Dr Ngai graduated from Faculty of Medicine, CUHK. Fellowship in Royal College of Surgeons of Edinburgh (Orthopaedic), Hong Kong College of Orthopaedic Surgeons, and Hong Kong Academy of Medicine (Orthopaedic Surgery).
Dr Ngai is active in education activities. She was appointed as Honorary Assistant Professor in Orthopaedics and Traumatology Department, Faculty of Medicine of the University of Hong Kong and Chinese University of Hong Kong since 2015.