Frontal Plane Projection Angle Research Articles

Foot and ankle characteristics and dynamic knee valgus in individuals with patellofemoral osteoarthritis

Study designControlled laboratory study; cross-sectional design.BackgroundFoot and ankle characteristics and dynamic knee valgus differ in people with and without patellofemoral (PF) pain. However, it is unknown if these characteristics are evident in people with PF osteoarthritis (OA), compared to pain-free older adults.ObjectivesTo compare foot and ankle mobility, foot posture and dynamic knee valgus, measured as the frontal plane projection angle (FPPA) during single-leg squatting, between individuals with and without PFOA.MethodsFifty-one participants with PFOA (66% women, mean ± SD age 57 ± 10 years, body mass index (BMI) 27 ± 6 kg/m2), and 23 controls (56% women, age 56 ± 9 years, BMI 24 ± 4 kg/m2) had ankle dorsiflexion measured using the knee-to-wall test, foot mobility calculated as the difference in midfoot height or width between non-weightbearing and weightbearing, and static foot posture characterized utilizing the Foot Posture Index. Peak FPPA was determined from video recordings while participants performed 5 single-leg squats. Linear regressions examined between-groups relationships for foot and ankle characteristics and the FPPA.ResultsThe PFOA group had less ankle dorsiflexion (odds ratio 6.7, 95% confidence interval 2.46–18.2), greater midfoot height mobility (5.2, 1.78–15.14) and width mobility (4.3, 1.33–14.39), and greater foot mobility magnitude (8.4, 2.32–30.69) than controls. There was no difference in FPPA (knee valgus angle) between groups (15, 0.63–377.99).ConclusionFoot and ankle characteristics were different in individuals with PFOA compared to control participants, however there was no difference in dynamic knee valgus during single leg squat. Clinical interventions to address greater foot mobility may be relevant for PFOA.

Gluteal activation and increased frontal plane projection angle during a step-down test in young women

PurposeTo investigate how the activation of gluteus maximus and gluteus medius interacts with different frontal plane projection angles (FPPA) in healthy young women presenting dynamic knee valgus in one limb while performing the step-down test.MethodsThe total of 18 young women presenting FPPA > 15° during the step-down test in one limb (dynamic knee valgus) were assessed. The other limb should present less than 15° for comparisons. The amplitude of muscle activation was assessed through surface electromyography of gluteus medius and gluteus maximus during 8 subsequent weight bearing step-down tests.ResultsFPPA was positively correlated with gluteus maximus activation and with the assessed side showing FPPA > 15°, which also revealed increased activation of gluteus maximus. No differences were noted for gluteus medius. The principal component analysis explained 73% of the variance in 2 components, with gluteus maximus explaining 48% of the variance on the 1st component. Gluteus medius explained 25% on the 2nd component.ConclusionsGluteus maximus seems to be a major component to explain dynamic knee valgus in women without symptoms of patellofemoral pain, probably owing to weakness and lack of stabilization of other proximal muscles of the hip-knee complex during the task.

The effects of a four week jump-training program on frontal plane projection angle in female gymnasts

ObjectivesTo investigate the effects of a four week jump training program on frontal plane projection angle (FPPA) in young female gymnasts. DesignIntervention study, consisting of a four week jump training program performed for 15 min as part of a warm-up, three days per week for four weeks. SettingGymnastics training center. ParticipantsFourteen youth female gymnasts (age: 13.5 ± 2.14 years, height: 1.54 ± 0.11 m, body mass: 46.23 ± 7.68 kg). Main outcome measuresChange in FPPA during a 30 cm drop landing and tuck back somersault. ResultsLarge and significant decreases (p < 0.001) in FPPA of 6.8° (39%) and 8.4° (37%) during the drop landing and tuck back somersault, respectively. ConclusionThe jump training program was successful in improving FPPA in female gymnasts and is advised to be implemented into the warm-ups and training programs of competitive female gymnasts to improve FPPA and therefore reduce the risk factors associated with knee injuries.

P57: 2D video Frontal Plane Projection Angle and 3D inertial sensor based assessment of Dynamic Knee Valgus. A Comparison

P57: 2D video Frontal Plane Projection Angle and 3D inertial sensor based assessment of Dynamic Knee Valgus. A Comparison

The effect of visual perturbation upon femoral acceleration during the single and bilateral squat

ObjectivesRecord femoral accelerations using a smartphone accelerometer attached to the distal thigh during single-legged (SLS) and bilateral squats, and each squat condition occurred under two visual conditions: 1) normal vision and 2) visual perturbation with stroboscopic glasses. DesignRepeated-measures cross-over with counter-balanced order for four total conditions. SettingLaboratory. Participants22 females and 16 males without lower extremity pathologies. Main outcome measures2D video assessment of frontal plane projection angle, composite amplitude index of smartphone accelerometer measurements, and bivariate correlations between these two outcomes. ResultsA significant interaction was found for stance x vision as the difference occurred within the SLS stance condition between the visual conditions (Normal: 9.85 ± 0.06; Stroboscopic: 9.86 ± 0.07; p = 0.008 with an adjusted alpha of 0.25). Femoral accelerations were not associated (r = −0.07) with 2D video assessment of frontal plane projection angle. ConclusionsSimilar to other studies using smartphone accelerometry to assess movement quality, we found that the device could detect movement variation via femoral accelerations during SLS with visual perturbation in healthy individuals.

The reliability and criterion validity of 2D video assessment of single leg squat and hop landing

The objective was to assess the intra-tester, within and between day reliability of measurement of hip adduction (HADD) and frontal plane projection angles (FPPA) during single leg squat (SLS) and single leg landing (SLL) using 2D video and the validity of these measurements against those found during 3D motion capture. 15 healthy subjects had their SLS and SLL assessed using 3D motion capture and video analysis. Inter-tester reliability for both SLS and SLL when measuring FPPA and HADD show excellent correlations (ICC2,1 0.97–0.99). Within and between day assessment of SLS and SLL showed good to excellent correlations for both variables (ICC3,1 0.72–91). 2D FPPA measures were found to have good correlation with knee abduction angle in 3-D (r=0.79, p=0.008) during SLS, and also to knee abduction moment (r=0.65, p=0.009). 2D HADD showed very good correlation with 3D HADD during SLS (r=0.81, p=0.001), and a good correlation during SLL (r=0.62, p=0.013). All other associations were weak (r<0.4). This study suggests that 2D video kinematics have a reasonable association to what is being measured with 3D motion capture.

The huddle-technique app - a new instrument imaging knee-instability of young high performance football players. Comparison of measured angles, KT1000, KLT and subjektiv instability

Aims and Objectives:Is there a correlation between measured frontal plane projection angle, KT1000, KLT and subjektiv instability recognized by player or examiner in a cohort of 101 young high performance football players. We want to establish a reproducible tool that recognizes knee instability in a dynamic movement to prevent knee injury in young high performance athletes.Materials and Methods:Rupture of anterior cruciate ligament (ACL) is a serious knee injury. Several epidemiological studies have shown a correlation between coordination, neuromuscular control and incidence of ACL injuries. In a prospective study of 101 young high performance football players we measured the frontal plane projection angle (FPPA) in drop test with the huddle-technique app. Furthermore we captured subjektiv instability in drop test, single hop test and figure of eight test as well as basic instability criteria as lachmann test, pivot shift test, KT 1000 and KLT.Results:Low FFPA angles (valgus knee) in drop test correlate with higher subjective knee instability recognized by players as well as by examiner. KT 1000 and KLT as a basic instability criteria are not reproducible relating to the subjective instability. Furthermore we investigate a correlation between measured instability with the huddle-technique app, shooting foot and shape of muscular system.Conclusion:The huddle-technique app is a new instrument which gives us an advise of knee instability of young high performance football players. With measuring the FFPA angle in drop test we have a reproducible tool that recognizes instability in a dynamic movement. Our aim is to identify high risk players and modify their movement pattern to avoid knee injury, especially rupture of anterior cruciate ligament. The FFPA angle measured with huddle-technique app additionally can help us to supervise success of special training programs.

Self-reported knee pain and disability among healthy individuals: reference data and factors associated with the Knee injury and Osteoarthritis Outcome Score (KOOS) and KOOS-Child.

To develop normative reference data for the Knee injury and Osteoarthritis Outcome Score (KOOS) and KOOS-Child, as well as investigate socio-demographic, psychological and physical factors associated with knee pain and disability among healthy adults. The KOOS or KOOS-Child (each containing five subscales) was administered to participants aged 8-101 years within the 1000 Norms Project, an observational study of 1000 self-reported healthy individuals. Self-efficacy, physical activity, body mass index (BMI), lower limb alignment, knee frontal plane projection angle (FPPA), knee range of motion (ROM), knee and hip strength, six-minute walk, 30-second chair stand and timed up and down stairs tests were collected. KOOS data were dichotomised using established cut-off scores and logistic regression analyses were conducted for each subscale. Socio-demographic characteristics were similar to the Australian population. Normative reference data were generated for children (8-17 years) and adults (18-101 years). Female adults were up to twice as likely to report knee pain, symptoms and sport/recreation (Sport/Rec) limitations compared to males (P<.05). Older age, lower self-efficacy, greater BMI, varus lower limb alignment, lower knee flexion ROM and lower hip external rotation (ER) strength were independently associated with knee pain and disability among adults. Age- and gender-stratified reference data for the KOOS and KOOS-Child have been developed to guide interpretation of results in practice and research for individuals with knee disorders. Psychological and physical factors are linked with self-reported knee pain/disability among adults, and longitudinal studies to investigate causation are required.

ASSOCIATION BETWEEN FRONTAL PLANE KNEE CONTROL AND ACUTE LOWER EXTREMITY INJURIES

BackgroundSingle-leg squat (SLS) is a clinical tool used to assess knee control. Previous studies have proposed that knee valgus motion in the SLS could be related to injury risk, but...

CSM 2017 Orthopaedic Section Platform Presentations (Abstracts OPL1–OPL64)

CSM 2017 Orthopaedic Section Platform Presentations (Abstracts OPL1–OPL64)

The Relationship Between 2-Dimensional Knee-Valgus Angles During Single-Leg Squat, Single-Leg-Land, and Drop-Jump Screening Tests.

Injuries to the anterior cruciate ligament (ACL) and patellofemoral joint (PFJ) are a significant problem in female athletes. A number of screening tasks have been used in the literature to identify those at greatest risk of injury. To date, no study has examined the relationship in 2-dimensional (2D) knee valgus between common screening tasks to determine whether individuals exhibit similar movement patterns across tasks. To establish whether frontal-plane projection angle (FPPA) during the single-leg squat (SLS), single-leg land (SLL), and drop jump (DJ) are related. Cross-sectional study. University laboratory. 52 national-league female football players and 36 national-league female basketball players. 2D FPPA during the SLS, SLL, and DJ screening tasks. Significant correlations were found between tasks. FPPA in the SLS was significantly correlated with SLL (r = .52) and DJ (r = .30), whereas FPPA in the SLL was also significantly correlated to DJ (r = .33). FPPA was significantly greater in the SLS than in the SLL (P < .001) and DJ (P < .001) and in the SLL than in the DJ (P < .001). The results showed that 2D FPPA is correlated across the SLS, SLL, and DJ tasks. However, significantly greater FPPA values in the unilateral tasks suggest that the DJ may not identify risk of injury in sports where primary injury mechanisms are during unilateral loading tasks. Therefore, it is recommended that both unilateral and bilateral tasks be included when screening for ACL and PFJ injury risk.

Single-Leg Squat as a Tool to Evaluate Young Athletes' Frontal Plane Knee Control.

To determine the agreement between 2-dimensional video analysis and subjective visual assessment by a physiotherapist in evaluating young athletes' knee control, and to determine the intrarater reliability and inter-rater reliability of the single-leg squat test. Frontal plane knee control was assessed by a physiotherapist on a 3-point scale. Frontal plane projection angles were calculated from video images. To determine the intrarater reliability, a physiotherapist reassessed 60 subjects' performances from a video. For the inter-rater reliability, 20 subjects were assessed by both the physiotherapist and a nonexperienced tester. The study continued for 3 test years. Research institute. Three hundred and seventy-eight floorball, basketball, ice hockey, and volleyball players. Knee control was assessed to be good, reduced, or poor. Agreement between the video analysis and subjectively assessed frontal plane knee control. Intrarater reliability and inter-rater reliability. There were statistically significant differences in the mean frontal plane knee angles between subjects rated as having "good," "reduced," or "poor" knee control. Intrarater reliability was fair for the assessments in the first year, moderate (dominant leg) and good (nondominant leg) for the second year, and very good (dominant leg) and good (nondominant leg) for the third year. Inter-rater reliability was fair/poor. This study suggests that by using the subjective assessment of the single-leg squat task, it is possible to detect differences in frontal plane knee control in young team sport athletes. The assessment can be considered to be reliable for clinical use when performed by an experienced tester.

A Comparison of Frontal Plane Projection Angle Across Landing Tasks in Female Gymnasts

The aim of this study was to compare FPPA between three landing tasks and determine the reliability of FPPA in 15 competitive female gymnasts (age 13.5 ± 2.07 years). Reliability of FPPA was highest in the drop landing task, with no learning effect present. The backaway task showed the greatest FFPA (right: 26.75 ± 9.57°; left: 19.67 ± 9.03°), which was greater than the drop landing task (right: 19.07 ± 7.42°; left: 12.18 ± 4.83°). Individuals involved in training young female gymnasts are encouraged to screen for injury risk using FPPA during the drop landing task.

Reliability and concurrent validity between two-dimensional and three-dimensional evaluations of knee valgus during drop jumps.

PurposeThe aim of this study was to establish the concurrent validity and reliability of four different two-dimensional (2D) video-based techniques for quantifying frontal plane knee kinematics during a 40 cm double-legged drop jump.Participants and methodsA convenience sample of 16 healthy participants (nine males and seven females; age: [mean ± standard deviation] 25.5±2 years; body mass index: 24.33±2.98 kg/m2) participated in this investigation. A total of five trials during a 40 cm drop jump maneuver with a countermovement jump were used as the functional task. Four knee valgus measures, such as two different frontal plane projection angle measures, knee-to-ankle separation ratio (KASR), and knee separation distance (KSD), were measured using 2D and three-dimensional (3D) systems. To generalize to the greater population of possible evaluators, the testers performing the biomechanical analyses were three novice physical therapists. Intra- and intertester intraclass correlation coefficients (ICCs) were estimated for 2D analysis variables. ICCs were estimated for all measures between systems to determine concurrent validity of the 2D system.ResultsAll four 2D measures showed good to excellent reliability (ICC: 0.89–0.99). KASR and KSD showed excellent correlation (ICC: 0.96; 95% CI: 0.82–0.98 and ICC: 0.94; 95% CI: 0.90–0.96, respectively) with the 3D system, while both methods of frontal plane projection angle showed poor to moderate correlation (ICC: 0–0.57) with the 3D system.Conclusion2D KASR and KSD measures are cost effective, reliable, and highly correlated with the same measures using 3D techniques for the evaluation of knee valgus.

Relationship between frontal plane projection angle of the knee and hip and trunk strength in women with and without patellofemoral pain.

It is theorized that increased dynamic knee valgus relates to decreased hip posterolateral muscle strength. The aim here was to assess the relationship between the frontal plane projection angle (FPPA) of the knee and hip and trunk muscle strength in women with and without patellofemoral pain (PFP). The sample comprised 43 women: Patellofemoral Pain Group (PPG, n = 22) and Control Group (CG, n = 21). Muscle strength for hip abduction, extension, external rotation and lateral core were measured using a handheld dynamometer. The FPPA was recorded during step-down. The PPG showed a deficit for hip muscles torque and increased FPPA (P < 0.05). Negative correlation of the FPPA-Peak was found in the CG for the hip abductor (r = -0.31) and posterolateral complex (r = -0.32) (P < 0.05). In the PPG, the FPPA-Peak showed a moderate negative correlation to the torque of external rotators and posterolateral hip muscles, although this correlation did not reach statistical significance. These findings suggest that women with patellofemoral pain present greater dynamic knee valgus and hip muscle weakness. Abductor and posterolateral hip muscles strength are associated with increased FPPA only in the pain-free population.

Q-angle in patellofemoral pain: relationship with dynamic knee valgus, hip abductor torque, pain and function

ObjectiveTo investigate the relationship between the q-angle and anterior knee pain severity, functional capacity, dynamic knee valgus and hip abductor torque in women with patellofemoral pain syndrome (PFPS). MethodsThis study included 22 women with PFPS. The q-angle was assessed using goniometry: the participants were positioned in dorsal decubitus with the knee and hip extended, and the hip and foot in neutral rotation. Anterior knee pain severity was assessed using a visual analog scale, and functional capacity was assessed using the anterior knee pain scale. Dynamic valgus was evaluated using the frontal plane projection angle (FPPA) of the knee, which was recorded using a digital camera during step down, and hip abductor peak torque was recorded using a handheld dynamometer. ResultsThe q-angle did not present any significant correlation with severity of knee pain (r=−0.29; p=0.19), functional capacity (r=−0.08; p=0.72), FPPA (r=−0.28; p=0.19) or isometric peak torque of the abductor muscles (r=−0.21; p=0.35). ConclusionThe q-angle did not present any relationship with pain intensity, functional capacity, FPPA, or hip abductor peak torque in the patients with PFPS.

The relationship of foot and ankle mobility to the frontal plane projection angle in asymptomatic adults.

BackgroundThe frontal plane projection angle (FPPA) is frequently used as a measure of dynamic knee valgus during functional tasks, such as the single leg squat. Increased dynamic knee valgus is observed in people with knee pathologies including patellofemoral pain and anterior cruciate injury. As the foot is the primary interface with the support surface, foot and ankle mobility may affect the FPPA. This study investigated the relationship between foot and ankle mobility and the FPPA in asymptomatic adults.MethodsThirty healthy people (aged 18–50 years) performed 5 single leg squats. Peak FPPA and FPPA excursion were determined from digital video recordings. Foot mobility was quantified as the difference in dorsal midfoot height or midfoot width, between non-weightbearing and bilateral weightbearing positions. Ankle joint dorsiflexion range was measured as the maximum distance in centimetres between the longest toe and the wall during a knee-to-wall lunge. Linear regressions with generalised estimating equations were used to examine relationships between variables.ResultsHigher midfoot width mobility was associated with greater peak FPPA (β 0.90, p < 0.001, odds ratio [OR] 2.5), and FPPA excursion (β 0.67, p < 0.001, OR 1.9). Lower midfoot height mobility was associated with greater peak FPPA (β 0.37, p = 0.030, OR 1.4) and FPPA excursion (β 0.30, p = 0.020, OR 1.3). Lower ankle joint dorsiflexion was also associated with greater peak FPPA (β 0.61, p = 0.008, OR 1.8) and greater FPPA excursion (β 0.56, p < 0.001, OR 1.7).ConclusionsFoot and ankle mobility was significantly related to the FPPA during the single leg squat in healthy individuals. Specifically, higher midfoot width mobility, or lower ankle joint dorsiflexion range and midfoot height mobility, were associated with a greater FPPA. These foot mobility factors should be considered in the clinical management of knee-related disorders that are associated with a high FPPA.

Between Days Reliability of 2D Video Analysis during Landing while Undertaking a Crossover Hop Test

The Crossover Hop Test is a Functional Performance Test (FPT), which is used to demonstrate the leg muscles strength and performance, and evaluate symmetry between lower limbs, while evaluating the hop distance. Hop tests have been shown to be reliable for both injured and active subjects. The current study aims to establish the between days reliability of 2-Dimensional (2D) video analysis measuring knee valgus angles (frontal plane projection angle; FPPA) during each landing whilst undertaking a crossover hop test. Nine recreational male athletes (age 33.89 ± 3.96, height 170 ± 8.59 cm, weight 86.94 ± 20.86 kg) participated in the experiment. Each individual performed three repetitions of the cross over hop test, for both legs, and then repeated the same test seven days later. Results showed from the four landings that the first and third, for both legs demonstrated excellent Intraclass Correlation Coefficient (ICC) values for FPPA between days, while good to excellent ICC values for FPPA of the second landing and moderate ICC values for FPPA for the fourth. Standard Error Measurement (SEM) scores ranged from 1.04° to 2.42° for the right FPPA during the four landings, while the range of SEM values for the left FPPA were from 0.82° to 2.08°. The landing strategy adopted by participants, as defined by FPPA, would appear to be consistent between sessions. Hence, researchers and clinicians will be able to use crossover hop tests, which incorporate 2D video analysis, to assess simultaneously the limbs' performance functionality and the valgus angle of the knee. Therefore, this will save the athletes' and researchers' time, which will subsequently reduce the amount of fatigue resulting from over testing.

Ângulo‐q na dor patelofemoral: relação com valgo dinâmico de joelho, torque abdutor do quadril, dor e função

ObjectiveTo investigate the relationship between the Q‐angle and anterior knee pain severity, functional capacity, dynamic knee valgus and hip abductor torque in women with patellofemoral pain syndrome (PFPS). MethodsThis study included 22 women with PFPS. The Q‐angle was assessed using goniometry: the participants were positioned in dorsal decubitus with the knee and hip extended, and the hip and foot in neutral rotation. Anterior knee pain severity was assessed using a visual analogue scale, and functional capacity was assessed using the anterior knee pain scale. Dynamic valgus was evaluated using the frontal plane projection angle (FPPA) of the knee, which was recorded using a digital camera during step down, and hip abductor peak torque was recorded using a handheld dynamometer. ResultsThe Q‐angle did not present any significant correlation with severity of knee pain (r=−0.29; p=0.19), functional capacity (r=−0.08; p=0.72), FPPA (r=−0.28; p=0.19) or isometric peak torque of the abductor muscles (r=−0.21; p=0.35). ConclusionThe Q‐angle did not present any relationship with pain intensity, functional capacity, FPPA, or hip abductor peak torque in the patients with PFPS.

Expert Versus Novice Interrater and Intrarater Reliability of the Frontal Plane Projection Angle During a Single-Leg Squat

The high rate of ACL injury has led to the need for large-scale injury risk screening to aid in prevention. Cost and time alternatives to three-dimensional assessments of knee injury risk factors are necessary for largescale, clinical use. The purpose of this study was to determine the expert versus novice interrater reliability and test-retest reliability of the frontal plane projection angle (FPPA) during the single-leg squat (SLS) test. Excellent interrater reliability was demonstrated for session 1 and session 2. Excellent intrarater (i.e., test-retest) reliability was demonstrated for both the novice and expert. The minimal training requirements and excellent reliability of the FPPA during the SLS test make it a key screening tool for large-scale assessment of injury risk.