Patellofemoral instability in children requires surgery when recurrent dislocation occurs. The aim of this study is to report the 5-year clinical and radiographic outcomes following lateral wedge augmentation trochleoplasty of the femoral trochlea. This is a review of 23 (mean age: 12.5 years) patients who underwent surgery for recurrent patellar dislocations related to a flat trochlea. In every case, a lateral wedge augmentation trochleoplasty was performed with preservation of the growth plate. This surgery was consistently associated with a soft tissue procedure. All patients were reviewed for a clinical and radiographic evaluation [computed tomography (CT)-scan]. No case of recurrent patellar dislocation was reported and all patients were satisfied with the procedure; three patients reported anterior knee pain after physical activities. CT scan analysis revealed improvement of the trochlear shape measurements in all cases, but osteoarthritis lesions (narrowing of the lateral patellofemoral compartment) were visible on four CT scans. This trochleoplasty technique augmented by a soft tissue procedure on the extensor apparatus led to acceptable clinical mid-term results in terms of stability for patients with a flat trochlea (grade B according to Dejour classification). However, at the 5-year follow-up, four patients showed signs of osteoarthritis on CT scan evaluation. This warrants serious concern in this young population, and alternative methods should be considered whenever possible.