Project Tendura: The Impact of Blood Flow Restriction Resistance Training (BFR-RT) in Patients With Achilles Tendon Rupture (ATR) Repair

NCT07498166 | Active Not Recruiting FDA Device

• 1 other identifier: IRB#2026P000071
• Study Type: interventional
• Target: 75
• Locations: 1 country
• Sites: 1

Brief Summary

The goal of this clinical trial is to determine whether blood flow restriction resistance training (BFR-RT) improves postoperative muscle recovery and functional outcomes following primary surgical repair of acute Achilles tendon rupture (ATR) in adults undergoing standard rehabilitation. The main questions it aims to answer are: Does patient-specific BFR-RT improve ankle plantarflexion strength recovery compared with sham BFR-RT or standard rehabilitation alone? Does BFR-RT improve gastrocnemius-soleus muscle morphology and patient-reported functional outcomes following ATR repair? Researchers will compare (1) BFR-RT combined with standard physical therapy, (2) sham BFR-RT combined with standard physical therapy, and (3) standard physical therapy alone to determine whether BFR-RT enhances muscle recovery, functional outcomes, and return-to-activity timelines following surgical ATR repair. Participants will: Be randomized to BFR-RT + standard physical therapy, sham BFR-RT + standard physical therapy, or standard physical therapy alone Perform supervised rehabilitation exercises using a personalized tourniquet system calibrated to limb occlusion pressure (LOP) depending on group allocation Undergo isometric ankle plantarflexion strength testing using the Fysiometer platform Receive ultrasound imaging of the gastrocnemius-soleus complex to assess muscle cross-sectional area Complete patient-reported outcome measures assessing pain and physical function Attend follow-up evaluations at 6 weeks, 3 months, 4.5 months, 6 months, and 12 months postoperatively

Conditions

Achilles Tendon Rupture; Blood Flow Restriction Therapy; Achilles Tendon Repairs/Reconstructions; Dynamic Blood Flow Restriction

Keywords

Achilles Tendon; Tendon Injuries; Blood Flow Restriction Training; Achilles Rehabilitation; Postoperative Physical Therapy; Hypoxic Muscle Recovery

Outcome Measures

Primary Outcomes (1)

• Achilles Tendon Total Rupture Score (ATRS)

  The Achilles Tendon Total Rupture Score (ATRS) is a validated patient-reported outcome instrument used to assess symptoms and physical function following Achilles tendon rupture. The score ranges from 0 to 100, with higher scores indicating better function and fewer symptoms.

  12 months postoperatively

Secondary Outcomes (12)

• Ankle Plantarflexion Isometric Strength (Limb Symmetry Index)

  3 months, 4.5 months, 6 months, and 12 months postoperatively

• Gastrocsoleus Muscle Cross-Sectional Area

  6 weeks, 3 months, 4.5 months, 6 months, and 12 months postoperatively

• Visual Analog Scale (VAS) Pain Score

  6 weeks, 3 months, 4.5 months, 6 months, and 12 months postoperatively

• Patient-Reported Outcomes Measurement Information System (PROMIS) Pain Interference Score

  6 weeks, 3 months, 4.5 months, 6 months, and 12 months postoperatively

• Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function Score

  6 weeks, 3 months, 4.5 months, 6 months, and 12 months postoperatively

Other Outcomes (1)

• Return-to-Sport Status and Time

  Up to 12 months postoperatively

Study Arms (3)

Blood Flow Restriction Resistance Training + Standard Physical Therapy

EXPERIMENTAL

Participants receive standard postoperative Achilles tendon rehabilitation combined with blood flow restriction resistance training using the Delfi Personalized Tourniquet System. Cuffs are calibrated to 80% limb occlusion pressure to induce controlled vascular restriction during low-load resistance exercises. All sessions are supervised by trained physiotherapists following the standardized Massachusetts General Hospital Achilles rehabilitation protocol.

Device: Blood Flow Restriction Resistance Training (BFR-RT); Behavioral: Standard Physical Therapy

Sham Blood Flow Restriction + Standard Physical Therapy

SHAM COMPARATOR

Participants receive the same standardized postoperative rehabilitation protocol while wearing Delfi tourniquet cuffs inflated to 20 mmHg, a pressure insufficient to induce blood flow restriction. This sham condition controls for potential placebo effects associated with the device while maintaining identical exercise protocols and therapist supervision.

Device: Sham Blood Flow Restriction; Behavioral: Standard Physical Therapy

Standard Physical Therapy Alone

ACTIVE COMPARATOR

Participants undergo the standardized Massachusetts General Hospital postoperative Achilles tendon rehabilitation program including range-of-motion exercises, progressive strengthening, and return-to-sport phases. No blood flow restriction device is used during rehabilitation sessions.

Behavioral: Standard Physical Therapy

Interventions

Blood Flow Restriction Resistance Training (BFR-RT) DEVICE

Blood flow restriction resistance training will be performed using the Delfi Personalized Tourniquet System applied to the affected limb during supervised rehabilitation exercises. The device automatically determines limb occlusion pressure (LOP) and applies 80% of LOP during low-load resistance exercises. This controlled vascular restriction produces metabolic stress intended to stimulate muscle hypertrophy and strength recovery while minimizing mechanical load on the healing Achilles tendon. Sessions are conducted under physiotherapist supervision within the standardized postoperative rehabilitation protocol.

Also known as: Delfi Personalized Tourniquet System

Blood Flow Restriction Resistance Training + Standard Physical Therapy

Sham Blood Flow Restriction DEVICE

Participants assigned to the sham group will wear the Delfi tourniquet cuff during rehabilitation sessions; however, cuff pressure will be inflated only to 20 mmHg, a level insufficient to induce vascular occlusion. This condition mimics the experience of the intervention device while avoiding physiologic blood flow restriction, thereby controlling for potential placebo effects associated with device use.

Sham Blood Flow Restriction + Standard Physical Therapy

Standard Physical Therapy BEHAVIORAL

Participants will undergo the standardized postoperative Achilles tendon rehabilitation program used at Massachusetts General Hospital. The protocol includes progressive weight-bearing, range-of-motion exercises, strengthening maneuvers, and return-to-sport progression phases supervised by trained physiotherapists.

Also known as: Standard Postoperative Achilles Rehabilitation Protocol

Blood Flow Restriction Resistance Training + Standard Physical Therapy; Sham Blood Flow Restriction + Standard Physical Therapy; Standard Physical Therapy Alone

Eligibility Criteria

• Age: 18 Years - 75 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Adults aged 18 to 75 years
• Acute unilateral midportion Achilles tendon rupture
• Primary surgical repair performed within 2 weeks of injury
• Willingness and ability to comply with the postoperative rehabilitation protocol and follow-up schedule

You may not qualify if:

• Cognitive impairment or inability to follow study instructions
• Planned postoperative follow-up at another institution
• Use of fluoroquinolone antibiotics or systemic corticosteroids within the past 6 months
• Previous Achilles tendon rupture in either limb
• Simultaneous bilateral Achilles tendon rupture
• History of venous thromboembolism (deep venous thrombosis or pulmonary embolism)
• Diabetes mellitus
• Reduced lower extremity function due to conditions other than Achilles tendon rupture
• Uncontrolled hypertension
• Peripheral vascular disease or ankle-brachial index less than 1.0
• Chronic kidney disease or heart failure with lower extremity edema
• Lower extremity dialysis access
• Lower extremity thrombophlebitis
• Active cancer or ongoing chemotherapy treatment
• Prior lymphadenectomy

Sponsors & Collaborators

• Massachusetts General Hospital: lead

Study Sites (1)

Massachusetts General Hospital, Department of Orthopaedics

Boston, Massachusetts, 02114, United States

Location

Related Publications (11)

• O'Neill S, Weeks A, Norgaard JE, Jorgensen MG. Validity and intrarater reliability of a novel device for assessing Plantar flexor strength. PLoS One. 2023 Mar 31;18(3):e0282395. doi: 10.1371/journal.pone.0282395. eCollection 2023.

  PMID: 37000780 BACKGROUND

• Callanan MC, Plummer HA, Chapman GL, Opitz TJ, Rendos NK, Anz AW. Blood Flow Restriction Training Using the Delfi System Is Associated With a Cellular Systemic Response. Arthrosc Sports Med Rehabil. 2020 Dec 27;3(1):e189-e198. doi: 10.1016/j.asmr.2020.09.009. eCollection 2021 Feb.

  PMID: 33615264 BACKGROUND

• Rolnick N, Licameli N, Moghaddam M, Marquette L, Walter J, Fedorko B, Werner T. Autoregulated and Non-Autoregulated Blood Flow Restriction on Acute Arterial Stiffness. Int J Sports Med. 2024 Jan;45(1):23-32. doi: 10.1055/a-2152-0015. Epub 2023 Aug 10.

  PMID: 37562444 BACKGROUND

• Hwang PS, Willoughby DS. Mechanisms Behind Blood Flow-Restricted Training and its Effect Toward Muscle Growth. J Strength Cond Res. 2019 Jul;33 Suppl 1:S167-S179. doi: 10.1519/JSC.0000000000002384.

  PMID: 30011262 BACKGROUND

• Centner C, Jerger S, Lauber B, Seynnes O, Friedrich T, Lolli D, Gollhofer A, Konig D. Similar patterns of tendon regional hypertrophy after low-load blood flow restriction and high-load resistance training. Scand J Med Sci Sports. 2023 Jun;33(6):848-856. doi: 10.1111/sms.14321. Epub 2023 Feb 3.

  PMID: 36703264 BACKGROUND

• Centner C, Lauber B, Seynnes OR, Jerger S, Sohnius T, Gollhofer A, Konig D. Low-load blood flow restriction training induces similar morphological and mechanical Achilles tendon adaptations compared with high-load resistance training. J Appl Physiol (1985). 2019 Dec 1;127(6):1660-1667. doi: 10.1152/japplphysiol.00602.2019. Epub 2019 Nov 14.

  PMID: 31725362 BACKGROUND

• Hughes L, Rosenblatt B, Haddad F, Gissane C, McCarthy D, Clarke T, Ferris G, Dawes J, Paton B, Patterson SD. Comparing the Effectiveness of Blood Flow Restriction and Traditional Heavy Load Resistance Training in the Post-Surgery Rehabilitation of Anterior Cruciate Ligament Reconstruction Patients: A UK National Health Service Randomised Controlled Trial. Sports Med. 2019 Nov;49(11):1787-1805. doi: 10.1007/s40279-019-01137-2.

  PMID: 31301034 BACKGROUND

• Hughes L, Paton B, Rosenblatt B, Gissane C, Patterson SD. Blood flow restriction training in clinical musculoskeletal rehabilitation: a systematic review and meta-analysis. Br J Sports Med. 2017 Jul;51(13):1003-1011. doi: 10.1136/bjsports-2016-097071. Epub 2017 Mar 4.

  PMID: 28259850 BACKGROUND

• Eliasson P, Agergaard AS, Couppe C, Svensson R, Hoeffner R, Warming S, Warming N, Holm C, Jensen MH, Krogsgaard M, Kjaer M, Magnusson SP. The Ruptured Achilles Tendon Elongates for 6 Months After Surgical Repair Regardless of Early or Late Weightbearing in Combination With Ankle Mobilization: A Randomized Clinical Trial. Am J Sports Med. 2018 Aug;46(10):2492-2502. doi: 10.1177/0363546518781826. Epub 2018 Jul 2.

  PMID: 29965789 BACKGROUND

• Heikkinen J, Lantto I, Piilonen J, Flinkkila T, Ohtonen P, Siira P, Laine V, Niinimaki J, Pajala A, Leppilahti J. Tendon Length, Calf Muscle Atrophy, and Strength Deficit After Acute Achilles Tendon Rupture: Long-Term Follow-up of Patients in a Previous Study. J Bone Joint Surg Am. 2017 Sep 20;99(18):1509-1515. doi: 10.2106/JBJS.16.01491.

  PMID: 28926379 BACKGROUND

• Mashimo S, Nozaki T, Amaha K, Tanaka K, Kubota J, Sato H, Kitamura N. Quantitative Assessment of Calf Muscle Volume, Strength, and Quality After Achilles Tendon Rupture Repair: A 1-Year Prospective Follow-up Study. Am J Sports Med. 2023 Dec;51(14):3781-3789. doi: 10.1177/03635465231206391. Epub 2023 Nov 13.

  PMID: 37960840 BACKGROUND

MeSH Terms

Conditions

Tendon Injuries

Condition Hierarchy (Ancestors)

Wounds and Injuries

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: OUTCOMES ASSESSOR
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Foot & Ankle Orthopaedic Surgeon; Director, Minimally Invasive Foot & Ankle Surgery Assistant Professor of Orthopaedic Surgery, Harvard Medical School

Model Details: This study is a prospective, three-arm, parallel-group randomized controlled trial with a 1:1:1 allocation ratio. Participants undergoing primary surgical repair of an acute unilateral midportion Achilles tendon rupture will be randomly assigned to one of three groups: (1) blood flow restriction resistance training (BFR-RT) combined with standard physical therapy, (2) sham BFR-RT combined with standard physical therapy, or (3) standard physical therapy alone. The intervention and sham groups will use a Delfi Personalized Tourniquet System calibrated to 80% limb occlusion pressure and 20 mmHg, respectively. All participants will follow an identical postoperative rehabilitation protocol and will be assessed longitudinally at predefined postoperative time points over a 12-month follow-up period. Outcomes will be compared between groups to evaluate the efficacy and safety of BFR-RT in postoperative Achilles tendon rupture rehabilitation.

Study Record Dates

• First Submitted: March 23, 2026
• First Posted: March 27, 2026
• Study Start: February 1, 2026
• Primary Completion (Estimated): December 31, 2026
• Study Completion (Estimated): February 1, 2027
• Last Updated: April 1, 2026

Record last verified: 2026-03

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)