Lateral condylar (LC) and olecranon (OC) fractures occurring concurrently on one side are rare phenomena with limited scientific literature. Our study aims to evaluate the radiologic, clinical, and functional consequences of lateral to medial injury of the elbow (LAMEINE) in pediatric patients, simultaneously comparing with lateral to medial diagonal injury of the elbow (MELAINE). Eighteen males and 10 females were diagnosed with LAMEINE. The average age at the time of injury was 3.8 ± 2.3 years (range, 1-9). Out of the 28 fractures, 19 (67.9%) occurred on the left side and nine (32.1%) on the right side. The OC fractures were classified according to the Weiss system, two being type I, 17 type II, and nine type III fractures. Based on the specific case characteristics, the OC fractures were further subdivided into five types corresponding to two types of AO classification: 24 (85.7%) cases of AO 21u-M/2. 1 incomplete fractures [3 type I (10.7%), 16 type II (57.1%), and five type III fractures (17.9%)], and four (14.3%) cases of AO 21u-M/3.1 complete simple fractures [2 type IV (7.1%) and two type V fractures (7.1%)]. All patients underwent surgical intervention. Their clinical and functional outcomes were evaluated using the carrying angle (CA) and elbow performance score (EPS). These results were then compared with those of our MELAINE patients. All patients were followed up for 42.9 ± 23.5 months (range, 15-88). Radiographs indicated that all fractures healed in 5.9 ± 1.4 weeks (range, 4-10). At the last follow-up, the CA and EPS of the injured side were 11.3° ± 2.8° and 97.7 ± 3.7, respectively. All patients had favorable outcomes: 27 patients (96.4%) had excellent EPS, and only one patient (3.6%) had good EPS. The LAMEINE group displayed lower age, displacement, incidence of elbow dislocation, and CA than the MELAINE group (P <
0.05). Although relatively rare, LAMEINE should not be neglected. Surgical treatment aims to stabilize the elbow and avoid varus deformity. With appropriate diagnosis and treatment, good clinical and radiographic outcomes can be achieved for both patterns of 'diagonal lesions' of the pediatric elbow. Level of evidence: III.