Effects of isometric quadriceps activation on the Q-angle in women before and after quadriceps exercise

Clinical Significance of the Static and Dynamic Q-angle

Q-angle represents the resultant force vector of the quadriceps and patellar tendons acting on the patella. An increased Q-angle has been considered a risk factor for many disorders and injuries. This literature review challenges the clinical value of static Q-angle and recommends a more dynamic movement evaluation for making clinical decisions. Although there are many articles about static Q-angle, few have assessed the value of dynamic Q-angle. We searched Scopus and PubMed (until September 2021) to identify and summarize English-language articles evaluating static and dynamic Q-angle, including articles for dynamic knee valgus (DKV) and frontal plane projection angle. We also used textbooks and articles from references to related articles. Although static Q-angle measurement is used systematically in clinical practice for critical clinical decisions, its interpretation and clinical translation present fundamental and intractable limitations. To date, it is acceptable that mechanisms that cause patellofemoral pain and athletic injuries have a stronger correlation with dynamic loading conditions. Dynamic Q-angle has the following three dynamic elements: frontal plane (hip adduction, knee abduction), transverse plane (hip internal rotation and tibia external rotation), and patella behavior. Measuring one out of three elements (frontal plane) illustrates only one-third of this concept. Static Q-angle lacks biomechanical meaning and utility for dynamic activities. Although DKV is accompanied by hip and tibia rotation, it remains a frontal plane measurement, which provides no information about the transverse plane and patella movement. However, given the acceptable reliability and the better differentiation capability, DKV assessment is recommended in clinical practice.

Genu varum and football participation: Does football participation affect lower extremity alignment in adolescents?

BACKGROUND

Genu varum is one of the most common anatomical variations of knee alignment which is considered a risk factor for anterior knee pain and anterior cruciate ligament injury among football players. Considering that millions of children participate in high-level football training, the purpose of this study was to determine the genu varum development in adolescent football players and non-athlete peers. The hypothesis of this study was that genu varum incidence was higher in adolescent football players compared with non-athletic peers.

METHODS

The design was a cross-sectional study. Two-hundred and thirty-seven male football players (FG) and aged-matched and anthropometrically similar non-athletes (CG) were recruited into the study. The quadriceps angle and intercondylar-intermalleolar distance were measured to evaluate the leg alignment. The distance between the medial edges of the condyles and malleoli was measured in millimeters using a digital caliper while angle measurements were performed using a photographic technique in a standing position. To analyze the variables, comparison, correlation and regression statistical tests were performed.

RESULTS

The intercondylar-intermalleolar distance and quadriceps angle values were significantly higher in FG than CG in all ages. In FG, a very strong correlation was found between number of training years and the intercondylar-intermalleolar distance. The prevalence of genu varum was markedly higher in FG than CG (~37% vs. 2%, respectively) based on intercondylar-intermalleolar distance.

CONCLUSION

This study determined that the prevalence of genu varum and abnormal quadriceps angles in adolescent football players is significantly higher compared with their non-athletic peers.

Assessment of quadriceps angle in children aged between 2 and 8 years

Aim:

The quadriceps angle is the angle between the line drawn from the spina iliaca anterior superior to the midpoint of the patella, and the line drawn from the midpoint of the patella to the tuberositas tibiae. It is important for lower extremity posture. The aim of this study was to determine the normative quadriceps angle value by measurement, and to assess the probable effect of factors such as measurement position, age, sex, and presence of pes planus on these values.

Material and Methods:

A total of 599 children consisting of 296 (49.4%) girls and 303 (50.6%) boys aged between 2 and 8 years, were included in the study. The children were divided into three groups by age as 2–4 years, 4–6 years, and 6–8-years. After the children’s demographic data were collected, the quadriceps angle was measured using an electronic goniometer. Pes planus was assessed by drawing the Feiss line.

Results:

In bilateral measurement, it was found that the quadriceps angle decreased with age both in the supine and standing positions (p<0.05). It was observed that sex and presence of pes planus had no effect on the quadriceps angle independent from measurement positions (p>0.05). A low negative correlation was found between body mass index and the quadriceps angle in both measurement positions (p<0.05).

Conclusion:

It was found that positional changes and weight bearing on limbs did not cause any change in knee position in healthy children. We consider that the decrease in quadriceps angle in this age group is due to growth rate asymmetry between the femur shaft and pelvic diameter.

Effect of various parameters on Quadriceps angle in adult Indian population

BACKGROUND

The purpose of this study was to compare the values of quadriceps angle (Q angle) in relation to age, weight, height, gender, bilateral and postural variations, and strenuous activities on the weight bearing limbs in order to observe its variability.

MATERIALS AND METHODS

A total of 450 adult healthy volunteers (150 male students, 150 female students and 150 male labourers) were enrolled in this cross sectional study. Each volunteer had its height, weight and Q angles measured. Q angle was measured in all subjects bilaterally in both supine and standing position with the same goniometer. Comparison of Q angles and various parameters and groups were studied and tabulated. Correlation between age, weight, height and Q angles was determined by Karl Pearson's correlation coefficient.

RESULTS

Females had statistically significant higher Q angles in both knees than males of either group, and difference between males of two groups was insignificant. It was more often greater on left side (42.36%) as compared to right, both in males and females. Majority of subjects showed an increase in angle from supine to standing position. There was negative correlation between height and Q angle with both standing and supine position all three groups. Weight and age did not show significant correlation with Q angle. Physical activity did not show any significant effect on the angle.

CONCLUSION

Q angle is an important parameter to assess quadriceps muscle's function and its effect on knee. An increase in the angle is clearly associated with patellofemoral problems. Higher Q angle among females may predispose them to sports related injuries. It is important to take into consideration of such factors like sex, height, posture, side, foot rotation and muscle's relaxation while measuring and comparing the angle.

Does the lower extremity alignment affect the risk of falling?

Objectives

This study aims to investigate the effects of knee and foot alignments on the risk of falling.

Patients and methods

Between April 2016 and December 2016, a total of 74 individuals (24 males, 50 females; mean age 32.2±4.9 years; range 18 to 65 years) were included in the study. The knee Q angle and Chippaux-Smirak Index (CSI), Arch Index, and foot progression angle (FPA) evaluated by pedobarography were used for the assessment of the lower extremity alignment. The fall risk was evaluated by the Fall Index, Fourier 56 Index (F56), and Stability Index.

Results

The fall index was found to be correlated with the Q angle, CSI, the Arch index, and FPA (p<0.05). Q angle, Arch Index, and FPA which were explained 40% of the variance of the fall index. The Q angle was correlated with F56 and the stability index at the most position (p<0.05). The CSI was correlated with the F56 and the stability index at two and three positions, respectively (p<0.05); however, the Arch Index and FPA were not correlated with the F56 and Stability Index at any of the eight positions (p>0.05). According to the categorical regression analysis, the Q angle was the most effective on the F56 and Stability Index.

Conclusion

Our study results suggest that lower extremity malalignment increases the risk of falling. We believe that the risk of falling can be decreased by the reduction of these malalingments and, thus, mortality and morbidity associated with the fall can be reduced as well.

Evaluation of Q angle in differents static postures

OBJECTIVE:

To compare the value of Q angle in different positions, in the external and internal rotations of lower limbs.

METHODS:

This is a descriptive cross-sectional study. We have evaluated 62 volunteers, 32 women and 30 men in the following positions: supine positions with parallel feet, supine with abduction (external rotation of lower limbs), and standing position with parallel feet and with external rotation. All the participants were sedentary and without previous history of acute injury or complaints regarding lower limbs. In order to calculate the Q angle we used computerized biophotogrammetry through ALC image 2.1^(r) program.

RESULTS:

The results of the comparisons showed significant difference between the standing position with feet parallel and orthostatic positions with abductees feet on the left side for both genders (p = 0.000). We also found a significant difference between supine and standing position with abducted feet and with feet parallel on the left side (p = 0.046) in females.

CONCLUSION:

From these results, we can conclude that there are significant differences in the standing position with abducted feet and parallel to the left leg, and symmetry between the lower limbs independent of rotation of limbs in the supine posture. Level of Evidence II, Diagnostic Studies Investigating a Diagnostic Test.

Does the change in Q angle magnitude in unilateral stance differ when comparing asymptomatic individuals to those with patellofemoral pain?

OBJECTIVE

To determine if Q angle changes in magnitude from bilateral stance when compared to unilateral stance and then if they are significantly different changes related to the presence of patellofemoral joint pain.

DESIGN

Observational correlation.

SETTING

University biomechanics laboratory.

PARTICIPANTS

60 Asymptomatic females and 12 females with patellofemoral joint pain.

MAIN OUTCOME MEASURE

Bilateral and unilateral stance Q angle.

RESULTS

Sixty females had their Q angles measured in bilateral and unilateral stance. Linear regressions showed predictive equations and positive correlations for unilateral and bilateral stance Q angles (r=0.81-0.89, p<0.001). The equations generated were used to predict unilateral Q angle from bilateral Q angle measurements in 12 patients with patellofemoral joint pain. The actual unilateral Q angle measurement of the symptomatic knee was significantly greater than that predicted for each individual (p=0.01), whilst the asymptomatic knee showed no significant difference (p=0.16).

CONCLUSION

This study showed a strong positive relationship between bilateral and unilateral stance Q angles which could be represented in a positive linear regression equation. The linear regression equation was then used to predict the effect on the Q angle of moving from a bilateral to a unilateral stance. It has been found previously that patients with patellofemoral joint pain on loading the limb in unilateral stance in activities such as walking and stair descent have increased knee valgus angle. The current study supports those findings indicating that when taking up unilateral stance patients with patellofemoral joint pain demonstrate greater than expected increase in Q angle which could increase loading on the patellofemoral joint.

Proximal and distal influences on hip and knee kinematics in runners with patellofemoral pain during a prolonged run

STUDY DESIGN

Cross-sectional experimental laboratory study.

OBJECTIVES

To investigate the relationships between hip strength and hip kinematics, and between arch structure and knee kinematics during prolonged treadmill running in runners with and without patellofemoral pain syndrome (PFPS).

BACKGROUND

Hip weakness can lead to excessive femoral motions that adversely affect patellofemoral joint mechanics. Similarly, foot mechanics, which are influenced by foot structure, are also known to influence patellofemoral joint mechanics. Thus, proximal and distal factors should be considered when studying individuals with PFPS.

METHODS AND MEASURES

Twenty recreational runners with PFPS (5 male, 15 female) and 20 matched uninjured runners participated in the study. Hip abduction and hip external rotation isometric strength measurements were collected before and after a prolonged run, while the arch height index was recorded on all runners before the run. Lower extremity kinematic data were collected at the beginning and end of the run. Two-way repeated-measures analyses of variance (ANOVAs) were used for analysis.

RESULTS

Both groups displayed decreases in hip abductor and external rotator strengths at the end of the run. The PFPS group displayed significantly lower hip abduction strength [(kg x cm)/body mass] compared to controls (PFPS group: begin 15.3, end 13.5; uninjured group: begin 17.3, end 15.4). At the end of the run, the level of association between hip abduction strength and the peak hip adduction angle for the PFPS group was statistically significant, indicating a strong relationship (r = -0.74). No other associations with hip strength were observed in either group. Arch height did not differ between groups and no significant association was observed between arch height and peak knee adduction angle during running.

CONCLUSIONS

Runners with PFPS displayed weaker hip abductor muscles that were associated with an increase in hip adduction during running. This relationship became more pronounced at the end of the run.

LEVEL OF EVIDENCE

Therapy, level 5.

Correlations between Hip Strength and Static Foot and Knee Posture

Context:

Hip-muscle weakness might be associated with impaired biomechanics and postures that contribute to lower extremity injuries.

Objective:

To examine relationships between hip-muscle strength, Q angle, and foot pronation.

Design:

Correlational study.

Setting:

Academic laboratory.

Participants:

33 healthy adults.

Main Outcome Measures:

Maximal isometric hip abduction (Abd), adduction (Add), external-rotation (ER) and internal-rotation (IR) strength; Q angle of the knee; and longitudinal arch angle of the foot. We analyzed Pearson product– moment (r) correlation coefficients between the Abd/Add and ER/IR force ratios, Q angle, and longitudinal arch angle.

Results:

The hip Abd/Add force ratio was correlated with longitudinal arch angle (r= .35,P= .025).

Conclusions:

Reduced strength of the hip abductors relative to adductors is associated with increased pronation at the foot. Clinicians should be aware of this relationship when examining patients with lower extremity impairments.

Efeitos na medida do ângulo Q com a contração isométrica voluntária máxima do músculo quadricipital

A proposta deste estudo foi verificar a diferença entre o ângulo quadricipital em indivíduos sintomáticos e assintomáticos, em duas diferentes situações de exame, com o quadríceps relaxado e em contração isométrica voluntária máxima (CIVM) através da mensuração radiográfica para contribuir na avaliação e tratamento de pacientes com disfunção femoropatelar (DFP). Foram avaliadas 20 mulheres (40 joelhos), com idade média de 21 anos, através de método radiológico padronizado. Os indivíduos foram posicionados em decúbito dorsal com um estabilizador podálico em "U", com os membros inferiores relaxados, com a utilização de película de chumbo sobre a tuberosidade anterior da tíbia. Para a análise estatística foram utilizadas as médias dos grupos assintomático e sintomático, em estado de relaxamento e em CIVM, e o teste t de Student, com nível de significância de p < 0,05. Os valores médios do ângulo Q para os assintomáticos foram de 17,15° em relaxamento e de 14,5° em CIVM, enquanto os sintomáticos apresentaram 21,45° e 15,8°, respectivamente. Nos resultados para a análise da igualdade entre os grupos sintomáticos e assintomáticos no estado de relaxamento obteve-se p = 0,004, e para o estado de contração isométrica voluntária máxima, p = 0,29. Considerando os dados obtidos no presente estudo, pode-se verificar que em estado de relaxamento há diferença entre o valor do ângulo Q entre indivíduos sintomáticos e assintomáticos, sendo este maior nos portadores da DFP, enquanto que em estado de contração isométrica máxima do músculo quadricipital não houve diferença estatística, ocorrendo redução do ângulo em ambos os grupos.

Q-angle undervalued? The relationship between Q-angle and medio-lateral position of the patella

BACKGROUND

For an accurate quadriceps angle measurement, the patella must be centralised in the femoral trochlear groove, numerous authors have described lateral displacement of the patella in patellofemoral pain patients, this leads to the intriguing possibility that the Q-angle might be undervalued within patellofemoral pain patients who have laterally displaced patella.

METHOD

109 asymptomatic subjects (51 male, 58 female) were assessed. Medio-lateral patella position was measured using a previous validated method and Q-angle was measured in standing with the quadriceps relaxed.

FINDINGS

Mean Q-angle was 11.6 degrees (SD 5.2) left knee, 11.3 degrees (SD 4.9) right knee in the male subjects and 14.4 degrees (SD 5.2) left knee, 13.3 degrees (SD 5.5) right knee for female subjects. 40 females and 28 males had laterally displaced patellae. 13 subjects had centrally placed patellae (7 females, 6 males) with 28 subjects having medially displaced patellae (11 females, 17 males). Recalculation of Q-angle for the laterally displaced group brought about a statistically significant increase in angle. In the medial displaced group failed to produce a statistically significant decrease.

INTERPRETATION

The adjusted Q-angle values for medially and neutral placed patellae brought the values very much into the centre of the reported ranges for Q-angles. After adjustment for lateral patella displacement, Q-angle values were towards the under end of values reported as normal, especially female values which were close to the previously reported pathological cut off point. Because of the inverse relationship between quadriceps strength and the magnitude of Q-angle and quadriceps crucial role in the aetiology of patellofemoral pain, any method which improves the reliability and applicability of Q-angle measurement could prove useful in investigations into the aetiology of and outcome from treatment of patellofemoral pain syndrome.