Functional outcomes of quadrupled semitendinosus vs. four strand semitendinosus / Gracilis graft for arthroscopic ACL reconstruction

Abstract

Introduction: Anterior cruciate ligament is a commonly disrupted ligament causing anterior instability of knee. Arthroscopic ACL reconstruction is the treatment of choice. Many graft options are available most common being the four-strand hamstring autograft. Four strand hamstring graft can be made either by doubling both Semitendinosus and Gracilis tendon (STG) or by quadrupling Semitendinosus tendon (ST4). Aim: To compare functional outcomes following ACL reconstruction with STG graft vs ST4 graft using femoral adjustable loop button and tibial bio-screw fixation.Material and Methods: This was a prospective cohort study in which 68 patients with isolated ACL tear with knee instability were enrolled during 2017-2018. Patients with multi-ligamentous injury, associated meniscal tears, chondral lesions, juxta-articular fractures and previous surgery on same knee were excluded. Patients were randomly allocated into two groups in which Group one patient underwent Arthroscopic ACL reconstruction by autologous four strand STG graft and Group two patients using quadrupled ST4 graft. Functional evaluation was done using Lysholm scoring system preoperatively and postoperatively at 1 year. Knee flexion strength was measured post-operatively at 1 year as maximum standing knee flexion angle. The side to side ratio of knee flexion angle was used for comparison. Appropriate statistical analysis of the data was done. Results: 68 patients were enrolled for the study in which, 38 patients underwent Arthroscopic ACL reconstruction by Autologous four strand STG graft and 30 patients using quadrupled ST4 graft. Out of 68 patients 52(76.47%) were male and 16 (23.53%) were female. 50 (73.5%) patients had right sided involvement and 18 (26.4%) had left side involvement. Mean age of patients was 29 years ranging from 19-45 years. Mean follow-up duration was 20 months (14-32 months). Average duration since injury was 6.22 ± 4.68 months (2-24 months). Mean Pre-operative Lysholm score in STG and ST4 groups were 69.78 ± 8.46 and 68.6 ± 10.41 respectively. Mean post-operative Lysholm scores at 1 year in STG and ST groups were 91.5 ± 6.13 and 92.96 ± 6.00 respectively. Lysholm score was reported as excellent in 49 patients (72%), good in 12 patients (17.6%) and fair in 7 patients (10.2%) with none of the patients reporting poor outcome. Mean maximum standing knee flexion angle ratio of operated knee compared to non -operated knee at 1 year was 90.51±6.37% and 94.45 ±2.89% in STG and ST4 groups respectively. There were no major complications reported with the procedure. Conclusion: Quadrupled Semitendinosus graft is a viable alternative to Semitendinosus/Gracilis graft for ACL reconstruction. Preserving Gracilis tendon results in better knee flexion. Hence Gracilis tendon harvest must be avoided whenever possible.