What does the Q angle of the knee joint measure?
The Q-angle is measured by extending a line through the center of the patella to the anterior superior iliac spine and another line from the tibial tubercle through the center of the patella. The intersection of these two lines is the Q-angle; the normal value for this angle is 13 to 18 degrees.
How does high Q angle cause knee pain?
A high Q angle means mal-tracking of the patella is likely. As a result it does not travel over the front of the knee joint as it should. Over time this causes microtrauma to the cartilage on the rear of the patella.
How do you assess anterior knee pain?
Lateral retinaculum tightness can be assessed with the patellar glide test. To determine if AKP has its source in the articular surface, the axial patellar compression test is used. Moreover, the sustained knee flexion test allows ruling out pain due to an increment in intraosseous patellar pressure (14).
What implications does Q angle have for patellofemoral problems?
The Q-angle is widely used as an indicator of patellofemoral problems such as patellofemoral pain syndrome (PFPS). When the Q-angle exceeds 15-20 degrees it is thought to contribute to knee extensor mechanism dysfunction and patellofemoral pain by increasing the tendency for lateral patella malposition .
How does the Q angle affect the function of the knee?
The Q angle formed by the vector for the combined pull of the quadriceps femoris muscle and the patellar tendon, is important because of the lateral pull it exerts on the patella. Any alteration in alignment that increases the Q angle is thought to increase the lateral force on the patella.
Does the Q angle contribute to more knee injuries in females?
Anatomy plays a big role in increased risk Furthermore, the Q-angle (the angle measured between one line drawn from the anterior superior iliac spine through the central patella, and a second line drawn from the central patella to the tibial tubercle) is 3° to 6° greater in women compared to men.
Why does having a larger Q angle potentially lead to a greater risk of knee injuries?
As Q angle represents the direction of the quadriceps muscle force vector in the frontal plane,9 excessive angulation is thought to predispose individuals to injuries caused by abnormal quadriceps forces acting at the knee and patellofemoral joints.
How does Q angle affect knee function?
A high Q angle interferes with the smooth movement of the patella in the femoral groove. Over time, and especially with sports activities and/or stair-climbing, this microtrauma causes a non-specific anterior knee pain. Patellofemoral pain syndrome develops when abnormal tracking continues, and causes muscle imbalance.
What is a normal Q angle in the knee?
Q-Angle. An increased Q-angle has been associated with an increased risk of patellar instability (Cooney). The normal Q-angle is 8°–17° in males and 12°–20° in females, with it being suggested that an increased Q-angle (greater than 20°) is associated with an increased risk of anterior knee pain and patellar instability (Cooney).
What is the relationship between Q angle and patellar instability?
An increased Q angle is traditionally associated with valgus knees and some of the highest Q angles are found in patients with a combination of genu varus and proximal tibial torsion (Dutton). Research shows that Q-angle is not a reliable indicator of patellar instability, however it may be a contributor.
What causes a high Q angle in valgus knees?
Interventions/Prognosis: An increased Q angle is traditionally associated with valgus knees and some of the highest Q angles are found in patients with a combination of genu varus and proximal tibial torsion (Dutton).
What is the patellar angle?
The angle formed by the bisection of two lines drawn from ASIS to the center of the patella and another line drawn from the center of the patella to the tibial tubercle. The angle is a measure of the tendency for the patella to move laterally when the quadriceps muscles are contracted (Dutton, Cooney).