Objective:To compare the clinical outcomes of internal fixation of McCrory-Bladin type III fracture of the lateral process of the talus (FLPT) with Kirschner wire Double-pully technique under subtalar arthroscopy and open reduction with Kirschner wire fixation.Methods:A retrospective cohort study was conducted to analyze the clinical data of 42 patients (42 feet) with McCrory-Bladin type III FLPT admitted to Xuzhou Central Hospital from May 2017 to May 2022, including 15 males (15 feet) and 27 females (27 feet); aged 18-55 years [(33.3±9.8)years]. Among them, 24 patients were treated with Kirschner wire Double-pully technique under subtalar arthroscopy (arthroscopy+Kirschner group), and 18 with open reduction and Kirschner wire fixation (open reduction+Kirschner group). The surgical duration, wound healing status, and assessment outcomes at 12 weeks, 12 months and the last follow-up, including American Orthopedic Foot & Ankle Society (AOFAS) ankle-hindfoot score, Patient-Reported Outcomes Measurement Information System Physical Function (PROMIS-PF) score, and Foot and Ankle Ability Measure (FAAM) [Activities of Daily Living (ADL) and Sports (S) subscores], were compared between the two groups, respectively. Complication rates were also compared at the last follow-up.Results:All the patients were followed up for 12-27 months [(17.6±4.9)months]. The surgical duration in the arthroscopy+Kirschner group [(53.7±11.8)minutes] was longer than that in the open reduction+Kirschner group [(43.9±7.2)minutes] ( P<0.05). Bone grafting was not required in either group and all incision healing was achieved by primary intention. At 12 weeks, 12 months and the last follow-up, the arthroscopy+Kirschner group had higher AOFAS ankle-hindfoot score [(91.3±4.4)points, (94.0±4.2)points, (94.7±4.5)points] compared with the open reduction+Kirschner group [(74.7±11.2)points, (77.9±12.0)points, (79.2±12.0)points] (all P<0.01); the arthroscopy+Kirschner group had higher PROMIS-PF score [(69.5±3.7)points, (71.6±3.3)points, (72.5±3.2)points] compared with the open reduction+Kirschner group [(61.7±6.7)points, (62.9±6.8)points, (63.3±7.0)points] (all P<0.01); the arthroscopy+Kirschner group had higher FAAM-ADL score [(89.8±3.8)points, (92.5±3.3)points, (93.2±3.4)points] compared with the open reduction+Kirschner group [(70.3±15.2)points, (72.1±15.2)points, (73.1±16.0)points] (all P<0.01); and the arthroscopy+ Kirschner group had higher FAAM-S score [(91.5±3.6)points, (94.4±3.6)points, (94.9±3.5)points] compared with the open reduction+Kirschner group [(76.9±15.0)points, (78.6±16.2)points, (79.0±16.0)points] (all P<0.01). Subtalar joint arthritis developed in 2 patients [8.3% (2/24)] in the arthroscopy+Kirschner group at the last follow-up, but in 6 [33.3% (6/18)] in the open reduction+Kirschner group ( P<0.05). No nerve injury was found in either group. Conclusion:For McCrory-Bladin type III FLPT, the Kirschner wire Double-pully technique under subtalar arthroscopy, despite longer surgical duration, results in better physical function, improved activities of daily living, enhanced ankle function, and a lower rate of subtalar joint arthritis compared with open reduction with Kirschner wire fixation.