Randomized Controlled Trial of a Nudge Intervention for Common Musculoskeletal Conditions
Phase: NA
Conditions: Any Non-traumatic Musculoskeletal Condition
Sponsor: University of Texas at Austin

 
 
 
Randomized Controlled Trial of a Nudge Intervention 
for Common Musculoskeletal Conditions 
 
Testing a Brief Reassurance Message Before a Musculoskeletal 
Clinic Visit 
 
 
 
 
Unique Protocol ID: STUDY00004831.3 
 
NCT Number: Not yet assigned 
 
15 December 2025 
 
 

Title: Randomized Controlled Trial of a Nudge Intervention for Common Musculoskeletal 
Conditions 
 
Hypothesis: 
Primary null hypothesis: 
There are no factors associated with patient pre-visit enthusiasm for a return visit, test, injection, 
or surgery, including exposure to a nudge towards information and reassurance alone compared 
to usual care. 
 
Secondary null hypothesis: 
There are no factors associated with planned return visits, diagnostic tests and treatments 
scheduled after a musculoskeletal specialist consultation, including whether the patient was 
exposed to a pre-visit nudge versus usual care. 
 
 
Authors: Niek Parser, Nadia Azib, David Ring, Emily Jaarsma 
Acknowledge: N/A 
Target journal: CORR, JAAOS or JBJS 
IRB-approval: Patient factors and PROM/PREM/ and PRAM (STUDY00004831) 
 
Introduction 
Background 
Variability in human thoughts and emotions regarding sensations from common musculoskeletal 
conditions contributes substantially to variations in reported symptom intensity (levels of 
discomfort and incapability). Attitudes towards optional (discretionary) visits, tests, and 
treatments may also be shaped by these thoughts and feelings about sensations. 
  
Rationale 
Nudge theory is grounded in the understanding that human thoughts and behaviors are largely 
automatic and influenced by non-rational cognitive processes. A nudge intervention uses 
principles from cognitive science to subtly alter choice architecture without restricting options. 
Given the important role of less healthy thoughts and feelings on healthcare utilization, a nudge 
intervention that provides reassuring, evidence-based information may encourage people to 
accommodate expected bodily changes and associated sensations. Such an approach has the 
potential to enhance personal health agency while reducing utilization of low-value visits, tests, 
and treatments.   
 
Proposed methods 
Study design: Single-site, two-arm Randomized Controlled Trial  
 
Recruitment methods (if applicable): 
Prior to a visit, new and return patients seeking care in one of several urban MSK specialty 
clinics will be invited to participate.  
 

Randomization:  
Participants will be randomized equally (1:1) to receive the nudge intervention or usual care. 
Randomization will occur via an online random number generator (random.org). 
 
Intervention: 
Participants randomized to the intervention will read LLM-generated information prior to their 
visit, reassuring them that most musculoskeletal pathophysiology is age-related or of uncertain 
(idiopathic) origin, that many people can adapt and accommodate the symptoms without seeking 
care, and that those who do seek care are generally able to manage their health on their own 
based on the advice and reassurance provided. This information will be embedded into RedCap 
as the first page for participants. After reading this, participants will rate their enthusiasm on the 
next page. 
 
Clinicians providing care will be blinded to participants’ group assignment. 
 
Consent 
Verbal informed consent will be obtained from all participants by a trained researcher 
 
Measurements 
Before a routine MSK specialty care visit, both participants in the intervention group and the 
non-intervention group will complete a questionnaire on a tablet.  
 
Both intervention and non-intervention groups will rate their preference for a return visit, a 
diagnostic test, an injection, and a surgery from 0, no interested at all, to 10, definitely want it. 
Participants in the intervention group will receive the following nudge statement prior to seeing 
the ratings: 'I think this one visit can meet all my needs’ pre-selected and the option “I’m nearly 
certain I will pursue additional visits, tests, or treatments” an optional choice that must be 
selected. People that continue with the default will be rated as 0 interest in additional visits, tests, 
injections, or surgery and the survey will close. The full text of the LLM-generated nudge 
intervention is provided in Appendix 1. 
 
Inclusion Criteria:  
Adult (18+) 
English or Spanish language 
 
New or return patient 
Any non-trauma condition 
 
Exclusion criteria: 
Cognitive or other impairment precluding completion of a survey on a tablet 
Acute traumatic pathophysiology – fracture, dislocation, sprain/strain 
 
Measured variables 
Response variables: 
Preference to pursue with (Rated from 0, I have no interest, to10, I definitely want it) 
Return visit 

Diagnostic test 
Physical therapy 
Injection 
Surgery 
 
Actual scheduled follow-up care (y/n) (entered by the researcher after the visit): 
 
Return visit 
 
Diagnostic test 
 
Physical therapy 
 
Injection 
 
Surgery 
 
 
 
Explanatory variables: 
Demographics 
Age (continuous) 
Gender (Man, Woman, Non-binary) 
 
Educational level (Elementary school, High school, Some college, Graduated college, Post-
college graduate degree (e.g., PhD), Other) 
Employment status (employed, unemployed, disabled, other (retired, student))  
Annual household income (Less than $15,000, From $15,000 to $29,999, From $30,000 to 
$49,999, From $50,000 to $99,999, More than $100,000, Prefer not to answer) 
Insurance status (Medicare, Medicaid, Private, Military, Self-pay (no health insurance), MAP, 
Other) 
 
Psychosocial measures 
Unhelpful thoughts regarding sensations (3 Questions) 
Feelings of distress regarding sensation (3 Questions) 
Social health (3 Questions) 
Personal Health Agency (3 Questions) 
 
Clinical (entered by researcher) 
Region of condition: LE, UE, Spine 
Specialty of original visit: Arthroplasty, hand/upper extremity, shoulder/sports, spine, foot/ankle 
Diagnosis (categorized based on enrollments) 
 
 
 
Statistical analysis 
 
Demographic, clinical, and psychosocial characteristics will be summarized using descriptive 
statistics. Continuous variables will be reported as means and standard deviations (or medians 
and interquartile ranges if distributions are non-normal), and categorical variables will be 
summarized as frequencies and percentages. 

 
• Primary outcome - Between-group differences (nudge intervention vs usual care) in 
enthusiasm scores for each outcome will be assessed using independent samples t-tests. 
Assumptions of normality and homogeneity of variance will be evaluated. If these 
assumptions are violated, non-parametric alternatives (Mann–Whitney U tests) will be 
used. Variables demonstrating p < 0.10 in bivariate analyses will be entered into 
multivariable analysis (linear regression model) 
• Secondary outcomes - Between-group differences in the proportion of participants with 
scheduled follow-up care will be assessed using chi-square tests or Fisher’s exact tests as 
appropriate. Variables demonstrating p < 0.10 in bivariate analyses will be entered into 
multivariable analysis (logistic regression model) 
 
All tests will be two-sided, and statistical significance will be set at p < 0.05. Analyses will be 
performed using StataMP version 18.0. 
 
 
Sample size 
An a priori sample size calculation was conducted using G*Power version 3.1 for a two-tailed 
independent samples t-test, comparing mean pre-visit enthusiasm scores between the study arms 
(primary outcome). Assuming a medium effect size (Cohen’s d = 0.5), a significance level (α) of 
0.05, and 80% power (1–β), the required sample size was calculated to be 128 participants (64 
per group). To ensure adequate power for the planned multivariable linear regression analyses of 
the primary outcome, a separate power calculation was performed for linear multiple regression 
(fixed model, R² deviation from zero). Assuming a medium effect size (f² = 0.15), a significance 
level (α) of 0.05, 80% power, and up to 6 predictor variables, the required sample size is 97 
participants. To account for an anticipated attrition or non-complete response rate of 
approximately 10%, the final target sample size was set at 144 participants (72 per group). 
 
Appendix 1 
 
Intervention paragraph: 
It is common to have some bone or joint pain as we get older. Your body can start to change 
even in your 20s or 30s. Sometimes the brain treats pain like a sign of injury, even when the 
body is not hurt. 
 
For people who have pain without a clear injury, the news is usually good. In most cases, the 
body is going through expected changes and is not damaged. 
 
You can decide how much medical care you want. Many people feel better with simple things 
like small changes to daily habits. Visits, tests, and treatments are often a choice, not a need.