Bifocal disruption of the knee extensor apparatus (“floating patella”) in a 13-year-old patient

We present the unusual case of a traumatic “floating patella” in a 13-year-old healthy boy. No predisposing factors were diagnosed. The obvious bony avulsion was treated by immediate open reduction and screwing, whereas the quadriceps tendon rupture was missed diagnostically in the first step. During the course of the treatment, the extension lag lead to the delayed diagnosis of the concomitant rupture of the quadriceps tendon. After the surgical treatment of the latter, the patient healed with full function of the extensor apparatus and full ROM. Bifocal injury of the knee extensor apparatus is therefore possible in young adolescents without presenting the predisposing factors and should thus be considered.