Bilateral patellar tendon rupture without predisposing systemic disease or steroid use: a case report and review of the literature.

Simultaneous bilateral patella tendon ruptures are very rare injuries of the knee extensor complex often associated with systemic disorders such as lupus erythematosus or rheumatoid arthritis. We describe the case of a 34-year-old man without concomitant systemic disease or steroid use and provide the most comprehensive review of the German and English literature. Furthermore, we discuss the predisposing factors and causal mechanisms as well as current diagnostic procedures and treatment options. In the literature review, only a few patients without systemic disorder or steroid medication present with potential predisposing factors that may be responsible for degenerative changes of the patella tendon, weakening its stability. In addition, in most of these cases, it remains difficult to explain the bilateral and simultaneous nature of this injury.