A model of anterior cruciate ligament injury in cynomolgus monkeys developed via arthroscopic surgery

The anterior cruciate ligament (ACL) is an important structure that maintains the stability of knee joints. Animal models of ACL injury are helpful to explore its underlying mechanisms, and strategies for prevention, treatment and rehabilitation. Therefore, the aim of the present study was to develop an efficient model of ACL injury in cynomolgus monkeys via arthroscopic techniques. In the present study, 18 cynomolgus monkeys were randomly divided into a model group (n=6), a sham operation group (n=6) and a blank control group (n=6). One-quarter of the ACL was removed under arthroscopy in the model group. In the sham operation group, only arthroscopic exploration was performed as a control. In the blank control group, monkeys were housed under the same conditions for the same length of time. Magnetic resonance imaging examination was performed pre- and post-operatively, as well as measurements of the circumference of the thigh and calf, and of the maximum flexion degree of the knee. Anterior drawer test, Lachman test and pivot-shift tests were also performed. The results revealed that the injured side of the knees in the model group became unstable, as determined from evaluation of the physical tests. In conclusion, based on these findings, the modeling method of ACL injury was effective, and may contribute to the associated research concerning ACL injury.