1] When compared to individuals with low Q-angle
(LQ-angle <15[degrees]), asymptomatic individuals with high Q-angle
(HQ-angle [greater than or equal to]15[degrees]) displayed anatomical cross-sectional areas of the vastus medialis and lateralis that were approximately 10% smaller when using the Q-angle
as an estimate of quadriceps muscle disorientation.
In our case, both the MCL injury and patellar dislocation were likely caused by the same injury, and MCL injury caused the dynamic increase in Q-angle
and acted as an adjunctive patellar destabilizer.
Theoretically, a higher Q-angle
increases the lateral pull of the quadriceps femoris muscle on the patella and potentiates patellofemoral disorders (5).
In the study, the Q-angle
was different between injured and non-injured runners.
In combination with their wider pelvis, a greater Q-angle
places the female knee in a greater position of instability or excessive genu valgum (Boden, Griffin, & Garret, 2000).
Knee pain is a problem that can be experienced due to many contributing factors, including: increased Q-angle
, genu-valgum and genu varum, muscle tightening through the gastrocnemius, lliotibial band and VMOs, hyperextension of the knee and tibial rotation and torsion.
Women's knees have an extra Q-angle
, and that has been shown to be a factor," McLaine says.
Static standing Q-angle
was measured with a standard long-arm goniometer.
Several factors have been proposed to cause patellofemoral pain syndrome such as patellar malalignment (Fredericson and Yoon 2006, Powers 2003), an increased Q-angle
(Elias et al 2004, Fredericson and Yoon 2006, Mizuno et al 2001, Naslund et al 2006), quadriceps weakness (Fredericson and Yoon 2006, Thomee et al 1995), decreased flexibility of the lower extremity (Fredericson and Yoon 2006, Piva et al 2005), overuse (Thomee et al 1999), and muscle imbalance (Thomee et al 1995) which have all been shown to result in an increase in cartilage and subchondral bone stress (Fredericson and Yoon 2006).
On physical examination, check for the quadriceps angle, or Q-angle
, which is the angle created between a line drawn from the center of the anterior superior iliac spine on the pelvis to the center of the patella and a second line from the center of the patella to the middle of the tibial tubercle.
The greater the Q-angle
the more likely a patient is to have PFPS, according to some studies.
is the angle between the hips and knees, which, in women, is more pronounced thanks to their having a wider pelvis and a lower centre of gravity.