What does the Q angle tell us?
The Q angle, which is also known as quadriceps angle, is defined as the angle formed between the quadriceps muscles and the patella tendon. Moreover, Q angle has become accepted as an important factor in assessing knee joint function and determining knee health in individuals suffering from an anterior knee pain [2–4].
What is Q angle and how does it affect patellar tracking?
The quadriceps angle (Q-angle) is considered as an important determinant of patellar mal-tracking because it imposes a lateral traction force , . Female individuals are generally considered to have a wider pelvis and a larger Q-angle than male individuals , and female patients may consequently have a greater …
What does a low Q angle indicate?
Ratings. (3) The Q angle is a very important indicator of biomechanical function in the lower extremity. This measurement reflects the effect of the quadriceps mechanism on the knee (hence the “Q” angle).
How do you measure someone’s Q angle?
Draw a line from ASIS to the midpoint of patella and then from the midpoint of the patella to the tibial tubercle. The resultant angle formed by the crossing of these two lines is called the Q angle.
What are people with a high Q angle at risk for?
Runners with a Q-angle >20 degrees had greater time lost due to injury. Conclusions: High school cross-country runners with large or asymmetric Q-angles may be at greater risk for running injury. Our study suggests that Q-angle measurement be included in preseason screening exams.
What does a large Q angle mean?
A large Q angle pulls the knee cap outwards due to the stronger lateral pull from the quadriceps and tight ITB. Coupled with a weakness of the inner aspect of the quadriceps (Vastus Medialis Oblique, VMO) the knee cap will track laterally instead of smoothly up and down within the knee groove.
How does high Q angle cause knee pain?
The commonly held conception is as follows: a greater Q angle will put more strain on the knees. Because the quadriceps muscles end up pulling the knee cap (patella) away from its natural ‘groove. ‘ This patella maltracking is thought to cause friction against structures under the knee.
What is a high Q angle?
A high Q-angle (intersection formed by lines drawn from the anterior superior iliac spine to the center of the patella and from the center of the patella to the tibial tuberosity; normally 13 degrees in males and 18 degrees in females) predisposes the patella to sublux laterally.
What are people with a high Q-angle at risk for?
What causes a greater Q angle?
Patella Instability Component rotation is one of the most important factors affecting the Q angle. Internal rotation of either the femur or the tibia increases the Q angle, which is associated with increasing forces across the patellar component and risk of subluxation or dislocation.
What causes increased Q angle?
The Q-angle is increased by genu valgum, external tibial torsion, femoral anteversion, lateral positioned tibial tuberosity, and tight lateral retinaculum. CT scan study of the patellofemoral articulation is found to be very helpful.
What is the normal Q angle of the knee?
In women, the Q angle should be less than 22 degrees with the knee in extension and less than 9 degrees with the knee in 90 degrees of flexion. In men, the Q angle should be less than 18 degrees with the knee in extension and less than 8 degrees with the knee in 90 degrees of flexion.
What is the best position to measure the Q angle?
Standing is usually more suitable, due to the normal weight-bearing forces being applied to the knee joint as occurs during daily activity. Traditionally, the Q angle has been measured with the knee at or near full extension (but not hyperextension) with subjects in supine and the quadriceps relaxed,…
Why is the Q angle important in the patellofemoral joint?
An understanding of the normal anatomical and biomechanical features of the patellofemoral joint is essential to any evaluation of knee function. 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.
What is an abnormal Q angle?
It has also been suggested that an abnormal Q angle may also influence neuromuscular responses and quadriceps reflex response time. Commonly called Knock Knee, is a condition in which the knees angle in and touch each other when the legs are straightened.