The present study analyses the outcome of open reduction and internal fixation (ORIF) of humerus medial epicondyle fracture with the use of Kirschner (K) wires, and determine the effect of elbow dislocation. The study included 112 patients operated on in 2005–2016. Of these, 81presented with an isolated medial epicondyle fracture (mean age 11.6 years), and 31 with an elbow dislocation (mean age 11.9 years). Out of 112 patients tested, 98 achieved an excellent treatment result, ten good and a mean Mayo Elbow Performance Score (MEPS); no significant differences were observed between dislocated and non-dislocated elbow groups. Those with an isolated medial epicondyle fracture demonstrated a mean flexion of 140.7° and extension deficit of 3.0°, while those with an elbow dislocation displayed a mean flexion of 134.5° and extension deficit 6.1°. The dislocation group demonstrated significantly greater extension and flexion deficits (p = 0.019, p < 0.001, respectively). One patient required revision surgery due to nonunion. Ulnar nerve function was normal in 110 patients: in the other two, it resolved spontaneously in one, and the nerve was transposed in the other. Medial elbow instability was found in seven patients: two with elbow dislocation and five without. ORIF with K wires is a safe procedure for treating medial epicondyle humeral fractures that yields good or very good results. Similar outcomes are observed between patients with and without dislocation according to MEPS; however, flexion and extension are more limited in the former group.