Our objective was to compare the results of reconstruction of isolated chronic posterior cruciate ligament (PCL) injury using a four-strand hamstring graft (4SHG) and a LARS artificial ligament. Thirty-six patients were divided into a 4SHG group (n=15) and a LARS group (n=21). The minimum follow-up time was two years. The outcome measures used were KT-1000 measurements, the International Knee Documentation Committee (IKDC) scoring system, Lysholm knee scoring scale and Tegner activity rating. Both groups improved significantly between the preoperative and postoperative assessment in terms of the knee laxity and functional examination (P<0.01). Meanwhile, knee stability was significantly improved in the LARS group when compared with the 4SHG group (P<0.05); this was also the case for the Lysholm, Tegner and IKDC scores (P<0.05). Our study indicates that using a LARS ligament for PCL reconstruction was clinically more useful than using a 4SHG in the treatment of the PCL-deficient knee.