Skeletal age is important to evaluate remaining growth. In 50% of normal children and adolescents, skeletal age does not differ from chronological age. During puberty, skeletal age is an important tool when performing a lower limb epiphysiodesis or when treating (conservatively or surgically) patients with spinal deformities. Skeletal age alone is not enough and should be assessed together with other clinical and radiological findings such as standing and sitting heights, Risser sign, Tanner stages and annual growth rate. Puberty starts at 11 years of skeletal age and ends at 13 years of skeletal age in girls; in boys, puberty starts two years later (13 years of skeletal age) and then ends at a skeletal age of 15. Most current clinical and radiographic markers do not help paediatric orthopaedic surgeons to clearly distinguish maturity levels prior to Risser I. Sauvegrain et al. developed a method to assess skeletal age by using elbow radiographs (AP and lateral projections). Between 11 and 13 years of skeletal age in girls and between 13 and 15 years of skeletal age in boys, the olecranon apophysis is characterised by a clear morphological development. This method is a reliable tool to assess skeletal age during puberty because significant morphological changes in the elbow happen every six months.