Percutaneous Dowel Bone Grafting of a Patella Nonunion in a Football Player

Abstract

The primary function of the patella is to increase the effi cacy of the quadriceps muscle by elevating the extensor mechanism from the knee’s axis of rotation.1 This provides a mechanical advantage by increasing the moment arm, thus allowing the knee to tolerate the substantial forces required by activities such as walking, rising from a chair, or jumping.1 This mechanism is often disrupted in the case of a patella fracture, but if the patellar retinaculum remains intact after a transverse fracture, the extensor mechanism of the knee can continue to function.2 Nonoperative treatment of transverse patellar fractures with knee immobilization followed by quadriceps strengthening exercises has been advocated in cases of minimal extensor mechanism disruption and 2-mm of articular surface step-off.3-5 However, persistent patellofemoral contact stress and distracting tensile forces across the fracture site may contribute to the development of a nonunion. The superior pole of the patella is pulled proximally by the quadriceps tendon while the inferior pole is pulled distally by the patellar ligament.4 This article presents a case of a 16-year-old multisport athlete with a nonunion of a minimally-displaced transverse patellar fracture. To our knowledge, treatment with percutaneous, autogeneic, dowel bone grafting and cannulated compression screw fi xation has not been previously reported in the literature.