Correlating quadriceps patellar tendon angle and lateral patellar tilt angle in patients with irregular alignment: a cross-sectional study with retrospective data.

Background: The newly defined angle, quadriceps-patella angle (QPA), reflects the combined force transmitted to the patella by the quadriceps muscles and patellar tendon. An increase in QPA may correlate with an increased force on the patella, which is significant in diagnosing patellofemoral instability and pain syndrome. In our study, we examined how various angles and pathologies vary depending on lateral patellar tilt angle (LPTA). QPA and patellar malalignment was investigated. Thus, the importance of understanding patellar malalignment and the research gap. Methods: Three hundred and fifty patients who underwent knee magnetic resonance imaging (MRI) examinations were included. The cross-sectional study conducted retrospectively between the years of 2018-2020 in a tertiary care outpatient clinic. Shapiro-Wilk normality, Chi-square, Mann-Whitney-U, Spearman correlation and receiver operating characteristic (ROC) curve analysis, statistical tests used for analysis. The patellar tendon length, patellar height, tibial tubercle-trochlear groove distance (TT-TG), patella angle, trochlear sulcus angle, trochlear groove depth (TGD), medial trochlea length (MT), lateral trochlea length (LT), medial trochlear/lateral trochlear length ratio (MT/LT), LPTA, patella-patellar tendon angle (PPTA), QPA, Insall-Salvati index (ISI), medial trochlear inclination (MTI), lateral trochlear inclination (LTI) were among these measurements. In addition, we aim to reveal whether there is a significant relationship between two important angles LPTA and QPA. Whether there is a significant increase in the development of chondromalacia for the patient group with LPTA >5°. We examined how the frequency of chondromalacia changes in the patient group with LPTA >5°. Results: Two hundred and seventy seven patients included in the study and many measurements were performed on MRI. Fad-pad edema was found to be significantly higher in the group with LPTA <5° (P=0.046). TT-TG distance was significantly higher, TGD and MT were significantly lower in patients with higher LPTA (P=0.001, P=0.002 and P=0.017, respectively). A low level of significant positive correlation was found between QPA and patellar tendon length. There is no significant difference between QPA and PPTA angles between the groups with LPTA <5° and >5° (P=0.503, P=0.188). In the ROC analysis performed to determine the cut-off value, the LPTA value ≤14.2° which significantly predicted the presence of fad-pad edema, had the highest sensitivity and specificity [sensitivity: 76.71%, specificity: 39.90%, area under the curve (AUC): 0.588, P=0.024]. Conclusions: QPA is independent from many angles of the knee and does not change significantly. As the patellar tendon length increases, QPA angle also increases. In patients with abnormal LPTA, the frequency of TT-TG distance and chondromalacia increased, while TGD and MT decreased. Patients with a low LPTA can be more carefully examined for chondromalacia and fad-pad edema in clinical and MRI examination.

Quadriceps Angle Measurement in Adolescents With Short Stature: Exploring the Relationship Between Postural Alignment and Lower Limb Mechanics.

Background The quadriceps angle (Q angle) is measured as an angle formed by two lines that extend from the anterior superior iliac spine to the midpoint of the patella and from the midpoint of the patella to the tibial tuberosity. The average Q angle value for children aged between seven to 12 years was 13.1˚±3.5˚in boys and 13.7˚±4.9˚ in girls, whereas 8˚-15˚ in men and 12˚-19˚ in women. Abnormal variation in Q angle is associated with patellofemoral pain syndrome, lateral patellar malposition, dislocation, chondromalacia patella, patella alta, genu varum, etc. Methodology The present study explores the status of Q angle values among adolescents with short stature and their comparison with age and gender-matched children between 10 and 15 years of age. Results We found a statistically significant difference between the Q angle value in the control group and the male with short stature group aged 14-15 years, with a mean difference of 3.7˚. However, among females, there was a significant difference between the control group and the short-stature group aged 12-13 and 14-15 years, with a mean difference of 2.8˚ and 2.5˚, respectively. Implications Early detection and timely remedial measures, e.g., quadriceps strengthening exercises, before skeleton maturity can prevent Q angle-related misalignments and abnormalities in the limb.

The Effect of Q Angle and Hamstring Length on Balance Performance in Gonarthrosis Patients.

Introduction Gonarthrosis (G) is a progressive disease that affects the knee joint and causes pain and limitation of movement in the knee. The determination of the morphometric status of G patients has been a subject of interest recently. The purpose of this study is to determine how hamstring length (HL) and patellofemoral angle (Q angle [QA]) affect the ability of individuals with G to maintain balance. Methods A total of 80 (40 G patients and 40 in the control group [CG]) participants aged 40-65 were included in the study. A goniometer was used to measure the participants' QA. The mean age of the participants was 50.18±7.16 in the G group and 51.40±6.64 in CG. HL was measured using the sit-and-reach test. Participants' dynamic balance state was evaluated using the Y balance test by stepping in the following directions: right-anterior (R-An), right-posteromedial (R-Pm), right-posterolateral (R-Pl), left-anterior (L-An), left-posteromedial (L-Pm), and left-posterolateral (L-Pl). Results According to the results of this research, the balance performance of G patients was significantly lower in all directions (R-An, R-Pm, R-Pl, L-An, L-Pm, L-Pl) compared to the CG. In both groups, R-QA, L-QA, and HL did not change. However, linear regression analysis indicated that in G patients, R-QA, L-QA, and HL affected balance performance. No significant interaction was found between these parameters and balance performance in the CG. Conclusion HL and QA have a significant role in determining body balance. In our study, we found that QA decreased in G patients, leading to genu varum in these individuals. The hamstring muscle shortening observed in G patients significantly negatively affected balance, especially in the R-An, R-Pm, L-An, L-Pm, and L-Pl directions. For healthcare professionals preparing treatment protocols for G patients, we recommend providing exercises to improve balance, especially in these directions.

The Influence of the Q-Angle and Muscle Strength on Idiopathic Anterior Knee Pain in Adolescents.

Background and Objectives: Idiopathic anterior knee pain is a common condition in adolescents and is mostly of unknown cause. The aim of this study was to examine the influence of the Q-angle and muscle strength on idiopathic anterior knee pain. Materials and Methods: Seventy-one adolescents (41 females and 30 males) diagnosed with anterior knee pain were included in this prospective study. The extensor strength in the knee joint and the Q-angle were monitored. The healthy extremity was used as a control. The Student's paired sample t-test was applied for testing the difference. Statistical significance was set at 0.05. Results: There was no statistically significant difference in the Q-angle value between the idiopathic AKP and the healthy extremity (p > 0.05) within the entire sample. A statistically significant higher Q-angle of the idiopathic AKP knee (p < 0.05) was obtained in the female subgroup. No statistically significant difference (p > 0.05) was found in the male subgroup. Within the male subgroup, the strength of the extensors within the knee joint of the healthy extremity had statistically significant higher values than the strength of these muscles in the affected extremity (p < 0.05). Conclusion: A greater Q-angle is a risk factor linked to anterior knee pain within the female population. Decreased muscle strength of knee joint extensors is a risk factor linked to anterior knee pain in both sex subgroups.

Age related changes in the Q angle of non-professional football players.

Background: Football practice involves a great muscular demand, leading to the development of the lower limbs that, on occasions, can cause deviations from the normal anthropometric values. The quadriceps angle (Q angle) is a value often taken as a reference for the alignment of the lower limbs. Objective: To observe the changes of the Q angle in young football players, because of muscular effort, analyzing the differences between four groups of different ages and to determine whether the playing position might influence these variations. Methods: A cross sectional study was carried out with 104 male subjects divided into four groups according to age: under 8 years-old, 8-17 years-old, 17-21 years-old and over 21 years-old. A photograph was taken in standing position and the Q angle was plotted with KINOVEA® software. As for the reliability of the measurements, intraclass intra and interobserver coefficient were 0.958 and 0.860 respectively. The study was conducted in mid-season. Results: Q angle value is greater in those under 8 years of age and decreases gradually and significantly (p < 0.005) until 17-21 years of age, where it stabilizes at values of 5.73° ± 2.78 for right Q angle and 5.88° ± 2.55 for left Q angle. Two way ANOVA demonstrated a significant group*position interaction for goalkeepers with a medium effect size in both angles (p < 0.001) with a medium effect (η2 Right Q angle = 0.31; η2 Left Q angle = 0.37). The values remain unchanged in subjects over 21 years of age (p > 0.005), except for goalkeepers, who suffered a difference in the evolution of the angle within their age category (p < 0.005) and with a high effect size with the other positions (value > 0.8) except forward (value < 0.5). Conclusion: This study determines that the Q angle in football players decreases with growth, reaching values below 15° at the end of development. Playing positions only influence players over the age of 21, and the Q-angle of goalkeepers is greater than that of other players.

Correlation between flat foot and patellar instability in adolescents and analysis of related risk factors.

INTRODUCTION: Flatfoot and patellar instability are both developmental limb deformities that occur frequently in adolescents. A high number of patients with both diseases can be seen in clinic, and there are no studies showing a correlation between the two. The goal of this study is to investigate the association between developmental patellar instability and flat feet in adolescents and its associated risk factors. METHODS: This experiment uses a cross-sectional study to select 74 adolescent patients with flat foot from a randomly selected middle school in this city since December 2021 and obtain relevant data. SPSS26.0 statistical software was used for data analysis. Quantitative data were expressed as mean ± standard deviation, and Pearson correlation coefficient was used for analysis. p < 0.05 indicates a statistically significant difference. RESULTS: A total of 74 people (40 men and 34 women) were included in this study. The correlation coefficients between Meary angle, Pitch angle, calcaneal valgus angle, CSI, BMI, and Beighton scores and knee joint Q angle are 0.358 (p < 0.01), -0.312 (p < 0.01), 0.403 (p < 0.01), 0.596 (p < 0.01), 0.427 (p < 0.01), and 0.293 (p < 0.05), respectively, indicating that flat foot, overweight, and Beighton scores are all correlated with Q angle. The correlation coefficients between Meary angle, Pitch angle, calcaneal valgus angle, CSI, and BMI were 0.431 (p < 0.01), -0.399 (p < 0.01), 0.319 (p < 0.01), and 0.563 (p < 0.01), respectively, indicating a correlation between flat foot and BMI. The correlation coefficients between Meary's angle, Pitch's angle, calcaneal valgus angle, CSI, and Beighton's score were 0.207 (p > 0.05), -0.240 (p < 0.05), 0.204 (p > 0.05), and 0.413 (p < 0.01), respectively, indicating a correlation between flat foot and Beighton's score. CONCLUSION: We believe that there is a significant correlation between adolescent flatfoot and patellar instability. Excessive weight and ligamental laxity during adolescent development are among the risk factors for flatfoot and patellar instability.

Patellofemoral Angle, Pelvis Diameter, Foot Posture Index, and Single Leg Hop in Post-Operative ACL Reconstruction.

Background and Objectives: Anterior cruciate ligament (ACL) injuries occur as a result of the deterioration of the static and dynamic stability of the knee. One of the structures involved in providing static stability is the patellofemoral angle (Q angle). The aim of this study was to investigate the relationships between Q angle, pelvis diameter, lower extremity length, and foot posture index (FPI) in patients who had undergone ACL reconstruction (ACLR) with the semitendinosus/gracilis (ST/G) technique on both the operated and non-operated sides. Materials and Methods: Twenty-five male recreational athletic patients between the ages of 18 and 35 who had undergone semitendinosus/gracilis (ST/G) anterior cruciate ligament reconstruction at least 6 months earlier were included in the study. Femur length, lower extremity length, pelvis diameter, and Q angle measurements, total foot posture index (FPI) scores, and single leg hop (SLH) and triple hop distance (THD) test results were determined on the operated and non-operated sides. Results: When the findings of the patients were evaluated statistically between the operated and non-operated sides, no significant differences were found in Q angle, femur length, and lower extremity length (p > 0.05). In terms of FPI scores, a significant difference was found only in the inversion/eversion of the calcaneus (CALC) parameter (p < 0.05). When the single hop test (SLHT) results were evaluated statistically on the operated and non-operated sides, the results were in favor of the non-operated side (p < 0.05). In the correlation analysis conducted for both the operated and non-operated sides, positive and significant correlations were found only between SLH and THD (p < 0.05). No significant difference was found in the other parameters. Conclusions: The fact that ST/G ACLR 6th month post-operative findings revealed similar results in Q angle, lower extremity length, and total FPI scores between the operated and non-operated sides showed that the 6-month process did not cause a difference in these parameters. However, it was found that the operated sides showed lower findings compared to non-operated sides for SLHTs, although these findings were within normal ranges in terms of the limb symmetry index.

Patellofemoral Pain, Q-Angle, and Performance in Female Chinese Collegiate Soccer Players.

Background and objective: Female sports injuries have been neglected by science, and few relevant studies have considered female subjects. Knee pain in female soccer players is more common than in male soccer players. The number of days of absence from training and competition has been shown to be higher in females than males. The reporting of knee pain is common in female soccer players, but whether knee pain is associated with morphological features is unclear. The Q-angle of the knee has been hypothesized to be a causal factor in knee pain. Asian females have shown higher levels of valgus than non-sporting Caucasian populations, but no data exist for female Chinese players. The aim of our study was to investigate whether there are associations between knee pain, the Q-angle of the lower limb, jump performance, play time, and perceived exertion in female Chinese collegiate soccer players. Materials and Methods: We measured the Q-angle, patellofemoral/anterior knee pain (SNAPPS questionnaire), and CMJ and SJ performance of 21 subjects (age: 20.09 ± 1.13 years, weight: 56.9 ± 6.26 kg, height: 164.24 ± 4.48 cm, and >10 years of practice) before and after a match; Borg scale and play time results were also recorded. Results: We found that our studied group had higher Q-angles in comparison to other ethnic groups reported in the literature, as well as an association of the Q-angle with the age, height, and weight of the players; however, contrary to other studies, we did not find any association between the Q-angle and knee pain, jumps, play time, or perceived exertion. Knee pain was not associated with any of the measured variables. Conclusions: Female Chinese soccer players showed higher Q-angles than players of other ethnic groups, a result that was associated with anthropometrics. The Q-angle was not found to be associated with knee pain, for which the sole determinant was body height.

Anatomical Variation in Quadriceps Angle With Regard to Different Anthropometric Parameters in a Tertiary Care Center in Northern India: A Descriptive Study.

BACKGROUND: The quadriceps angle, commonly known as the Q-angle, is the angle formed between the vectors of the pull of the quadriceps muscle and the patellar tendon. The literature varies in terms of the values of Q angles measured by various researchers. It is well appreciated that the normal Q-angle should fall between 12° and 20°, with males being at the lower end of this range and females having higher measurements. An increase in Q-angle beyond the normal range has been associated with knee extensor dysfunction leading to patellar instability. Keeping in mind the clinical and biomechanical importance of the Q-angle, the aim of this study was to compare and establish the range of the Q-angle in healthy individuals and evaluate its variations with respect to age, weight, height, gender, dominant side, and femoral bicondylar distance. These observations will be helpful for sports therapists in understanding the evaluation of Q-angle in athletes as a prognostic value for probable knee pathologies that may appear in the future. METHODS: The current study was conducted at a tertiary care center, and a total of 100 healthy adults between the ages of 18 and 35 were enrolled in the study (50 males and 50 females), following which their Q-angles, bicondylar distances, and femur lengths were measured. Individuals with any lower limb injury that resulted in a ligamentous, muscular, or bony defect; any spinal or neurological injury; any diagnosed knee disorder, such as a fracture, acute or chronic knee pain, patellar dislocation, or prior orthopaedic surgery in the lower extremities, were excluded from the study. Data were analyzed using paired t-tests, independent sample t-tests, ANOVA, and Pearson correlation coefficients. RESULT AND CONCLUSION: The mean Q-angle in males was found to be 11.14° ± 1.9° on the right side and 10.84° ± 1.86° on the left side. In females, it was found to be 13.68° ± 1.87° on the right side and 13.61° ± 2.04° on the left side. Among males, right and left Q-angles showed significant positive correlations with height, weight, BMI, right femur length, left femur length, right bicondylar distance, and left bicondylar distance (p<0.05). The highest correlation was found between weight and BMI. Among females, the right Q-angle showed significant positive correlations with weight and BMI (p<0.05). The highest correlation was found with weight.

The effect of three types of exercises programs on the patella location in athletes with patellofemoral pain.

BACKGROUND: The aim of this study was to compare the effect of exercises focusing on the proximal and distal joints to knee and knee local exercises on the Patellar location in athletes with patellofemoral pain (PFP). METHODS: A randomized controlled, single-blinded trial was conducted. Thirty-five athletes with PFP were randomly divided into three groups; proximal (12), distal (11) and local (12). Q Angle was measured with goniometer, tilt and congruence angle were measured with digital radiology before and after the exercise programs. The exercises were performed three sessions of 70 min per week, for 8 weeks. Data were analyzed by mixed analysis of variance, post hoc test and dependent t-test. RESULTS: In the pre-intervention, no significant difference was observed between the groups (P > 0.05). But in the post-intervention, Q angle, tilt angle, congruence angle and knee pain in the proximal group were significantly less than the distal and local groups (P < 0.01); while there were no significant differences between the distal and local groups (P > 0.05). Also, in the proximal group, there were significant differences between pre-intervention and post intervention in Q angle, tilt angle and congruence angle (P = 0.001), but no significant differences were observed in the distal and local groups (P > 0.05). Knee pain in all three groups showed significant differences between pre-intervention and post-intervention (P < 0.01). CONCLUSIONS: The findings of the present study indicated further improvement in patellar location and knee pain in the proximal group. Accordingly, proximal group exercises can improve the pain and performance of athletes with PFP by patellar relocation to the normal position.

Relationship of Anterior Knee Pain with Quadriceps Angle and Anthropometric Measurements in an Asian Female Population.

Introduction: Quadriceps angle (Q-angle) is the angle formed from the intersection of quadriceps femoris muscle and patellar tendon. Q-angle can be used to assess mechanical aspects of the patellofemoral discomfort and attracts considerable attention from clinicians. Anterior knee pain (AKP) is defined as mild pain localised around the peripatellar area exacerbated by physical activity such as climbing stairs, squatting, jumping, running, and/or sitting with the knee flexed for long periods. A higher Q-angle is one of the risk factors for AKP. In addition, several studies have found a relationship between anthropometric parameters, especially body mass index (BMI), to the occurrence of AKP. This study aims to determine the Q-angle and several anthropometric parameters between the population with AKP and without AKP in the adult population in Indonesia. Materials and methods: This cross-sectional, analytic experimental study was performed on female population divided into the comparison group consisted of 40 patients aged between 18-25 years with right side anterior knee pain (Kujala score <82) and the control group consisted of 40 patients aged between 18-25 years without anterior knee pain (Kujala score >82). Both groups had to be right-handed and had no history of knee fractures, knee surgery, congenital anomalies, or obesity. The Q-angle of the right knee was measured in all participants using a universal goniometer. Results: The mean Q-angle in the comparison group was 20.60±1.26°, and in the control group was 14.85±0.99°. All of these differences were statistically significant (p<0.001). There was no significant correlation between anthropometric parameters (body weight, body height, and body mass index) with AKP. Conclusion: The Q-angle can be used to predict the risk of AKP in the female population. The greater the Q-angle the higher the risk of AKP. Anthropometric measurements cannot predict the risk of AKP.

Lower-Limb Kinematic Change during Pelvis Anterior and Posterior Tilt in Double-Limb Support in Healthy Subjects with Knee Malalignment.

This study aimed to investigate lower-limb kinematic changes during pelvic tilting in participants with knee malalignment. To define participants with lower-limb malalignment, the quadriceps angle (Q-angle) was used in this study. The sample population was divided into two groups in accordance with the Q-angle: the experimental group (ABQ) consisted of participants with an abnormal Q-angle greater than the normal range, and the control group (CON) consisted of participants with a normal Q-angle. All participants performed anterior and posterior pelvic tilts in double-limb support. Kinematic change in the lower limb was evaluated using a three-dimensional motion analysis system (Motion Analysis, Santa Rosa, CA, USA). The horizontal plane hip angle in the ABQ was significantly different compared with that in the CON in all positions (p < 0.05), and no significant difference was observed in the other lower-limb kinematic variables (p > 0.05). A significant correlation was identified only between the Q-angle and horizontal plane hip angle in all positions. Based on the results, the Q-angle was strongly related to the thigh, although it may not be related to malalignment with other segments during double-limb support.

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.

Analysis of Predictors Affecting Biomechanical Function of the Knee Joint and Its Relation to Anterior Knee Pain.

BACKGROUND: Anterior knee pain is the most common problem in the young and sporting population. Quadriceps femoris angle and condylar distance are tools to assess the bio-mechanical function of the knee joint. The aim of this research was to give comparative data of quadriceps femoris angle and condylar distance in the Indian population (sedentary/sportsperson). The study also aims to know which parameter (condylar distance/quadriceps angle) is the better predictor for knee pain in the young Indian population. MATERIALS AND METHODS: This study was composed of a total of 130 individuals suffering from anterior knee pain which was divided into two categories; Sedentary and sportsperson. Each category consisted of 65 individuals. Q angle (goniometric method) and condylar distance (manual caliper) of each participant were calculated. A comparison of body parameters was done by independent t-test. Comparison between the two parameters (condylar distance and quadriceps angle) was done to know which is the better predictor of anterior knee pain. RESULTS: Statistically significant sexual variation (p<0.05) was observed in both quadriceps angle and condylar distance in sedentary and sportsperson groups. Females had a higher value of Q angle than males (p<0.05). The difference in quadriceps angle was statistically significant (p<0.05) between sedentary and sportsperson groups. Cohen's kappa coefficient of Q angle was 0.72 while that of bi-condylar distance was 0.49.  Conclusion: Q angle is a better indicator for anterior knee pain than condylar distance. Females in either category; sedentary and sportsperson, had higher Q angle in comparison to males making them more susceptible to disorders of the patellofemoral joint. Hence, encouragement and awareness are needed not only to carry out periodic screening of the susceptible population but also to emphasize its usage in clinical practice and the prognosis of the affected individual after treatment.

Quadriceps muscle volume has no effect on patellofemoral cartilage lesions in patients with end-stage knee osteoarthritis.

PURPOSE: The quadriceps muscle has a positive effect on anterior knee pain. However, its effect on the patellofemoral (PF) cartilage in patients with end-stage knee osteoarthritis is unknown. The present study aimed to evaluate whether the quadriceps muscle area had a positive effect on the PF cartilage and whether this muscle had a positive effect on the clinical scores. MATERIALS AND METHODS: Patients with confirmed cartilage status and clinical scores who underwent total knee arthroplasty (TKA) were included. The PF cartilage status was evaluated during TKA. The thickness and the area of the quadriceps muscle were measured using a knee computed tomography scan obtained before the surgery. The Q-angle, hip-knee-ankle angle, alignment, and Insall-Salvati ratio were measured by radiography. RESULTS: Altogether, 204 patients were included in the study. Logistic regression was performed including factors associated with PF cartilage lesions. The regression model was found to be statistically significant (Hosmer-Lemeshow test, χ2 = 0.493). A smaller hip-knee-ankle (HKA) angle was associated with a higher incidence of PF cartilage lesions (p = 0.033) and only the alignment had an effect on the PF cartilage lesions. PF cartilage lesions did not correlate with the clinical scores. A thicker medial portion of the quadriceps muscle was associated with a significantly higher Knee Society Knee Score (KSKS) (p = 0.028). CONCLUSIONS: Quadriceps muscle thickness and area, Q-angle, and patellar height were not associated with PF cartilage lesions, while a smaller HKA angle was associated with PF cartilage lesions. The presence of PF cartilage lesions did not affect the clinical symptoms. However, a thicker medial portion of the quadriceps muscle was associated with a higher KSKS.

Assessing the racial differences in Q angle measurements in relevance to articular cartilage of the femoral condyle: a retrospective ultrasound study / Evaluación de las diferencias raciales en las mediciones del ángulo Q en relación con el cartílago articular del cóndilo femoral: un estudio ecográfico retrospectivo

SUMMARY: The Q-angle is defined as the acute angle formed by the vectors for combined pull of the quadriceps femoris muscle and the patellar tendon. This study aimed to investigate the variations in Q angle with respect to race. Moreover, this study performed ultrasound to evaluate of the thickness of articular cartilage covering the medial and lateral femoral condyle in volunteers with an increased Q angle. The study included 487 Jordanian and 402 Malaysians with age range 18-23 years. Moreover, the study included 30 participants aged between 18 and 22 years, with a total of 15 volunteers with Q >14° and 15 patients with Q ≤14°. Both Q angle and condylar distance were measured by well-trained medical practitioners according to a well-established protocol. The thickness of articular cartilage covering the medial and lateral femoral condyle of the femoral bone was measured using ultrasound. Regardless of race, Q angle was greater in females. Furthermore, Q angle was significantly greater in Arab volunteers compared to Malay volunteers. Q angle significantly increase with increasing condylar distance in both races. Finally, the statistical analysis showed a significantly reduced thickness of articular cartilage on both medial and lateral femoral condyle (P = 0.05) in the Q >14° group. Multiple factors including race and condylar distance and even the articular cartilage of femoral condyle should be considered during the examination and management of knee fractures and condylar diseases.

RESUMEN: El ángulo Q se define como el ángulo agudo formado por los vectores de tracción combinada del músculo cuádriceps femoral y el tendón patelar. Este estudio tuvo como objetivo investigar las variaciones en el ángulo Q con respecto a la raza. Además, se realizó una ecografía para evaluar el grosor del cartílago articular que cubre los cóndilos femorales medial y lateral en voluntarios con un ángulo Q aumentado. El estudio incluyó a 487 jordanos y 402 malayos con un rango de edad de 18 a 23 años. Además, el estudio incluyó a 30 participantes con edades comprendidas entre 18 y 22 años, 15 voluntarios con Q> 14 ° y 15 pacientes con Q ≤ 14 °. Tanto el ángulo Q como la distancia condilar fueron medidos por médicos bien entrenados de acuerdo con un protocolo establecido. El grosor del cartílago articular que cubre los cóndilos femorales medial y lateral del fémur se midió mediante ecografía. Independientemente del grupo racial, el ángulo Q fue mayor en las mujeres. Además, el ángulo Q fue significativamente mayor en los voluntarios árabes en comparación con los voluntarios malayos. El ángulo Q se aumenta significativamente al incrementarse la distancia condilar en ambas grupos raciales. Finalmente, el análisis estadístico mostró una reducción significativa del grosor del cartílago articular en los cóndilos femorales medial y lateral (P = 0,05) en el grupo Q> 14. Durante la exploración y el tratamiento de las fracturas de rodilla y de las enfermedades condilares, se deben considerar múltiples factores, incluida la raza y la distancia condilar e incluso el cartílago articular del cóndilo femoral.

Linear influence of distal femur osteotomy on the Q-angle: one degree of varization alters the Q-angle by one degree.

PURPOSE: The effect of a distal femur varization osteotomy on patellofemoral biomechanics in genu valgum is unknown. The purpose of this study was to quantify the influence of frontal leg axis correction on the Q-angle with a novel three-dimensional (3-D) measurement method. METHODS: 3-D surface models of ten lower extremities were generated using patient computed tomography (CT) data. The preoperative 3-D Q-angle was measured using a novel defined and validated 3-D measurement method. Biplanar supracondylar osteotomies were simulated with different degrees of varus correction (from 1° to 15°) in one-degree steps beginning from the preoperative valgus deformity, resulting in a total of 150 simulations. Additionally, mechanical leg axis and 3-D Q-angle measurements were performed on 3-D surface models of the postoperative CT scans of the same individuals. Further, pre- and postoperative TT-TG distance was measured. RESULTS: Mean preoperative Q-angle was 15.8 ± 3.9° (range 10°-21.4°) with a mean preoperative mechanical leg axis of 6.5° ± 2.4 valgus (range 3.8°-11.6° valgus). The Q-angle changed linearly 0.9 ± 0° per 1° of varization. No difference was detected between simulated 3-D Q-angles and effectively corrected postoperative values (n.s.). TT-TG distance changed irregularly and minimally, and with no correlation to the degree of varization. CONCLUSION: Distal femur varization osteotomy has a linear effect on the Q-angle with a change of 1° per 1° of varization. The difference in TT-TG distance was mainly due to an unintentional rotational component implemented during surgery.

Dynamic Q-angle is increased in patients with chronic patellofemoral instability and correlates positively with femoral torsion.

PURPOSE: The purpose of the study was to evaluate the frontal gait patterns in patients with chronic patellofemoral instability compared to healthy controls. The hypothesis was that internal-rotation-adduction moment of the knee as altered dynamic Q-angle is evident in patients and correlates positively with increased femoral torsion. METHODS: Thirty-five patients with symptomatic recurrent patellofemoral instability requiring surgical treatment were matched for average age, sex, and body mass index with 15 healthy controls (30 knees). Several clinical and radiographic measurements were taken from each participant: internal and external rotation (hipIR, hipER), Q-angle, tubercle sulcus angle (TS-angle), femoral antetorsion (femAT), tibial tubercle-trochlear groove (TT-TG) distance, and frontal leg axis. Additionally, three frontal gait patterns were defined and recorded: (1) internal-rotation-adduction moment of the knee during normal walking, (2) dynamic valgus of the knee, and (3) Trendelenburg's sign in a single-leg squat. Randomized videography was evaluated by three independent blinded observers. Statistical analysis was performed using regression models and comparisons of gait patterns and clinical and radiological measurements. Furthermore, observer reliability was correlated to gradings of radiological parameters. RESULTS: Patients showed altered dynamic Q-angle gait pattern during normal walking (p < 0.001) compared to healthy controls (interrater kappa = 0.61), whereas highest observer agreement was reported if femAT was greater than 20° (kappa = 0.85). Logistic regression model revealed higher femAT (18.2° ± 12.5 versus 11.9° ± 7.0 (p = 0.004) as a significant variable, as well as lower TT-TG distance (23.6 mm ± 2.8 vs. 16.6 mm ± 4.9, p = 0.004) on evident dynamic Q-angle gait pattern. Dynamic valgus in a single-leg squat was observed significantly more often in patients (p < 0.001) compared to controls (interrater kappa = 0.7). However, besides the static measured Q-angle as the only significant variable on evident dynamic valgus pattern (13.6° ± 4.6 vs. 10.3° ± 5.2, p = 0.003), no radiological parameter was detected to correlate significantly with dynamic valgus and Trendelenburg's sign (n.s.). CONCLUSIONS: Clinical detection of pathologic torsion and bony alignment may be difficult in patients with patellofemoral instability. The present study demonstrated that dynamic Q-angle gait pattern is significantly altered in patients with chronic patellofemoral instability compared to healthy controls. Moreover, dynamic Q-angle correlates positively with higher femoral torsion and negatively with higher TT-TG distance. Therefore, clinical and radiological assessment of maltorsion should be added to the standard diagnostic workup in cases of patellofemoral instability. LEVEL OF EVIDENCE: Level II.

Load Distribution at the Patellofemoral Joint During Walking.

We combined computational modelling with experimental gait data to describe and explain load distribution across the medial and lateral facets of the patella during normal walking. The body was modelled as a 13-segment, 32-degree-of-freedom (DOF) skeleton actuated by 80 muscles. The knee was represented as a 3-body, 12-DOF mechanical system with deformable articular cartilage surfaces at the tibiofemoral (TF) and patellofemoral (PF) joints. Passive responses of the knee model to 100 N anterior-posterior drawer and 5 Nm axial torque tests were consistent with cadaver data reported in the literature. Trajectories of 6-DOF TF and PF joint motion and articular joint contact calculated for walking were also consistent with measurements obtained from biplane X-ray imaging. The force acting on the lateral patellar facet was considerably higher than that on the medial facet throughout the gait cycle. The vastus medialis, vastus lateralis and patellar tendon forces contributed substantially to the first peak in the PF contact force during stance whereas all three portions of the vasti and rectus femoris were responsible for the second peak during swing. A higher lateral patellar contact force was caused mainly by the laterally-directed shear force applied by the quadriceps muscles, especially the vastus lateralis, intermedius and rectus femoris. A better understanding of the contributions of the individual knee muscles to load distribution in the PF compartment may lead to improved surgical and physiotherapy methods to treat PF disorders.

Relationship between movement dysfunctions and sports injuries according to gender of youth soccer player.

The purpose of this study is to investigate relationship between movement dysfunctions and sports injuries according to gender of youth soccer player. Thirty-eight middle school soccer players participated in this study and they were divided into male (n=19) and female (n=19) groups. The Functional Movement Screen (FMS) and the Quadriceps-angle (Q-angle) during single-leg squat were analyzed for identifying imbalance and asymmetry of the body, and sports injury questionnaire was examined for 6 months after FMS test. The number of sports injuries did not show significant difference between youth male and female soccer athletes. In FMS results, the scores of overhead squat, hurdle step, in-line lunge, shoulder mobility, active straight leg raise, and rotary stability and the total scores were no significant differences between gender, but the score for the trunk stability push-up was significantly higher in male group than female group. There was no significant difference of Q-angle values between the left and right legs, but Q-angle value between youth male and female groups significantly showed interaction. Therefore, the present data suggested that FMS and Q-angle during single-leg squat might be indicators to predict and/or prevent sports injury in youth male and female soccer players.