Optimising graft selection in ACL reconstruction (GRASE ACL): a study protocol for a randomised controlled clinical trial investigating quadriceps, hamstring and patella tendon for reconstruction in patients with primary ACL rupture

Introduction

Anterior cruciate ligament (ACL) reconstruction (ACL-R) is recommended for active patients aiming to return to demanding sports or occupations after ACL rupture. Primary graft options are bone-patellar tendon-bone (BPTB), hamstring tendons (HT) and quadriceps tendon (QT) autografts. However, consensus regarding the optimal graft remains lacking. This trial compares graft selection effects on patient-reported knee function and neuromuscular control after ACL-R.

Methods and analysis

The GRASE ACL trial is a single-centre assessor-blinded randomised controlled trial with a three-group parallel design conducted at Copenhagen University Hospital Amager-Hvidovre, Denmark. A total of 150 patients aged 18–40 years with primary ACL rupture are randomised in a 1:1:1 ratio to ACL-R using BPTB, HT or QT autografts. Recruitment was completed in August 2025.

The trial uses a dual-primary-outcomes framework evaluated at 12 months. The primary patient-reported outcome is the International Knee Documentation Committee Evaluation Form score, analysed within a non-inferiority framework. The primary biomechanical outcome is the Limb Symmetry Index of Rate of Torque Development (RTD-LSI) during isometric knee flexion, analysed within a superiority framework.

Secondary outcomes include patient-reported knee function, return-to-sport and return-to-work outcomes, neuromuscular control, muscle strength, movement biomechanics, clinical knee stability, adverse events and MRI-assessed muscle morphology. Assessments occur at 1, 6, 12, and 24 months postoperatively.

Ethics and dissemination

This trial has been approved by the scientific ethics committee for the Capital Region of Denmark and conducted in accordance with the Declaration of Helsinki. Reporting will adhere to Consolidated Standards of Reporting Trials (CONSORT) guidelines and disseminated through peer-reviewed publications and ClinicalTrials.gov updates.

Trial registration

ClinicalTrials.gov: NCT05342441 , protocol V.1.5, 24 September 2025, https://clinicaltrials.gov/study/NCT05342441 .