REST-Knee: A Pilot RCT of 72-Hour Knee Immobilization and Pain Outcomes (REST-Knee)

Effect of 72-Hour Extension Splint Immobilization on Pain After Total Knee Arthroplasty: A Pilot Randomized Clinical Trial

Postoperative pain following total knee arthroplasty (TKA) is often difficult to manage, particularly with the increasing use of outpatient surgery where patients recover at home. This study aims to evaluate whether wearing a knee extension brace for the first 72 hours after surgery can reduce pain and improve recovery.

This pilot randomized controlled trial will compare two groups of patients undergoing primary unilateral TKA: one group will wear an extension brace continuously for 72 hours after surgery, while the control group will follow standard care with early mobilization. Participants will be followed for up to 12 months.

The primary objective of this pilot study is to assess the feasibility of conducting a larger trial, including recruitment rates, adherence to the intervention, follow-up completion, safety, and acceptability. Clinical outcomes will also be explored, including pain at 2 and 6 weeks after surgery (measured using a visual analog scale), knee function, range of motion, opioid consumption, complications, healthcare use, and quality of life.

The study hypothesizes that short-term immobilization of the knee in full extension will reduce postoperative pain and may improve early recovery outcomes. Findings from this pilot study will inform the design of a larger definitive trial and may contribute to improving postoperative care and pain management after knee replacement surgery.

Study Overview

• Status: Recruiting
• Conditions: Total Knee Arthroplasty
• Intervention / Treatment: Device: Knee Extension Brace (Zimmer-type); Other: Early Mobilization (Standard Care)

Detailed Description

Postoperative pain following total knee arthroplasty (TKA) remains a significant clinical challenge, particularly in the context of increasing use of outpatient surgical pathways. Optimizing early postoperative pain management is essential to improve recovery, reduce unplanned healthcare utilization, and support enhanced recovery after surgery (ERAS) principles.

This study aims to evaluate the effect of short-term postoperative immobilization using a knee extension brace (Zimmer-type) worn continuously for 72 hours following primary unilateral TKA on postoperative pain at 2 and 6 weeks, measured using the Visual Analog Scale (VAS). The study hypothesizes that maintaining the knee in full extension during the immediate postoperative period will reduce pain and improve early recovery outcomes.

Study Design

This study is a pilot randomized controlled trial with a 1:1 allocation ratio and a single-blind design, in which outcome assessors are blinded to group allocation. The study is conducted at a single center (CHUS, Estrie, Canada).

Participants undergoing primary unilateral TKA will be randomized into one of two groups:

Intervention group: immobilization of the operated knee in full extension using a Zimmer-type brace for 72 hours postoperatively, followed by standard physiotherapy care.

Control group (standard of care): no restriction in movement, with early supervised mobilization according to usual physiotherapy practice.

The study adopts a pragmatic approach, allowing variability in physiotherapy delivery to reflect real-world clinical practice and enhance external validity. Timing and frequency of physiotherapy sessions will be recorded.

Study Objectives

The primary objective of this pilot study is to assess feasibility, including:

Recruitment rate and participant flow (inclusion, exclusion, refusal) Follow-up completion rate (target ≥80%) Intervention adherence (target ≥80% compliance in the intervention group) Safety, based on postoperative complication rates (including deep vein thrombosis, wound complications, and joint stiffness) Acceptability of the intervention and study procedures among patients and healthcare providers Estimation of variance in VAS pain scores to inform sample size calculation for a future definitive trial

The clinical primary outcome is postoperative pain at 2 and 6 weeks measured using the VAS, reported as mean differences between groups with 95% confidence intervals.

Secondary clinical outcomes include:

Knee range of motion (ROM) Postoperative opioid consumption Postoperative complications Emergency department visits and hospital readmissions Health-related quality of life (EQ-5D-5L) Knee function (Knee Society Score [KSS] and Functional KSS) Blood loss (hemoglobin levels) Postoperative inflammation (C-reactive protein) Study Population

The study population includes adults aged 18 years and older undergoing primary unilateral TKA for knee osteoarthritis at CHUS.

Key exclusion criteria include:

Known thrombophilia or bleeding disorders History of thromboembolic events Contraindications to brace use (e.g., material allergy) Revision or constrained knee prostheses Use of continuous postoperative nerve block infusion Sample Size

The pilot study aims to recruit 106 participants (53 per group) over an 18-month period, representing approximately 15% of the estimated sample size required for a definitive trial. Data from this pilot will be used to refine sample size calculations.

Recruitment and Procedures

Eligible patients will be identified during orthopedic consultations and approached for participation. After informed consent, baseline data (demographics, clinical characteristics, and preoperative measures) will be collected.

Randomization will occur on the day of surgery. The intervention will be applied by the orthopedic surgeon.

Follow-up assessments will occur at:

2-5 days postoperatively 2 weeks 6 weeks 3 months 12 months

Data collected include patient-reported outcomes, clinical assessments, laboratory values, and healthcare utilization. Participants in the intervention group will record brace wear time and opioid consumption using daily logs.

Data Collection and Outcomes

Pain will be assessed using the Visual Analog Scale (VAS). Additional outcomes include ROM measured with a goniometer, validated questionnaires (KSS, FKSS, EQ-5D-5L), laboratory markers (hemoglobin and C-reactive protein), and postoperative complications.

Opioid consumption and brace adherence will be self-reported using patient diaries. Healthcare utilization (emergency visits and readmissions) will be collected retrospectively.

Data Analysis

Feasibility outcomes will be analyzed descriptively using an intention-to-treat approach. Recruitment, adherence, and completion rates will be reported with 95% confidence intervals.

Comparisons between groups for exploratory clinical outcomes will be conducted using appropriate statistical tests depending on data distribution. This pilot study is not powered for definitive efficacy conclusions but will provide estimates to guide a larger trial.

• Study Type: Interventional
• Enrollment (Estimated): 106
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Sonia Bédard, Masters; Phone Number: 13927 1-819-346-1110; Email: sonia.bedard2@usherbrooke.ca
• Study Contact Backup: Name: Yoan Bourgeault-Gagnon, MD FRCSC; Email: yoan.bourgeault-gagnon@usherbrooke.ca

Study Locations

• Canada
  • Quebec
    • Sherbrooke, Quebec, Canada, J1K 2P2
      • Recruiting
      • CIUSSS de l'Estrie-CHUS, 3001, 12e Ave Nord, Sherbrooke, Qc, Canada, J1H 5N4
      • Contact: Sonia Bédard, Masters; Phone Number: 13927 1-819-346-1110; Email: sonia.bedard2@usherbrooke.ca
      • Sub-Investigator: Emile Loiselle, MD
      • Sub-Investigator: Annie Deshaies, MD FRCSC
      • Sub-Investigator: Loïc St-Laurent-Lebeux, MD

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Person undergoing primary unilateral TKA for knee osteoarthritis at CHUS

Exclusion Criteria:

• Known thrombophilia or bleeding disorders
• History of thromboembolic events
• Contraindications to brace use (e.g., material allergy)
• Revision or constrained knee prostheses
• Use of continuous postoperative nerve block infusion

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Extension Brace Group; Participants will undergo postoperative immobilization of the operated knee in full extension using a Zimmer-type knee brace for 72 hours following primary total knee arthroplasty, followed by standard physiotherapy care.	Device: Knee Extension Brace (Zimmer-type); Participants will wear a knee extension brace maintaining the operated knee in full extension for 72 hours following surgery. The brace is to be worn continuously (target ≥23 hours per day), after which standard physiotherapy care will be initiated.
Active Comparator: Standard Care Group; Participants will receive standard postoperative care consisting of early mobilization without movement restriction and supervised physiotherapy according to usual clinical practice.	Other: Early Mobilization (Standard Care); Participants will receive standard postoperative care, including early mobilization without restriction and supervised physiotherapy according to usual clinical practice.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Study feasibility	Feasibility will be assessed by recruitment rate, follow-up completion (target ≥80%), intervention adherence (target ≥80%), and safety based on postoperative complications.	Up to 18 months (study completion)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Postoperative Pain (VAS)	Pain measured using a 100-mm Visual Analog Scale.	2 weeks, 6 weeks, 3 months, 12 months
Knee Range of Motion (ROM)	Measured with a goniometer.	2 weeks, 6 weeks, 3 months, 12 months
Opioid Consumption	Self-reported number of tablets consumed.	Up to 6 weeks
Postoperative Complications	Includes wound complications, infection, and thromboembolic events.	Up to 6 weeks
Healthcare Utilization	Emergency visits and hospital readmissions.	Up to 6 weeks
Quality of Life (EQ-5D-5L)	Standardized questionnaire.	Baseline, 2 weeks, 6 weeks, 3 months, 12 months
Knee Function (KSS/FKSS)	Validated functional scores.	Baseline, 6 weeks, 3 months, 12 months
Inflammation (CRP)	2-5 days, 2 and 6 weeks	Blood test marker.
Hemoglobin	Blood test.	2-5 days and 6 weeks
Global Improvement (PGI-C)	Patient-reported change.	2 and 6 weeks
Brace Compliance	Self-reported hours of wear.	First 72 hours
Perceived Safety	Study-specific questionnaire.	2 weeks

Collaborators and Investigators

• Sponsor: Université de Sherbrooke
• Investigators: Principal Investigator: Yoan Bourgeault-Gagnon, MD FRCSC, Universite de Sherbrooke; Study Director: François Vaillancourt, MD FRCSC, Universite de Sherbrooke

Study record dates

Study Major Dates

• Study Start (Actual): March 3, 2026
• Primary Completion (Estimated): December 31, 2027
• Study Completion (Estimated): December 31, 2028

Study Registration Dates

• First Submitted: March 30, 2026
• First Submitted That Met QC Criteria: March 30, 2026
• First Posted (Actual): April 6, 2026

Study Record Updates

• Last Update Posted (Actual): April 6, 2026
• Last Update Submitted That Met QC Criteria: March 30, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Keywords: total knee arthroplasty; postoperative pain; knee replacement; Knee immobilization; Extension brace
• Additional Relevant MeSH Terms: Pain; Neurologic Manifestations; Postoperative Complications; Pathologic Processes; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Pain, Postoperative; Health Services Administration; Health Care Quality, Access, and Evaluation; Therapeutics; Quality of Health Care; Quality Indicators, Health Care; Patient Care; Rehabilitation; Aftercare; Continuity of Patient Care; Standard of Care; Early Ambulation
• Other Study ID Numbers: 2026-6097

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: De-identified individual participant data (IPD) will be made available upon reasonable request to the corresponding investigator.
• IPD Sharing Time Frame: Data will be available beginning 6 months following publication of the primary results and ending 5 years after publication.
• IPD Sharing Access Criteria: Access will be granted to researchers who provide a methodologically sound proposal. Requests will be reviewed by the study team, and data sharing will require a data use agreement.

Drug and device information, study documents

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