2025 ISAKOS Biennial Congress Paper
Outcomes from the DOSTAR Study: A Double Blinded Randomised Controlled Trial Comparing Dual and Single Tendon Hamstring Graft Anterior Cruciate Ligament Reconstruction
Peter D'Alessandro, MBBS Hons. (UWA) FRACS FAOrthA, Claremont, WA AUSTRALIA
Rebecca Rogers, MD, Perth, Western Australia AUSTRALIA
Stephanie O'Brien, MD, West Leederville, WA AUSTRALIA
Adam Malcolm Lawless, MB BCH BAO LRCP&SI, Cottesloe, WA AUSTRALIA
Peter Edwards, PhD, Perth, WA AUSTRALIA
Peter Samuel Edward Davies, MBChB, Dundee, Angus UNITED KINGDOM
Josephine Kate McEwan, BM, Nedlands, WA AUSTRALIA
Shahbaz S Malik, BSc, MB BCh, MSc (Orth Engin), LLM, FRCS (Tr&Orth), Birmingham UNITED KINGDOM
Randeep Singh Aujla, MBChB ChM FRCS (Tr&Orth) MFSEM, Leicester, Leicestershire UNITED KINGDOM
Jay R. Ebert, PhD, Perth, WA AUSTRALIA
Orthopaedic Research Foundation of Western Australia, University of Western Australia, Perth, Western Australia, AUSTRALIA
FDA Status Cleared
Summary
Single Tendon Hamstring Grafts for ACL Reconstruction using Tibial Adjustable Button Fixation results in Significantly Lower Donor Site Morbidity
Abstract
Introduction
In spite of the popularity of Hamstring Tendon Grafts for Anterior Cruciate Ligament (ACL) reconstruction, hamstring tendon harvest has been linked to reduced strength, donor site pain and muscle strains after surgery, whilst the impact of additional Gracilis tendon harvest remains unclear. Traditional graft fixation methods using a tibial interference screw generally require both Semitendinosus and Gracilis tendons, but newer techniques allow for a short single tendon (Semitendinosus) graft and suspensory fixation on the tibia with the theoretical benefit of minimising hamstring donor site morbidity and possibly graft laxity. This study aims to prospectively compare outcomes between single-tendon (ST) and dual-tendon (DT) hamstring grafts for ACL reconstruction.
Methods
This prospective randomized controlled trial (RCT) allocated 138 patients to ACLR with one of the two hamstring tendon graft options (ST=71, DT=67) followed by a structured rehabilitation program. All anaesthetic and surgical techniques were uniform between the groups aside from graft technique and tibial fixation-Adjustable 'UltraButton' for ST and 'BioRCI' interference screw for DT (both Smith & Nephew, Boston USA). Patients were assessed pre-surgery and at 3, 6, and 12 months, with a range of patient-reported outcome measures (PROMs) including the IKDC, Lysholm and Cincinnati Knee Scores, as well as a validated donor-site morbidity score. Graft laxity, peak isokinetic knee extensor and flexor strength and a 6-hop performance battery were assessed. Limb Symmetry Indices (LSIs) were calculated.
Results
There have been no patients lost to follow up at 1 year. No significant group differences (p>0.05) were observed in patient demographics (age, sex, height and body mass) or surgical characteristics (concomitant meniscal repairs and tenodeses). While graft diameter was ≥8mm in all cases, mean graft diameter was significantly smaller in the ST group compared to the DT group (mean difference [MD], -0.67mm; 95% CI, -0.91 to -0.43; p<0.001). All PROMs significantly improved (p<0.0001) and were largely similar between groups (p>0.05). No group differences were observed for knee laxity or LSIs for hop measures (p>0.05). While the ST group demonstrated a greater peak knee flexor torque LSI at 6 months (p=0.020), no other strength-based LSI group differences were observed. Significant differences however were seen regarding graft site morbidity, with significantly lower morbidity reported in the ST group at 6 (p=0.002) that persisted at 12 months (p=0.017).
Conclusion
To the best of our knowledge this study provides the first demonstration in a prospective, randomised trial of significantly reduced donor site morbidity using single tendon hamstring ACL grafts with adjustable suspensory tibial fixation. This results in a smaller mean graft diameter, but there is no compromise on other post-operative outcomes including PROMs, knee laxity and functional assessments. Ongoing longer-term clinical and MRI follow-up is continuing to further validate these results.