Peroneus Longus Autograft Yields Better Knee Strength 6 Months After ACL Reconstruction Compared to Hamstrings Autograft

Objective: Anterior cruciate ligament (ACL) reconstruction (ACLR) is standard post-ACL injury; however, re-injury rates persist, and many patients fail to return to sport. Hamstring tendon (HT) and patellar tendon autografts are most used to reconstruct the ACL. More recently, the peroneus longus tendon (PLT) has emerged as a viable alternative with previous studies showing comparable graft properties, along with lower donor-site morbidity compared with HT autografts. No research to our knowledge has evaluated strength or functional differences between these graft types. The aim of this pilot study was to compare early strength and functional asymmetries between patients having undergone ACLR with either HT or PLT autografts. Methods: We conducted a non-randomised observational pilot study of 34 ACLR patients (HT = 23, PLT = 11). All patients were evaluated at 6 months post-surgery. The primary outcome was peak knee flexor torque (PKFT) limb symmetry index (LSI) measured using isokinetic dynamometry. Secondary outcomes included peak knee extensor torque LSI, isometric soleus strength LSI, countermovement jump concentric impulse LSI, and single-leg vertical jump LSI. Independent t-tests were used for group comparisons, and effect sizes (Hedges’ g) were calculated. Results: At 6 months, knee flexor strength symmetry was significantly less in the HT group compared to the PLT group (mean difference -16.1%, Hedges’ g = -0.99, 95% CI -1.72 to -0.24, p = 0.01). No differences were found in any other strength or functional outcomes (p > 0.05). Discussion: At 6 months post-ACLR, patients with a PLT graft showed significantly less knee flexor strength deficits than those with an HT graft, suggesting better early hamstring strength recovery. This pilot study provides initial evidence to inform a larger randomised trial to confirm these observations and further explore the impact of graft choice on early ACLR recovery.