ObjectivesTo systematically review the differences of operative outcomes between early surgery and delayed surgery in multiple ligament injury of knee joint (MLIK) patients.MethodsPubMed, The Cochrane Library, EMbase, CNKI, CBM, WanFang Data and VIP databases were searched to collect cohort studies about operative outcomes of different surgery times in MLIK patients from inception to September 23rd, 2018. Two reviewers independently screened literature, extracted data and assessed risk of bias of included studies. Meta-analysis was then performed using RevMan 5.3 software.ResultsA total of 8 cohort studies involving 153 early and 90 delayed operatively treated patients were included. The results of meta-analysis showed that: compared with delayed surgery, early surgery received higher Lysholm score (MD=7.52, 95%CI 2.00 to 13.04, P=0.008) and superior IKDC score rate (OR=2.97, 95%CI 1.51 to 5.84, P=0.002). There were no significant differences in Tegner score (MD=–0.08, 95%CI –1.07 to 0.92, P=0.88) and ROM (MD=4.08, 95%CI –2.38 to 10.55, P=0.22) between two groups. The main adverse reactions of MLIK included neurovascular injury, deep venous thrombosis of lower extremities, common peroneal nerve injury, tourniquet paralysis and limited joint activity. Early surgery had a lower incidence of complications than delayed surgery (7.1% vs. 30%).ConclusionThe current evidence shows that early surgery can receive higher Lysholm score and superior IKDC score rate in treatment of MLIK, and have a lower incidence of complications. Due to limited quality and quantity of the included studies, more high-quality studies are required to verify above conclusions.