Objective To investigate the feasibility of establishing an anterior cruciate ligament (ACL) reconstruction model using hamstring tendon autograft in cynomolgus monkeys. Methods Twelve healthy adult male cynomolgus monkeys, weighing 8-13 kg, were randomly divided into two groups (n=6). In the experimental group, the ACL reconstruction model of the right lower limb was prepared by using a single bundle of hamstring tendon, and the ACL of the right lower limb was only cut off in the control group. The survival of animals in the two groups was observed after operation. Before operation and at 3, 6, and 12 months after operation, the knee range of motion, thigh circumference, and calf circumference of the two groups were measured; the anterior tibial translation D-value (ATTD) was measured by Ligs joint ligament digital body examination instrument under the loads of 13-20 N, respectively. At the same time, the experimental group underwent MRI examination to observe the graft morphology and the signal/ noise quotient (SNQ) was caculated. Results All animals survived to the end of the experiment. In the experimental group, the knee range of motion, thigh circumference, and calf circumference decreased first and then gradually increased after operation; the above indexes were significantly lower at 3 and 6 months after operation than before operation (P<0.05), and no significant difference was found between pre-operation and 12 months after operation (P>0.05). In the control group, there was no significant change in knee range of motion after operation, showing no significant difference between pre- and post-operation (P>0.05), but the thigh circumference and calf circumference gradually significantly decreased with time (P<0.05), and the difference was significant when compared with those before operation (P<0.05). At 6 and 12 months after operation, the thigh circumference and calf circumference were significantly larger in the experimental group than in the control group (P<0.05). At 3 and 6 months after operation, the knee range of motion was significantly smaller in the experimental group than in the control group (P<0.05). Under the loading condition of 13-20 N, the ATTD in the experimental group increased first and then decreased after operation; and the ATTD significantly increased at 3, 6 months after operation when compared with the value before operation (P<0.05). But there was no significant difference between the pre-operation and 12 months after operation (P>0.05). There was no significant change in ATTD in the control group at 3, 6, and 12 months after operation (P>0.05), and which were significantly higher than those before operation (P<0.05). At each time point after operation, the ATTD was significantly smaller in the experimental group than in the control group under the same load (P<0.05). The MRI examination of the experimental group showed that the ACL boundary gradually became clear after reconstruction and was covered by the synovial membrane. The SNQ at each time point after operation was significantly higher than that before operation, but gradually decreased with time, and the differences between time points were significant (P<0.05). Conclusion The ACL reconstruction model in cynomolgus monkey with autogenous hamstring tendon transplantation was successfully established.
ObjectiveTo summarize the early postoperative pain management strategies for anterior cruciate ligament reconstruction (ACLR), and to select a reasonable and effective pain management plan to promote functional rehabilitation after ACLR. MethodsThe literature about the early postoperative pain management strategies of ACLR both domestically and internationally in recent years was extensiverly reviewed, and the effects of improving postoperative pain were reviewed. ResultsCurrently, physical therapy and oral medication have advantages such as economy and simplicity, but the effect of improving postoperative pain is not satisfactory, often requires a combination of intravenous injection or intravenous pump, which is also a common way to relieve pain. However, in order to meet the analgesic needs of patients, the amount of analgesic drugs used is often large, which increases the incidence of various adverse reactions. Local infiltration analgesia (LIA), including periarticular or intra-articular injection of drugs, can significantly improve the early postoperative pain of ACLR, and achieve similar postoperative effectiveness as nerve block. LIA can be used as an analgesic technique instead of nerve block, and avoid the corresponding weakness of innervated muscles caused by nerve block, which increases the risk of postoperative falls. Many studies have confirmed that LIA can alleviate postoperative early pain in ACLR, especially the analgesic effects of periarticular injection are more satisfactory. It can also avoid the risk of cartilage damage caused by intra-articular injection. However, the postoperative analgesic effect and timeliness still need to be improved. It is possible to consider combining multimodal mixed drug LIA (combined with intra-articular and periarticular) with other pain intervention methods to exert a synergistic effect, in order to avoid the side effects and risks brought by single drugs or single administration route. LIA is expected to become one of the most common methods for relieving postoperative early pain in ACLR. ConclusionEarly pain after arthroscopic ACLR still affects the further functional activities of patients, and all kinds of analgesic methods can achieve certain effectiveness, but there is no unified standard at present, and the advantages and disadvantages of various analgesic methods need further research.