A reliable Q angle measurement using a standardized protocol.

Area of Science:

• Orthopedics
• Biomechanics
• Sports Medicine

Background:

• Q angle measurements have historically shown unreliability.
• Imaging studies often replace Q angle for tibial tubercle lateralization assessment.
• A standardized protocol with normative values can offer a reliable, cost-effective alternative.

Purpose of the Study:

• To establish a standardized protocol for measuring the Q angle.
• To determine normative Q angle values for a general population.
• To provide a reliable clinical reference for tibial tubercle lateralization.

Main Methods:

• A standardized Q angle measurement protocol using a long-armed goniometer was applied.
• Measurements were taken on both knees of 30 men and 27 women.
• Subjects with prior knee issues or patellofemoral abnormalities were excluded.

Main Results:

• The overall mean Q angle was 14.8° (95% CI: ±5.4°).
• Male mean Q angle was 13.5° (95% CI: ±5.2°), and female mean was 15.9° (95% CI: ±4.8°).
• No significant difference was found between right and left knees in either sex.

Conclusions:

• A standardized Q angle measurement protocol (SQA) is presented for reliable tibial tubercle lateralization assessment.
• This protocol serves as a valid clinical reference, usable at first encounter and intra-operatively.
• The SQA method avoids the need for expensive imaging techniques, enhancing accessibility for clinicians and sports medicine personnel.