The effectiveness of low-load Blood flow restriction Exercise in patients with an acute Achilles tendon rupture treated Non-surgically (BEAN): Protocol for a randomized controlled trial.

Background: Blood flow restriction exercise (BFRE) has been proposed as a viable method for preserving muscle mass and function after an injury during periods of load restrictions such as after an acute Achilles tendon rupture. However, its effectiveness and safety in patients with an Achilles tendon rupture have yet to be evaluated in a randomized trial.

Objectives: First, to investigate the effectiveness of early initiated BFRE in patients with non-surgically treated acute Achilles tendon rupture. Second, to evaluate whether it is better to apply BFRE in the beginning (1-12 weeks) or later (13-24 weeks) in the rehabilitation period.

Methods: This is an assessor-blinded, randomized, controlled multicenter trial with patients assigned in a 1:1 ratio to two parallel groups, that either receive BFRE in weeks 1-12 followed by usual care in weeks 13-24, or receive usual care in weeks 1-12 followed by BFRE in weeks 13-24. The BFRE program is performed three times weekly on the injured leg at 80 % of the pressure required to fully restrict the arterial blood flow. Post-intervention tests are conducted in week 13, comparing early BFRE with usual care, and in week 25, comparing early BFRE with late BFRE. At the 13-week evaluation, the primary outcome is the Single-Leg Heel-Rise test which assesses the patient's ability to raise the heel of the injured leg a minimum of 2 cm. At the 25-week evaluation, the primary outcome is the Achilles tendon Total Rupture Score which assesses the patient's self-reported symptoms and physical ability.