Hip Abduction Moment Research Articles

The effects of symmetric and asymmetric foot placements on sit-to-stand joint moments

The purpose of this study was to determine the effects of symmetric and asymmetric foot placements on joint moments during sit-to-stand movements. Three symmetric (foot-neutral, foot-back, and foot-intermediate) and three asymmetric foot placements (preferred stagger, nonpreferred stagger, and intermediate stagger) were tested. Standard (46cm) and low (41cm) seat heights were chosen to represent an average public seat height and a 10% lower seat height. Using inverse dynamics, maximum ankle plantarflexion, knee extension, hip extension, and hip abduction moments were calculated. Hip extension moments were significantly increased when using foot-neutral as compared to foot-back. Ankle plantarflexion and knee extension moments were significantly increased when a foot was placed in the posterior position as compared to the anterior position for preferred and nonpreferred stagger. Knee extension moments were significantly increased at the low seat height as compared to the standard seat height. When shifting the feet anterior or posterior for symmetric placements during sit-to-stand, the most dramatic effect was an increase in hip extension moments when the feet are shifted anteriorly. Utilizing asymmetric foot placements during sit-to-stand produced increases in ankle plantarflexion and knee extension moments for the posteriorly placed limb, with reductions in the anteriorly placed limb.

Biomechanics During Exercise with a Novel Stairclimber

The current study aimed to investigate the stair-climbing biomechanics related to the lower extremities when subjects used the novel designed stair-climber, which could provide opportunity for both sagittal and frontal movements. 12 volunteers were required to step while either keeping the trunk static (STATIC) or allowing the trunk to shift with weight bearing (SHIFT). A motion analysis system and the 6-axis force and torque sensor embedded in the pedal were used to collect data. Foot contact forces and joint moments were calculated to represent loading characteristics. The joint angle and corresponding moments at the terminal point of the stance phase were computed to serve as the indicator of safety. Significant differences were found in peak foot contact forces, knee extensor moment, and hip abductor moment. At the end of the stance phase, various directions of moment between conditions were found in the knee and the ankle. The knee valgus angle, hip abductor moment, and knee extensor moment were significantly greater in SHIFT than in STATIC. The various stepping strategies caused differences in joint loading characteristics; therefore, these findings need to be given greater consideration in the design of training protocols.

The Influence Of Different Marker Sets On Lower Extremity Dynamics During Walking

PURPOSE: Two different marker cluster sets (heel plate, HP and dorsal plate, DP) have traditionally been used to track the foot during inverse dynamic calculations of the lower extremity, however, comparisons between these two methods have not been reported. This study examines the differences in sagittal and frontal plane lower extremity dynamics during the stance phase of gait when tracking the foot with HP and DP triads. METHODS: Eight subjects (5 males, 3 females) performed 3-5 trials of barefoot gait at their self-selected speed with DP and HP triads affixed to their dominant foot. The HP spanned the proximal, distal, and lateral calcaneus. The DP spanned the proximal and distal cuboid to the medial cuneiform. Mean peak joint angles and moments were compared using Paired-t tests. Coefficient of Multiple Correlation was used to analyze joint dynamics throughout the stance phase. RESULTS: Sagittal plane ankle kinematics (R=.846), as well as ankle (R=.868), knee (R=.811) and hip (R=.807) moments were strongly correlated between the two conditions throughout stance. There was a significant increase in peak plantar flexion (p<.01), knee flexion (p<.01) and hip flexion (p<.05) moments with the DP. Frontal plane ankle kinematics (R=.577), and ankle (R=.400), knee (R=.442) and hip (R=.582) moments were moderately correlated throughout stance. There was a significant increase in peak ankle eversion (p<.01), knee abduction (p<.01) and hip abduction (p <.01) moments with the DP. CONCLUSIONS: Use of a DP increases peak ankle plantar flexion and eversion angles, effectively altering kinetic calculations at the ankle, knee and hip in the sagittal and frontal planes. Caution should be taken when analyzing intra- and inter-study results that use different triad locations.

Trunk And Lower Extremity Kinetics During Variations Of The Forward Lunge Exercise

The forward lunge (FL) is commonly used for rehabilitation, injury prevention, and improving athletic performance. While the FL is an effective functional exercise, it trains movement primarily in the sagittal plane and previous research has shown that the hip extensors have relatively low activation compared to the knee extensors. By altering the FL, it is possible to increase the activation of the sagittal plane hip extensors and the frontal plane hip abductors/adductors. PURPOSE: To observe the changes in the kinetics of the trunk and lower extremities due to variations of the FL. METHODS: Eleven healthy males participated in the study (age 25±3 yr, height 180±5 cm, mass 84±15 kg). Four types of lunges were completed with 2 hand-held dumbbell loads (13.6, 27.2 kg): FL, FL with trunk forward (FLTF), wide step lunge at 30° (WSL), and WSL with trunk forward (WSLTF). Each lunge was performed 3 times (24 total trials). Lunges were performed on 2 portable force platforms while 33 retroreflective markers were tracked. Joint moments were calculated at the knee, hip, and L5/S1 joints, then normalized to body mass (Nm/kg). Multivariate ANOVA was used to test for significant differences (p<0.05). RESULTS: WSL and WSLTF had higher hip adduction (0.89±0.26 vs. 0.32±0.23), knee varus (0.51±0.21 vs. 0.29±0.13) and knee valgus moments (0.48±0.10 vs. 0.28±0.18) than FL and FLTF. FL and FLTF had higher hip abduction moments (0.56±0.32 vs. 0.09±0.07) than WSL and WSLTF. FLTF and WSLTF had higher hip extension (2.85 ± 0.43 vs. 2.40 ± 0.33) and L5/S1 extension moments (1.96 ± 0.42 vs. 1.38 ± 0.38) than FL and WSL. Higher dumbbell load resulted in higher peak hip extension (2.85 ± 0.43 vs. 2.40 ± 0.33) and L5/S1 extension moments (1.83 ± 0.53 vs. 1.51 ± 0.40) than lower dumbbell load. CONCLUSION: Wide step lunges may strengthen hip adductor muscles, but increased knee varus and valgus moments may be harmful to the knee joint. Trunk forward lunges and doubling the dumbbell load increased hip and L5/S1 extension moments without increasing knee varus and valgus moments. Trunk forward lunges and increased dumbbell loads may strengthen hip extensors while sparing the knee joints, but may be harmful to the lower back. Changes in joint loading as a function of lunge technique should be considered when training and when rehabilitating knee, hip, and low back injuries.

Effects of obesity on the biomechanics of stair-walking in children

Anthropometric characteristics, particularly body mass, are important factors in the development and progression of varus/valgus angular deformities of the knee and have long-term implications including increased risk of osteoarthritis. However, information on how excessive body weight affects the biomechanics of dynamic activities in children is limited. The purpose of this study was to test the hypothesis that during stair-walking lower extremity joint moments normalized to body mass in obese children are greater than those in normal-weight children. Eighteen obese children (10.5±1.5 years, 148±10cm, 56.6±8.4kg) and 17 normal-weight children (10.4±1.3 years, 143±9cm, 36.7±7.5kg) were recruited. A Vicon system and two AMTI force plates were used to record and analyze the kinematics and kinetics of ascending and descending stairs. Significant differences in spatio-temporal, kinematic and kinetic parameters during ascending and descending stairs between obese and normal-weight children were detected. For stair ascent, greater hip abduction moments (+23%; p=0.001) and greater knee extension moments (+20%; p=0.008) were observed. For stair descent, smaller hip extension moment (−52%; p=0.031), and greater hip flexion moments (+25%; p=0.016) and knee extension moments (+15%, p=0.008) were observed for obese subjects. To date, it is unclear if and how the body may adapt to greater joint moments in obese children. Nevertheless, these differences in joint moments may contribute to a cumulative overloading of the joint through adolescence into adulthood, and potentially result in a greater risk of developing knee and hip osteoarthritis.

Sequential fatigue progressively alters lower extremity biomechanics

BackgroundNon-contact anterior cruciate ligament (ACL) injury has been reported to occur during the later stages of a game, when fatigue is most likely present. Few studies have focused on progressive...

Motion analysis of a single-limb squat with resistance

BackgroundThe activity of the gluteal muscles is important in preventing external valgus moment of the knee, which is a major factor in anterior cruciate ligament injury. Therefore, for the prevention...

Does the anterior approach for total hip arthroplasty better restore stair climbing gait mechanics?

While total hip arthroplasty (THA) provides pain relief and restores mobility, gait anomalies persist even years after surgery. A muscle sparing surgical approach could result in better postoperative gait mechanics. Our purpose was to compare both the anterior muscle sparing approach and the direct lateral approach (LAT) to a matched control group by using three-dimensional motion analysis while performing stair ascent and descent tasks. Lower-limb kinematics and kinetics were recorded for 20 patients that had an anterior approach (ANT), 20 that had a LAT, and 20 age- and weight-matched control participants. Patients were assessed on average 10 months after surgery. Compared to the control group, during stair ascent, the anterior group had reduced peak hip extension, peak hip flexion moment, and peak hip power. The lateral group had reduced peak hip abduction, hip frontal plane range of motion, and peak hip internal rotation. In stair descent, the anterior group had reduced peak hip flexion, peak hip abduction moment and internal rotation, as well as peak hip power. The lateral group had reduced peak hip flexion, peak knee extension moment, and peak hip power. Therefore, gait anomalies persist after THA for both approaches, which could be due to other factors such as preoperative gait adaptations.

Dynamic loading of the knee and hip joint and compensatory strategies in children and adolescents with varus malalignment

Three-dimensional gait analysis is a diagnostic tool that can be used to gain a better understanding of the relationship between joint loading and the onset or progression of articular cartilage degeneration in subjects with varus malalignment. The purpose of the present study was to investigate knee and hip joint angles and moments in children and adolescents with pathological varus alignment of the knee without signs of knee osteoarthritis (OA). Moreover, we wanted to know if compensatory mechanisms are present in this young patient group. Fourteen, otherwise healthy patients with varus malalignment of the knee and 15 healthy control subjects were analysed. Patients showed a reduced knee extension and a significantly lower maximum knee extension moment in terminal stance compared to controls. The maximum knee adduction moment in mid and terminal stance and the maximum hip abduction moment in loading response were significantly higher in the patient group. In the transverse plane, abnormally increased knee internal rotation and hip external rotation moments were present in patients with varus malalignment. These findings imply that varus malalignment is not an isolated problem in the frontal plane. In contrast to adult patients with established medial knee OA, the young patients assessed in the present study did not show typical compensatory mechanisms such as increased foot progression angle or reduced walking speed. This suggests that children and adolescents with varus malalignment of the knee probably do not need to alter their spatio-temporal gait parameters in order to decrease knee joint loading.

Hip abductor moment arm - a mathematical analysis for proximal femoral replacement

BackgroundPatients undergoing proximal femoral replacement for tumor resection often have compromised hip abductor muscles resulting in a Trendelenberg limp and hip instability. Commercially available proximal femoral prostheses offer several designs with varying sites of attachment for the abductor muscles, however, no analyses of these configurations have been performed to determine which design provides the longest moment arm for the hip abductor muscles during normal function.MethodsThis study analyzed hip abductor moment arm through hip adduction and abduction with a trigonometric mathematical model to evaluate the effects of alterations in anatomy and proximal femoral prosthesis design. Prosthesis dimensions were taken from technical schematics that were obtained from the prosthesis manufacturers. Manufacturers who contributed schematics for this investigation were Stryker Orthopaedics and Biomet.ResultsSuperior and lateral displacement of the greater trochanter increased the hip abductor mechanical advantage for single-leg stance and adduction and preserved moment arm in the setting of Trendelenberg gait. Hip joint medialization resulted in less variance of the abductor moment arm through coronal motion. The Stryker GMRS endoprosthesis provided the longest moment arm in single-leg stance.ConclusionsHip abductor moment arm varies substantially throughout the hip's range of motion in the coronal plane. Selection of a proximal femur endoprosthesis with an abductor muscle insertion that is located superiorly and laterally will optimize hip abductor moment arm in single-leg stance compared to one located inferiorly or medially.

Gait patterns comparison of children with Duchenne muscular dystrophy to those of control subjects considering the effect of gait velocity

3D analysis of the gait of children with Duchenne muscular dystrophy (DMD) was the topic of only a few studies and none of these considered the effect of gait velocity on the gait parameters of children with DMD. Gait parameters of 11 children with DMD were compared to those of 14 control children while considering the effect of gait velocity using 3D biomechanical analysis. Kinematic and kinetic gait parameters were measured using an Optotrak motion analysis system and AMTI force plates embedded in the floor. The data profiles of children with DMD walking at natural gait velocity were compared to those of the control children who walked at both natural and slow gait velocities. When both groups walked at similar velocity, children with DMD had higher cadence and shorter step length. They demonstrated a lower hip extension moment as well as a minimal or absent knee extension moment. At the ankle, a dorsiflexion moment was absent at heel strike due to the anterior location of the center of pressure. The magnitude of the medio-lateral ground reaction force was higher in children with DMD. Despite this increase, the hip abductor moment was lower. Hip power generation was also observed at the mid-stance in DMD children. These results suggest that most of the modifications observed are strategies used by children with DMD to cope with possible muscle weakness in order to provide support, propulsion and balance of the body during gait.

Individuals with severe knee osteoarthritis (OA) exhibit altered proximal walking mechanics compared with individuals with less severe OA and those without knee pain

To examine hip, pelvis, and trunk walking biomechanics in individuals with medial compartment knee osteoarthritis (OA) of varying radiographic disease severities and others without knee pain. Hip, pelvis, and trunk kinematics and hip kinetics were assessed in 75 individuals with radiographically confirmed OA and 20 asymptomatic individuals. Differences in peak hip adduction and abduction angles, the amount of contralateral pelvic drop, and peak lateral trunk lean measured by 3-dimensional gait analysis were examined using analyses of variance. Peak external hip abduction and adduction moments were compared using analyses of covariance, with gait speed as a covariate. Those with severe OA disease exhibited significantly less peak hip adduction (5.0°), but more ipsilateral trunk lean toward the study extremity (5.0°) than all other groups (P < 0.001). Those in the severe (1.1°) and asymptomatic (0.9°) groups also exhibited significantly less lateral trunk lean toward the non-study extremity (P = 0.004). No significant differences in hip joint moments or contralateral pelvic drop were observed between the groups (P > 0.02). Gait changes at the hip and trunk were evident across the groups based on radiographic disease severity and compared with those without knee pain. Although not conclusive from this cross-sectional study design, the results provide initial evidence to support increased lateral trunk lean as being a compensatory response to the disease.

Can Motion Control Running Shoes Inhibit the Purported Mechanism of Lateral Tibiofemoral Knee Osteoarthritis Progression?

Knee osteoarthritis (OA) is a leading cause of disability in the population. Conservative interventions, such as knee bracing, foot orthotics and footwear have been suggested to potentially decrease abnormal knee joint mechanics associated with knee OA progression. Research on individuals with lateral knee OA has shown that medially wedged foot orthotic devices can reduce knee symptoms. A motion control running shoe may function similarly to a medially wedged foot orthotic device by providing medial support, however little research has been conducted on the effect of footwear on knee mechanics related to lateral knee OA. PURPOSE: To determine if the dense medial sole of motion control running shoes will increase the peak knee abduction moment compared to a cushioning shoe in males and females age 20-50 without degenerative knee osteoarthritis. METHODS: Thirty males and female volunteers between the ages of 18-50 years with no history of connective tissue knee injury took part in the study. Subjects were asked to complete a gait analysis at a self-selected intentional walking speed in both the motion control (MC) and cushioning (CU) shoe. The average of five trials was used to analyze frontal plane angles and internal joint moments at the knee, hip, and rearfoot. In order to assess potential gender effects, two way ANOVAs were used to assess the interaction of gender and footwear on lower extremity mechanics (p<0.05). RESULTS: There was a significant interaction for peak knee abduction moment with females exhibiting a greater magnitude in the CU compared to the MC, while there was no notable change in the males. Shoe main effects were also found with the CU condition displaying an increased peak inversion moment and peak hip abduction moment in the CU condition. Gender main effects were observed such that females exhibited greater peak hip abduction moment, peak hip adduction and hip adduction excursion compared to males. CONCLUSION: Contrary to our expectations, in this young asymptomatic population, frontal plane moments in the lower extremity were elevated in the CU condition. It may be that the CU condition allowed for greater midfoot pronation and thus increased frontal plane moments. It may be that the relationship between the foot and footwear would be improved with the use of an arch support.

Competitive Female Runners With a History of Iliotibial Band Syndrome Demonstrate Atypical Hip and Knee Kinematics

Cross-sectional experimental laboratory study. To examine differences in running mechanics between runners who had previously sustained iliotibial band syndrome (ITBS) and runners with no knee-related running injuries. ITBS is the second leading cause of knee pain in runners and the most common cause of lateral knee pain. Despite its prevalence, few biomechanical studies have been conducted to better understand its aetiology. Because the iliotibial band has both femoral and tibial attachments, it is possible that atypical hip and foot mechanics could result in the development of ITBS. The running mechanics of 35 females who had previously sustained ITBS were compared to 35 healthy age-matched and running distance-matched healthy females. Comparisons of hip, knee, and ankle 3-dimensional kinematics and internal moments during the stance phase of running gait were measured. The ITBS group exhibited significantly greater peak rearfoot invertor moment, peak knee internal rotation angle, and peak hip adduction angle compared to controls. No significant differences in peak rearfoot eversion angle, peak knee flexion angle, peak knee external rotator moment, or peak hip abductor moments were observed between groups. Females with a previous history of ITBS demonstrate a kinematic profile that is suggestive of increased stress on the iliotibial band. These results were generally similar to those reported for a prospective study conducted within the same laboratory environment.

CSM 2010 Orthopaedic Section Platform Presentations (Abstracts OPL1-OPL67)

CSM 2010 Orthopaedic Section Platform Presentations (Abstracts OPL1-OPL67)

Immediate Effect of Lateral-Wedged Insole on Stance and Ambulation After Stroke

To perform kinematic and kinetic analyses on the static standing and ambulation in subjects after stroke with and without wearing a 5-degree lateral-wedged insole. Ten hemiparetic individuals with unilateral stroke were recruited. Participants performed quiet stance and ambulation with no insole wedge, paretic side wedged, and nonparetic side wedged in a random order. The vertical ground reaction force and temporal-spatial parameters of gait were measured. Symmetry index was also calculated. During quiet stance, the symmetry index of weight bearing improved significantly with nonparetic side-wedged (P < 0.017), but not with paretic side-wedged insoles. During ambulation, the symmetry indices of kinematic and kinetic measurements in the frontal plane were not significantly different among the three conditions. However, the contralateral knee abductor moment was significantly (P < 0.05) less than that of the nonparetic limb during nonparetic side-wedged ambulation. The ipsilateral hip and knee abductor moments were significantly (P < 0.05) less than the nonparetic limb during paretic side-wedged ambulation. Application of nonparetic side wedge insole can improve stance symmetry and tends to reduce the paretic knee abductor load during ambulation. The effects of paretic side-wedged insole are different. The present results provide guidelines for the placement of wedges in the shoes of individuals after stroke.

Association of Dynamic Joint Power With Functional Limitations in Older Adults With Symptomatic Knee Osteoarthritis

Segal NA, Yack HJ, Brubaker M, Torner JC, Wallace R. Association of dynamic joint power with functional limitations in older adults with symptomatic knee osteoarthritis. Objectives To determine which lower-limb joint moments and powers characterize the level of gait performance of older adults with symptomatic knee osteoarthritis (OA). Design Cross-sectional observational study. Setting University motion analysis laboratory. Participants Community-dwelling adults (N=60; 27 men, 33 women; age 50–79y) with symptomatic knee OA. Interventions Not applicable. Main Outcome Measures Physical function was measured using the long-distance corridor walk, the Short Physical Performance Battery, and the Late Life Function and Disability Instrument (LLFDI Function). Joint moments and power were estimated using an inverse dynamics solution after 3-dimensional computerized motion analysis. Results Subjects aged 64.2±7.4 years were recruited. Ranges (mean ± SD) for the 400-m walk time and the LLFDI Advanced Lower-Limb Function score were 215.3 to 536.8 (304.1±62.3) seconds and 31.5 to 100 (57.0±14.9) points, respectively. In women, hip abductor moment (loading response), hip abductor power (midstance), eccentric hamstring moment (terminal stance), and power (terminal swing) accounted for 41%, 31%, 14%, and 48% of the variance in the 400-m walk time, respectively (model R 2=.61, P<.003). In men, plantar flexor and hip flexor power (preswing) accounted for 19% and 24% of the variance in the 400-m walk time, respectively (model R 2=.32, P=.025). Conclusions There is evidence that men and women with higher mobility function tend to rely more on an ankle strategy rather than a hip strategy for gait. In higher functioning men, higher knee extensor and flexor strength may contribute to an ankle strategy, whereas hip abductor weakness may bias women with lower mobility function to minimize loading across the knee via use of a hip strategy. These parameters may serve as foci for rehabilitation interventions aimed at reducing mobility limitations.

Patients with type II diabetes mellitus display reduced toe-obstacle clearance with altered gait patterns during obstacle-crossing

Patients with type II diabetes mellitus (DM) have been reported to be at high risk of falls that may be further increased by the effects of challenging activities such as obstacle-crossing. The purpose of this study was to compare the end-point trajectory and joint kinematic and kinetic patterns of the lower extremities between healthy subjects and individuals with DM during obstacle-crossing with the leading limb. Fourteen patients with type II DM, with no to minimal peripheral neuropathy (PN), and 14 healthy controls walked and crossed obstacles of three different heights (10%, 20% and 30% of leg length) while kinematic and kinetic data were measured using a motion analysis system and two forceplates. Compared to normal, the DM group had similar walking speeds and horizontal footobstacle distances but significantly reduced leading toe-obstacle clearances, suggesting an increased risk of tripping over the obstacle. When the swing toe was above the obstacle, the DM group showed greater pelvic anterior tilt, stance ankle dorsiflexion, and smaller swing hip abduction, with reduced hip abductor moments but greater knee flexor and ankle plantarflexor and adductor moments. It is suggested that patients with type II DM, with no or minimal PN, should also be targeted for prevention of falls. Possible therapeutic interventions to decrease falls for those with DM may include strengthening of the knee flexors and ankle plantarflexor muscles, together with proprioception and balance training.

Hip resurfacing: expectations and limitations

Hip resurfacing: expectations and limitations

Biomechanics of walking with silicone prosthesis after midtarsal (Chopart) disarticulation

Background Currently accepted understanding is that silicone foot prostheses have little influence on biomechanics of walking; however clinical observations suggest several beneficial effects. The objective of this study was to characterize biomechanics of gait in a group of subjects with disarticulation through the talonavicular (T-N) and calcaneocuboid (C-C) (midtarsal) joints wearing two different prosthetic solutions: silicone prostheses and conventional prostheses. Methods Four subjects that underwent Chopart partial foot amputation were included in the study. Silicone prosthesis was custom manufactured for each individual subject. Instrumented gait analysis was performed in each subject in four experimental conditions: barefooted, barefooted and wearing silicon prosthesis, wearing footwear with conventional prosthesis and wearing footwear with silicon prosthesis. Comparisons and statistical analysis were made between both barefooted conditions and both foot-wearing conditions. Findings Our results show that silicone prosthesis without reinforced sole increases gait velocity, improves generation of ankle plantarflexion moment throughout the stance phase and enables greater power generation at push-off. The most important changes, however, occur in the frontal plane, where improved hip adduction angles and higher hip abduction moment in the stance enable more normal pelvic movement and consequently also less trunk inclination toward amputated side. Interpretation We conclude that silicone prostheses are not solely for cosmetic reasons but may be also biomechanically superior over other prosthetic solutions, especially for walking barefoot.