# Carpometacarpal Osteoarthritis: Understanding the Intersection of Muscle Mechanics, Joint Instability, and Pain

> **NIH NIH R01** · UNIVERSITY OF FLORIDA · 2022 · $447,167

## Abstract

PROJECT SUMMARY
Individuals with thumb carpometacarpal osteoarthritis (CMC OA) can lose up to 50% of hand function.
Unfortunately, current conservative and surgical treatments do not provide the pain relief, strength, and mobility
needed to restore both fine and gross motor function. Improvements in clinical treatments are limited by a lack
of understanding regarding the complex relationship between thumb biomechanics and musculoskeletal pain. In
this proposal, we address this critical knowledge gap by examining the role of thumb muscles in modulating the
two primary symptoms of CMC OA: pain and joint instability. Individuals across the full spectrum of disease
severity and healthy controls will be studied to evaluate individuals who present with only joint instability, only
pain, both, or neither. In Aim 1, to what extent muscle structure changes in the presence of CMC OA and how
these changes affect muscle force-generating capacity will be evaluated. Collected data will include fascicle
length and cross-section area measured in vivo through ultrasound imaging and thumb muscle operating ranges
calculated through musculoskeletal simulations. Completion of this aim will identify changes in muscle structure
that mitigate versus aggravate CMC OA symptoms and also establish baseline data describing healthy targets
for thumb muscle force-generating parameters. In Aim 2, how thumb muscle activity influences pain will be
examined through an experiment that integrates biomechanical techniques (e.g., electromyography) and
quantitative pain testing (e.g., movement-evoked pain, quantitative sensory testing). Completion of this aim will
enhance our understanding the relationship between muscle activity and pain, thereby elucidating protective
versus detrimental compensatory movement strategies adopted by individuals with CMC OA. In Aim 3, how
thumb muscle activity influences joint stability will be examined. Collected data will include experimental
measurements of muscle activity, thumb kinematics, and thumb kinetics during functional and range of motion
tasks as well as biomechanical assessments of joint instability in the presence of active versus passive muscle
contraction. Completion of this aim will identify how CMC OA and muscle activity influences CMC joint stability,
thereby informing clinical decisions regarding how muscles should (or should not) be considered during CMC
OA treatment. Overall, this study will critically advance our mechanistic understanding of how the structure and
function of thumb muscles change in the presence of CMC OA. By evaluating muscle mechanics (Aim 1), pain
(Aim 2), and joint stability (Aim 3) in individuals with and without CMC OA, we will elucidate the co-evolution of
muscle mechanics, symptom severity, and disease severity. This knowledge will inform current and future
treatment of CMC OA, thereby improving the quality of life of individuals living with this disease.

## Key facts

- **NIH application ID:** 10444241
- **Project number:** 1R01AR078817-01A1
- **Recipient organization:** UNIVERSITY OF FLORIDA
- **Principal Investigator:** Jennifer A. Nichols
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $447,167
- **Award type:** 1
- **Project period:** 2022-04-01 → 2027-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10444241

## Citation

> US National Institutes of Health, RePORTER application 10444241, Carpometacarpal Osteoarthritis: Understanding the Intersection of Muscle Mechanics, Joint Instability, and Pain (1R01AR078817-01A1). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10444241. Licensed CC0.

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