CMC-1 Replacement Arthroplasty Versus Trapeziectomy

Thumb carpometacarpal (CMC-1) osteoarthritis is a common condition causing pain and disability, particularly among middle-aged and older women. When non-operative treatment fails, surgery is indicated. In Sweden, trapeziectomy (TE), with or without tendon-based adjuncts, is the standard procedure and recommended in the National Care Program introduced in 2022. However, total joint arthroplasty (TJA) has gained popularity because of reports of faster recovery and improved early function, although concerns remain regarding complications, durability, and cost. Comparative studies are therefore needed.

The aim of this study is to compare patient-reported outcomes after dual-mobility TJA versus TE, with or without tendon-based adjuncts, for CMC-1 osteoarthritis using data from the Swedish Hand Surgery Quality Register (HAKIR). To reduce bias in observational data, the study will emulate a hypothetical randomized target trial.

This registry-based cohort study will include adults aged 45 years or older undergoing primary surgery for CMC-1 osteoarthritis. Patients with previous CMC-1 surgery, bilateral procedures, inflammatory joint disease, or extensive missing baseline data will be excluded. Baseline is defined as the date of surgery, and patients will be followed using patient-reported outcome measures collected preoperatively and at 3 and 12 months.

The primary outcome is change in pain on load measured with the HQ-8 questionnaire at 12 months. Secondary outcomes include pain at 3 months, low pain levels at 12 months, other HQ-8 domains, QuickDASH score, patient satisfaction, grip and pinch strength, thumb range of motion, time to reoperation, and postoperative complications.

Potential confounders will be identified using a directed acyclic graph (DAG). Measured confounders include age, sex, surgical centre, calendar year, baseline pain, baseline function, and smoking. Unmeasured factors such as surgeon preference, patient preference, and disease severity not captured in the registry may still cause residual confounding.

Primary analyses will use linear mixed-effects regression to compare adjusted mean pain outcomes between groups at 12 months while accounting for clustering by patient and centre. Secondary outcomes will be analysed using ordinal logistic regression, Cox proportional hazards regression, and logistic regression. Missing data will be handled using multiple imputation, and sensitivity analyses using inverse probability weighting will assess the impact of reoperations and selection bias

Study Overview

• Status: Completed
• Conditions: Osteoarthritis in the Carpometacarpal (CMC) Joint

• Study Type: Observational
• Enrollment (Estimated): 1000

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Eligible patients are adults aged ≥45 years with a diagnosis of CMC-1 osteoarthritis (ICD-10 code M18) who have failed non-operative treatment and are scheduled for primary CMC-1 surgery.

Description

Inclusion Criteria:

adults aged ≥45 years with a diagnosis of CMC-1 osteoarthritis (ICD-10 code M18) who have failed non-operative treatment and are scheduled for primary CMC-1 surgery.

Exclusion Criteria:

• Bilateral CMC-1 surgery or other simultaneous hand interventions
• Previous CMC-1 surgery on the affected hand
• Inflammatory joint disease affecting the hands (e.g., rheumatoid arthritis, systemic lupus erythematosus)
• 30% missing baseline (preoperative) variables

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort
Adults diagnosed with and operated for CMC1 OA (ICD-10 M18*); Trapeziectomy (TE) with or without tendon adjunct according to routine practice with Flexor Carpi Radialis/Extensor Carpi Radialis Longus/Abductor Pollicis Longus/Palmaris Longus).; Total joint thumb base dual mobility arthroplastyDual mobility TJA

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change from baseline to 12 months in pain on load motion measured with the HAKIR questionnaire.	Pain on load motion assessed using the HQ-8 patient-reported outcome questionnaire. Responses are reported on an 11-point numerical rating scale ranging from 0 (no symptoms or discomfort) to 100 (worst imaginable symptoms or discomfort) in increments of 10.	Baseline and 12 months postoperatively

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change from baseline to 12 months in pain on unloaded motion measured with the HAKIR questionnaire	Pain on unloaded motion assessed using the HQ-8 patient-reported outcome questionnaire. Responses are reported on an 11-point numerical rating scale ranging from 0 (no symptoms or discomfort) to 100 (worst imaginable symptoms or discomfort) in increments of 10.	Baseline and 12 months after surgery
Change from baseline to 12 months in pain at rest measured with the HQ-8 questionnaire	Pain at rest assessed using the HQ-8 patient-reported outcome questionnaire. Responses are reported on an 11-point numerical rating scale ranging from 0 (no symptoms or discomfort) to 100 (worst imaginable symptoms or discomfort) in increments of 10.	Baseline and 12 months postoperatively
Change from baseline to 12 months in stiffness measured with the HQ-8 questionnaire	Stiffness assessed using the HQ-8 patient-reported outcome questionnaire. Responses are reported on an 11-point numerical rating scale ranging from 0 (no symptoms or discomfort) to 100 (worst imaginable symptoms or discomfort) in increments of 10.	Baseline and 12 months postoperatively
Change from baseline to 12 months in weakness measured with the HQ-8 questionnaire	Weakness assessed using the HQ-8 patient-reported outcome questionnaire. Responses are reported on an 11-point numerical rating scale ranging from 0 (no symptoms or discomfort) to 100 (worst imaginable symptoms or discomfort) in increments of 10.	Baseline and 12 months postoperatively
Change from baseline to 12 months in activities of daily living measured with the HQ-8 questionnaire	Activities of daily living assessed using the HQ-8 patient-reported outcome questionnaire. Responses are reported on an 11-point numerical rating scale ranging from 0 (no symptoms or discomfort) to 100 (worst imaginable symptoms or discomfort) in increments of 10.	Baseline and 12 months postoperatively
Change from baseline to 12 months in Quick Disabilities of Arm, Shoulder and Hand Questionnaire (Quick DASH)	Upper extremity disability and symptoms assessed using the Quick Disabilities of the Arm, Shoulder and Hand (QuickDASH) questionnaire. Scores range from 0 to 100, where higher scores indicate greater disability and worse upper extremity function.	Baseline and 12 months postoperatively
Change in key pinch strength	kg	Baseline and 12 months postoperatively
Change in grip strength	jamar (kg)	Baseline and 12 months postoperatively
Change in thumb radial abduction	radial abduction (degrees)	Baseline and 12 months postoperatively
Change in thumb plamar abduction	palmar abduction (degrees)	From preoperatively to 12 months postoperatively
Time to first reoperation* of the index hand		primary horizon: 12 months; secondary: maximum available follow-up
Risk of any (non-reoperation) complication within 12 months	occurrence of any registered postoperative complication of the index hand recorded in HAKIR	within 12 months after surgery

Collaborators and Investigators

• Sponsor: Karolinska Institutet
• Collaborators: Erasmus Medical Center

Study record dates

Study Major Dates

• Study Start (Actual): January 1, 2011
• Primary Completion (Actual): December 31, 2025
• Study Completion (Actual): December 31, 2025

Study Registration Dates

• First Submitted: April 29, 2026
• First Submitted That Met QC Criteria: May 6, 2026
• First Posted (Actual): May 13, 2026

Study Record Updates

• Last Update Posted (Actual): May 13, 2026
• Last Update Submitted That Met QC Criteria: May 6, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: osteoarthritis; PROM; joint replacement; trapeziectomy; CMC-1; thumb base
• Additional Relevant MeSH Terms: Musculoskeletal Diseases; Arthritis; Joint Diseases; Rheumatic Diseases; Osteoarthritis; Capillary Malformations, Congenital, 1
• Other Study ID Numbers: HAKIRcmc1

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED
• IPD Plan Description: Data generated and analyzed during this study are stored within HAKIR and are subject to Swedish data protection legislation and the GDPR. Due to legal and ethical restrictions, individual-level participant data cannot be made publicly available. Access to de-identified study data may be granted to qualified researchers upon reasonable request and subject to approval by the Swedish Ethical Review Authority and the HAKIR steering committee. Access to the statistical code will be granted after reasonable request.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No