Effects of Early Rehabilitation Using Blood Flow Restriction and/or Surface Electromyography Biofeedback on Quadriceps Activation and Strength After Anterior Cruciate Ligament Reconstruction: A Multicenter Randomized Controlled Trial

NCT ID: NCT07145606

Last Updated: 2025-08-28

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

NOT_YET_RECRUITING

Clinical Phase

NA

Total Enrollment

200 participants

Study Classification

INTERVENTIONAL

Study Start Date

2026-01-02

Study Completion Date

2031-01-02

Brief Summary

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Many patients experience quadriceps inhibition after anterior cruciate ligament (ACL) reconstruction, delaying strength recovery, hindering return to sport, and potentially increasing the risk of re-injury. Two rehabilitation strategies-low-load blood flow restriction (BFR) training and surface electromyography (sEMG) biofeedback-aim to enhance neuromuscular activation and strength while limiting joint load. However, comparative and combined evidence in pragmatic, multicenter settings remains limited.

AMIRACL is a multicenter, prospective, randomized, controlled, parallel-group trial with four arms enrolling 200 adults (18-35 years) undergoing a first-time ACL reconstruction. Participants are randomized with center stratification; outcome assessors are blinded to allocation. The four groups are: (1) standard rehabilitation; (2) standard + early BFR; (3) standard + early sEMG biofeedback; and (4) standard + combined BFR and sEMG biofeedback. Interventions begin about 2 weeks postoperatively, are delivered over 6 weeks at three supervised sessions per week, and are integrated into contemporary ACL rehabilitation. BFR uses individualized, auto-regulated cuff pressure during low-load isometric and then dynamic exercises. sEMG biofeedback provides real-time visual and/or auditory feedback to optimize quadriceps recruitment during targeted tasks. The combined arm receives both modalities concurrently.

The primary objective is to compare quadriceps activation (sEMG) and maximal isometric knee extensor strength between groups at 3 and 6 months. Secondary objectives include return-to-sport readiness and patient-reported function (e.g., ACL-RSI, IKDC), broader knee outcomes (e.g., KOOS, Lysholm), adherence and adverse events across arms, and ACL re-injury (ipsilateral graft rupture or contralateral ACL injury) within 2 years. Longer-term patient-reported quality of life is explored up to 5 years.

Key eligibility criteria include age 18-35 years, first ACL reconstruction, and preinjury sport participation; major exclusions include revision ACL surgery, concomitant multi-ligament repair, neuromuscular disorders, and contraindications to BFR or sEMG. The planned sample size is 200 (50 per arm), powered to detect a clinically meaningful between-group difference in quadriceps activation. Analyses will follow the intention-to-treat principle using mixed-effects models for repeated measures. The study is conducted under Good Clinical Practice and applicable Swiss regulations; all participants provide written informed consent. Overall, AMIRACL will determine whether early BFR, sEMG biofeedback, or their combination meaningfully improves quadriceps activation, strength, and clinical recovery after ACL reconstruction compared with standard rehabilitation alone.

Detailed Description

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Conditions

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Anterior Cruciate Ligament Injuries Knee Injuries Muscle Weakness

Study Design

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Allocation Method

RANDOMIZED

Intervention Model

PARALLEL

Primary Study Purpose

TREATMENT

Blinding Strategy

SINGLE

Outcome Assessors

Study Groups

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Standard Rehabilitation

Participants receive the standardized postoperative ACL rehabilitation program only. Sessions are supervised approximately 3 times per week for 6 weeks, starting about 2 weeks after surgery. Content includes progressive range of motion, quadriceps activation and strengthening, functional tasks, and return-to-activity progressions delivered per protocol.

Group Type ACTIVE_COMPARATOR

Standard Rehabilitation

Intervention Type BEHAVIORAL

Standardized postoperative ACL rehabilitation only. Begins \~2 weeks after surgery; supervised \~3 sessions/week for 6 weeks. Includes progressive range of motion, quadriceps activation/strengthening, functional drills, and return-to-activity progressions delivered per protocol.

Standard Rehabilitation + Blood Flow Restriction (BFR)

Participants receive the standardized postoperative ACL rehabilitation plus low-load BFR training. BFR is applied with individualized limb occlusion pressure during prescribed isometric and then dynamic exercises. Sessions are supervised \~3 times per week for 6 weeks beginning \~2 weeks postoperatively.

Group Type EXPERIMENTAL

Blood Flow Restriction (BFR) Training

Intervention Type BEHAVIORAL

Low-load resistance exercises performed with individualized limb occlusion pressure (LOP) determined each session; target %LOP per protocol. Progresses from isometric to dynamic open/closed-chain tasks. Delivered under supervision \~3 sessions/week for 6 weeks; monitoring of tolerance and adverse events per safety LOP.

Standard Rehabilitation + sEMG Biofeedback

Participants receive the standardized postoperative ACL rehabilitation plus surface EMG biofeedback to optimize quadriceps recruitment during targeted tasks (e.g., isometric contractions and functional movements). Real-time visual and/or auditory feedback is provided during supervised sessions \~3 times per week for 6 weeks starting \~2 weeks after surgery.

Group Type EXPERIMENTAL

sEMG Biofeedback

Intervention Type BEHAVIORAL

Real-time surface electromyography biofeedback to optimize quadriceps recruitment during targeted tasks (e.g., isometric contractions, straight-leg raise, sit-to-stand, mini-squat, gait drills). Visual and/or auditory feedback with progressive targets. Supervised \~3 sessions/week for 6 weeks; outcome assessors remain blinded.

Standard Rehabilitation + Combined BFR and sEMG Biofeedback

Participants receive the standardized postoperative ACL rehabilitation with both adjuncts delivered concurrently: individualized low-load BFR training and sEMG biofeedback during targeted tasks. Sessions are supervised \~3 times per week for 6 weeks beginning \~2 weeks postoperatively.

Group Type EXPERIMENTAL

Blood Flow Restriction (BFR) Training

Intervention Type BEHAVIORAL

Low-load resistance exercises performed with individualized limb occlusion pressure (LOP) determined each session; target %LOP per protocol. Progresses from isometric to dynamic open/closed-chain tasks. Delivered under supervision \~3 sessions/week for 6 weeks; monitoring of tolerance and adverse events per safety LOP.

sEMG Biofeedback

Intervention Type BEHAVIORAL

Real-time surface electromyography biofeedback to optimize quadriceps recruitment during targeted tasks (e.g., isometric contractions, straight-leg raise, sit-to-stand, mini-squat, gait drills). Visual and/or auditory feedback with progressive targets. Supervised \~3 sessions/week for 6 weeks; outcome assessors remain blinded.

Interventions

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Standard Rehabilitation

Standardized postoperative ACL rehabilitation only. Begins \~2 weeks after surgery; supervised \~3 sessions/week for 6 weeks. Includes progressive range of motion, quadriceps activation/strengthening, functional drills, and return-to-activity progressions delivered per protocol.

Intervention Type BEHAVIORAL

Blood Flow Restriction (BFR) Training

Low-load resistance exercises performed with individualized limb occlusion pressure (LOP) determined each session; target %LOP per protocol. Progresses from isometric to dynamic open/closed-chain tasks. Delivered under supervision \~3 sessions/week for 6 weeks; monitoring of tolerance and adverse events per safety LOP.

Intervention Type BEHAVIORAL

sEMG Biofeedback

Real-time surface electromyography biofeedback to optimize quadriceps recruitment during targeted tasks (e.g., isometric contractions, straight-leg raise, sit-to-stand, mini-squat, gait drills). Visual and/or auditory feedback with progressive targets. Supervised \~3 sessions/week for 6 weeks; outcome assessors remain blinded.

Intervention Type BEHAVIORAL

Eligibility Criteria

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Inclusion Criteria

* Adults aged 18-35 years.

First-time anterior cruciate ligament (ACL) reconstruction.

Pre-injury activity level Tegner ≥ 6.

Marx activity scale ≥ 12.

Body mass index \< 35.

With or without associated meniscal injury.

Exclusion Criteria

* Revision ACL surgery.

Concurrent repair of other knee ligaments.

Neurological or systemic musculoskeletal disorders.

Contraindications to blood flow restriction (BFR) or surface EMG monitoring/biofeedback.

Pregnancy or lactation.

Language barrier or cognitive impairment preventing valid informed consent; vulnerable populations not enrolled.
Minimum Eligible Age

18 Years

Maximum Eligible Age

35 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

No

Sponsors

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Haute Ecole ARC Sante

OTHER

Sponsor Role lead

Responsible Party

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Forelli Florian

Assistant Professor ; PhD

Responsibility Role PRINCIPAL_INVESTIGATOR

Locations

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Orthosport

Domont, , France

Site Status

Movare

Bulle, , Switzerland

Site Status

Centre de l'Appareil Locomoteur et du Sport, Hôpitaux Universitaires de Genève (HUG)

Geneva, , Switzerland

Site Status

Exotherapie

Geneva, , Switzerland

Site Status

Countries

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France Switzerland

Central Contacts

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Florian Forelli, PhD

Role: CONTACT

0041329301654

Facility Contacts

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Ayrton Moiroux -- Sahraoui

Role: primary

+33634099012

Loic Bel, MSc

Role: primary

+41792749573

Anna Stitelmann, MSc

Role: primary

+4122372 33 11

Maxime Gard

Role: primary

+41796518623

Other Identifiers

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AMIRACL

Identifier Type: -

Identifier Source: org_study_id

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