Quadriceps Tendon Graft Leads to Stronger Flexion and Weaker Extension of the Knee Than Hamstring Graft Post-ACLR: Systematic Review and Meta-Analysis

Purpose: The optimal autograft for restoring knee strength and expediting return-to-sport following anterior cruciate ligament reconstruction (ACLR) remains debated. This systematic review and meta-analysis compared isokinetic strength and patient-reported outcomes after ACLR using quadriceps tendon (QT), hamstring tendon (HT), or bone–patellar tendon–bone (BTB) autografts to determine graft-specific recovery patterns. Methods: PubMed, Cochrane Library, EMBASE, and Google Scholar were systematically searched for comparative studies evaluating isokinetic strength following primary ACLR using QT, HT, or BTB autografts. Non-English, unavailable full-text, animal/cadaveric, and physeal-sparing studies were excluded. MINORS and Detsky evaluated bias risk. Key findings were quantified, and subgroup meta-analyses were performed on limb symmetry index (LSI) values (significance: p < 0.05). Results: Seventeen studies (1,705 patients: QT = 765, HT = 725, BTB = 215) with follow-ups through 48 months were included. Due to data heterogeneity, four to six studies qualified for each meta-analysis. Among 13 QT vs. HT studies, QT grafts demonstrated weaker extensor strength in nine (56.3%) and greater flexor strength in six (37.5%). No differences were reported in extensor or flexor strength in four (25.0%) and seven (43.8%) studies, respectively. For QT vs. BTB, two studies (12.5%) showed similar extensor strength, whereas two reported conflicting results. QT had greater flexor strength in one (6.3%) and similar strength in three (18.8%) studies. Postoperative pain was comparable between QT and HT. Conclusions: QT autografts resulted in stronger flexion and weaker extension than HT autografts after ACLR. Tailored rehabilitation targeting graft-specific deficits may accelerate recovery. Further research is required to clarify outcomes between QT and BTB autografts. Level of evidence: IV.