A semitendinosus with adjustable button graft construct in patients undergoing hamstring ACL reconstruction results in improved knee flexor strength symmetry and less donor site pain and morbidity: Outcomes from the DOSTAR randomized controlled trial.

Purpose: To compare donor site morbidity and patient-reported outcome measures (PROMs), knee laxity and early strength and functional outcomes, following anterior cruciate ligament reconstruction (ACLR) using a semitendinosus (ST) tendon autograft with suspensory adjustable button tibial fixation or semitendinosus-gracilis (STG) autograft with tibial screw fixation.

Methods: While 153 patients were prospectively recruited and randomized to an ST or STG autograft, 131 (62 ST and 69 STG) were retained following ACLR and followed post-surgery. Standardized surgical techniques were employed, varying only in graft selection and fixation. The primary study outcomes were early hamstring pain, donor site morbidity and strength recovery. However, several outcomes were assessed pre-surgery and at 3 and 6 months, encompassing the Donor-site-related Functional Problems following Anterior Cruciate Ligament Reconstruction (DFPACLR) score, Visual Analogue Scale (VAS) for hamstring pain and other commonly employed PROMs, anteroposterior laxity (KT-1000), isokinetic hamstring and quadriceps strength, hop testing, complications and re-operations. Intention-to-treat analysis was performed using linear mixed models for continuous data and Mann-Whitney U tests where appropriate.

Results: At 6 months, ST patients reported significantly lower hamstring pain (p < 0.001) and DFPACLR (p < 0.001) scores. A significantly higher (p < 0.001) peak knee flexor strength limb symmetry index (LSI) was observed for the ST group, though no other group differences in side-to-side laxity, hop tests or other normalized strength measures or LSIs were observed.

Conclusions: ACLR using an ST autograft resulted in less donor site pain and morbidity, and improved knee flexor strength symmetry at 6 months, while demonstrating comparable functional outcomes to the STG autograft.

Level Of Evidence: Level 1 prospective, double-blinded, randomized controlled trial.