Q Angle Test

Orthopedic Exam / Special Tests for Physical Therapy: KNEE/ HIP

In the lower extremity, a large quadriceps angle, more commonly called the Q angle, is a postural distortion involving patellofemoral biomechanics. An exaggerated Q angle can lead to knee pain and knee pathologies, as well as compensations in other regions of the body.

The patella’s ability to track straight in the trochlear groove is determined by the quadriceps’ angle of pull. When the Q angle is greater, the quadriceps pull the patella in a more lateral direction. The unequal pull on the patella causes increased tensile stress on soft tissues around the knee. Too much lateral pull on the patella also can drag it against the lateral femoral condyle and eventually cause degeneration of the cartilage on the underside of the patella – a condition known as chondromalacia patellae. Problems associated with the patella and its correct movement during flexion and extension are referred to as patellar tracking disorders. In addition to patellar tracking disorders, a larger Q angle also can be a major factor in patellar subluxation or dislocation, as well as anterior cruciate ligament sprains.

Q Angle Test – Measurement – Quadriceps Angle Test

Note: The Q angle is the angle between the quadriceps tendon and the patellar tendon. The Q-angle is formed from a line drawn from the ASIS to the center of the kneecap, and from the center of the kneecap to the tibial tubercle. To find the Q-angle, measure that angle, and subtract from 180 degrees.

q angle test

Video Demo Instructions, Procedure, Positive Test:

Q Angle Measurement Video Demo (Procedure below):

Q Angle Measurement – Q Angle Test Video:

To Measure Q Angle:

Patient is standing or supine, with the knee in extension (femur neutral: no internal or external rotation) and patient’s feet in a neutral position (no pronation or supination).

Normal Test Result:

  • A normal Q angle with the knee extended and the quadriceps muscle relaxed is 18° degrees for women and 13° degrees for men.
  •  A Q angle that is less than normal allows the patella to track medially between femoral condyles, placing extra stress on the medial articulating facets of the patella which leads to Chondromalacia Patellae • A Q angle that is greater than normal allows the patella to track laterally, stressing the lateral facets which is associated with patellar tracking dysfunction, chondromalacia patellae and patellar subluxation.