ObjectiveTo investigate the effectiveness of minimally invasive plate and medial supporting cannulated screw fixation via tarsal sinus approach in treatment of Sanders type Ⅱ and Ⅲ calcaneal fractures. Methods A clinical data of 46 patients with Sanders type Ⅱand Ⅲ calcaneal fractures met the selective criteria between March 2016 and March 2021 was retrospectively analyzed. The factures were fixed with minimally invasive plate and medial supporting cannulated screws via tarsal sinus approach in 20 cases (group A) and with minimally invasive plate in 26 cases (group B). There was no significant difference between groups in term of the gender, age, injury causes, fracture type and side, the time from injury to operation, and preoperative calcaneal length and width, Böhler angle, Gissane angle, and visual analogue scale (VAS) score (P>0.05). The operation time, intraoperative blood loss, hospital stay, and the interval between operation and full weight-bearing were recorded. The pain improvement of patients was evaluated by VAS scores before operation and at 48 hours after operation. The ankle joint function was evaluated by American Orthopaedic Foot and Ankle Society (AOFAS) score at 3 and 12 months after operation. Besides, the calcaneal length and width, Böhler angle, and Gissane angle were measured by X-ray films before and after operation. Furthermore, the difference (loss value) between 3, 12 months and 1 day after operation was calculated. Moreover, the fracture healing and healing time was observed. ResultsAll operations of two groups were successfully completed. The incisions healed by first intention, and no vascular/nerve injury or incision infection occurred. The operation time of group A was significantly longer than that of group B (P<0.05). There was no significant difference in the intraoperative blood loss, hospital stay, and the interval between operation and full weight-bearing (P>0.05). All patients were followed up 12-36 months (mean, 14.8 months). The VAS scores at 48 hours after operation were significantly lower than those before operation in the two groups (P<0.05); there was no significant difference in the difference of pre- and post-operative VAS score between groups (P>0.05). The AOFAS scores at 12 months after operation were significantly higher than those at 3 months after operation in the two groups (P<0.05); and there was no significant difference between groups at 3 and 12 months (P>0.05). X-ray films showed that the fractures of the two groups healed and there was no significant difference in healing time (P>0.05). There was no significant difference in calcaneal length and width and Gissane angle between groups at each time point (P>0.05), but there was significant difference in Böhler angle between groups at 12 months (P<0.05). The imaging indexes of the two groups significantly improved at each time point after operation when compared with those before operation (P<0.05). There was no significant difference between different time points after operation (P>0.05) in the imaging indexes of group A. There were significant differences in the calcaneal length, calcaneal width, and Gissane angle of group B between 12 months and 1 day, 3 months after operation (P<0.05), and there was no significant difference between 1 day and 3 months after operation (P>0.05). The differences in Böhler angle of group B between different time points after operation were significant (P<0.05). There was no significant difference between groups in the loss of all imaging indexes at 3 months after operation (P>0.05). The losses of calcaneal width, Böhler angle, and Gissane angle in group A at 12 months after operation were significantly smaller than those in group B (P<0.05), and there was no significant difference in the loss of calcaneus length between groups (P>0.05). ConclusionCompared with only minimally invasive plate fixation, the combination of minimally invasive plate and medial supporting cannulated screw fixation via tarsal sinus approach for Sanders type Ⅱ and Ⅲ calcaneal fractures has the advantages of less trauma, less incision complications, reliable fracture reduction and fixation, and good long-term stability.