Hip Moments Research Articles

Patellofemoral joint stress measured across three different running techniques

BackgroundPatellofemoral pain (PFP) is the most common running-related injury. It has been shown in previous studies that gait retraining may have a beneficial effect on patellofemoral joint stress (PFJS). Research questionIs there a reduction of PFJS across 4 running conditions: 1. runner’s typical rearfoot strike pattern, 2. forefoot landing, 3. step rate increase by 10% and 4. forward trunk lean? MethodsNineteen healthy runners (28.05 ± 5.03 years; 26.58 ± 8.85 km/week, 6.00 ± 4.51 years of running experience) completed one running trial for each condition, at the same subject-specific comfortable speed on a treadmill. Kinetic and kinematic data were collected and measures of hip, knee and ankle joint moments and PFJS were calculated. ResultsCompared to rearfoot strike condition, peak PFJS and PFJS-time integral per step were significantly (P < 0.01) lower during forefoot landing and step rate increase conditions. PFJS per kilometer was significantly reduced for forefoot landing (17.01%; P < 0.01) and increased step rate (12.90%; P = 0.003). Forward trunk lean technique showed no significant differences in peak PFJS (P = 0.187), PFJS-time integral per step (P = 0.815) and PFJS per kilometer (P = 0.077) compared to rearfoot strike pattern. InterpretationThe comparison between techniques revealed greater reductions on PFJS by forefoot landing, followed by 10% step rate increase condition. These changes were the result of different lower limb movement strategies across the 2 running conditions. We conclude that compared to a rearfoot strike pattern, both a forefoot landing and step rate increase result in lower cumulative PFJS joint stress in healthy runners, with the forefoot landing being the most effective. These running technique modifications could be recommended to reduce PFJS loads and may have implications for PFP prevention.

Differences in EMG-moment relationships between ACL-injured and uninjured adults during a weight-bearing multidirectional force control task.

Anterior cruciate ligament injury (ACLi) reduces mechanical knee joint stability. Differences in muscle activation patterns are commonly identified between ACLi individuals and uninjured controls (CON); however, how and which of these differences are adaptations to protect the knee or adversely increase risk of joint instability remain unclear. Since the neuromuscular system integrates activity of all muscles crossing the knee to create a moment-of-force that opposes an external load, this study sought to quantify differences in individual muscle electromyography (EMG)-moment relationships between ACLi and CON. Participants isometrically modulated ground reaction forces during a standing force matching protocol to elicit combinations of sagittal, frontal and transverse plane moments. Partial least squares regressions determined which internal joint moment(s) predicted activation of 10 leg muscles for each group. Compared to CON, ACLi demonstrated greater contribution of rectus femoris to knee extension, semitendinosus and gastrocnemii to knee flexion, and lateral gastrocnemii to knee external rotation moments. ACLi also showed lower contributions of biceps femoris to knee flexion, medial gastrocnemius to internal rotation, and varied hip muscle contributions to frontal plane hip moments. Between group differences in EMG-moment relationships during static conditions suggest neuromuscular contributions to sagittal plane stability increases after ACL injury, while knee stability during knee abduction and external rotation is reduced. Clinical Significance: Clinical assessments of ACLi should account for deficits in frontal and rotational plane stability by including tasks that elicit such loads. Improving hamstring muscle balance, hip abductor and gastrocnemius function may benefit ACLi rehabilitation interventions and should be studied further. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.

Passive elastic contribution of hip extensors to joint moments during walking in people with low back pain

BackgroundIt has been found that alterations in passive muscle properties may be associated with low back pain, and these may be responsible for the altered gait parameters often observed in subjects with back pain. The purpose of the present study was to assess total hip and passive hip extensor moments in people with or without low back pain during the hip flexion component of walking. Methods52 subjects volunteered for this study (low back pain group, n = 25 (male n = 13, female n = 12), control group, n = 27 (male n = 15, female n = 12)). Passive hip moments were calculated using an adapted force transducer during supine testing. A biomechanical model and predictive equation were used to calculate passive hip moments during walking. Total hip moments were calculated with the use of a 9 camera, 3-D motion-capture system. FindingsIndependent samples t-tests demonstrated no significant differences between groups for gait parameters or hip or knee angles. Results of the ANOVAs demonstrated significant differences in passive hip flexor moments during the second half of hip flexion (P < 0.05).There were also significant differences in hip power and work done during peaks of power absorption and the second peak of power generation (P < 0.05). InterpretationThe present data demonstrates that subjects with low back pain have altered passive hip extensor and total power and work done during walking compared with healthy controls. Biomechanical models should include individual measurements of passive joint moments.

Effects of barbell back squat stance width on sagittal and frontal hip and knee kinetics.

Different stance widths are commonly utilized when completing the barbell back squat during athletic general preparedness training. Width manipulation is thought to influence sagittal plane stimuli to the hip and knee extensors, the primary extensor musculature in the squat. However, how width manipulation affects frontal plane stimuli is less understood. Knowledge of hip and knee net joint moments (NJM) could improve exercise selection when aiming to improve sport-specific performance and prevent injuries. Fourteen adult amateur rugby athletes were recruited for this study. After a familiarization period, participants performed wide- (WIDE, 1.5× greater trochanter width) and narrow-stance (NARROW, 1× greater trochanter width) barbell back squats to femur parallel depth, using relative loads of 70% and 85% of one-repetition maximum. Sagittal and frontal plane hip and knee kinetics and kinematics were compared between widths. A Bonferroni-corrected alpha of 0.01 was employed as the threshold for statistical significance. Knee flexion angle was statistically greater in NARROW than WIDE (P<0.0001, d=2.56-2.86); no statistical differences were observed for hip flexion angle between conditions (P=0.049-0.109, d=0.33-0.38). Hip-to-knee extension NJM ratios and knee adduction NJMs were statistically greater in WIDE than NARROW (P<0.007, d=0.51-1.41). At femur parallel, stance width manipulation in the barbell back squat may provide substantial differences in biomechanical stimulus in both the sagittal plane and the frontal plane. In certain contexts, these differences may have clinically relevant longitudinal implications, from both a performance and a injury prevention standpoint, which are discussed.

Reducing the Energy Cost of Human Running Using an Unpowered Exoskeleton.

In this paper, we present a new perspective to design an unpowered exoskeleton for metabolic rate reduction in running. According to our studies on human biomechanics, it was observed that having a torsional spring that applies torque as a linear function of the difference between two hips angles ( -angle), compared with a local spring which applies torque as a function of hip angle ( -angle), provides a better condition for hip moment compensation and, consequently, metabolic rate reduction. Accordingly, a new type of unpowered exoskeleton device for realization of this idea was designed, and a prototype of this exoskeleton was constructed. This exoskeleton was tested on 10 healthy active subjects for running at 2.5 m s-1. In this experiment, 8.0 ± 1.5% (mean ± s.e.m.) metabolic rate reduction (compared with the no-exoskeleton case) was achieved.

Supracondylar femoral rotation osteotomy affects frontal hip kinetics in children with bilateral cerebral palsy.

To evaluate the influence of supracondylar femoral derotation osteotomy (FDO) on hip abduction muscle force and frontal hip moments in children with bilateral cerebral palsy. For this retrospective cohort study 79 children (36 females, 43 males; mean age at surgery 11y [SD 3y]; range 4-17y) with bilateral cerebral palsy and preoperatively and 1-year postoperatively documented frontal hip moments who received supracondylar FDO in 134 limbs were included. The control group consisted of eight children (two females, six males; mean age 11y [SD 4y]; range 5-17y) who received single-event multi-level surgery without FDO. Hip joint impulse (p<0.001) and the first peak of frontal hip moments (p=0.003) increased, whereas the second peak decreased (p<0.001) from preoperatively to postoperatively. Hip abductor strength improved (p=0.001) from preoperatively to postoperatively. Despite the compensatory mechanism, frontal hip moments are decreased preoperatively. Supracondylar FDO results in increased frontal hip moments. Changes in anteversion directly influence hip kinetics, although no direct change of the proximal bony geometry is performed. Internal rotation gait cannot fully restore the frontal hip moment. Supracondylar femoral derotation osteotomy (FDO) influences frontal hip kinetics in children with bilateral cerebral palsy. Supracondylar FDO changes the curve progression of frontal hip moments. Supracondylar FDO restores the hip abductor moment arm. Supracondylar FDO leads to an increase in hip abductor muscle force.

Differences in impact characteristics, joint kinetics and measurement reliability between forehand and backhand forward badminton lunges

ABSTRACT This study identified the effect of badminton lunging directions on impact characteristics, joint kinetics and measurement reliability. A total of 14 badminton players performed 20 lunges in both forehand and backhand sides. Ground reaction force (GRF) and three-dimensional joint moment variables were determined for further analyses. Paired t-tests and Wilcoxon signed-rank tests were performed to determine any differences between the two lunge directions and intra-class correlation (ICC) and sequential averaging analysis (SAA) were used to estimate the minimum number of trials. Compared to the forehand side, participants experienced significantly larger total GRF impulse (+ 3.8%, p = 0.021) and transverse moment (hip + 63.5%, p < 0.001; knee + 80.7%, p = 0.011), but smaller hip (−7.7%), knee (−18.7%) and ankle frontal moments (−58.0%, p < 0.05) in backhand lunges. The minimum number of trials was similar for both lunge directions, as the averaged absolute differences was less than one in both ICC and SAA. Furthermore, smaller minimal number of trials was determined by the ICC (7.9–8.0), compared with the SAA approach (9.5–10.3). Lunge direction would influence GRF and joint loading, but not on the measurement reliability. These results give important insights to establish performance or equipment evaluation protocols during badminton lunges.

Joint moments’ contributions to vertically accelerate the center of mass during stair ambulation in the elderly: An induced acceleration approach

Falls are a serious problem faced by the elderly. Older adults report mostly to fall while performing locomotor activities, especially the ones requiring stair negotiation. During these tasks, older adults, when compared with young adults, seem to redistribute their lower limb joint moments. This may indicate that older adults use a different strategy to accelerate the body upward during these tasks. The purposes of this study were to quantify the contributions of each lower limb joint moment to vertically accelerate the center of mass during stair ascent and descent, in a sample of community-dwelling older adults, and to verify if those contributions were correlated with age and functional fitness level. A joint moment induced acceleration analysis was performed in 29 older adults while ascending and descending stairs at their preferred speed. Agreeing with previous studies, during both tasks, the ankle plantarflexor and the knee extensor joint moments were the main contributors to support the body. Although having a smaller contribution to vertically accelerate the body, during stair descent, the hip joint moment contribution was related with the balance score. Further, older adults, when compared with the results reported previously for young adults, seem to use more their knee extensor moment than the ankle plantarflexor moment to support the body when the COM downward velocity is increasing. By contributing for a better understanding of stair negotiation in community dwelling older adults, this study may help to support the design of interventions aiming at fall prevention and/or mobility enhancement within this population.

Sex-specific walking kinematics and kinetics in individuals with unilateral, symptomatic hip osteoarthritis: A cross sectional study

BackgroundHip osteoarthritis (OA) is a significant cause of disability, with hip pain and reduced external hip moments during walking being key features of the condition. The external hip adduction moment is greater in healthy women than men, however these between-sex differences are not evident in those with end-stage hip OA. Whether sex-specific hip kinetics are associated with early-midstage hip OA has not been investigated and may be a potential target for directed treatment. MethodsThirty-eight women and twenty-eight men with a diagnosis of symptomatic, unilateral, mild-to-moderate hip OA (Kellegren-Lawrence Grade 2 or 3) underwent three-dimensional gait analysis of normal walking gait using Vicon motion capture. Hip joint, trunk and pelvic angles and hip moments were calculated using the Plug-in-Gait model. The external peak flexion moment, and the first peak, second peak and mid-stance minimum of the hip adduction moment during the stance phase of walking as well as hip, trunk and pelvic kinematics occurring at the three moment time points were compared between groups using an analysis of covariance. ResultsWomen with hip OA exhibited a greater external hip adduction moment (mean difference 0.8–1.3 N m/BW.Ht(%), P < 0.05) and greater hip adduction angles (mean difference 2.8–4.9 degrees, P < 0.05) throughout stance than men. Men walked with a greater forward trunk lean than women during early to midstance (mean difference 2.9–3.5 degrees, P < 0.05) than women. SignificanceIn contrastto late stage hip OA, between-sex difference in hip joint kinematics and kinetics are preserved in early-midstage hip OA.

Effects of virtual reality with robot training on the gait of subacute stroke patients

Ambulation is always one of the most significant issues for post-stroke patients as well as a formidable challenge. There was few study, to our best knowledge, focusing on the kinetic and kinematic changes resulting from training using robotic devices with virtual reality (VR) for subacute stroke patients. Thus, we analyzed the gait parameters of these patients at 1week and 3 weeks after they suffered the disease. Twenty patients were included in this single blind randomized control study. Patients were randomized to either a VR with robot group ( n = 10) or non-VR group ( n = 10). The training was performed on a robotic gait-training system with situational interaction. Subjects in VR group were trained 5 times a week for two weeks for approximately 30 minutes every time. Others were trained by traditional therapies. After the two-week training, the step time of patients in VR group significantly decreased (from 0.88 ± 0.29 to 0.77 ± 0.16), while the stride length average (from 0.72 ± 0.26 to 0.81 ± 0.25), step length average (from 0.36 ± 0.12 to 0.42 ± 0.10) and walking speed average (from 0.49 ± 0.25 to 0.59 ± 0.23) significantly increased ( P < 0.05). Subjects in VR group demonstrated an obviously larger improvement in the maximum hip moment and minimum ankle moment ( P = 0.028 and P = 0.040, respectively) compared with those in non-VR group. VR training with robot system could also be applied, as traditional therapy, in rehabilitation process of subacute stroke patients, especially in the improvement of step length and walking speed.

Determining loads acting on the pelvis in upright and recumbent birthing positions: A case study

BackgroundThe biomechanics of mothers' birthing positions and their impact on maternal and newborn health outcomes are poorly understood. Our objectives were to determine the loads applied to the female pelvis during dynamic movement that may occur during childbirth; findings are intended to inform clinical understanding and further research on birth positioning mechanics. MethodsAn optical motion capture system and force platforms were used to collect upright and supine movement data from two pregnant and three non-pregnant participants. Using an inverse dynamics approach, normalized three-dimensional hip and sagittal plane lumbosacral joint moments were estimated during squatting, all-fours, and supine activities. FindingsDuring squatting, peak hip abduction moments were greater for our pregnant (compared with non-pregnant) participants and lumbosacral extension moments substantially exceeded those during walking. The all-fours activity, conversely, generated flexion moments at the L5/S1 joint throughout most of the cycle. In supine, the magnitude of the ground reaction force reached 100% body weight with legs and upper body raised (McRoberts' position); the centre of pressure remained cranial to the sacrum. InterpretationSquatting generated appreciable moments at the hip and lumbosacral joints that could potentially affect pelvic motion during childbirth.

Differences in lower limb biomechanics between ballet dancers and non-dancers during functional landing tasks

ObjectivesTo determine the differences in the lower limb landing biomechanics of adolescent ballet dancers compared to non-dancers when performing a hop and a stop jump task. DesignCross-sectional. SettingLaboratory. ParticipantsThirteen adolescent female ballet dancers (11.8 ± 1.1 years) and 17 non-dancers (10.9 ± 0.8 years) performed hop and stop jump tasks. Main outcome measuresVertical ground reaction force, and three-dimensional ankle, knee and hip joint angles and moments during the landing phase. ResultsDancers displayed greater sagittal plane joint excursions during the hop and stop jump at the ankle (mean difference = 22.0°, P < 0.001, 14.8°, P < 0.001 respectively), knee (mean difference = 18.1°, P = 0.001, 9.8°, P = 0.002 respectively) and hip (stop jump task; mean difference = 8.3°, P = 0.008). Dancers displayed a larger hip extensor moment compared to non-dancers (P < 0.001) during the stop jump task only. Dancers also took longer to reach peak vGRF and jumped three times higher than non-dancers (P < 0.001) during the stop jump task. No difference in peak vGRF between groups was displayed for either task. ConclusionsAdolescent dancers demonstrate a transfer of landing technique to non-ballet specific tasks, reflective of the greater jump height and sagittal plane joint excursions. This landing strategy may be associated with the low rate of non-contact ACL injuries in female dancers.

Does Squat Depth and Width Influence Hip and Knee Joint Moments?

Squats are a popular closed-chain exercise that can benefit strength, power, balance, and range of motion. Proper squat technique includes varying depths and widths. PURPOSE: This study investigated sagittal plane knee and hip moments during 9 different squat variations. METHODS: 10 healthy, college-aged adults (7 female, 3 male, mass = 67.4 ± 10.7 kg; height = 1.68 ± 0.08 m) performed body-weight squats at 3 widths (standard (shoulder width), wide (150% of shoulder width), and widest (200% of shoulder width)) and 3 squat depths (shallow (55 degree knee flexion), parallel (90 degree knee flexion), and deep (125 degree knee flexion)). Anthropometric, marker coordinate, and force data were combined to calculate peak hip and knee moments during the eccentric (downward) and concentric (upward) phases of the squat. 2x3 ANOVAs were used to evaluate the effect of squat depth and width on peak hip and knee eccentric and concentric moments. RESULTS: Generally, concentric and eccentric hip and knee moments increased with greater squat depth and decreased with greater squat width. At the deep depth, the eccentric moments for the wide and widest stance widths were significantly less when compared to the standard width at the knee (standard = 1.23 ± 0.29 Nm/kg, wide = 1.09 ± 0.21 Nm/kg, widest = 0.98 ± 0.15 Nm/kg; p < 0.01) and at the hip (standard = 0.99 ± 0.21 Nm/kg, wide = 0.89 ± 0.19 Nm/kg, widest = 0.78 ± 0.17 Nm/kg; p < 0.001). At the parallel depth, the eccentric hip moment for the widest stance width (0.78 ± 0.13 Nm/kg) was significantly less than the eccentric hip moment for the standard (0.94 ± 0.18 Nm/kg) and wide stance widths (0.90 ± 0.14 Nm/kg; p < 0.01). The knee concentric moment for the deep depth was significantly less at the widest stance width (1.07 ± 0.20 Nm/kg) when compared to the wide (1.19 ± 0.21 Nm/kg) and standard stance widths (1.30 ± 0.28 Nm/kg; p < 0.01). CONCLUSIONS: Squat depth and stance width influence hip and knee joint moments, and both should be considered when performing a squat. If deep squats are used to increase lower-extremity muscle activation and overall work, increasing stance width will reduce sagittal plane hip and knee moments and possibly joint loads. Further research is needed to investigate other methods of reducing lower-extremity joint load while exercising.

Relationship between movement time and hip moment impulse in the sagittal plane during sit-to-stand movement: a combined experimental and computer simulation study

BackgroundThe association between repetitive hip moment impulse and the progression of hip osteoarthritis is a recently recognized area of study. A sit-to-stand movement is essential for daily life and requires hip extension moment. Although a change in the sit-to-stand movement time may influence the hip moment impulse in the sagittal plane, this effect has not been examined. The purpose of this study was to clarify the relationship between sit-to-stand movement time and hip moment impulse in the sagittal plane.MethodsTwenty subjects performed the sit-to-stand movement at a self-selected natural speed. The hip, knee, and ankle joint angles obtained from experimental trials were used to perform two computer simulations. In the first simulation, the actual sit-to-stand movement time obtained from the experiment was entered. In the second simulation, sit-to-stand movement times ranging from 0.5 to 4.0 s at intervals of 0.25 s were entered. Hip joint moments and hip moment impulses in the sagittal plane during sit-to-stand movements were calculated for both computer simulations.Results and conclusionsThe reliability of the simulation model was confirmed, as indicated by the similarities in the hip joint moment waveforms (r = 0.99) and the hip moment impulses in the sagittal plane between the first computer simulation and the experiment. In the second computer simulation, the hip moment impulse in the sagittal plane decreased with a decrease in the sit-to-stand movement time, although the peak hip extension moment increased with a decrease in the movement time. These findings clarify the association between the sit-to-stand movement time and hip moment impulse in the sagittal plane and may contribute to the prevention of the progression of hip osteoarthritis.

Predicting net joint moments during a weightlifting exercise with a neural network model

The purpose of this study was to develop and train a Neural Network (NN) that uses barbell mass and motions to predict hip, knee, and ankle Net Joint Moments (NJM) during a weightlifting exercise. Seven weightlifters performed two cleans at 85% of their competition maximum while ground reaction forces and 3-D motion data were recorded. An inverse dynamics procedure was used to calculate hip, knee, and ankle NJM. Vertical and horizontal barbell motion data were extracted and, along with barbell mass, used as inputs to a NN. The NN was then trained to model the association between the mass and kinematics of the barbell and the calculated NJM for six weightlifters, the data from the remaining weightlifter was then used to test the performance of the NN – this was repeated 7 times with a k-fold cross-validation procedure to assess the NN accuracy. Joint-specific predictions of NJM produced coefficients of determination (r2) that ranged from 0.79 to 0.95, and the percent difference between NN-predicted and inverse dynamics calculated peak NJM ranged between 5% and 16%. The NN was thus able to predict the spatiotemporal patterns and discrete peaks of the three NJM with reasonable accuracy, which suggests that it is feasible to predict lower extremity NJM from the mass and kinematics of the barbell. Future work is needed to determine whether combining a NN model with low cost technology (e.g., digital video and free digitising software) can also be used to predict NJM of weightlifters during field-testing situations, such as practice and competition, with comparable accuracy.

Hip joint moments during walking in people with hip osteoarthritis: a systematic review and meta-analysis

This systematic review and meta-analysis investigated surrogate measures of hip joint loading during walking in people with hip osteoarthritis (OA). Five databases were searched up to January 14th, 2018. Studies that measured hip joint moments in the frontal or sagittal plane during walking in people with hip OA and used either a healthy control group or the unaffected leg to compare hip joint moments were included. Standardised mean differences (SMD) in sagittal and frontal plane moments were pooled as appropriate, using a random effect approach. Methodological quality was assessed using the Downs and Black checklist. Thirteen studies with 1,141 participants were eligible and suitable for meta-analyses. Overall, people with hip OA had lower sagittal (SMD-0.55 (95% confidence interval (CI)-1.00 to-0.10) and frontal plane moments (SMD-0.63 (95% CI-0.92,-0.34) compared to controls. However, substantial heterogeneity was observed (I2≤89%). Results by disease stage suggest that people with end-stage hip OA have lower sagittal (SMD-0.96;-1.30,-0.61; I2=69%) and frontal (SMD-1.17; 95% CI-1.71,-0.64; I2=85%) plane moments compared to controls. People with less severe hip OA than end-stage disease have comparable sagittal (SMD 0.37; 95% CI-0.17, 0.90; I2=69%) and frontal (SMD-0.24; 95% CI-0.76, 0.27; I2=51%) plane moments compared to controls. Hip joint loading may be dependent on disease stage. People with end-stage hip OA under-loaded compared to controls, while those who were not awaiting hip joint replacement had comparable hip joint loads to controls.

Patients with sacroiliac joint dysfunction exhibit altered movement strategies when performing a sit-to-stand task

Summary of Background DataThe ability to rise from a chair is a basic functional task that is frequently compromised in individuals diagnosed with orthopedic disorders in the low back and hip. There is no published literature that describes how this task is altered by sacroiliac joint dysfunction (SIJD). PurposeThe objective of this study was to compare lower extremity biomechanics and the onset of muscle activity when rising from a chair in subjects with SIJD and in healthy persons. Study DesignSix women with unilateral SIJD and six age-matched healthy controls performed a sit-to-stand task while we measured kinematics, kinetics, and muscle activity. Materials and MethodsSubjects stood up at a preferred speed from a seated position on an armless and backless adjustable stool. We measured kinematics with a 10-camera motion capture system, ground reaction forces for each leg with force plates, and muscle activity with surface electromyography. Joint angles and torques were calculated using inverse dynamics. Leg-loading rate was quantified as the average slope of vertical ground reaction (VGRF) force during the 500-millisecond interval preceding maximal knee extension. ResultsBetween-leg differences in loading rates and peak VGRFs were significantly greater for the SIJD group than for the control group. Maximal hip angles were significantly less for the SIJD group (p=.001). Peak hip moment in the SIJD group was significantly greater in the unaffected leg (0.75±0.22 N⋅m/kg) than in the affected leg (0.47±0.29 N⋅m/kg, p=.005). There were no between-leg or between-group differences for peak knee or ankle moments. The onset of activity in the latissimus dorsi muscle on the affected side was delayed and the erector spinae muscles were activated earlier in the SIJD group than in the control group. ConclusionsSubjects with SIJD have a greater VGRF on the unaffected leg, generate a greater peak hip moment in the unaffected leg, use a smaller range of motion at the hip joint of the affected leg, and delay the onset of a key muscle on the affected side when rising from a seated position.

Hip joint loading during walking in people with hip osteoarthritis: a systematic review and meta-analysis

Purpose: Hip osteoarthritis (OA) is a prevalent and costly chronic musculoskeletal condition that often results in pain and physical dysfunction. Evidence-based modifiable treatment targets for hip OA remain somewhat elusive and are largely based on evidence from the knee OA literature. Osteoarthritis is considered, at least in part, a mechanical disease. Preliminary evidence implicates abnormal hip joint loading in the pathogenesis of hip OA. Given that hip joint loading is potentially modifiable, there is a need to synthesise the evidence regarding hip joint loading during walking in individuals with hip OA to inform appropriate treatment targets. This systematic review and meta-analysis investigated hip joint loading during walking in people with hip osteoarthritis (OA). Methods: Five databases were searched up to March 29th, 2017. Studies that measured hip joint moments in the frontal or sagittal plane during walking in people with hip OA and contained either a healthy control group or the unaffected leg for comparison were included. Standardised mean differences (SMD) in measures of sagittal and frontal plane loading were pooled as appropriate, using a random effect approach. Univariate meta-regressions were further performed to explore if study and participant characteristics could explain heterogeneity. Among the variables evaluated as predictors of study heterogeneity were sample size, age, body mass index, sex, and walking speed. A further disease-stage sub-group analysis between studies with participants with end-stage hip OA, defined as awaiting hip replacement, and studies with participants with less severe hip OA (early, mild-to-moderate; not awaiting hip replacement) was performed. Methodological quality was assessed using the Downs and Black checklist. Results: Eleven studies with 1,036 participants were eligible and 10 studies were suitable for meta-analyses. Overall, people with hip OA had lower sagittal (SMD −0.83; 95%CI −0.99, −0.67) and frontal plane loading (SMD −0.70; 95%CI −1.12, −0.12) compared to controls. However, substantial heterogeneity was observed (I2 ≤ 90%). Meta-regression analysis determined no association between the SMD in peak external hip flexion moment with any of the study or participant characteristics investigated. In the frontal plane, the meta-regression analysis found an association between the SMD in peak external hip adduction moment and sample size (unstandardized ß −0.01; 95%CI −0.03, 0.00), such that the difference increased as sample size increased. Results by disease stage suggest that people with less severe hip OA have comparable sagittal (SMD 0.04; 95%CI −0.50, 0.58; I2 = 70%) and frontal (SMD 0.01; 95%CI −0.41, 0.43; I2 = 0%) plane loading compared to controls. People with end-stage hip OA have lower sagittal (SMD −1.04; 95%CI −1.45, −0.64; I2 = 74%) and frontal (SMD −0.67; 95%CI −1.12, −0.12; I2 = 71%) plane loading compared to controls. The methodological quality of the studies was generally moderate (and ranged from 53%–92%), with higher scores indicating better quality. Conclusions: Collective consideration of all studies and findings from the meta-analyses suggests that people with hip OA have lower sagittal and frontal plane hip joint loading compared with healthy controls. However, analysis on a limited number of studies indicates that differences in hip joint loading may be dependent on disease stage. People with end-stage hip OA exhibit lower hip joint loading compared to controls, while those with less severe disease appear to be comparable with controls. These findings may have relevance for management in early stages of the disease pathway.

Joint moment strategies during stair descent in patients with peripheral arterial disease and intermittent claudication

ObjectiveTo determine the lower limb joint kinetic strategies during stair descent in claudicants with peripheral arterial disease (PAD-IC). DesignCross-sectional observation study. SettingUniversity laboratory. ParticipantsA total of 22 participants; 10 healthy controls and 12 patients diagnosed with PAD-IC. Main outcome measuresBetween-group comparisons of ground reaction force (GRF) and, hip, knee and ankle kinetics during steady-state stair descent. ResultsThe claudicating-limb group demonstrated reduced vertical and posterior GRF compared to healthy controls (ES = −1.46 [−2.32,−0.69] and ES = −1.08 [−0.42,−0.26]) as well as demonstrating an greater contribution to support moment from the ankle and trends towards a smaller hip contribution (42 ± 14% vs 28 ± 7%, P = .005 and Hip 16 ± 8% vs 21 ± 11%, P = .056, respectively). A unique sub-group was identified within the PAD-IC cohort demonstrating different hip moment strategies during weight acceptance: a novel hip extensor group (PAD-IC HExt) and stereotypical hip flexor group (PAD-IC HFlex). Compared to both healthy controls and the PAD-IC HFlex groups, the PAD-IC HExt group demonstrated increased hip extensor moment (ES = 3.05 [1.67,4.42] and ES = 3.62 [1.89,5.35]) and reduced knee extensor moment (ES = −2.00 [−3.15,−0.85] and ES = −1.36 [−2.60,−0.11] respectively) during weight acceptance. ConclusionsA novel hip extensor strategy was identified in a sub-group of claudicants which acts to reduce the demand on the knee extensors, but not the plantarflexors. Weakness in the knee extensors may prevent redistribution of the task demand, typically seen in older adults in stair descent, away from the functionally limited plantarflexor muscle group. Further investigation into multi-level joint strength and the relationship to functional tasks is warranted to inform targeted intervention programmes.

Multi-plane, multi-joint lower extremity support moments during a rapid deceleration task: Implications for knee loading

The principle of lower limb support, and the contribution of hip, knee and ankle moments to an overall limb support strategy for an impact-like, rapid deceleration movement may help explain individual moment magnitude changes, thereby providing insight into how injury might occur or be avoided. Twenty subjects performed single limb, impact-like, deceleration landings at three different knee flexion angles in the range of 0–25, 25–50 and 50–75°. Kinematic and kinetic measures identified hip, knee and ankle moment contribution to limb support moments (LSMs) in three planes. Repeated measures ANOVA compared LSMs and the contribution of individual joint moments at initial contact (IC) and 50 ms after. There were no significant differences in the overall LSMs at IC in any plane when the deeper knee flexion landings (25–50° and 50–75°) were compared to the 0–25° landing position but there were significant changes in the 50 ms period after IC. There were greater overall extensor LSMs, less resistance to medial opening of the knee and decreased support against internal tibia rotation when landing in greater knee flexion. The role of individual joint moments changed rapidly in the 50 ms period after initial landing; and, the relative contribution of the hip and ankle moments depended on the degree of limb flexion at landing. Analyses of individual joint moments emphasized the critical role that the hip joint moments have in balancing potentially injurious knee moments in all three planes for all three landing conditions.