Roentgen stereophotogrammetric analysis of growth pattern after pronation ankle injuries in children

In a prospective study of ankle fractures in children, the posttraumatic growth pattern was registered with a roentgen stereophotogrammetric technique. This method allows determination of growth rates within 3 months after fracture, and the prognosis for future growth can be determined within 6-8 months after fracture. The ankle fractures were classified anatomically according to Salter-Harris and traumatologically according to Gerner-Smidt. Nine cases were classified as due to pronation: two pronation-abduction injuries and seven pronation-eversion injuries. The pronation-abduction injuries had Salter-Harris type I injury in distal fibula and tibia, respectively, and showed initial growth stimulation and symmetric growth. The pronation-eversion injuries had a Salter-Harris type II injury in distal tibia and showed three types of growth pattern: initial growth stimulation (3 cases), growth arrest (2 cases), and progressive growth retardation (1 case), besides one case with no significant growth registered bilaterally. Asymmetric growth within the growth region was found in four cases; in three mainly as a varus position, in one mainly as antecurvation of the ankle joint. In conclusion, the pronation-abduction injuries showed growth stimulation, whereas the older showed progressive growth retardation or growth arrest.