The use of additional strands to increase graft diameter in primary ACL reconstruction provides optimal outcomes and does not compromise healing at 12-months follow-up.

Abstract

The aim of this study was to compare graft size, clinical outcomes, knee stability, graft healing and re-tear rates between 4-strand and 6-strand hamstring autografts in primary anterior cruciate ligament (ACL) reconstruction at a minimum 12-month follow-up. This was a retrospective analysis of prospectively collected patients who underwent primary ACLR using HS autograft between 2019 and 2022, with a minimum follow-up of 12-month. Baseline characteristics and intraoperative information were collected. Postoperative clinical outcomes and knee laxity were collected and analysed. Graft signal and tunnel widening were collected and analysed using the 12-month magnetic resonance imaging (MRI). Continuous and categorical variables were compared. P values < 0.05 were considered significant. Overall, data from 235 consecutive patients were analysed. Quadrupled Semitendinosus graft was used in 67.7% of the cases (4HS, 159 knees), with the addition of a doubled Gracilis tendon in 32.3% (6HS, 76 knees). The 6HS group was associated with a significantly greater graft diameter at both the femoral (p = 0.001) and tibial (p = 0.005) ends, measured intra-operatively using calibrated sizing blocks. LET was performed in 12% of the 6HS and 35% of the 4HS (p < 0.001). No differences between the two groups were reported for return to sport testing (RTS), anterior knee laxity, and patient-reported outcomes (PROMs). All the patients reported high satisfaction and no difference in re-tear rate between 6HS (7%) and 4HS (3%, p = 0.234). The signal-to-noise quotient (SNQ) was comparable between 4- and 6-HS whilst 6-HS was associated with a greater tibial tunnel widening > 50% (20% vs. 4% of the patients, p = 0.003). 6-strands configuration in primary ACLR using HS autograft is a safe and reliable technique. Increasing graft size did not compromise clinical outcomes or graft healing at short-term follow-up.