Management of double-layered patellae by compression screw fixation.

Tripartite patella is a form of double-layered patella in which the anterior layer is bipartite. It was first described by Büttner in 1925 (1). More recently, an association with multiple epiphyseal dysplasia has been described (2,3). In this article, we describe a case of symptomatic tripartite patella in a 13-year-old child who was subsequently found to have features of multiple epiphyseal dysplasia. Her patellae had an abnormal excursion with a click and a visible jump in the longitudinal line of movement, but no lateral instability. We present a surgical solution not previously described by fusion of the two main components and report an excellent result.