Reninoma is a rare renal secretory tumor，prevalent in the young population. This disease is mostly surgically resected，and the use of microwave ablation to treat reninoma in children is scarce. A case of reninoma in a child was reported in this paper. The patient presented with refractory hypertension，hypokalemia，hyperreninemia and hyperaldosteronemia. Enhanced CT and contrast-enhanced ultrasound showed mass in the lower pole of the right kidney，which was considered as reninoma and microwave ablation was performed. The renin concentration decreased to 68.42 pg/ml at 4 hours after surgery. After 1 year of postoperative follow-up，there was no recurrence of hypertension and hypokalemia，and no signs of tumor recurrence were seen on repeated ultrasound examinations.

Reninoma is a rare renal secretory tumor，prevalent in the young population. This disease is mostly surgically resected，and the use of microwave ablation to treat reninoma in children is scarce. A case of reninoma in a child was reported in this paper. The patient presented with refractory hypertension，hypokalemia，hyperreninemia and hyperaldosteronemia. Enhanced CT and contrast-enhanced ultrasound showed mass in the lower pole of the right kidney，which was considered as reninoma and microwave ablation was performed. The renin concentration decreased to 68.42 pg/ml at 4 hours after surgery. After 1 year of postoperative follow-up，there was no recurrence of hypertension and hypokalemia，and no signs of tumor recurrence were seen on repeated ultrasound examinations.

Objective:To compare of the efficacy of Steinman pin-assisted and manual reduction for the treatment of distal femoral fracture with anterograde intramedullary nail.Methods:From January 2014 to August 2018, data of 54 patients with distal femoral fracture were retrospectively analyzed. According to the fracture reduction methods, patients were divided into two groups: bare-handed reduction group and Steinman pin-assisted reduction group (referred to Steinman pin group). There were 16 males and 10 females in bare-handed reduction group, with age of 37.5±9.2 years (range, 21-59 years). According to AO/OTA classification, 16 cases were type 32-A, 7 type 32-B, 3 type 32-C. There were 19 males and 9 females in Steinman pin reduction group, with age of 36.4±9.8 years (range, 18-55 years). According to AO/OTA classification, 19 cases were type 32-A, 7 type 32-B, 2 type 32-C. The reduction time, fluoroscopy times, intraoperative blood loss, fracture healing time, and knee joint function score of American hospital for special surgery (HSS) were compared between the two groups.Results:The amount of blood loss during operation was 142.78±29.76 ml in the bare-handed group, and 94.81±17.71 ml in the Steinman pin group. The reduction time of fracture was 14.19±2.50 min in the bare-handed group and 5.02±1.69 min in the Steinman pin group. The times of fluoroscopy during reduction was 12.56 ±2.01 in the bare-handed group and 5.01±1.51 in the Steinman pin group. There were significant differences in the above indexes ( t=12.19, 4.02, 5.47; all P < 0.05). All 54 patients were followed up for 12-51 months, with an average of 23.4 months. All the fractures healed, and there was no delayed union or nonunion. The healing time was 7.01±1.15 months in the bare-handed group and 5.99±0.97 months in the Steinman pin group. There were no significant difference. The HSS score of knee joint function was 23.7±4.1 before operation, 61.3±4.5 at 1 month after operation, 70.2±4.2 at 2 months after operation, 78.9±5.9 at 3 months after operation, 87.9±4.6 at 6 months after operation, and 93.1±5.8 at 12 months after operation, in the bare-handed group. Meanwhile, in the Steinman pin group, 22.5±3.8 before operation, 62.2±5.1 at 1 month after operation, 69.1±4.7 at 2 months after operation, 79.2±4.3 at 3 months after operation, 88.6±5.3 at 6 months after operation, and 92.3±6.1 at 12 months after operation. There were no significant difference between the two groups ( t=1.113, 0.689, 0.908, 0.212, 0.519, 0.494, P > 0.05). There were significant differences between the two groups at each time point before and after operation ( F=716.42, 815.52, P < 0.001). There were no complications such as injection point infection, vascular and nerve injury, failure of internal fixation and so on. Conclusion:Both groups had good functional recovery after operation. However, compared with bare-handed reduction, Steinman pin groupreduction has less intraoperative blood loss, shorter reduction time and less fluoroscopy times, which is a safer reduction method.