Registry-randomized Comparison of Rehabilitation Regimens After Flexor Tendon Injury in the Thumb

Registry-randomized Comparison of Rehabilitation Regimens After Flexor Pollicis Longus Injury in the Thumb

Flexor tendon injuries in the thumb occur across all ages and genders. Each year, approximately 400 patients undergo surgery for a flexor tendon injury in Sweden. These injuries are exclusively treated at one of the seven specialized hand surgery clinics, as the surgery is technically demanding, and postoperative rehabilitation is critical, specialized, and requires expertise from hand therapists. To prevent tendon adhesions and stiffness in the thumb or fingers, controlled active motion therapy is usually initiated within a few days after surgery. Studies on finger flexor tendon injuries have shown that early active movement therapy leads to better mobility compared to immobilization. Consequently, early active training is now the standard treatment following flexor tendon repair. However, during postoperative rehabilitation, the repaired flexor tendon may rupture, often necessitating revision surgery.

The rupture rate after flexor tendon repair in the thumb is approximately three times higher than in other fingers (10% vs. 3%). While most studies on flexor tendon injuries focus on finger tendons, research on the outcomes of thumb flexor tendon injuries is limited. The biomechanics and anatomy of the thumb's flexor tendon differ significantly from those of finger tendons.

The objective of this study is to determine whether the rupture rate following thumb flexor tendon surgery can be reduced by immobilizing the thumb in a cast for four weeks postoperatively, compared to standard early active motion therapy, without negatively affecting joint mobility and thumb strength. Additionally, the study will evaluate patient-reported outcomes one year post-surgery for both rehabilitation regimens (immobilization vs. mobilization).

This study is a registry-randomized clinical trial (RRCT) involving five hand surgery clinics in Sweden. Data following randomization between the two rehabilitation protocols will be collected through follow-up in the Swedish National Hand Surgery Quality Registry (HAKIR).

Study Overview

• Status: Recruiting
• Conditions: Flexor Tendon Rupture; Rehabilitation Program; Thumb Injury; Flexor Tendon Injury
• Intervention / Treatment: Other: Early active motion training after operated FPL injury; Other: Immobilisation in plaster cast 4 weeks after operated FPL injury

• Study Type: Interventional
• Enrollment (Estimated): 380
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Maria Wilcke, MD, Associate professor; Phone Number: +46812362022; Email: maria.wilcke@ki.se

Study Locations

• Sweden
  • Linköping, Sweden
    • Recruiting
    • Hand- och plastikkirurgiska kliniken Linköpings Universitetssjukhus
    • Contact: Erika Nyman, MD, Associate professor; Phone Number: +4610-105 96 90
    • Contact: Email: erika.nyman@regionostergotland.se
  • Stockholm, Sweden
    • Recruiting
    • Handkirurgiska kliniken Södersjukhuset
    • Contact: Maria Wilcke, MD, Associate professor; Phone Number: +4681236022; Email: maria.wilcke@ki.se
  • Umeå, Sweden
    • Recruiting
    • Handkirurgiska kliniken Norrlands Universitetssjukhus
    • Contact: Gustav Andersson, MD, Associate professor; Phone Number: +46907850000; Email: gustav.andersson@regionvasterbotten.se
  • Uppsala, Sweden
    • Recruiting
    • Handkirugiska kliniken Uppsala Akademiska Sjukhus
    • Contact: Sara Edsfeldt, MD, Phd; Phone Number: +4618-6110000; Email: sara.edsfeldt@akademiska.se
  • Örebro, Sweden
    • Recruiting
    • Handkirurgiska kliniken Örebros Universitetssjukhus
    • Contact: Eva Lundqvist, MD, Phd; Phone Number: +196021000; Email: eva.lundqvist@regionorebrolan.se+46+

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

Complete laceration of the thumb flexor tendon (Flexor Pollicis Longus; FPL) within zone 1 and 2.

Age over 15 years. Minors (<18 years) are considered to have sufficient maturity to understand the implications of the research.

Swedish-speaking / able to understand spoken and written Swedish. Surgery performed within 14 days from the time of injury.

Exclusion Criteria:

Tendon injury with a defect requiring tendon grafting. Another complete tendon injury in the same hand. Extensive associated injuries, such as fracture, vascular injury with circulatory impairment, large skin defect, or preoperative signs of infection. Patient deemed unsuitable for early active motion therapy due to factors such as lack of cooperation, cognitive impairment, or substance abuse issues.

Patient declines follow-up in the HAKIR quality registry. Wound infection making early active motion therapy inappropriate.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Early active motion; Early active motion 2-5 days postoperatively.	Other: Early active motion training after operated FPL injury; Early active motion training after operated FPL injury
Active Comparator: Immobilisation in plaster cast 4 weeks; Immobilisation in plaster cast 4 weeks postoperatively	Other: Immobilisation in plaster cast 4 weeks after operated FPL injury; Immobilisation in plaster cast 4 weeks after operated FPL injury

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Tendon rupture rate	Clinically diagnosed rupture of an operated flexor pollicis longus injury	Within one year after operation

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Active range of motion in the joints of the operated thumb MCP joint	Active range of motion of the MCP joint of the operated thumb measured with a goniometer	3 and 12 months postoperatively
Active range of motion of the IP-joint in the opererated thumb	Measured with a goniometer	3 and 12 months postoperatively
Grip strength	Measured using a Jamar dynamometer and compared to the uninjured side.gauge.	3 and 12 months postoperatively
Key pinch strength	Key pinch between the thumb and index finger assessed with a pinch gauge.	3 and 12 months postoperatively
HQ-8 questionnaire	A Patient-rated outcome measurse (PROM).The HAKIR questionnaire (HQ-8) consists of seven questions regarding symptoms in the operated hand, such as aching, pain, numbness, weakness, and cold sensitivity, as well as one question on perceived hand function. All questions are answered on a 0-100 scale (0, 10, 20, etc.). An additional question in the questionnaire addresses satisfaction with the surgical outcome, rated from completely dissatisfied to completely satisfied.	3 and 12 months postoperatively
Quick DASH	A patient-rated outcome measure (PROM). The short version of the Disabilities of the Arm, Shoulder, and Hand (QuickDASH) contains 11 questions covering activity limitations, symptoms, and participation. The responses are summed into a total score ranging from 0 to 100, where 100 represents maximum perceived disability of the hand and arm.	3 and 12 months postoperatively
Overall satisfaction with rehabilitation	Five-point Likert scale of overall satisfaction with rehabilitation: the five response options are: (1) Yes, to a very large extent, (2) Yes, to a large extent, (3) To a certain extent, (4) To a small extent, and (5) Not at all.	3 and 12 months

Collaborators and Investigators

• Sponsor: Karolinska Institutet
• Collaborators: Region Östergötland; Region Stockholm; Region Örebro County; Region Västerbotten; Uppsala County Council, Sweden

Study record dates

Study Major Dates

• Study Start (Actual): May 1, 2025
• Primary Completion (Estimated): December 31, 2031
• Study Completion (Estimated): December 31, 2031

Study Registration Dates

• First Submitted: February 7, 2025
• First Submitted That Met QC Criteria: February 14, 2025
• First Posted (Actual): February 20, 2025

Study Record Updates

• Last Update Posted (Actual): June 3, 2026
• Last Update Submitted That Met QC Criteria: May 31, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: Thumb; Immobilisation; RRCT; Flexor pollicis longus injury; Early active motion; flexor tendon injury
• Additional Relevant MeSH Terms: Rupture; Wounds and Injuries; Tendon Injuries; Investigative Techniques; External Fixators; Orthopedic Fixation Devices; Orthopedic Equipment; Surgical Equipment; Equipment and Supplies; Surgical Fixation Devices; Immobilization; Casts, Surgical
• Other Study ID Numbers: RRCT HAKIR fpl

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Deidentified data might be shared upon request for metaanalyses.
• IPD Sharing Time Frame: After the results are analyzed and publish and 10 years ahead
• IPD Sharing Access Criteria: Researchers with an ethical permitt, as descibed above, by request to maria.wilcke@ki.se
• 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
• product manufactured in and exported from the U.S.: No