One option for correcting angular deformities around the knee is hemiepiphyseal stapling. We have invented a percutaneously guided grooved staple which allows placing of the staple exactly, with a minimal incision and little surgical time. We used this technique on five children (16 bones). The deformities were fully corrected in all except one patient in whom staples were used to postpone definitive surgery until skeletal maturity. The mean time of surgery per physis was 7 min (range, 4–13 min). Less than 10 min was required to insert each staple. Using grooved staples allowed the surgeon to perform hemiepiphysiodesis efficiently and precisely.