FIGURE 2

The progressive nature and severity of overgrowth in PS. Panel a shows a teenager with valgus deformity of the knee, fixation of the knee joint due to bony overgrowth surrounding the joint and external rotation of lower leg of more than 90°. Panel b shows the same patient a few years later with continued external rotation of the leg that now exceeds 135° with onset of bowing of the tibia. The surgical correction of such deformities is challenging.