Screw depth sounding in proximal humerus fractures to avoid iatrogenic intra-articular penetration

Unstable and displaced proximal humerus fractures remain a treatment challenge. The use of locked plates has improved construct stability, but complication rates remain high. Biomechanical studies have emphasized the importance of anchoring screws in the subchondral bone of the humeral head to improve implant stability. However, the spherical shape of the proximal humerus and the limited tactile sensation of its soft cancellous bone make determining accurate screw length difficult, and reported rates of intraoperative screw penetration are high. Iatrogenic screw penetration, even if recognized and corrected before leaving the operating room, may lead to late failure. We present a simple technique of quickly and safely determining screw length using a blunt-tipped Kirschner wire and instruments found in basic orthopaedic sets.