Abstract:[Objective] To analyze the long-term clinical outcomes of knee arthroscopic surgeries for lateral meniscus injury by stratification. [Methods] A retrospective study was conducted on 326 patients (331 knee) who had the lateral meniscus injury treated arthroscopi-cally in our hospital from October 2008 to December 2018, involving 202 males and 124 females with a mean age of (39.3±11.3) years. The clinical data were compared by stratification based on gender, age, injury time, injury type and operation method. [Results] In term of gender, there were no significant differences in VAS, Lysholm, Tegner and Rasmussen scores, as well as maximum knee flexion ROM, loss of maximum knee extension and knee space tenderness between male and female (P>0.05). In term of age, the patients aged ≤40 years proved significantly superior to those aged >40 years in Lysholm score [(88.5±1.6) vs (84.1±1.1), P<0.001], Tegner score [(6.7±0.8) vs (5.5±0.9), P< 0.001], Rasmussen score [(27.6±1.3) vs (23.8±1.4), P<0.001], maximum knee flexion ROM [(134.4±3.0)° vs (124.2±1.8)°, P<0.001], whereas the former was significantly inferior to the latter in VAS score [(2.1±0.5) vs (1.5±0.7), P<0.001] and loss of maximum knee extension [(1.2±0.9)° vs (0.2±0.0)°, P<0.001] at the latest follow-up. In term time interval from the injury to operation, patients with time ≤28 days were significantly better than those with > 28 days regarding abovesaid scores and the maximal knee flexion ROM and loss of maximum knee extension before and at the last follow-up (P<0.05). In term of injury extent, the patients with simple injury proved significantly superior to those with complex injuries in above scores, maximum knee flexion and loss of maximum knee extensions before and at the last followup (P<0.05). In term of the surgical method, the patients received partial meniscectomy were significantly superior to those underwent meniscus suture and subtotal meniscectomy in abovementioned scores, maximum knee flexion ROM and loss of maximum knee extension before operation and at the last follow-up (P<0.05). In addition, the patients received partial meniscectomy had significantly higher ratio of preoperative joint space tenderness than those received meniscus suture and subtotal meniscectomy (P<0.05), although there was no a significant difference in the ratio of joint space tenderness among the three groups at the latest follow-up (P>0.05). [Conclusion] The longterm consequence of arthroscopic treatment for lateral meniscus injury of the knee is good, especially for patients with young age, short interval from injury to surgery and simple injury type.