Objective:To investigate the therapeutic effects of internal fixation via the posterolateral combined posteromedial approach in the treatment of posterior pilon fracture (Klammer type Ⅲ).Methods:A retrospective study was performed to analyze the 69 posterior pilon fractures (Klammer type Ⅲ) which had been treated by internal fixation with hollow screws or a buttress plate at Department of Orthopaedic Trauma, Yantai Shan Hospital from January 2015 to January 2020. There were 36 males and 33 females with an age of (45.3±10.0) years and duration from injury to surgery of (6.0±1.5) d. They were assigned into 2 groups according to different surgical approaches. The observation group (41 cases) was treated through the posterolateral combined posteromedial approach while the control group (28 cases) through the posterolateral approach alone. The therapeutic effects were evaluated by comparing the 2 groups in terms of incision length, intraoperative bleeding, operation time, fracture union time, fracture reduction (evaluated by the Burrwell-Charnley radiological score), the ankle-hindfoot score of American Orthopaedic Foot and Ankle Society (AOFAS) and complications.Results:There was no significant difference in the preoperative general data between the 2 groups, showing comparability ( P>0.05). All the 69 cases were followed up for (16.9±4.0) months, revealing primary healing of all the incisions and no vascular injury or wound infection. The incision length [(11.2±1.8) cm] and operation time [(76.0±6.6) min] in the observation group were significantly shorter than those in the control group [(12.4±1.9) cm and (79.7±6.8) min], the excellent and good rate of reduction in the observation group (97.6%, 40/41) was significantly higher than that in the control group (89.3%, 25/28), and the ankle-hindfoot scores of AOFAS at 1, 3 and 12 months after operation in the observation group [(78.4±5.6), (79.5±2.8) and (86.9±2.1)] were significantly higher than those in the control group [(75.2±5.5), (78.0±3.2) and (85.8±2.3)] (all P<0.05). There was no significant difference in the intraoperative bleeding between the 2 groups ( P>0.05). In the control group, 2 patients developed numbness in the dorsum of foot, which gradually disappeared after 3 months of treatment, but no other complications like persistent pain or flexor contracture within 1 year after operation. Conclusion:In the treatment of Klammer type Ⅲ posterior pilon fracture, the posterolateral combined posteromedial approach can result in satisfactory therapeutic effects, because the surgical approach can fully expose the fracture and facilitate better reduction.