Bipartite patella fracture with quadriceps rupture is an unusual injury. It is quite often mistaken as an avulsion fracture of patella, and the X-ray of contra-lateral knee is useful for diagnosis, and appropriate treatment should be decided at the time of surgery. We report a single case of this entity in which bipartite patella fracture was misdiagnosed initially as a patellar fracture. IntroductionThe secondary ossification centre of patella that fails to coalesce with the primary ossification centre results in bipartite patella. The incidence of bipartite patella in general population is about 2%, and about 50% are bilateral, and only 2% are symptomatic.Research suggests that 75% of patellae ossify by single centre and 23% ossify by two to three centres [1]. These secondary ossification centres usually appear around the age of 12 [1-3]. The primary centre of ossification generally appears between 21 and 54 months in girls and 36 and 72 months in boys [1].Saupe, in 1943, classified bipartite patella into the following three types: type I, located at the inferior pole, 5% of patients; type II, located at the lateral margin, 20% of patients; and type III is the superolateral location (most common type), 75% of patients [13].

The aim of this single centre retrospective study was to assess the outcome of patients after the fixation of slipped upper femoral epiphysis (SUFE) using a single cannulated screw. Thirty-eight slips, 28 stable and 10 unstable were treated with single in-situ screw fixation. The minimum follow-up was 1 year. The overall adverse outcome in terms of avascular necrosis (AVN), chondrolysis and revision surgery for slip progression was 18%, which was considered satisfactory. Slip progression of more than 10° was higher in the unstable when compared with the stable group but not statistically significant. Two out of the nine satisfactorily fixed unstable slips required revision surgery as opposed to none in the stable group. The incidence of AVN in the unstable group was 20%. There were no cases of AVN in the stable group. The adverse outcome in terms of AVN, chondrolysis and revision surgery for slip progression was significantly higher in the unstable group. In our study, results of single screw fixation for SUFE were found to be satisfactory as shown by earlier studies with the unstable SUFEs as expected having a poorer outcome when compared with the stable SUFEs.

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