To investigate the effect of meniscus on the stability of knee joint after anterior cruciate ligament rupture and reconstruction.

From January 2017 to October 2018, patients undergone anterior cruciate ligament reconstruction were included in the research prospectively. Partial anterior cruciate ligament rupture and multiple ligaments injury cases were excluded. Unstable meniscus tears diagnosed by arthroscopy were recorded and treated with partial meniscus resection. All the cases were divided into several groups according to the position and degree of the injury meniscus. KT-1000 test was used to quantify the anterior translation of the tibia (ATT) before surgery and at three and six months postoperatively. Independent t test was used to compare quantitative data between groups.

A total of 158 patients with anterior cruciate ligament reconstruction were included in the research in which including 61 patients with a normal meniscus, 49 patients with a posterior horn of the medial meniscus (PHMM) tear (19 cases of avulsion <total width 40%; 30 cases of avulsion ≥total width 40%), 35 patients with lateral meniscus tear (12 cases of avulsion <total width 40%; 23 cases of avulsion ≥total width 40%) and medial meniscus tear (six cases of avulsion <total width 40% ; seven cases of avulsion≥total width 40%). Only the ATT of PHMM avulsion (>40% of the total width) group was significantly different from those of patients with normal meniscus (t=12.141; P<0.01). At the time of three and six months after surgery, there was no significant difference in KT-1000 test between the patients with meniscus tear and those with normal meniscus (P>0.05).

Tear of posterior horn of medial meniscus and rupture of anterior cruciate ligament can increase the instability of knee joint, and partial meniscectomy has no effect on the stability of knee joint after anterior cruciate ligament reconstruction.