Although there are many factors that are likely to influence the need for open reduction and percutaneous pinning (ORPF) in the treatment of pediatric supracondylar humerus fractures (SCHFs), the role of surgeon’s experience (as represented by the total number of surgically treated SCHFs) on the need for ORPF has seldom been investigated. We reviewed the data on all completely displaced, pediatric SCHFs that were treated surgically by a single, fellowship-trained, pediatric orthopedic surgeon over the first 10 years of the surgeon’s clinical practice. The incidence of ORPF was calculated as the percentage of open reductions among surgically treated, completely displaced, consecutive SCHFs at any given time during the 10-year period. From September 2005 to August 2015, a total of 212 completely displaced SCHFs were treated surgically at our institution by a single surgeon. When analyzing the incidence of ORPFs among surgically treated, completely displaced SCHFs at any given time, a bimodal curve was found: there was an increasing slope over the first 30 surgically treated SCHFs, with a progressive decreasing slope afterward. The incidence of ORPF within the first 10, 20, and 30 surgically treated, completely displaced SCHFs was 10.0, 30.0, and 26.7%, respectively, decreasing to 16.0, 9.0, 6.7, and 5.0% within the first 50, 100, 150, and 200 surgeries, respectively. The incidence of ORPF was almost 17-fold higher within the first 30 surgically treated, completely displaced SCHFs (17%), when compared with the following 182 (1.1%) cases (P<0.00001). Although it is likely that many factors influence the need for ORPF in the treatment of completely displaced SCHFs, surgeon’s experience appears to play a significant role. Strategies aimed to accelerate the learning curve in the treatment of pediatric SCHFs should be undertaken.