Carpal Tunnel Release Efficacy Trial (FOCUS)

eFficacy Of Carpal tUnnel releaSe (FOCUS) - Protocol for Randomised Controlled Multicentre Triple-Blinded Placebo Surgery Carpal Tunnel Release Trial With Observational Group

Background Carpal tunnel syndrome (CTS) is a prevalent condition that affects 2.7% of the population, especially women. It arises due to compression of the median nerve in the wrist and is linked to factors like diabetes, obesity, and physical workload. Non-surgical treatments such as splinting and corticosteroid injections are often the first approach for mild to moderate CTS but show mixed long-term results. Surgical intervention, carpal tunnel release (CTR), is frequently necessary and has a success rate of 75-88%. CTR is a safe procedure, but like any surgery, it carries risks, including scarring and nerve injury.

Rationale Despite its widespread use, the effectiveness of CTR surgery has not been rigorously tested through randomised controlled trials (RCT) against placebo. This leaves a critical gap in understanding whether observed improvements result from surgery or the natural course of CTS, which can sometimes resolve on its own. Previous RCT in hand surgery have faced methodological issues, emphasising the need for high-quality research to validate the benefits of CTR surgery.

Objectives

FOCUS (eFficacy Of Carpal tUnnel release) trial, aims to provide robust evidence of CTR's effectiveness compared to placebo. The null and alternative hypotheses of the trial are as follows:

• Null Hypothesis: The treatment effect of CTR is not superior to placebo surgery.
• Alternative Hypothesis: The treatment effect of CTR is superior to placebo surgery

Trial Design This multinational, triple-blinded RCT includes two groups: one receiving CTR and the other undergoing placebo surgery. An additional observational cohort will enhance the trial's generalisability. Recruitment begins in Finland, with plans to expand to Denmark, China and Australia. Experienced hand surgeons will perform all procedures, and the study adheres to rigorous international guidelines (SPIRIT).

Methods Eligible participants are screened and randomised 1:1 to receive either CTR or placebo surgery. In CTR, surgeons relieve pressure on the median nerve through a small incision. Placebo surgery involves a similar incision without addressing the nerve compression. Both procedures use the same pre- and post-operative care protocols to maintain participant blinding.

Data collection involves comprehensive patient assessments at six months, one, two, and five years. A validated tool, the 6-CTS scale, is the primary outcome measure, while secondary measures include nerve conduction tests, hand strength, and patient-reported satisfaction.

The study includes 96 participants, allowing for statistical analysis with 80% power to detect meaningful differences in outcomes.Trial is triple-blinded ensuring that participants, outcome assessors, and investigators remain unaware of treatment assignments, minimising bias. Patients will be randomly assigned to 1:1 parallel groups using an internet-based randomisation program.

Ethical considerations The trial complies with the Declaration of Helsinki and national regulations. Participants provide informed consent and can withdraw at any time.

Data Management and Safety Data is securely stored in compliance with GDPR, and interim analyses are conducted to monitor safety. An independent Data Safety and Monitoring Committee (DSMC) oversees the trial, reviewing any serious adverse events.

Expected Outcomes and Significance

Discussion The trial seeks to determine whether CTR surgery provides superior outcomes compared to placebo, addressing a critical gap in evidence for this common procedure. By including patient-reported outcomes and rigorous blinding, the study emphasises improvements that matter most to individuals with CTS.

This research has far-reaching implications for patients, surgeons, and policymakers, offering insights into the value of CTR surgery. The results could refine treatment guidelines, ensuring that surgical interventions are evidence-based and benefit those most in need.

Conclusion The FOCUS-trial represents a significant step forward in validating the effectiveness of CTR surgery. By setting a high standard for surgical research, it aims to provide clarity on a widely performed procedure, contributing to improved care and outcomes for individuals with CTS worldwide.

Study Overview

• Status: Not yet recruiting
• Conditions: Carpal Tunnel Syndrome (CTS); Carpal Tunnel Surgery
• Intervention / Treatment: Procedure: Carpal tunnel release; Procedure: Placebo surgery

• Study Type: Interventional
• Enrollment (Estimated): 96
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Mikko P Räisänen, MD; Phone Number: +358503763994; Email: mikko.raisanen@pshyvinvointialue.fi
• Study Contact Backup: Name: Susanna B Hiltunen, MD; Phone Number: +358447176260; Email: susanna.hiltunen@pshyvinvointialue.fi

Study Locations

• Finland
  • Northern Savonia
    • Kuopio, Northern Savonia, Finland, 70200
      • Kuopio University Hospital
      • Contact: Mikko P Räisänen, MD; Phone Number: +358503763994; Email: mikko.raisanen@pshyvinvointialue.fi

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• CTS diagnosed with ENMG, Symptoms typical for CTS, Ability to understand and answer the questionnaires, ≥ 18 years old.

Exclusion Criteria:

• Recurrent CTS; Ongoing systematic steroid treatment, chemotherapy, or immunomodulatory treatment; Pregnancy or breast feeding; Intrinsic muscle atrophy; Peripheral neuropathies; and Profound cognitive impairment

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: CTR surgery; Carpal tunnel release will be performed.	Procedure: Carpal tunnel release; The operating surgeons will make a skin incision distally from the distal wrist crease and ulnar to the thenar crease. The appropriate tissues, including the subcutaneous tissue, palmar fascia, flexor retinaculum, and antebrachial fascia, will then be divided in CTR group. Haemostasis will be achieved using bipolar coagulation. The skin will be closed, and an appropriate dressing will be applied.
Placebo Comparator: Placebo surgery; Only skin incision will be performed.	Procedure: Placebo surgery; Only an skin incision will be made and the same time as CTR operation takes will be waited until skin closure. An appropriate dressing will be applied.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
CTS-6	The 6-item Carpal Tunnel Syndrome Symptoms Scale questionnaire (6-CTS) is a CTS-specific instrument addressing pain and numbness in daily living. 6-CTS gives a value between 1 (best) and 5 (worst).	Preoperative vs 1 year. Secondary time points 6 months, 2 years and 5 years

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
ENMG	Electroneuromyography (ENMG) has been adopted as a standard procedure when diagnosing CTS, and it can help to track improvements in nerve conduction postoperatively.	Preoperatively and 1 year
2-PD	Two-point discrimination (2-PD) has been shown to improve after CTR.	Preoperatively, 6 months, 1 year
Grip, tripod grasp, and pinch strength	Grip, tripod, and pinch strength have been shown to increase after CTR	Preoperatively, 6 months, 1 year
Global rating	Patient-rated global improvement will be assessed using the question: "How would you rate the function and pain of your hand compared to the situation before the treatment?" Participants will provide responses on a 7-step Likert scale, ranging from "Much worse" to "Much better."	Preoperatively, 6 months, 1 year, 2 years, 5 years
EQ-5D-3L	EuroQoL 5-Dimension 3-Level (EQ-5D-3L) is a Quality-of-Life assessment tool, validated in multiple languages. Scores value usually between 1.00 (perfect health) and 0 (death), but a minimum value obtainable is -0.594 (health condition worse than death). Higher score is better.	Preoperatively, 6 months, 1 year, 2 years, 5 years
VAS for pain	Visual analogue scale (VAS) has been validated for pain evaluation. Values range from 0 to 100mm, higher is worse.	Preoperative, 6 months, 1 year, 2 years, 5 years
VAS for nocturnal numbness	Visual analogue scale (VAS) has been used for evaluation of numbness after CTR. Values range from 0 to 100mm, higher is worse.	Preoperative, 6 months, 1 year, 2 years, 5 years
Willingness for a re-treatment	Willingness for a re-treatment will be assessed using the question: ""Would you prefer the same treatment again, if the result would be the same as it is now?" Possible answers are "Yes" and "No". Yes is a better answer and No is a worse answer.	1 year
Adverse events	Adverse events will be recorded and monitored.	6 months, 1 year, 2 years

Collaborators and Investigators

• Sponsor: Kuopio University Hospital
• Collaborators: University of Eastern Finland
• Investigators: Principal Investigator: Susanna B Hiltunen, MD, Wellbeing services county of North Savo, Kuopio University Hospital

Study record dates

Study Major Dates

• Study Start (Estimated): January 1, 2026
• Primary Completion (Estimated): June 1, 2029
• Study Completion (Estimated): December 1, 2033

Study Registration Dates

• First Submitted: April 11, 2025
• First Submitted That Met QC Criteria: April 11, 2025
• First Posted (Actual): April 18, 2025

Study Record Updates

• Last Update Posted (Estimated): September 19, 2025
• Last Update Submitted That Met QC Criteria: September 15, 2025
• Last Verified: September 1, 2025

More Information

Terms related to this study

• Keywords: Randomized controlled trial; Carpal tunnel syndrome; Carpal tunnel release; Sham surgery; Placebo surgery
• Additional Relevant MeSH Terms: Nervous System Diseases; Wounds and Injuries; Neuromuscular Diseases; Peripheral Nervous System Diseases; Median Neuropathy; Mononeuropathies; Nerve Compression Syndromes; Cumulative Trauma Disorders; Sprains and Strains; Carpal Tunnel Syndrome
• Other Study ID Numbers: 89/2024

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Pseudonymised patient level data can be shared within the EU/ETA. Anonymous patient level data will be available globally. These include all gathered data. Data will be shared after the trial has been finished.
• IPD Sharing Time Frame: Protocol will be published during 2025. SAP will be published with the protocol. ICF will be uploaded to clinicaltrials.gov. Primary results will be published in a peer-reviewed journal in 2030. Analytic code will be submitted with the results.
• IPD Sharing Access Criteria: Data will be shared to researchers who provide a methodologically sound proposal. Proposals should be directed to mikko.raisanen@pshyvinvointialue.fi
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ICF; ANALYTIC_CODE; CSR

Drug and device information, study documents

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