Patellar Sleeve Fracture

Abstract

Patellar fractures in children are uncommon; however, sleeve fractures comprise the majority of such injuries, are unique to the pediatric and adolescent population, and are more common in boys. They are typically caused by a rapid contraction of the quadriceps muscle, while the knee is in a flexed position, often while jumping or during a fall. These injuries most commonly present with the acute onset of anterior knee pain, swelling, and difficulty straightening the leg. On exam, patients with patellar sleeve fractures typically have a limp, tenderness to palpation over the extensor mechanism, an effusion, and often an extensor lag. A high-riding patella and a palpable patellar gap may be present, as well. A lateral knee x-ray is helpful in making the diagnosis but can underestimate some injuries, so MRI or ultrasound should be utilized, if there is a high index of suspicion of patellar sleeve fracture. Minimally or nondisplaced fractures can be treated conservatively with casting, while displaced fractures require surgery.