“Arcuate” sign and Lateral Meniscus “Mid-air” sign Implied for Severe Posterolateral Complex Injury: a 6-years follow-up case report and literature reviewAoqiu Wu1#, Quanchao Li1#, Junliang Liu1, Weihong Zhu1*,Department of Orthopaedics, The Second Xiangya Hospital, Central South University, Changsha, Hunan Province, P. R. China.*Corresponding Author : Weihong Zhu, M.D., Ph.D.Department of Orthopaedics, The Second Xiangya Hospital, Central South University, 139 Middle Renmin Road, Changsha, Hunan Province 410011, P. R. China.Phone: +86 13873171921Email: zhuweihong@csu.edu.cnKeywords arcuate sign-tibial eminence fracture-posterolateral complex•floating meniscusKey clinical message ：A 33-year-old male with a tibial eminence fracture, fibular head avulsion, and severe PLC injury underwent surgery after a traffic accident. Preoperative MRI revealed a ”mid-air” lateral meniscus. Post-surgery, the patient achieved full knee stability, restored range of motion, and returned to pre-injury activity levels with excellent clinical outcomes at 6 years.