Epiphysiodesis Screw Bending.

Percutaneous epiphysiodesis using transphyseal screws is a common method for treatment of limb length discrepancy and angular deformity. The authors report 3 cases of a previously unreported complication following treatment with percutaneous epiphysiodesis using transphyseal screws: bending of the transphyseal screw. In each case, this rare complication was associated with difficult removal of the screw. This retrospective case report accessed the medical records of 3 children, 2 boys and 1 girl, 9 to 14 years old. All of the children had 4.0-mm cannulated stainless steel screws ranging from 40 to 50 mm in length. Two of the patients had partially threaded and 1 had fully threaded screws with bending noted a minimum of 6 months following implantation. Additionally, each of the screws bent near the physis of the bone, which was not located at the center of the screw in every case or at the transition from threaded to nonthreaded portions in each partially threaded screw. To the authors' knowledge, these are the first reported cases of cannulated screw bending following transphyseal tibial or femoral placement for the correction of leg length or angular deformity in a pediatric population. Although the true incidence rate is unknown, screw bending following percutaneous epiphysiodesis presents complications in the hardware removal process. Further biomechanical tests should be conducted to determine the best screw design to minimize bending of transphyseal screws from physiologic growth. [Orthopedics. 2017; 40(4):e717-e720.].