Q-angle.. is it real.. does it matter?
An increased Q-angle is often mentioned as a risk factor for injuries around the patella, in particular patella subluxation and patellofemoral pain syndrome (PFPS).
(image credit www.researchgate.net/figure/Effect-of-Patellar-Displacement-on-Q-angle_fig3_266563025)
But many questions exist over its relevance, the reproducibility of is measurement, and indeed its contribution to any injury around the patellofemoral joint. Let's take a look:
The Quadriceps or Q-angle was initially described by Brattstrom in 1964 . It is an index of the vector for the combined pull of the extensor mechanisms and the patellar tendon . It is measured by drawing a line from the anterosuperior iliac spine to the centre of the patella, and a second line from the centre of the tibial tubercle to the centre of the patella. The angle where these lines intersect is regarded as the Q-angle.
Traditionally, the Q-angle has been measured with subjects in supine, knee extended and with the quadriceps muscle relaxed. This is regarded as the ‘traditional’ or ‘conventional’ method of assessing Q-angle. The Q-angle has also been assessed standing.
Apart from the many other problems with the Q-angle, there is widespread disagreement on the actually criteria for normalcy. It is extremely difficult to find, let alone standardise, a "normal" measure for the Q angle anywhere in the literature, let alone quantify this for both male and female cohorts.
So.. let's try to get a handle on this one! Read on..
Director of Bartold Clinical