Abstract:Objective To investigate the clinical application value of Slot of dynamic flat-panel X-ray photography system of whole lower extremities in total knee arthroplasty. Methods From November 2013 to March 2017, a retrospective analysis was made that a total of 89 total knee arthroplasty patients,which were 99 knee joints, received the radiography of whole lower extremities in standing position by slot of dynamic flat-panel X-ray photography system pre-and post-surgery, respectively. Score manner (0 - 2 marks) was used to evaluate the image quality. The lower limb alignment and femorotibial angle of patients' surgery knee were measured with the post-processing software. All knees were evaluated completely before surgery and the surgery effect was evaluated by comparing X-ray findings pre- and post-surgery. Results (1) All the 89 patients with the slot examinationhad a success rate of 100% with short imaging time, simple and convenient surgery, high quality images (mark 2), which completely met diagnostic and clinical requirements. (2) All the patients with Genuv arum (n = 17), genuvalgum (n = 8) and no Genu varum or valgum (n = 64) were fully and accurately evaluated before surgery. The surgery effects for all 89 patients were good, and 25 patients of genu varum or valgum has been corrected well. (3) All patients' prosthesis have good alignment, without fracture around the prosthesis. The lower limb line and femorotibial angle (FTA) were allin normal reference range. Compared with the pre-surgery ones, the FTA in 17 cases with varus knee deformity was statistically significant (t = -6.59, P < 0.001); in 8 cases of valgus knee deformity, the difference of FTA was statistically significant (t =5.597, P < 0.05), the varus and valgus deformity of knee was corrected better than pre-surgery; there were no statistically significant differences for the angle between lower limb line and gravity of vertical and the angle between lower limb line and FTA between pre- and post-surgery (tpre = 0.725, P = 0.487, and tpost =-2.09, P = 0.07, respectively). Conclusions Slot radiography of whole lower extremities has high success rate, fast acquisition and low radiation dose. It is also with simple image stitching performance and excellent quality images, which meets the needs of clinical diagnosis and is of important value for preoperative planning and postoperative evaluation.