hunt-Crossley or Elastic Foundation contact models. Key contact parameters (target force, contact area, and stiffness) were then systematically varied through 432 forward dynamic simulations to examine how these parameters influenced estimation of finger-tip forces. Across all simulations, variation in target force, contact area, and stiffness parameters impacted the computation time required to complete the simulations and the accuracy of the predicted finger-tip force. Computation time was over three times longer in simulations with high versus low values of contact area and stiffness in both contact models. For both contact models, larger contact area and stiffness values resulted in simulations that more closely predicted target force. However, across all simulations, the Hunt-Crossley model produced a greater proportion of accurate finger-tip force simulations than the Elastic Foundation model, suggesting that the Hunt-Crossley contact model may be preferable for modeling the fingerpad. Overall, our study demonstrates how the Hunt-Crossley and Elastic Foundation contact models behave in low-force biomechanical scenarios, such as those experienced during hand-object manipulation, and provides a foundation for incorporating contact mechanics into musculoskeletal models of the hand.