Tibial tubercle fractures are a relatively uncommon pediatric fracture and account for less than 1% of epiphyseal injuries. Of all proximal tibial fractures, approximately 3% are tibial tubercle avulsion fractures. There are four stages of tibial tubercle development: cartilaginous, apophyseal, epiphyseal, and bony union. The cartilaginous stage exists before the development of a secondary ossification center. The apophyseal stage occurs when a secondary ossification center appears, at approximately 8 to 14 years of age. The apophysis coalesces with the proximal tibial epiphysis during the epiphyseal phase. In the final stage, bony union and closure of the physis occur during years 10 to 15 in girls and 11 to 17 in boys.