OBJECTIVE:To systematically review the clinical effect of blood flow restriction training on rehabilitation after anterior cruciate ligament reconstruction to provide a reference for clinical practice. METHODS:Databases including CNKI,WanFang,PubMed,Web of Science and EBSCO were searched to collect randomized controlled trials of blood flow restriction training in the intervention of anterior cruciate ligament reconstruction from inception to August 10,2022.Outcomes included knee muscle strength,knee muscle mass,and knee function evaluation,all of which were continuous variables.Two reviewers independently screened the literature and extracted data.Cochrane bias risk assessment tool and Physiotherapy Evidence Database Scale were used to evaluate the bias risk of the included articles.Meta-analysis was then performed using RevMan 5.4 software. RESULTS:A total of 9 publications were included,including 226 subjects,114 in the trial group and 112 in the control group.Meta-analysis results showed that compared with conventional resistance training,the blood flow restriction training group could significantly improve knee muscle strength[SMD=0.54,95%CI(0.29,0.79),P＜0.01],muscle mass[SMD=0.26,95%CI(0.06,0.46),P=0.01]and knee joint function[SMD=1.17,95%CI(0.53,1.80),P＜0.01].Subgroup analysis showed that only when the intervention time was more than 4 weeks,there were significant improvements in knee joint muscle strength[SMD=0.68,95%CI(0.38,0.97),P＜0.01]and muscle mass[SMD=0.38,95%CI(0.09,0.68),P=0.01]. CONCLUSION:Current evidence shows that blood flow restriction training can improve muscle strength and knee function in patients with anterior cruciate ligament reconstruction and reduce muscle atrophy.It is recommended that the postoperative intervention time should be more than 4 weeks to achieve better muscle strength and muscle mass improvement.

Objective To analyze the differences of von Mises stress distribution in knee cartilage and meniscus in female with generalised joint hypermobility (GJH) and healthy female during drop jump landing. Methods The kinematic and ground reaction force (GRF) characteristics of knee joint in female with GJH and healthy female at the moment of peak vertical GRF (VGRF) during loading phase of drop jump landing were collected. The knee joint reaction force was calculated via inverse dynamics, and the combined force of knee joint along long axis of the femur was applied as the load. Based on three-dimensional (3D) finite element model of a female knee joint, numerical simulations were performed separately during drop jump landing of subjects in two groups, and von Mises stresses and stress distribution of knee cartilage and meniscus were calculated. Results At the moment of peak VGRF during drop jump landing, knee flexion and valgus angles in GJH group and control group showed a statistical significance (P<0. 05). Compared with control group, knee flexion angle decreased and valgus angle increased in GJH group. During drop jump landing, GJH group bore larger stress inside the knee joint, and stress distribution in weight-bearing areas of the medial and lateral tibiofemoral compartments was uneven, while the lateral femoral cartilage lateral condyle, the anterior and middle lateral of lateral tibial cartilage, the anterior angle and body lateral margin of lateral meniscus were stress concentration sites. Conclusions For females with GJH, the stability of knee joint decreases and force lines change in jumping events, due to the increased range of motion of knee joint and relaxation of joint capsule, which increases the risk of cartilage and meniscal injury in lateral knee joint. During jumping sports, females with GJH should especially prevent knee joint injury caused by altered force lines in frontal plane of knee joint.