[Objective] To explore the feasibility and clinical efficacy of applying gyroscope to femoral bone marrow positioning osteotomy for total knee arthroplasty. [Methods] 61 knees of 53 patients who underwent primary total knee arthroplasty from March 2020 to January 2021 were included, of which 27 cases underwent total knee arthroplasty with gyro extramedullary positioning femoral side osteotomy, and 34 cases underwent total knee arthroplasty. Traditional intramedullary guide rod positioning femoral side osteotomy for total knee arthroplasty, the clinical efficacy of the two groups was compared. [Results] ① The operation time of the two groups were 97.19±7.40 and 112.65±8.95 P＜0.001, the femoral osteotomy time was 6.19±1.73 and 7.41±1.91, P＜0.001, the intraoperative blood loss was 115.56±13.33 and 178.97, respectively ±22.42, P＜0.001, postoperative drainage volume was 115.56±18.67 and 217.06±26.80 P＜0.001, the difference was statistically significant; ②There was no statistically significant difference in knee KSS scores between the two groups of patients at 3 months postoperatively; There were no statistically significant differences in the hip, knee, ankle, and femoral tibial angles before and after surgery between the two groups; [Conclusion] The clinical effect of total knee replacement gyroscope femoral osteotomy outside the bone marrow is positive, which can reduce the operation time, reduce intraoperative blood loss and postoperative drainage.