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Objective:To explore the clinical outcome of measured resection combined with gap balancing technique in total knee arthroplasty (TKA).Methods:From January 2016 to October 2017, 61 cases of varus knee joint flexion deformity were applied the procedure of measured resection combined with gap balancing technique in primary total knee arthroplasty, including 24 male and 37 female; the average age was 66.80±8.2 years old (range from 60 to 78 years old). All patients underwent antero-medial incision of knee joint,medial parapatellar approach and posterior stabilized prosthesis. Measurement osteotomy technique was used to localize osteotomy. Gap balancing technique was vitrificated flexion and extension. Operation time, surgical blood loss and osteotomy volume were recorded. Radiographic evaluation included alignment of lower extremity, knee joint linedistance, tibiofemoral joint angle, rotation angle of femoral prothesis and posterior condylar offset (PCO). Joint functions were assessed including KSS scores, ROM and patient satisfaction.Results:The average operation time was 54±12 min (range from 45 to 65 min). The average postoperative drainage was 140±26 ml (range from 120 to 180 ml). The difference in hemoglobin values were 22±8.5 g/L(range from 20 to 30 g/L) between preoperative and postoperative 5 days. The lateral proximal tibial bone mass was 10.2±1.5 mm (range from 9.2 to 11.5 mm). The lateral distal femoral bone mass was 9.1±1.5 mm (range from 8.8 to 10 mm). The bone mass of posterior lateral condyle of femur was 8.6±1.5 mm (range from 7.8 to 10 mm). The bone mass of posterior medial condyle of femur was 9.2±1.2 mm (range from 8.6 to 10 mm), compared with the bone mass of posterior lateral condyle of femur, and the difference was statistically significant ( t=2.44, P=0.006). The intraoperative angle between osteotomy line of gap balanced osteotomy technique (line B) and connecting line of screw hole in measure osteotomy (line A) was 1.15°±0.47° (range from 1.02° to 2°). The external rotation angle was27.8%, the internal rotation angle was72.2%. There was no significant difference between preoperative knee joint line distance 40.55±4.32 mm and postoperative knee prosthesis joint line distance 40.99±3.86 mm. Postoperative knee straight and bent-knee 90° stress X-ray demonstrated that medial-lateral tibiofemoral joint angle showed no significant difference ( P >0.05). Cross-sectional CT of knee joint post operation, rotation angle of femoral prosthesis ≤±2°. Most of them were mainly concentrated in the internal rotation angle. There was no significant difference between preoperative PCO 31.55±3.18 mm and postoperative PCO 31.55±3.18 mm ( P>0.05). The KSS score and patient satisfaction score post operationwere significantly higher than those preoperation. The KSS score and patient satisfaction score at 3 months after operation were 89.2±9.4 points and 7.2±2.6 points, which were higher than that at 1 month after operation (78.0±3.5 points and 5.2±1.8 points), with statistically significant differences ( t=1.897, P=0.026; t=1.753, P=0.038). The KSS score was above 90 at 6 months after operation. The knee ROM after 1 month (94.7°±10.6°) had no statistical significance compared with that preoperation (91.9°±12.5°) ( t=1.286, P=0.245). The knee ROM at 3 months after surgery (105.8°±14.7°) was significantly higher than that before operation (91.9°±12.5°) ( t=1.924, P=0.041). There was no significant difference between the scores of the follow-up time points and those of 3 months after operation ( P >0.05). Conclusion:TKA were performed by using measured resection combined with gap balancing technique. Not only can good alignment of lower extremity be restored, but also flexion-extension gap balance can be obtained. Equal osteotomy with less soft tissue release. There are better ROM of knee and KSS functional scores in the early postoperative period. However, it is easy to cause femoral pseudointernal rotation.