Clinical, morphologic, and demographic characteristics of bipartite patella in patients referred to Iranian academic clinics

In a descriptive cross-sectional study, we evaluated clinical, morphologic, and demographic characteristics of bipartite patella (BP) in 20 patients referred to clinics affiliated to Iran University of Medical Sciences from 2011 to 2015. Simple radiography, computerized topography scanning, and magnetic resonance imaging characteristics of BP plus demographic data include age, gender, co-morbidities, and side of involvement were recorded. Male to female ratio was 17:3 (5.6) with total mean age of 39.1 ± 13.4 years. Sixteen patients (80%) had unilateral involvement, and among them right- and left-side involvements were seen in 11 and 5 patients, respectively. The BP position included superolateral (8 patients, 40%), lateral (5 patients, 25%), and inferomedial (7 patients, 35%). Knee pain, joint stiffness, and decrease the motion range were seen in 13 (65%), 7 (35%), and 11 (55%) patients, respectively. Chondromalacia (7 patients, 35%) and bone marrow edema (7 patients, 35%) were the most common co-morbidities. The mean diameter of the cartilage that covered the segment in right and left sides were 8.92 ± 3.63 and 9.01 ± 2.22 mm, respectively (P > 0.05). The right and left sides distance of segment to patella were 2.50 ± 0.86 and 3.17 ± 1.45 mm, respectively (P > 0.05). No significant associations were detected between age, gender, decrease the motion range, pain, and joint stiffness with sides of involvement (P > 0.05). Just patients with bone marrow edema had significant higher diameter of cartilage that covered the segment in comparison to patients without bone marrow edema (P = 0.010). In summary, higher percentage of male, existence of pain, and decrease the motion range plus superolateral position of the bipartite segment were noticeable which must be considered in the future research.