ORIGINAL ARTICLE
Q ANGLE - RELEVANCE FOR EVALUATION OF ANTERIOR KNEE PAIN
Jyoti Agrawal1, Leena Raichandani2, Sushma K. Kataria3, Surbhi Raichandani4
HOW TO CITE THIS ARTICLE:
Jyoti Agrawal, Leena Raichandani, Sushma K. Kataria, Surbhi Raichandani.“QAngle - Relevance for Evaluation
of Anterior Knee pain”. Journal of Evolution of Medical and Dental Sciences 2013; Vol. 2, Issue 51, December
23; Page: 10066-10070.
ABSTRACT: CONTEXT: The Q angle describes the angle of the knee from a frontal view. The Q angle
gives an idea how the thigh muscles function to move the knee and also how the knee cap (patella)
tracks in the groove of the knee joint. A normal knee cap should move up and down within the
groove with flexion and extension of the knee. When the Q angle is excessive, the knee cap tends to
track out of alignment and hence causes wear and tear (degeneration) of the cartilage behind the
knee cap.Study design: The study was an observational, cross-sectional and descriptive in nature
with some analytical components.Selections of the subjects: Consisted two groups: – One case
group consisted of 50 outpatients (25men, and 25 women) aged between 15 and 35 years, with
anterior knee pain. Other control group consisted of 50 outpatients (25 men, and 25 women) with
the same age distribution, who presented with different problems in the upper extremities and no
knee problems. METHODS: The Q-angle of each knee was measured in all participants, using a
universal goniometer. Informed consent was obtained from each subject prior to study. RESULTS:
Patients with anterior knee pain have larger Q-angles than healthy individuals.
KEYWORDS: Anterior knee pain, patellar mal-alignment, quadriceps angle (Q–angle).
INTRODUCTION: Patellofemoral pain syndrome is a descriptive term applied to patients with
nonspecific anterior knee pain, and is the most common knee problem1, 2. The pain in most
patellofemoral disorders is generalized to the anterior part of the knee3, 4. One important concept in
patella femoral joint function is the quadriceps angle (Q-angle). Theoretically, a higher Q-angle
increases the lateral pull of the quadriceps femoris muscle on the patella and potentiates
patellofemoral disorders5.
To understand how the Q angle contributes to knee pathologies, it's helpful to look at the
anatomical relationships in the region. The patella is embedded in the quadriceps tendon.
There is a ridge on the underside of the patella that must fit in the trochlear groovebetween
the two condyles of the femur (Figure 1). The patella moves superiorly and inferiorly in this groove
during knee flexion and extension.
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. 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.
Journal of Evolution of Medical and Dental Sciences/Volume 2/Issue 51/ December 23, 2013
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ORIGINAL ARTICLE
Figure No. 1
There is an increased incidence of these knee disorders in women, The Q angle is greater in
women due to the wider pelvis, which places the ASIS farther away from the patellar midline,
thereby increasing the Q angle.
There are numerous causes of anterior knee pain. Several of these can be related to an
excessive Q angle. It's not necessary to pull out the protractor and determine the exact Q angle.
However, a visual estimation of the Q angle can give important clues about the role this postural
distortion plays in a variety of pain complaints. That is why this study was undertaken to evaluate
the relationship between the anterior knee pain and Q-angle.
What is Q angle: Three landmarks are needed to determine the Q–angle:
 Anterior Superior Iliac Spine (ASIS): The ASIS is the front of the pelvic bone that is felt in
front of the hip at the level of your waist.
 Center of the Patella: The center of the patella is best identified by locating the top, bottom
and each side of the patella, and then drawing intersecting lines.
 Tibial Tubercle: The tibial tubercle is the bump about 5 centimeters below the patella on
the front of the shin bone (tibia).
The Q-angle is formed from a line drawn from the ASIS to the center of the patella, and from
the center of the patella to the tibial tubercle. To find the Q-angle, measure that angle, and subtract
from 180 degrees.
A normal Q-angle in men is 14 degrees and in women is 17 degrees.
Figure No. 2
Journal of Evolution of Medical and Dental Sciences/Volume 2/Issue 51/ December 23, 2013
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ORIGINAL ARTICLE
[Instruments used to measure Q angle: Long arm goniometer(figure 3)
How Do You Measure The Q Angle?
The Q angle can be measured in laying or standing. Standing is usually more suitable, due to
the normal weight-bearing forces being applied to the knee joint as occurs during daily activity.
Place the centre of the goniometer over the centre of the patella and position the bottom arm
in line with the patella tendon and tibial tuberosity. Next position the upper arm so that it is pointed
directly at the anterior inferior iliac spine (AIIS) of the ilium (point to which Rectus
Femorisattaches). The small angle of the goniometer is the Q angle.
Figure No. 3
METHOD: This cross section study was performed on two groups:
One case group consisted of 50 outpatients (25men, and 25 women) aged between 15 and 35
years, with anterior knee pain.
Other control group consisted of 50 outpatients (25 men, and 25 women) with the same age
distribution, who presented with different problems in the upper extremities and no knee problems.
The Q-angle of each knee was measured in all participants, using a universal goniometer.
RESULTS:The mean Q-angle for men and women in the case group was 15.2 and 20.4 degrees,
respectively. In the normal control group the angles were 12.3 and 15.9 respectively.
Category
Men Women
Case group
15.2
20.4
Control Group 12.3
15.9
Table No. 1
Table no.1 showing mean Q- angle of both males and females in both case and control
groups.
All these differences were statistically significant.
A few similar studies have been previously performed with less noticeable values. Hand and
Spalding reported that Q-angle measurement was a good predictor of patellofemoral pain
syndrome.6
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ORIGINAL ARTICLE
Tallay A in his epidemiological study could not identify any statistically significant intrinsic
risk factors, although changes in the Q-angle might be related to an increased prevalence of
patellofemoral pain syndrome.7
Herrington and Nester reported that any method that improved the reliability and
applicability of Q-angle measurement could be useful in investigating the etiology and outcome of
patellofemoral pain syndrome treatment.8 Moreover, this study searched for the relationship
between anterior knee pain and Q-angle, as an important concept in patellofemoral joint function.
CONCLUSION:These results substantiate the fact that patients with anterior knee pain have larger
Q-angles than healthy individuals.
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and Winter's Q–angle Pediatric Orthopedics. 5th ed. Philadelphia: Williams and Wilkins; 2001:
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2. Sibley MB. Knee Injuries. In: Sato H, ed. Sport Injuries. 2nd ed. Philadelphia: Williams and
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3. McBeath AA. The patellofemoral joint. In: Evarts, C. McCollister, ed. Surgery of the
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6. Hand CJ, Spalding TJ. Association between anatomical features and anterior knee pain in a "fit"
service population.J R Nav Med Serv. 2004; 90: 125–134.
7. Tallay A, Kynsburg A, Toth S, Szendi P, Pavlik A, Balogh E, et al. Prevalence of patellofemoral
pain syndrome. Evaluation of the role of biomechanical malalignments and the role of sport
activity [Hungarian]. OrvHetil. 2004; 145: 2093 – 2101.
8. Herrington L, Nester C. Q–angle undervalued? The relationship between Q-angle and mediolateral position of the patella.ClinBiomech (Bristol, Avon). 2004; 19: 1070–1073.
9. Caylor D, Fites R, Worrell TW.The relationship between quadriceps angle and anterior knee
pain syndrome.J Orthop Sports PhysTher.1993; 17: 11– 16.
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Am. 1976; 58: 1 – 8.
11. Neely FG. Biomechanical risk factors for exercise-related lower limb injuries. Sports Med.
1998; 26: 395–413.
12. Insall J. "Chondromalacia patellae": patellar malalignment syndrome. OrthopClin North Am.
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13. Aglietti P, Insall JN, Cerulli G. Patellar pain and incongruence. Clin Orthop Relat Res. 1983; 176:
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mechanics.ActaOrthop Scand. 1981; 52: 661–666.
Journal of Evolution of Medical and Dental Sciences/Volume 2/Issue 51/ December 23, 2013
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AUTHORS:
1. Jyoti Agrawal
2. Leena Raichandani
3. Sushma K. Kataria
4. Surbhi Raichandani
PARTICULARS OF CONTRIBUTORS:
1. M.Sc. Student, Department of Anatomy, Dr. S.N.
Medical College, Jodhpur, Rajasthan.
2. Professor,
Department
of
Anatomy,
Department of Anatomy, Dr. S.N. Medical
College, Jodhpur, Rajasthan.
3. Professor and H.O.D, Department of Anatomy,
Department of Anatomy, Dr. S.N. Medical
College, Jodhpur, Rajasthan.
4.
M.B.B.S. Student, Department of Anatomy,
Department of Anatomy, Dr. S.N. Medical
College, Jodhpur, Rajasthan.
NAME ADDRESS EMAIL ID OF THE
CORRESPONDING AUTHOR:
Dr.Jyoti Agrawal,
W/o. Dr. I.K. Bansal,
1062, Sector – 3, Huda Colony.
Email-drjib@yahoo.com
Date of Submission: 11/11/2013.
Date of Peer Review: 13/11/2013.
Date of Acceptance: 26/11/2013.
Date of Publishing: 23/12/2013
Journal of Evolution of Medical and Dental Sciences/Volume 2/Issue 51/ December 23, 2013
Page 10070