Background: Stability and functional restoration of the knee requires reconstruction surgery for injuries in the anterior cruciate ligament (ACL), which are frequent in people that are physically active. A popular strategy for attaining good functional results is quadruple hamstring autografts for arthroscopic reconstruction. This systematic study assessed functional results, range of motion, return to pre-injury activity status, postoperative stability, and complications related to quadruple hamstring autografts used in ACL reconstruction.

Methods: This review protocol was registered in PROSPERO with registration number CRD42025637560. A comprehensive search was done using the PubMed database through March 2024, employing specific search terms related to arthroscopic ACL reconstruction using a quadrupled hamstring autograft. The risk of bias was evaluated using the ROBINS-I tool, and only high-quality studies were included. Due to significant heterogeneity in methodologies and outcomes, findings were summarized narratively without meta-analysis. Data extraction and analysis were performed according to the PRISMA guidelines.

Results: Out of the screened studies, eight met the inclusion criteria, examining outcomes in ACL reconstruction using different graft types, such as autologous semitendinosus (ST), combined semitendinosus and gracilis (ST+G), and allogeneic fascia lata. Across studies, peak torque and total work did not significantly differ between graft types. For instance, Adachi et al. (2003) reported no significant differences in isokinetic strength between ST and ST+G groups at 60°/second and 180°/second. Nakamura et al. (2002) observed that the maximum active knee flexion angle was significantly lower in the ST+G group, showing reductions up to 80.2% (p < 0.01) relative to the contralateral side. Similarly, Tashiro et al. (2003) reported significantly lower torque in the ST+G group at 70° and 90° knee flexion (p < 0.05), emphasizing the impact of graft choice on deep knee flexion strength. Functional scores, including Lysholm and IKDC, showed minimal variance across graft types. For instance, Goyal et al. reported no significant difference in Tegner-Lysholm and IKDC scores between the all-inside tibial tunnel and complete tibial tunnel techniques (p > 0.05). Additionally, Streich et al. noted that knee stability was well-preserved in the ST-only group, with an average side-to-side laxity difference of 0.78 ± 1.85 mm using KT-1000 measurements (p < 0.05), demonstrating excellent stability in the long term.