Differences in hip–knee joint coupling during gait after anterior cruciate ligament reconstruction

BackgroundAfter anterior cruciate ligament injury, patients have increased risk for developing degenerative osteoarthritis, potentially due to the kinematic changes that persist after surgical reconstruction. Current research only describes single joint kinematic differences rather than the way in which two joints behave concurrently, termed joint coupling. The purpose of this study was to compare knee motion relative to hip motion in anterior cruciate ligament reconstructed and healthy limbs during walking and jogging.MethodsThirty-seven recreationally active volunteers (22 reconstructed, 15 healthy) walked and jogged at 4.83 km/h and 9.66 km/h respectively. Vector coding methods were used to calculate stride-to-stride variability, magnitude, and vector angle of 6 joint couples during walking and jogging: hip frontal–knee frontal planes, hip frontal–knee sagittal, hip frontal–knee transverse, hip sagittal–knee frontal, hip sagittal–knee transverse, and hip transverse–knee frontal planes.FindingsThe hip sagittal–knee frontal and hip sagittal–knee transverse joint couples had decreased variability during mid-stance, and all other couples had increased variability during the stance phase in the reconstructed group. The reconstructed group had decreased magnitude of joint excursion in the hip frontal–knee sagittal couple during all phases of gait during walking. Vector angles of the hip frontal–knee transverse couple increased in the reconstructed group during the loading, middle, and terminal stance phases, and swing phase of gait during walking.InterpretationThe increased variability and decreased magnitude of joint excursion indicate that movement patterns were less consistent during walking gait despite employing a more constrained system during movement in the reconstructed limb compared to healthy controls.     

A most painful knee does not induce interlimb differences in knee and hip moments during gait in patients with knee osteoarthritis

BackgroundPatients with knee osteoarthritis can adapt their gait to unload the most painful knee joint in order to try to reduce pain and improve physical function. However, these gait adaptations can cause higher loads on the contralateral joints. The aim of the study was to investigate the interlimb differences in knee and hip frontal plane moments during gait in patients with knee osteoarthritis and in healthy controls.MethodsForty patients with knee osteoarthritis and 19 healthy matched controls were measured during comfortable treadmill walking. Frontal plane joint moments were obtained of both hip and knee joints. Differences in interlimb moments within each group were assessed using statistical parametric mapping and discrete gait parameters.FindingsNo interlimb differences were observed in patients with knee osteoarthritis and control subjects at group level. Furthermore, the patients presented similar interlimb variability as the controls. In a small subgroup (n = 12) of patients, the moments in the most painful knee were lower than in the contralateral knee, while the other patients (n = 28) showed higher moments in the most painful knee compared to the contralateral knee. However, no interlimb differences in the hip moments were observed within the subgroups.InterpretationPatients with knee osteoarthritis do not have interlimb differences in knee and hip joint moments. Patients and healthy subjects demonstrate a similar interlimb variability in the moments of the lower extremities. In this context, differences in knee pain in patients with knee osteoarthritis did not induce any interlimb differences in the frontal plane knee and hip moments.     

Associations of lower limb joint asymmetry with fatigue and disability in people with multiple sclerosis

BackgroundAn early symptom of multiple sclerosis is unilateral weakness, particularly in the lower limbs, which is associated with strength asymmetries. The purpose of this exploratory study was to examine strength asymmetries at the hip, knee, and ankle joints, and to investigate the associations between lower limb strength asymmetries and self-reported fatigue severity and disability in people with multiple sclerosis.MethodsSixteen mildly-disabled people with multiple sclerosis (females = 9) completed isokinetic maximal voluntary contractions of the hip extensors and flexors, knee extensors and flexors, and ankle plantar flexors and dorsiflexors. Asymmetry indices between the strength of the more- and less-affected lower limbs at each muscle group and the percent agreement between self-reported and objectively-determined more-affected lower limb were calculated. Patient Determined Diseases Steps and Fatigue Severity Scale were also completed.FindingsAll joints showed asymmetry (asymmetry indices ≥10%). Knee flexors (mean [SD]; 49.9 [37.8%]) and ankle plantar flexors (46.6 [35.5%]) had the largest asymmetry indices. Hip and knee extensors had the lowest asymmetry indices (21.1 [18.1%] and 30.1 [24.7%], respectively) and the highest agreement between self-reported and objectively-determined more-affected lower limb (93.3 and 93.8, respectively). The hip extensor asymmetry index was correlated with the Fatigue Severity Scale (r = 0.542, p = 0.037).InterpretationFor the assessment of strength asymmetries in people with multiple sclerosis, it is suggested to 1) include measures of hip, knee, and ankle strength asymmetries, 2) include subjective perceptions and objective measures of strength asymmetries concurrently, and 3) to include measures of sensory function (proprioception).     

The effect of body weight on joint torques in teenagers: Investigation of sit-to-stand movement

BackgroundObesity is becoming more common in the world. This causes various health problems, especially musculoskeletal disorders. Previous studies have examined the kinematic effects of increasing weight on joints. However, the mechanical effects of movement patterns have not yet been described. The aim of this study was to investigate joint torques in sit-to-stand movement in teenagers with a range of body mass indices (BMI).Methods20 participants (12–17 years old) participated the study. They were divided into 4 groups according to BMI. Participants performed sit-to-stand movements and the video was captured. Angular displacement, angular velocity, and angular acceleration were calculated for each joint. A four-degree-of-freedom link-segment model was created for a dynamic analysis of sit-to-stand. Joint torques were calculated using the inverse dynamic method.FindingsOverweight increases joint torques in hips, knees, and ankles. In obese participants with a BMI 36% higher than normal-weight participants, joint torques in hips, knees, and ankles were higher by 46, 48, and 33%, respectively. In underweight participants with a BMI 21% lower than normal-weight participants, joint torques in neck, hip, knee, and ankle were lower by 20, 30, 17, and 7%, respectively.InterpretationOverweight participants have a different sit-to-stand movement pattern. Movement differences and overweight may cause an overload on joints.     

The effect of ankle–foot orthosis plantarflexion stiffness on ankle and knee joint kinematics and kinetics during first and second rockers of gait in individuals with stroke

BackgroundStiffness of an ankle–foot orthosis plays an important role in improving gait in patients with a history of stroke. To address this, the aim of this case series study was to determine the effect of increasing plantarflexion stiffness of an ankle–foot orthosis on the sagittal ankle and knee joint angle and moment during the first and second rockers of gait.MethodsGait data were collected in 5 subjects with stroke at a self-selected walking speed under two plantarflexion stiffness conditions (0.4 Nm/° and 1.3 Nm/°) using a stiffness-adjustable experimental ankle–foot orthosis on a Bertec split-belt fully instrumented treadmill in a 3-dimensional motion analysis laboratory.FindingsBy increasing the plantarflexion stiffness of the ankle–foot orthosis, peak plantarflexion angle of the ankle was reduced and peak dorsiflexion moment was generally increased in the first rocker as hypothesized. Two subjects demonstrated increases in both peak knee flexion angle and peak knee extension moment in the second rocker as hypothesized. The two subjects exhibited minimum contractility during active plantarflexion, while the other three subjects could actively plantarflex their ankle joint.InterpretationIt was suggested that those with the decreased ability to actively plantarflex their ankle could not overcome excessive plantarflexion stiffness at initial contact of gait, and as a result exhibited compensation strategies at the knee joint. Providing excessively stiff ankle–foot orthoses might put added stress on the extensor muscles of the knee joint, potentially creating fatigue and future pathologies in some patients with stroke.     

Kinematic predictors of star excursion balance test performance in individuals with chronic ankle instability

BackgroundThe Star Excursion Balance Test has identified dynamic postural control deficits in individuals with chronic ankle instability. While kinematic predictors of Star Excursion Balance Test performance have been evaluated in healthy individuals, this has not been thoroughly examined in individuals with chronic ankle instability.MethodsFifteen individuals with chronic ankle instability completed the anterior reach direction of the Star Excursion Balance Test and weight-bearing dorsiflexion assessments. Maximum reach distances on the Star Excursion Balance Test were measured in cm and normalized to leg length. Three-dimensional trunk, hip, knee, and ankle motion of the stance limb were recorded during each anterior reach trial using a motion capture system. Sagittal, frontal, and transverse plane displacement observed from trial initiation to the point of maximum reach was calculated for each joint or segment and averaged for analysis. Pearson product–moment correlations were performed to examine the relationships between kinematic variables, maximal reach, and weight-bearing dorsiflexion. A backward multiple linear regression model was developed with maximal reach as the criterion variable and kinematic variables as predictors.FindingsFrontal plane displacement of the trunk, hip, and ankle and sagittal plane knee displacement were entered into the analysis. The final model (p = 0.004) included all three frontal plane variables and explained 81% of the variance in maximal reach. Maximal reach distance and several kinematic variables were significantly related to weight-bearing dorsiflexion.InterpretationIndividuals with chronic ankle instability who demonstrated greater lateral trunk displacement toward the stance limb, hip adduction, and ankle eversion achieved greater maximal reach.     

Surgical correction of leg alignment in unilateral knee osteoarthrosis reduces the load on the hip and knee joint bilaterally

Seventeen patients with strictly unilateral medial knee osteoarthrosis that justified surgical treatment constituted the study group. No patient had any symptoms from the hip or ankle joints or from the other knee. Eight patients were operated with high tibial osteotomy and nine were operated with unicompartmental prosthetic replacement (Brigham model). The forces and the external moment about the hip, knee, and ankle joints of the involved and uninvolved leg were calculated before and 1 year after corrective surgery and compared to the external moment in 10 normal controls. Clinical examinations was performed and the hip-knee-ankle angle in the involved leg was determined from whole-leg weightbearing radiographs before and 1 year after surgery. The external moments about the hip, knee, and ankle joints and the knee moment arms at mid-stance in the frontal plane during gait were determined with a Kistler force plate and a videorecording system. All patients improved clinically after surgery. The mean hip-knee-ankle angle changed from 11 degrees of varus to 0 degrees. In the uninvolved leg the mid-stance adduction moments about the hip and knee joints were significantly increased compared to normal subjects in the control group before surgery, but reduced to a normal level 1 year after surgery. This reduction was mainly due to a significant reduction of the medially directed force. The moments about the ankle joints were not found to be changed by the knee deformity or by the corrective surgery. RELEVANCE: This study demonstrates that a varus malalignment in the osteoarthrotic knee is accompanied by increased load about the uninvolved hip and knee joint. One might expect a more rapid progression of degenerative changes in joint cartilage as a consequence of such increased load. The reduced load after surgical correction of leg alignment might be beneficial to patients with osteoarthrosis of their hip and knee joints.     

Varying alignment affects lower extremity joint and limb loading during yoga's triangle (Trikonasana) pose

BackgroundLimited biomechanical data exist describing how yoga asanas (postures) load the limbs and joints, and little evidence-based recommendations for yoga injury prevention are available. This study aimed to establish joint loading metrics for an injury-prone, yet common yoga pose, the Triangle asana (Trikonasana) by identifying how stance width adjustments alter lower extremity loading.MethodsEighteen yoga practitioners underwent 3D motion analysis while performing Trikonasana with self-selected (SS) stance width and −30, −20, −10, +10, +20, and +30% of SS stance width. Ground reaction forces (GRFs), joint forces, and joint moments were calculated for the leading and trailing limb ankle, knee, and hip. One-way repeated-measures analysis of variance determined differences in loading due to stance width.ResultsGRFs, net joint forces, and net joint moments were significantly affected by stance width where increasing stance width increased leading limb loading but decreased trailing limb loading.ConclusionsAltering stance width of Trikonasana influences lower extremity limb loading, and these loading responses were limb-dependent. Yoga practitioners and instructors can use this information to objectively support increasing or decreasing stance width to reduce or increase limb loading according to their goals or to make accommodations to groups such as beginners or at-risk populations for safer, more accessible yoga practices. Cuing a wider or narrower stance width will not have the same effect on both limbs.     

Comparison of the ankle,knee, hip,and trunk corrective action shown during single-leg stance on firm,foam, and multiaxial surfaces

OBJECTIVE: To compare the quantity of ankle, knee, hip, and trunk corrective actions shown during single-leg stance. DESIGN: Counter-balanced crossover design. Single-leg stance under the conditions of eyes open on firm, foam, and multiaxial surfaces and eyes closed on a firm surface were recorded for 12 seconds in 18 participants. SETTING: A university neuromuscular research laboratory. PARTICIPANTS: Eighteen healthy and recreationally active college students. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE: Average angular displacement magnitude between successive sampling instances for the ankle, knee, hip, and trunk. RESULTS: A significant condition by joint interaction was revealed. Post hoc comparisons revealed that the ankle dominated as the source of corrective action across each of the testing conditions. As the challenge became greater because of foam surface or eyes closed, more corrective action occurred at proximal joints (hip and/or knee). CONCLUSIONS: The ankle is of primary importance during single-leg stance on firm, foam, and multiaxial surfaces, with proximal joints having an increased role under more challenging conditions. These results provide a scientific basis for clinicians' and researchers' decisions about support surface and visual condition during single-leg postural control testing and training.     

Contribution of ankle-foot orthosis moment in regulating ankle and knee motions during gait in individuals post-stroke

BackgroundAnkle-foot orthosis moment resisting plantarflexion has systematic effects on ankle and knee joint motion in individuals post-stroke. However, it is not known how much ankle-foot orthosis moment is generated to regulate their motion. The aim of this study was to quantify the contribution of an articulated ankle-foot orthosis moment to regulate ankle and knee joint motion during gait in individuals post-stroke.MethodsGait data were collected from 10 individuals post-stroke using a Bertec split-belt instrumented treadmill and a Vicon 3-dimensional motion analysis system. Each participant wore an articulated ankle-foot orthosis whose moment resisting plantarflexion was adjustable at four levels. Ankle-foot orthosis moment while walking was calculated under the four levels based on angle-moment relationship of the ankle-foot orthosis around the ankle joint measured by bench testing. The ankle-foot orthosis moment and the joint angular position (ankle and knee) relationship in a gait cycle was plotted to quantify the ankle-foot orthosis moment needed to regulate the joint motion.FindingsAnkle and knee joint motion were regulated according to the amount of ankle-foot orthosis moment during gait. The ankle-foot orthosis maintained the ankle angular position in dorsiflexion and knee angular position in flexion throughout a gait cycle when it generated moment from − 0.029 (0.011) to − 0.062 (0.019) Nm/kg (moment resisting plantarflexion was defined as negative).InterpretationsQuantifying the contribution of ankle-foot orthosis moment needed to regulate lower limb joints within a specific range of motion could provide valuable criteria to design an ankle-foot orthosis for individuals post-stroke.     

Trunk and lower limb biomechanics during stair climbing in people with and without symptomatic femoroacetabular impingement

BackgroundFemoroacetabular impingement is a pathomechanical hip condition leading to pain and impaired physical function. It has been shown that those with femoroacetabular impingement exhibit altered gait characteristics during level walking and stair climbing, and decreased muscle force production during isometric muscle contractions. However, no studies to-date have looked at trunk kinematics or muscle activation during dynamic movements such as stair climbing in this patient population. The purpose of this study was to compare biomechanical outcomes (trunk and lower limb kinematics as well as lower limb kinetics and muscle activation) during stair climbing in those with and without symptomatic femoroacetabular impingement.MethodsTrunk, hip, knee and ankle kinematics, as well as hip, knee and ankle kinetics and muscle activity of nine lower limb muscles were collected during stair climbing for 20 people with clinical and radiographic femoroacetabular impingement and compared to 20 age- and sex-matched pain-free individuals.FindingsThose with femoroacetabular impingement ascended the stairs slower (effect size = 0.82), had significantly increased peak trunk forward flexion angles (effect size = 0.99) and external hip flexion moments (effect size = 0.94) and had decreased peak external knee flexion moments (effect size = 0.90) compared to the control group.InterpretationFindings from this study indicate that while those with and without femoroacetabular impingement exhibit many biomechanical similarities when ascending stairs, differences in trunk forward flexion and joint kinetics indicate some important differences. Further longitudinal research is required to elucidate the cause of these differences as well as the clinical relevance.     

Effect of shoe insole on the dynamics of lower extremities in individuals with leg length discrepancy during walking

IntroductionThe aim of the present study was to investigate the effect of Internal and External Heel Lift Insoles (IHLI, EHLI) on pelvic kinematics and lower extremity joint moments in subject with mild leg length discrepancy (LLD) during the Stance Phase of walking.MethodsFrom twenty-eight men with mild LLD, kinematic and kinetic data were collected while they walked under each of three conditions (IHLI, EHLI and shoe). Data were collected for both limbs using a six-camera system synchronized with a force platform. For comparisons the dependent variables among the conditions, repeated measures ANCOVA and Bonferroni's post hoc test were used (P ≤ 0.05).ResultsFor both IHLI and EHLI, there were significant decreases in peak long leg lateral and anterior pelvic tilt, long leg hip and knee abduction moments, and short leg ankle plantar flexor moment (P ≤ 0.001). Furthermore, significant increases in peak lateral and anterior pelvic tilt of the short leg were observed in the IHLI and EHLI conditions as compared to the shoe (SH) condition (p ≤ 0.01). In addition, a significant difference was observed between the IHLI and EHLI conditions in the peak values of anterior pelvic tilt of the long leg (p = 0.043) and ankle plantar flexor moment of the short leg (p = 0.044).ConclusionFindings suggest that the use of IHLI and EHLI may be effective in improving pelvic movements (lateral and anterior tilt) and gait dynamics in individuals with LLD. The EHLI could reduce more the peak plantar flexor moment of the short leg and peak anterior pelvic tilt of the long leg than IHLI during stance phase of walking.     

Exploring of two different equated instability resistance training programs on measure of physical fitness and lower limb asymmetry in pre-pubertal weightlifters

Background

In the postpandemic era, wearing protective masks in public places will still be an important means of blocking popular viruses in the future. The purpose of this study was to explore whether sports performance was affected by mask wearing and exercise duration during 15-min treadmill running at a speed of 75% maximal aerobic speed.

Methods

Thirty-six males were randomly divided into mask and nonmask groups. The kinematic and kinetic data were obtained at four time points (RN_0–1 min, RN_5–6 min, RN_9–10 min, and RN_14–15 min) during running. Two-way mixed ANOVA was applied to examine the effects between groups and times with Bonferroni post hoc comparison and independent samples t-test.

Results

The results showed that there was no difference between mask and nonmask group during running (p?>?0.05). As running time increased, hip joint ROM, hip joint flexion/extension max, and ankle joint plantarflexion max angles increased; knee joint flexion min and ankle joint dorsiflexion max angles decreased; average peak vertical ground reaction forces (PVGRF) increased after 9 min-running (p?<?0.05).

Conclusions

Wearing a medical protective mask does not affect the joint angle and touchdown PVGRF of lower extremities during treadmill running while affected by running time and changed after 9 min-treadmill running. Future studies will examine the effects of wearing masks during the pandemic on muscle activation and blood biochemical values during exercise.

Trial registration No. ChiCTR2000040535 (date of registration on December 1, 2020). Prospectively registered in the Chinese Clinical Trial Registry.

     

Instrumented triple single-leg hop test: A validated method for ambulatory measurement of ankle and knee angles using inertial sensors

BackgroundHop tests are commonly used in clinical environments to measure function after sport-related knee injuries. Joint angle measurement during hopping is feasible in research-based environments equipped with motion-capture systems. Employing these systems in clinical research settings is inefficient, given the associated cost, preparation time, and expertise required to administer and interpret the findings. Therefore, this study aimed to introduce a wearable system comprising three inertial measurement units for 3D joint angular measurement during horizontal hop tests, validate the joint angles against a camera-based system, and evaluate its applicability in clinical research environments.MethodsTen able-bodied participants were outfitted with three inertial measurement units during triple single-leg hop trials. 3D knee and ankle angles were calculated using the strap-down integration method, and results were compared with camera-based joint angles. Additionally, knee and ankle range of motions (RoMs) during bilateral triple single-leg hop trials were compared for 22 participants with unilateral sport-related knee injuries and 10 uninjured participants.FindingsEstimated angles had root-mean-square and RoM error medians of less than 2.3 and 3.2 degrees for both joints, and correlation coefficients of above 0.92 when compared with the camera-based system, for all hop phases. Injured participants had smaller sagittal ankle RoM (P = .008) on their injured side, during the third hop. Concurrently, they demonstrated smaller knee RoM symmetry indices (P = .017) and injured knee sagittal RoMs (P = .009) compared to uninjured participants.InterpretationThe introduced system had appropriate accuracy to highlight post-injury modifications in hopping kinematics and reveal noteworthy differences in RoM of clinical samples.     

Single-limb drop landing biomechanics in active individuals with and without a history of anterior cruciate ligament reconstruction: A total support analysis

BackgroundThe purpose of this study was to characterize the magnitude and distribution of the total support moment during single-limb drop landings in individuals after anterior cruciate ligament reconstruction compared to a control group.MethodsTwenty participants after reconstruction and twenty control participants matched on sex, limb dominance and activity level were recruited. Motion analysis was performed during a single-limb drop landing task. Total support moment was determined by summing the internal extensor moments at the ankle, knee, and hip. Each relative joint contribution to the total support moment was calculated by dividing each individual contribution by the total support moment. Data were captured during a landing interval that started at initial contact and ended at the lowest vertical position of the pelvis. Data were then time-normalized and indexed at 25, 50, 75, and 100% of the landing interval.FindingsNo between-group differences for total support moment magnitude were observed. At both 75% and 100% of the landing, the relative contribution of the knee joint was lower in those with a history of surgery (p < 0.001). At the same instances, the relative contribution to the total support moment by the hip joint was greater in those with a history of surgery (p = 0.004).InterpretationIn active participants after anterior cruciate ligament reconstruction, relative contributions to anti-gravity support of the center of mass shifted from the knee to the hip joint during single-limb landing, which became evident towards the end of the landing interval.     

The impact of hearing loss on three-dimensional lower limb joint torques during walking in prepubertal boys

IntroductionIn children, the impact of hearing loss on biomechanical gait parameters is not well understood. Thus, the objectives of this study were to examine three-dimensional lower limb joint torques in deaf compared to age-matched healthy (hearing) children while walking at preferred gait speed.MethodsThirty prepubertal boys aged 8–14 were enrolled in this study and divided into a group with hearing loss (deaf group) and an age-matched healthy control. Three-dimensional joint torques were analyzed during barefoot walking at preferred speed using Kistler force plates and a Vicon motion capture system.ResultsFindings revealed that boys with hearing loss showed lower joint torques in ankle evertors, knee flexors, abductors and internal rotators as well as in hip internal rotators in both, the dominant and non-dominant lower limbs (all p < 0.05; d = 1.23–7.00; 14–79%). Further, in the dominant limb, larger peak ankle dorsiflexor (p < 0.001; d = 1.83; 129%), knee adductor (p < 0.001; d = 3.20; 800%), and hip adductor torques (p < 0.001; d = 2.62; 350%) were found in deaf participants compared with controls.ConclusionThe observed altered lower limb torques during walking are indicative of unstable gait in children with hearing loss. More research is needed to elucidate whether physical training (e.g., balance and/or gait training) has the potential to improve walking performance in this patient group.     

髋关节镜下治疗股骨髋臼撞击综合征的疗效及其X线指标分析*

目的分析髋关节镜下治疗不同解剖形态股骨髋臼撞击综合征(FAI)患者的临床疗效与相关X线指标情况。方法选择2015年9月-2016年12月在该院接受关节镜下手术治疗的FAI患者24例,分析患者的临床指标、术后疼痛、膝关节功能与活动度及并发症情况。结果与治疗前比较,患者治疗7 d、1个月、3个月及6个月后的视觉模拟评分法(VAS)评分较治疗前均明显降低,而Harris评分均明显增加,同时患者的膝关节活动度均明显增强,差异有统计学意义(P0.05)。凸轮型患者髋关节的α角明显高于钳夹型,而偏心距、髋臼深度、髋臼覆盖率及中心边缘角(CE)明显低于钳夹型,比较差异有统计学意义(P0.05);凸轮型患者的α角明显高于健康人髋关节、而偏心距明显低于健康人髋关节,比较差异有统计学意义(P0.05);钳夹型患者的髋臼深度、髋臼覆盖率及CE角高于健康人髋关节,比较差异有统计学意义(P0.05);而3者的髋臼前倾角比较,差异无统计学意义(P0.05)。24例髋关节镜下治疗患者的并发症发生率为20.83%。结论髋关节镜下治疗FAI可短期减轻患者疼痛,提高膝关节功能与活动度,效果良好,且不同髋关节解剖形态的X线片差异明显。     

Stair descent biomechanics reflect perceived instability in people with unilateral ankle sprain history

BackgroundEfforts have been exerted to establish the correlation between objective variables and subjectively perceived ankle instability. Whether or not biomechanical parameters during stair descent can serve as potential assessment tools for perceived stability in people with unilateral ankle sprain history is unknown.MethodsTwenty-four subjects with unilateral ankle sprain history were categorized into four groups according to the severity of perceived stability during stair descent. Kinematic and kinetic parameters during stair descent were obtained with a motion analysis system. Spearman's correlation coefficient (ρ) was utilized to test the correlation between the score of perceived stability during stair descent and biomechanical variables.FindingsSubjects with increased perceived instability were likely to show increased ankle inversion (ρ = −0.46, p = .025) and increased ankle plantarflexion (ρ = 0.46, p = .025), with increased hip adduction (ρ = −0.43, p = .036), hip flexion (ρ = −0.56, p = .004), knee adduction (ρ = 0.45, p = .027), and knee flexion (ρ = −0.44, p = .031). No significant correlation was detected between kinetic variables and perceived stability.InterpretationSagittal and coronal plane motions of the ankle might require rehabilitative intervention to produce improved self-reported outcomes. Kinematic assessment during stair descent can aid in the quantification of subjective ankle instability.     

Three-dimensional hip and knee kinematics during walking,running, and single-limb drop landing in females with and without genu valgum

BackgroundDynamic knee valgus in females has been associated with various knee pathologies. Abnormal 3D hip and knee kinematics contribute prominently to this presentation, and these may become more aberrant with more demanding tasks. Underlying genu valgus may also accentuate such kinematics, but this effect has never been tested. Therefore, the purpose of this study was to compare 3D hip and knee kinematics during walking, running, and single-limb drop landing in females with and without genu valgus malalignment. We expected abnormal kinematics to become more evident in the valgus subjects as task demands increased.MethodsEighteen healthy females with genu valgum and 18 female controls with normal alignment underwent 3D motion analysis while performing walking, running, and single-limb drop-landing trials. Sagittal, frontal, and transverse plane hip and knee kinematics were compared between groups across tasks using analyses of variance and between-group effect sizes.FindingsGroup differences did not generally increase with higher forces. The valgus females demonstrated decreased hip flexion (ES = 0.72–0.88) and increased knee abduction (ES = 0.87–1.47) across the tasks. During running and single-limb drop landing, they showed increased knee external rotation (ES = 0.69–0.73). Finally, during walking, the valgus females showed increased hip adduction (ES = 0.69).InterpretationThese results suggest that females with genu valgus alignment utilize aberrant hip and knee mechanics previously associated with dynamic valgus in the literature, but that these pathomechanics do not generally worsen with rising task demands. Healthy females that present with genu valgus may be natively at elevated risk for knee pathology.