Q-angle

The Q-angle (quadriceps angle) is a clinical measurement used in orthopedic and sports medicine to assess the alignment of the quadriceps muscle group relative to the kneecap (patella) and the patellar tendon. It is measured as the angle formed between a line drawn from the anterior superior iliac spine (the bony point at the front of the hip) to the center of the patella, and a line from the center of the patella to the tibial tubercle (the bony bump just below the knee).

Normal Q-angle values are approximately 14 degrees for males and 17 degrees for females. Women tend to have larger Q-angles due to wider hips relative to knee width. An abnormally large Q-angle (typically above 20 degrees) increases the lateral pull on the patella during knee extension, potentially contributing to patellofemoral pain syndrome (runner's knee), patellar subluxation or dislocation, chondromalacia patellae, and anterior knee pain.

The Q-angle is one of several biomechanical factors evaluated when patients present with knee pain, particularly anterior knee pain that worsens with activities like squatting, climbing stairs, or prolonged sitting. Understanding Q-angle helps guide treatment decisions including physical therapy exercises to strengthen the vastus medialis (inner quadriceps), patellar taping or bracing techniques, and in rare cases, surgical realignment procedures.

Q-angle assessment is part of a comprehensive knee examination for patients with anterior knee pain, patellar instability, or recurrent patellar dislocation. If you've been told you have a large Q-angle, targeted physical therapy focusing on VMO strengthening, hip abductor strengthening, and proper movement mechanics can reduce knee pain and improve patellar tracking.

The Q-angle is also relevant in understanding why women experience higher rates of certain knee injuries, including anterior cruciate ligament (ACL) tears and patellofemoral pain syndrome. Injury prevention programs that address these biomechanical differences through targeted strengthening and neuromuscular training have been shown to reduce injury rates.