Objective: To summarize research progress of the effect of knee flexion position on postoperative blood loss and knee range of motion (ROM) after total knee arthroplasty (TKA).
Methods: The relevant literature at home and abroad was reviewed and summarized from mechanism, research status, progress, and clinical outcome. The differences of clinical results caused by different positions, flexion angles, and keeping time were compared.
Results: Keeping knee flexion after TKA can reduce postoperative blood loss through the angle change of blood vessels and increase knee early ROM by improving flexion muscle strength. When the flexion angle of the knee is large and the flexion position is keeping for a long time, the postoperative blood loss and the knee ROM can be significantly improved. However, the amount of blood loss and ROM are not further improved in the patients with keeping knee flexion for more than 24 hours compared with less than 24 hours.
Conclusion: Keeping knee flexion after TKA is a simple and effective method to reduce postoperative blood loss and improve knee ROM. However, the optimal knee flexion angle and time are needed to be further explored.
目的: 总结人工全膝关节置换术（total knee arthroplasty，TKA）后保持膝关节屈曲位对术后失血及早期膝关节活动度影响的研究进展。.
方法: 查阅近年国内外有关文献，就 TKA 术后保持膝关节屈曲位减少失血及增加膝关节活动度的作用机制，膝关节屈曲及伸直位、不同屈曲角度及维持时间的疗效差异进行总结。.
结果: TKA 术后膝关节保持屈曲位可通过血管成角变化等减少术后失血、提高屈肌肌力，进而增加膝关节活动度。膝关节屈曲角度较大、维持屈曲位时间较长时，可显著改善术后失血和膝关节活动度；但维持时间≥24 h 与<24 h 相比，不能进一步减少失血并改善膝关节活动度。.
结论: TKA 术后保持膝关节屈曲位是减少术后失血，提高早期膝关节活动度的简单、有效方法，但膝关节最佳屈曲角度及维持时间有待进一步探究。.
Keywords: Total knee arthroplasty; flexion; knee; postoperative blood loss; range of motion.