We describe a new technique of percutaneous epiphysiodesis using transphyseal screws (PETS) and our experience with it in 32 cases of limb-length inequality and nine angular knee deformities. A subgroup of 18 patients with postfracture limb overgrowth formed a clinical model for study of the real efficacy of PETS. It proved a reliable method with few complications and many advantages such as simplicity of technique, short operating time, rapid postoperative rehabilitation, and reversibility. Bone-length inequality decreased from a preepiphysiodesis average of 2.47 cm(range, 1.5-4.6) to 0.51 cm at skeletal maturity. The tibiofemoral angle reduced from a preoperative average of 7.66° to 0.86° at maturity. The screws began to exert significant growth inhibition within 6 months of insertion, slowing down the distal femoral and upper tibial physes by 68 and 56%, respectively. They achieved maximum growth retardation over the ensuing 12 months, slowing down the distal femoral physis by 89% and the proximal tibial physis by 95%. At skeletal maturity, total femoral growth was 45% and total tibial growth was 52% that of the normal side.