Finnish Carpal Tunnel Surgery Study (FINCATS)

June 1, 2026 updated by: Susanna Stjernberg-Salmela, Helsinki University Central Hospital

Finnish Carpal Tunnel Study - a Randomised, Placebo-surgery Controlled Trial

Carpal tunnel syndrome (CTS) is a common condition caused by pressure from a ligament on a nerve in the wrist, leading to pain, numbness, and weakness in the hand. Surgery to cut the ligament is often recommended when non-surgical treatments do not provide sufficient symptom relief, but it is unclear how much of the improvement is due to the surgery itself versus natural recovery or placebo effects.

The FINCATS study will compare standard carpal tunnel surgery with a placebo procedure in which the ligament is not cut. Participants and the healthcare staff caring for them after the procedure will not know which procedure was performed. The study's main question is whether cutting the ligament provides greater symptom relief than a placebo procedure. In addition, eligible patients who are not willing to participate in randomized setting are invited to join a parallel observational group. Participants in this observational group are treated within usual care pathway.

Participants in both the randomized and observational group will be followed for five years to assess symptom improvement, hand function, pain, quality of life, and any side effects. The goal is to provide reliable evidence to help patients and doctors make informed decisions about treatment.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

180

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Age 18-75 years
  • Clinical manifestations of carpal tunnel syndrome: paresthesia and /or hypoesthesia in the distribution of the median nerve, possibly pain
  • Electrodiagnostically (ENMG or ENEG) verified compression of the median nerve at the carpal tunnel in the wrist, performed no more than a year before recruitment.
  • Duration of symptoms 3 months or longer
  • Patient living independently
  • Patient has not responded to the use of a resting splint supporting the wrist, nor to other possible conservative forms of treatment
  • Patient able and willing to give consent
  • The patient is willing to undergo surgical treatment for carpal tunnel syndrome.
  • The patient has access to a device that can be used to complete electronic symptom questionnaires.

Exclusion Criteria:

  • Work disability
  • Clinical findings of Abductor Pollicis Brevis atrophy
  • Symptoms and Electrodiagnostic findings of some other peripheral neural entrapment than carpal tunnel syndrome
  • Rheumatoid arthritis or other forms of systemic inflammatory disease
  • Diagnosed dementia
  • Neurologic disorders affecting the function of the hand
  • Other untreated systemic disorders or diseases with poor therapeutic balance: hypertension, epilepsy, pulmonary or cardiac disease, liver or renal insufficiency, diabetes mellitus, hypothyroidism, psychiatric disease
  • Other causes of pain and paresthesia in the hand
  • Previous trauma of the hand or wrist (e.g. distal radius fracture), which has resulted in compromised hand function
  • Previous carpal tunnel release in either hand
  • Previous nerve injury to the upper limb or cervical spine

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

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

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Carpal tunnel release
Open carpal tunnel release: skin incision, division of the palmar aponeurosis, and transverse carpal ligament.
Procedure: Carpal tunnel release
Open carpal tunnel release: skin incision, division of the palmar aponeurosis, and transverse carpal ligament.
Placebo Comparator: Placebo surgery
Placebo surgery: Skin incision and division of palmar aponeurosis
Procedure: Placebo surgery
Skin incision and division of the palmar aponeurosis
Other: Observational arm

Open carpal tunnel release: skin incision, division of the palmar aponeurosis, and division of the transverse carpal ligament.

Observational group: eligible participants included to assess potential selection bias.
Procedure: Carpal tunnel release
Open carpal tunnel release: skin incision, division of the palmar aponeurosis, and transverse carpal ligament.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Patient acceptable symptom state (PASS)
Time Frame: 4 months

PASS is used as a binary global outcome using the following question:

"Regarding your recovery from the carpal tunnel release, specifically pertaining to paresthesia, pain and overall function of the hand, would you be content if the clinical state of your hand would remain the same as it has been the past week?" Response options are: Yes, I would be content or No, I would not be content.
4 months

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Patient acceptable symptom state (PASS)
Time Frame: 6 and 9 months and 1,2,3,4 and 5 years

PASS is used as a binary global outcome measure and will be assessed using the following question:

"Regarding your recovery from the carpal tunnel release, specifically pertaining to paresthesia, pain and overall function of the hand, would you be content if the clinical state of your hand would remain the same as it has been the past week?" Response options are: Yes, I would be content or No, I would not be content.
6 and 9 months and 1,2,3,4 and 5 years
Numeric Pain Rating Scale (NRS)
Time Frame: At recruitment, 4, 6 and 9 months and 1,2,3,4 and 5 years
A patient-reported measure for pain intensity on an 11-point scale from 0 (no pain) to 10 (worst imaginable pain).
At recruitment, 4, 6 and 9 months and 1,2,3,4 and 5 years
Health-related quality of life (EuroQol 5-Dimension 5-Level (EQ-5D-5L) index value)
Time Frame: At recruitment, 4, 6 and 9 months and 1,2,3,4 and 5 years
EQ-5D-5L questionnaire, Finnish language version, using the Danish value set. Score ranges from values below 0 (health states considered worse than death) to 1.00 (full health), where higher scores indicate better health-related quality of life.
At recruitment, 4, 6 and 9 months and 1,2,3,4 and 5 years
Harms
Time Frame: Intervention (intra-operative), at 4, 6 and 9 months and 1,2,3,4 and 5 years. In addition, unprompted contacts from participant
Harms and healthcare contacts related to the operated hand will be collected systematically and unprompted using a standardized electronic case report files (eCRF). Events will be classified by type (Adverse event, Serious Adverse Event, Suspected Unexpected Serious Adverse Reaction), attribution, timing, and nature.
Intervention (intra-operative), at 4, 6 and 9 months and 1,2,3,4 and 5 years. In addition, unprompted contacts from participant
Global Impression of Improvement (PGI-I)
Time Frame: 4, 6 and 9 months and 1,2,3,4 and 5 years
A single-item patient-reported measure indicating overall perceived improvement since the start of treatment, rated on a 7-point scale from 1 (very much improved) to 7 (very much worse).
4, 6 and 9 months and 1,2,3,4 and 5 years
6-Item carpal tunnel syndrome (CTS) symptoms scale
Time Frame: At recruitment, 4, 6 and 9 months and 1,2,3,4 and 5 years
The CTS-6 is a validated six-item patient-reported questionnaire used to assess the severity of carpal tunnel syndrome symptoms, including pain, numbness or tingling, and functional impairment, with scores ranging from 0 (least severe) and 26 (most severe). A score >12 correlates with an 80% probability of CTS.
At recruitment, 4, 6 and 9 months and 1,2,3,4 and 5 years
Patient-Specific Functional Scale (PSFS)
Time Frame: At recruitment, 4, 6 and 9 months and 1,2,3,4 and 5 years
The Patient-Specific Functional Scale (PSFS) is a patient-reported measure that assesses level of functional limitations in 3-5 activities identified as important by the patient and deemed difficult to perform by the patient, due to the hand condition. The PSFS is rated on an ordinal scale from 0 (unable to perform the activity) to 10 (able to perform the activity at the same level as before the disease.)
At recruitment, 4, 6 and 9 months and 1,2,3,4 and 5 years
Health-related quality of life: EuroQol 5-Dimensions (EQ-5D) Visual Analogue Scale (VAS) (EQ VAS) )
Time Frame: At recruitment, 4, 6 and 9 months and 1,2,3,4 and 5 years
EQ-5D is a generic patient rated outcome measure (PROM) comprising five health dimensions (mobility, self-care, daily activities, pain/discomfort, anxiety/depression) and a VAS. EQVAS is a vertical visual analogue scale, on which patients rate their general health on a scale from 0 (worst imaginable health state) to 100 (best imaginable health state).
At recruitment, 4, 6 and 9 months and 1,2,3,4 and 5 years

Other Outcome Measures

Outcome Measure
Measure Description
Time Frame
Pillar pain - interview
Time Frame: At recruitment and 1 and 4 months after intervention.

Pillar pain will be assessed using two questions:

  1. Do you have pain at rest in the palm of your hand?
  2. Are you able to bear weight on your extended wrist and hand? Response options: Yes or No.
At recruitment and 1 and 4 months after intervention.
Pillar pain - pressure pain thresholds
Time Frame: At recruitment and 1 and 4 months after intervention.
Pillar pain will be assessed through pressure pain thresholds on thenar and hypothenar eminences with a digital algometer
At recruitment and 1 and 4 months after intervention.
Pillar pain - palmar skin sensation
Time Frame: At recruitment and 1 and 4 months after intervention.
Palmar skin sensation will be assessed at thenar and hypothenar eminences with a standard evaluation tool neuropen.
At recruitment and 1 and 4 months after intervention.
Blinding fidelity
Time Frame: At 4 months after intervention.
Blinding fidelity will be assessed by asking participants which treatment group they believe they were allocated to. Response options will include "Carpal tunnel release," "Placebo intervention," or "Unsure."
At 4 months after intervention.
Conduction velocity
Time Frame: At 4 months after intervention.
Nerve conduction velocities will be assessed in randomized participants using standard electroneurography techniques. Measurements will quantify median nerve function across the carpal tunnel to evaluate changes after intervention.
At 4 months after intervention.
Medication
Time Frame: At recruitment, 4, 6 and 9 months and 1,2,3,4 and 5 years
Need for medication due to pain. Response options: Every day, On most days of the week, 1-2 times a week, Rarely 5. Never
At recruitment, 4, 6 and 9 months and 1,2,3,4 and 5 years
Clinical examination
Time Frame: At recruitment; at 4, and 12 months; and at 5 years after primary surgery.
Standard hand surgical clinical examination and provocation tests: Tinell, Tethro, Phalen and atrophy evaluation
At recruitment; at 4, and 12 months; and at 5 years after primary surgery.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Helsinki University Central Hospital

Investigators

  • Study Director: Teppo LN Järvinen, Professor, Helsinki University Central Hospital

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

June 11, 2026

Primary Completion (Estimated)

May 30, 2029

Study Completion (Estimated)

December 31, 2035

Study Registration Dates

First Submitted

May 21, 2026

First Submitted That Met QC Criteria

May 21, 2026

First Posted (Actual)

May 29, 2026

Study Record Updates

Last Update Posted (Actual)

June 3, 2026

Last Update Submitted That Met QC Criteria

June 1, 2026

Last Verified

June 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • HUS/683/2025

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

All collected IPD provided that current legislation permits it.

IPD Sharing Time Frame

After publication of main results, to be specified later

IPD Sharing Access Criteria

To be determined

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • SAP
  • ICF
  • ANALYTIC_CODE

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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