Evaluation of Q Angle in Down syndrome

Background: Down Syndrome is a genetic disorder and the most common chromosomal abnormality. It is predominantly characterized by muscle hypotonia and joint hypermobility. Qangle is the angle formed between two imaginary lines one from ASIS to Center of Patella, another from Tibial tuberosity to the Center of Patella. Objectives: Aim of the study is to evaluate the Q-angle in male children with Down syndrome of 7-16 years of age and compare the values between children with internal and external tibial torsion. Methodology: It is an observational study done with convenient sampling carried out in 12 male children with Down syndrome. The tibial torsion was measured. Based on internal and external tibial torsion they were categorized into Group A and B respectively. Group A consisting of 7 children with internal tibial torsion and Group B consisting of 5 children with external tibial torsion. Q-angle was measured using standard goniometer. Results: There is no significant difference in P-value (P>0.05) between the right and left leg of children in Group A and in Group B. On comparison between Group A and Group B, there was a statistical significance in P-Value of 0.005 and 0.050 when compared mean of Q angle for right leg and left leg respectively. Conclusion: The study concluded that assessing Q-angle helps to evaluate the biomechanical changes in knee. In this study done for the male children with Down syndrome, the Q-angle lies within the normal range of 13.1±3.5. However children with internal tibial torsion has comparatively decreased angle and children with external tibial torsion has comparatively increased angle even though there is no deviation from the normal range for the age.