Objective To evaluate the minimally invasive treatment of calcaneal fractures of Sanders Ⅱ &Ⅲ by closed reduction or a sacral sinus arc-shaped minimally invasive incision under subtalar arthroscopy assisted by a self-designed cervical retractor and a self-designed reducer to expose and assist the reduction followed by internal fixation with hollow nails and Kirschner wires.Methods From June 2016 to February 2018,53 patients (60 feet) were treated at Department of Hand and Foot Surgery,Central Hospital of Linyi for closed intra-articular calcaneal fractures.Of them,24 (28 feet) received the minimally invasive treatment and 29 (32 feet) open surgery via the conventional lateral L-shaped incision.The 2 groups were compared in terms of B(o)hler angle,Gissane angle,and the width,length and height of the calcaneus before operation,one week after operation and at the final follow-up,as well as in terms of preoperative preparation time,operation time,surgical bleeding volume,incision complications,subtalar joint stiffness,and anklehindfoot score of the American Foot and Ankle Surgery Association (AOFAS).Results The 2 groups were comparable because there were no significant differences between them in the preoperative general data (P ＞ 0.05).All the patients were followed up for 10 to 22 months (average,16 months).The B(o)hler angles,Gissane angles,and the widths,lengths and heights of the calcaneus after operation and at the final follow-up were significantly better than the preoperative values in the minimally invasive group (all P ＜ 0.05).The preoperative preparation time (2.5 d ± 1.2 d) and operation time (62.6 min ± 6.3 min) in the minimally invasive group were significantly shorter than those (7.6 d ± 3.5 d and 85.9 min ± 9.7 min) in the conventional group (P ＜ 0.05),the surgical bleeding volume in the former (30.5 mL ± 3.8 mL) was significantly smaller than that in the latter (80.9 mL ± 8.3 mL) (P ＜ 0.05),and the rates of incision complications (0) and subtalar joint stiffness (10.7％) in the former were significantly lower than in the latter (9.4％ and 43.7％) (P ＜ 0.05).However,there was no significant difference between the 2 groups in the AOFAS anlle-hindfoot score (92.8 ± 5.9 versus 89.5 ± 7.5) (P ＞ 0.05).Conclusion The minimally invasive treatment of calcaneal fractures of Sanders Ⅱ & Ⅲ by closed reduction or a sacral sinus arc-shaped minimally invasive incision under subtalar arthroscopy assisted by a self-designed cervical retractor and a self-designed reducer to expose and assist the reduction followed by internal fixation with hollow nails and Kirschner wires can lead to satisfactory clinical results,because this method shortens significantly the time for hospitalization and leads to less invasion,fewer complications,accurate reposition and reliable fixation.