An analysis of Q angle with respect to various body parameters in athletes

Abstract

The Q-angle is defined as the acute angle formed by the vectors for combined pull of the quadriceps femoris muscle and the patellar tendon. This angle helps indicating the force vector acting on the patella and patellofemoral joint and improve their individual performance by suitable workout. The present study aimed at analyze the Q angle with respect to various body parameters in athletes of Dakshina kannada district of Karnataka state. For the collection of required data 50 male and female athletes were selected respectively. Selected subjects were participated in State, National, Inter university competition since last 5 years. The Q angle was measured using a full circle universal manual goniometer made of clear plastic in the erect weight-bearing position with the subject standing. The collected data was analyzed by using mean, standard deviation z value and represented the data with the help of suitable graphs and tables. Introduction The Q-angle is defined as the acute angle formed by the vectors for combined pull of the quadriceps femoris muscle and the patellar tendon. It can also be stated as a composite measure of pelvic position, hip rotation, tibial rotation, patella position and foot position. When measured with the knee in extension in the frontal plane, it provides a reasonable estimate of the resultant force vector between the quadriceps muscle group and the patellar tendon. The knee joint is one of the major weight bearing joints. It is most commonly injured, contributing to 50% of all Muscular-skeletal injuries. Quadriceps femoris muscle angle (QFM) was first described by Brattstrom in 1964. Anh-Dung says, a change in any one of these alignment could change the position of one or more land marks used to measure the Angle. Contraction of QFM pulls the patella laterally. To assess the lateral line of pull of QFM relative to patella, Q-angle is a meaningful clinical measure. It also provides clear information about the alignment of knee joint. If Q-angle exceeds the normal, the force of the lateral pull will increase. Insall et al. suggested that an increased Q-angle is indicative of pathological lateral forces on the patella. Thus it is considered as an important index of patello-femoral function and dysfunction. It is a risk factor for patello-femoral pain, patellar subluxation and dislocation. Many researchers found that women do have a greater Q-angle than men, may be due to their broader pelvis and shorter femur. Therefore they can be considered to have greater risk for patello-femoraldys function (PFD). Conventional methods of finding Q-angle is by measuring the acute angle formed by the intersection of two lines, one drawn from anterior superior iliac spine (ASIS) to centre of patella (CP) and another from CP to tibial tuberosity (TT). Subject can be in supine or standing position with QFM relaxed. Many studies done worldwide expressed that normal value of Q-angle varies with given population.