Clinical Translation of Biodegradable Magnesium Wire for Augmentation of Anterior Cruciate Ligament (ACL) Reconstruction From Bench Side to Bedside: A Multicentre, Double-blinded, Randomised Controlled Trial

Background: ACLR with autologous tendon graft is commonly used for the treatment of ACL injury. However, as the BTI healing is poor, this can lead to a failure rate of 5% in the first-year post-operation; a long and unpredictable rehabilitation period is expected and 35 % of patients never return to preinjury level of sports. Biological enhancement of BTI healing will help to cut down the medical cost related to poor prognosis. As a biodegradable metal, Mg has been developed as implants in orthopaedics for decades, yet without clinical implants developed for ACLR. Our team has been working on this area in the past 10 years preclinically. Our animal studies showed that supplementation of magnesium wire significantly promotes osteogenesis at BTI and improves mechanical strength in ACLR. Recently, our team developed a highly pure (99.99%) Mg wire (Fig 2) in collaboration with metallic engineers for tendon graft braiding during ACLR and with its improved physical quality and strength, it is suitable for graft braiding and then its degradation in vivo can promote tunnel bone formation and bone tendon interface integration.

Objective: To investigate if anterior cruciate ligament (ACL) reconstruction augmented with magnesium (Mg) wire enhances osteogenesis at the bone-tendon interface (BTI), improving post-op rehabilitation and leading to better clinical outcomes.

Hypothesis: Patients with ACL reconstruction using Mg wire will experience improved osteogenesis at the BTI, more effective rehabilitation, and superior knee strength and function.

Design and Subjects: A multicentre, double-blinded, randomized controlled trial will recruit patients aged 18-30 with unilateral ACL tear for primary ACLR with a hamstring graft at four sites.

Instruments: Mg-based wire.

Interventions: Participants will receive either 99.99% purity Mg wire or 2-0 vicryl as a control.

Main Outcomes: Osteogenesis will be assessed by High-Resolution Peripheral Quantitative Computed Tomography (HR-pQCT), muscle strength via Biodex tests, and functional recovery with International Knee Documentation Committee (IKDC) and Tegner scores at multiple post-op intervals. Knee stability will be checked with KT-1000 arthrometer. Blood samples will be analyzed for inflammatory markers and metabolic effects related to Mg wire.

Data Analysis and Expected Results: A repeated-measures ANOVA will be utilized for data analysis. The expectation is that Mg wire augmentation will significantly enhance osteogenesis at the BTI and improve rehabilitation outcomes.