Effect of Q-angle on patellar positioning and thickness of knee articular cartilages

The purpose of the present study was to investigate whether an increased quadriceps angle (Q-angle) has an effect on patellar positioning and/or the thickness of the medial and lateral tibiofemoral and patellofemoral articular cartilage and menisci, in a group of young asymptomatic individuals. These individuals were detected in a previous study with a decreased anatomical cross-sectional area of the vastus medialis and lateralis as a result of an increased Q-angle. Patellar positioning and the thickness of the articular cartilages were determined in 19 asymptomatic male individuals with high Q-angle (HQ-angle) (18.5° ± 2.6°) using magnetic resonance imaging (MRI). Seventeen male counterparts with low Q-angle (10.1° ± 1.9°) were used for comparison. The position of the patella was determined by measuring the sulcus angle, the lateral patella tilt, the patella-lateral condyle index and the bisect offset (BSO) with the quadriceps relaxed. The BSO, was also measured with the quadriceps under maximum isometric voluntary contraction. The thickness of the articular cartilages of the lateral and medial femoral condyles, the tibial condyles, the patellar facets and the menisci were also measured. Our data revealed that healthy individuals with HQ-angle are unlikely to demonstrate any changes in the position of the patella and/or the thickness of the knee articular cartilages. The decreased anatomical area of the vastus medialis and an almost equally atrophied vastus lateralis, which was previously observed in this group of individuals may prevent in part the misalignment of the patella and early wear of the tibiofemoral and patellofemoral articular cartilages.