Contralateral hip and knee gait biomechanics are unchanged by total hip replacement for unilateral hip osteoarthritis

Both the hip and knee contralateral to a total hip replacement (THR) have an increased risk of osteoarthritis (OA) progression, and ultimate joint replacement. It is also known that abnormal gait contributes to OA progression. For these reasons, we conducted a longitudinal analysis of contralateral hip and knee gait during the first year after unilateral THR to determine whether abnormal contralateral gait biomechanics emerge after THR. We analyzed the sagittal plane dynamic range of motion and 3D peak external moments from the asymptomatic hip and knee contralateral to a THR in a group of 26 subjects, evaluated preoperatively, and 3, 12, 24, and 52 weeks after THR, and a group of control subjects. We used t-tests and repeated measures ANOVA to test the hypotheses that contralateral hip and knee gait parameters are normal preoperatively, but change after THR. Preoperatively, the contralateral hip abduction moment and the contralateral knee adduction, flexion, and external rotation moments were significantly higher than normal in the THR group (p ≤ 0.048). Apart from the peak hip extension moment, which decreased three weeks after surgery but returned to its preoperative value thereafter, there were no longitudinal changes during the study period (p ≥ 0.141). Preoperative gait abnormalities persisted postoperatively. Notably, the contralateral knee adduction moment was 32% higher than normal in the THR group. These results indicate a biomechanical basis for the increased contralateral OA risk after unilateral THR, and suggest that some patients may benefit from strategies to reduce loading on the contralateral limb.     

Hip movement pathomechanics of patients with hip osteoarthritis aim at reducing hip joint loading on the osteoarthritic side

This study aims at defining gait pathomechanics in patients with hip osteoarthritis (OA) and their effect on hip joint loading by combining analyses of hip kinematics, kinetics and contact forces during gait. Twenty patients with hip OA and 17 healthy volunteers matched for age and BMI performed three-dimensional gait analysis. Hip OA level was evaluated based on plane radiographs using the Tönnis classification. Hip joint kinematics, kinetics as well as hip contact forces were calculated. Waveforms were time normalized and compared between groups using statistical parametric mapping analysis. Patients walked with reduced hip adduction angle and reduced hip abduction and external rotation moments. The work generated by the hip abductors during the stance phase of gait was largely decreased. These changes resulted in a decrease and a more vertical and anterior orientation of the hip contact forces compared to healthy controls. This study documents alterations in hip kinematics and kinetics resulting in decreased hip loading in patients with hip OA. The results suggested that patients altered their gait to increase medio-lateral stability, thereby decreasing demand on the hip abductors. These findings support discharge of abductor muscles that may bear clinical relevance of tailored rehabilitation targeting hip abductor muscles strengthening and gait retraining.     

Lower extremity joint moments throughout gait at two speeds more than 4 years after ACL reconstruction

BackgroundLong-term gait adaptations after anterior cruciate ligament reconstruction (ACLR) have been reported. However, it is still unclear if they persist more than 4 years after surgery and if they are affected by gait speed.Research question: To investigate differences between groups, legs and walking speeds for ankle, knee and hip joint moments in three planes throughout the stance phase of gait.MethodsReconstructed participants (n = 20 males, 32.5 years, 5.5 years post-ACLR) and healthy controls (n = 20 males, 30.6 years) took part in the study. Gait analysis was performed in two different speeds (self-selected and 30% faster). Sagittal, frontal and transverse plane external moments were measured for ankle, knee and hip and compared throughout the stance phase using 95% confidence intervals. Significant differences were established as a consecutive 5% of gait cycle in which 95% confidence interval did not overlap.ResultsThe reconstructed leg did not demonstrate higher joint moments; there were largely no differences while there was lower knee external rotation moment compared to the non-preferred leg of the control group. Higher joint moments were observed during fast speed walking on sagittal plane for knee and hip moments in both groups, and in the frontal and transverse plane for ankle moments.SignificanceGait kinetics appear to be largely normalized at a minimum of 4 years after ACLR. Faster walking speed increase lower extremity joint moments.     

Threshold of equinus which alters biomechanical gait parameters in children

The main aim of this study was to define the threshold angle of equinus beyond which significant changes in 3D lower limb kinematics and kinetics occur in typically developing children and to describe these changes.A customized orthosis was fitted on the right ankle of 10 typically developing children and was adjusted to +10° ankle dorsiflexion, 0°, ?10°, ?20° plantarflexion and maximum plantarflexion. Gait was analyzed using an optoelectronic system. A gait velocity of 1 m/s was imposed.Most of the kinematic and kinetic changes were significantly altered from the ?10° condition. In the sagittal plane, the results showed increased knee flexion at initial contact, increased knee flexion or hyperextension in stance, increased hip flexion at initial contact and increased anterior pelvic tilt. Other changes included increased knee varus, reduced hip adduction and more internal foot progression. The ankle plantarflexion moment was bi-phasic during stance, peak ankle power generation was reduced, peak knee extension moment was decreased and hip extension moments increased. On the contralateral side, there was a significant increase in ankle plantarflexion at initial contact and a significant decrease in knee flexion during swing phaseat maximum plantarflexion.Although slight modifications occurred for smaller degrees of equinus, the results suggest that significant kinematic and kinetic changes occurred during gait in both limbs from 10° of plantarflexion. The results of this study also provide some indications regarding the primary causes of gait deviations and secondary compensatory strategiesin children with a clinical dorsiflexion limitation.     

External loading of the knee joint during running and cutting maneuvers.

PURPOSE: To investigate the external loads applied to the knee joint during dynamic cutting tasks and assess the potential for ligament loading. METHODS: A 50-Hz VICON motion analysis system was used to determine the lower limb kinematics of 11 healthy male subjects during running, sidestepping, and crossover cut. A kinematic model was used in conjunction with force place data to calculate the three-dimensional loads at the knee joint during stance phase. RESULTS: External flexion/extension loads at the knee joint were similar across tasks; however, the varus/valgus and internal/external rotation moments applied to the knee during sidestepping and crossover cutting were considerably larger than those measured during normal running (P < 0.05). Sidestepping tasks elicited combined loads of flexion, valgus, and internal rotation, whereas crossover cutting tasks elicited combined loads of flexion, varus, and external rotation. CONCLUSION: Compared with running, the potential for increased ligament loading during sidestepping and crossover cutting maneuvers is a result of the large increase in varus/valgus and internal/external rotation moments rather than any change in the external flexion moment. The combined external moments applied to the knee joint during stance phase of the cutting tasks are believed to place the ACL and collateral ligaments at risk of injury, particularly at knee flexion angles between 0 degrees and 40 degrees, if appropriate muscle activation strategies are not used to counter these moments.     

Gait adaptations with aging in healthy participants and people with knee-joint osteoarthritis

The relationship between age and gait characteristics in people with and without medial compartment osteoarthritis (OA) remains unclear. We aimed to characterize this relationship and to relate biomechanical and structural parameters in a subset of OA patients. Twenty five participants with diagnosed unilateral medial knee OA and 84 healthy participants, with no known knee pathology were recruited. 3D motion capture was used to analyse sagittal and coronal plane gait parameters while participants walked at a comfortable speed. Participants were categorized according to age (18–30, 31–59 and 60+ years), and those with and without OA were compared between and within age groups. In a subset of OA patients, clinically available Computed Tomography images were used to assess joint structure. Differences in coronal plane kinematics at the hip and knee were noted in participants with OA particularly those who were older compared with our healthy controls, as well as increased knee moments. Knee adduction moment correlated with structural parameters in the subset of OA patients. Increased knee moments and altered kinematics were observed in older participants presenting with OA only, which seem to be related to morphological changes in the joint due to OA, as opposed to being related to the initial cause of medial knee OA.     

Increasing obstacle height and decreasing toe-obstacle distance affect the joint moments of the stance limb differently when stepping over an obstacle

Foot placement during gait is important in regulating the dynamics of the joints of the supporting limb and in maintaining balance of the whole body. We hypothesized that increasing obstacle height and decreasing toe-obstacle distance (distance between the trailing foot and the obstacle during stance of the trailing foot just prior to stepping over the obstacle) would affect the joint moments of the stance limb differently when stepping over an obstacle. A total of 14 healthy young adults stepped over an obstacle 51, 102, 153, and 204 mm in height in a self-selected manner (i.e. toe-obstacle distance was not controlled) and for toe-obstacle distance targets of 10, 20, 30, and 40% of their step lengths measured during unobstructed gait. The adduction and internal rotation moments at the ankle joint increased as toe-obstacle distance decreased. The adduction and internal rotation moments at the hip joint during early stance, the internal rotation moment at the knee joint during late stance, and the dorsiflexion moment at the ankle joint during late stance increased with obstacle height. Reductions in toe-obstacle distance had greater effects on the moments of the ankle joint, and increases in obstacle height had greater effects on the moments of the hip joint. These greater demands on joint moments may affect the abilities of those elderly having decreased muscle strengths to safely step over obstacles.     

Increased knee flexion and varus moments during gait with high-heeled shoes: A systematic review and meta-analysis

BackgroundHigh-heeled shoes have been thought to alter lower extremity joint mechanics during gait, however its effects on the knee remain unclear.Research questionThis systematic review and meta-analysis aimed to determine the effects of high-heeled shoes on the sagittal- and frontal-plane knee kinetics/kinematics during gait.Methods1449 studies from 6 databases were screened for the following criteria: 1) healthy adult females, 2) knee joint kinematics/kinetics reported for the early stance phase during gait under varying shoe heel heights (including barefoot). Excluded studies included those mixing different shoe styles in addition to altering the heel heights. A total of 14 studies (203 subjects) met the selection criteria, resulting in 51 and 21 Cohen’s d effect sizes (ESs) comparing the differences in knee sagittal- (flexion) and frontal-plane (varus) moment/angle, respectively, between shoes with higher heels and shoes with lower heels/barefoot.ResultsMeta-analyses yielded a significant medium-to-large effect of higher heels compared to lower heels on increasing knee flexion moment (overall ES = 0.83; P < 0.01), flexion angle (overall ES=0.46; P < 0.01), and varus moment (overall ES=0.52; P < 0.01) during the early stance phase of gait. The results of meta-regressions used to explore factors explaining the heterogeneity among study ESs revealed that a greater ES in the knee flexion moment was associated with an elevated heel height of the high-heeled shoes (P = 0.02) and greater body mass of the individuals (P = 0.012). A greater ES in the knee varus moment during high-heeled gait was associated with a greater body height (P = 0.003) and mass (P = 0.006).SignificanceGiven the association between increased knee flexion/varus moments and risk of developing knee osteoarthritis (OA), women who wear high-heel shoes frequently and for a long period may be more susceptible to knee OA. Preventive treatments, such as lower extremity muscle strengthening, may help improve shock absorption to decrease knee loading in high-heel users.     

Knee strength and knee adduction moments following arthroscopic partial meniscectomy

PURPOSE: This study investigated the relationship between muscular strength about the knee and knee joint moments during gait in patients who had undergone arthroscopic partial meniscectomy (APM). METHODS: One hundred and two APM patients and 42 age-matched nonoperated controls underwent strength testing and three-dimensional gait analysis. Patients were divided into weak and normal subgroups and compared with controls for spatiotemporal, kinematic, and kinetic gait parameters. RESULTS: Spatiotemporal parameters, kinematics, and sagittal plane kinetics were similar between APM patients and controls. The APM group displayed weaker concentric knee extension and flexion strength compared with controls. The weak APM subgroup had an increased average and peak knee adduction moments over stance compared with the APM subgroup with normal strength levels and controls. The normal strength APM subgroup had a larger peak knee adduction moment in early stance compared with controls. CONCLUSION: Achieving normal lower limb muscle strength following APM appears important to resume normal frontal plane loading of the knee while walking.     

Effects of artificially induced bilateral internal rotation gait on gait kinematics and kinetics

BackgroundBilateral internal rotation gait is a common gait abnormality in children with bilateral cerebral palsy, but still not fully understood.Research questionThe aim of this clinical study was to analyze the effects of artificially induced bilateral internal rotation gait on kinematics and kinetics. Our hypothesis was, that the internal rotation gait defined as increased dynamic internal hip rotation itself causes significant alterations in gait kinematics and kinetics.Methods30 typically developing children with a mean age of 12 (SD 3) years (range 8 – 16) performed three-dimensional gait analysis in two different conditions: with unaffected gait and with artificially induced bilateral internal rotation gait with two rotation bandages worn in order to internally rotate the hips. Kinematic and kinetic changes between these two conditions were calculated and compared using a mixed linear model with “gait condition” as fixed effect and both “limb” and “patient” as random effects.ResultsThe rotation bandages induced a significant increase in internal hip rotation and foot progression angle towards internal without affecting pelvic rotation. The peak hip internal rotator moment during loading response and the peak hip external rotator moment during the first half of stance phase increased significantly and the peak hip internal rotator moment during the second half of stance phase decreased significantly. Anterior pelvic tilt, hip flexion, knee flexion and ankle dorsiflexion increased significantly. The first peak of the frontal hip moment decreased, and the second increased significantly. The second peak of the frontal knee moment decreased significantly, while the first didn’t change significantly.SignificanceThe data suggest, that the bilaterally increased dynamic internal hip rotation itself has a relevant impact on frontal hip moments. The increased anterior pelvic tilt, hip and knee flexion may be either induced by the pull of the rotation bandage or a secondary gait deviation.     

Kinetics of compensatory gait in persons with myelomeningocele

This study investigated the kinetic strategy and compensatory mechanisms during self-ambulatory gait in children with lumbo-sacral myelomeningocele. Thirty-one children with mid-lumbar to low-sacral myelomeningocele who walked without aids and 21 control children were evaluated by three-dimensional gait analysis. Joint moments in all planes at the hip and knee and sagittal moments at the ankle, as well as joint power and work done at all three joints, were analyzed. Joint moment capacity lost due to plantarflexor and dorsiflexor weakness was provided instead by orthotic support, but other joints were loaded more to compensate for the weakness at the ankles and restricted ankle motion. Subjects with total plantarflexor and dorsiflexor paresis and strength in the hip abductors had more knee extensor loading due to plantarflexor weakness and dorsiflexion angle of the orthotic ankle joint. The subjects with orthoses also generated more power at the hip to supplement the power generation lost to plantarflexor weakness and fixed ankles. The most determinant muscle whose paresis changes gait kinetics was the hip abductor. Hip abductor weakness resulted in a characteristic pattern where the hips displayed an eccentric adduction moment, mediating energy transfer into the lower limbs, and the hips replaced the knees as power absorbers in early stance. Joint moment, power and work analyses complement a kinematic analysis to provide a complete picture of how children who have muscle paresis recruit stronger muscle groups to compensate for weaker ones.     

Gait patterns after anterior cruciate ligament reconstruction

The aim of this study is to analyse the changes in select gait parameters following anterior cruciate ligament (ACL) reconstruction. The study was performed on 15 subjects who underwent ACL reconstruction by the bone-patellar tendon-bone technique. Gait analysis was performed using the Elite three-dimensional (3D) optoelectronic system (BTS), a Kistler force platform and the Telemg telemetric electromyograph (BTS). Kinematic data were recorded for the principal lower limb joints (hip, knee and ankle). The examined muscles include vastus lateralis, rectus femoris, biceps femoris and semitendinosus. The results obtained from the operated subjects were compared with those of 10 untreated subjects and 5 subjects without ACL damage. In the operated subjects the knee joint angular values regained a normal flexion pattern for the injured limb during the stance phase. The analysis of joint moments shows: (a) sagittal plane: recovery of the knee flexion moment at loading response and during preswing; (b) frontal plane: recovery of the normal patterns for both hip and knee adduction-abduction moments during the entire stance phase. The examination of ground reaction forces reveals the recovery of frontal component features. The EMG traces show the normal biphasic pattern for the operated subjects as compared to the untreated subjects. The results suggest that the gait parameters shift towards normal value patterns.     

Toe-out angle changes after total knee arthroplasty in patients with varus knee osteoarthritis

Purpose

Toeing-out is a commonly proposed kinematic variable that has been suggested to reduce external knee adduction moment. Analyses of the toe-out angle after total knee arthroplasty (TKA) are useful for obtaining a proper understanding of the abnormal gait caused by varus knee osteoarthritis (OA), as well as performing rehabilitation after arthroplasty. Changes in the toe-out angle after arthroplasty have not yet been defined or analysed.

Methods

The study population consisted of 32 knees in 32 patients with varus knee OA who underwent TKA. The femorotibial angle was evaluated on standing anteroposterior radiographs before and after arthroplasty. The subjects underwent three-dimensional motion capture analyses to measure gait parameters (walking speed, cadence, stride length, step length, step width and the relative length of the single-limb support (SLS) percentage of one gait cycle) and the maximal hip adduction angle in the stance phase, the trunk lean angle in the coronal plane and the toe-out angle before and 4 weeks after arthroplasty.

Results

The femorotibial angle on the side of arthroplasty improved after surgery. Among the measured gait parameters, only the SLS percentage increased significantly. The hip adduction angle and toe-out angle on the side of arthroplasty increased significantly after surgery.

Conclusions

The knee alignment and hip adduction angle in the coronal plane and SLS phase were normalized after arthroplasty. The increase in the toe-out angle after arthroplasty may be attributable to the restoration of a normal knee alignment. These findings contribute to obtaining a proper understanding of the abnormal gait caused by varus knee OA and are useful for orthopaedic surgeons and rehabilitation therapists when treating patients after arthroplasty.

Level of evidence

Prospective study, Level II.     

Impact of subject-specific step width modification on the knee and hip adduction moments during gait

BackgroundPatients with hip osteoarthritis (OA) exhibit an increased step width (SW) during walking before and up to 2 years after total hip arthroplasty. Wider SW is associated with a reduction in the external knee adduction moment (KAM), but there is a lack of research regarding the effect of SW on the hip adduction moment (HAM).Research questionIs a wider SW an effective compensatory mechanism to reduce the hip joint loading? We hypothesized that (1) an increased SW reduces, (2) a decreased SW increases the KAM/HAM, and (3) secondary kinematic gait changes have an effect on the KAM/HAM.MethodsTwenty healthy individuals (24.0 ± 2.5 years of age) underwent instrumented gait analyses with 4 different subject-specific SW modifications (habitual, halved, double, and triple SW). The resulting external KAMs and HAMs were compared using statistical parametric mapping (SPM).ResultsPost hoc testing demonstrated significantly lower HAM for both the double (p < 0.001, 15–31 % and 61–98 % of the stance phase) and the triple SW (p < 0.001, 1–36 % and 58–98 %) compared to the habitual SW. The extent of the reduction at the first and second peak was comparable for HAM (15–25 % reduction) and less pronounced at the first peak of KAM (9–11 % reduction) compared to the second peak of KAM (19–28 % reduction). In contrast, halving the SW did not lead to a significant change in KAM or HAM compared to the habitual SW (p > 0.009).SignificanceAn increase in SW is an effective and simple gait mechanism to reduce the frontal plane knee and hip joint moments. However, hypothesis 2 could not be confirmed, as halving the SW did not cause a significant change in KAM or HAM. Given the results of the present study, gait retraining with regard to an increased SW may be an adequate, noninvasive option for the treatment of patients with hip OA.     

Kinematic changes in patients with severe knee osteoarthritis are a result of reduced walking speed rather than disease severity

BackgroundKinematic changes in patients with knee osteoarthritis (OA) have been extensively studied. Concerns have been raised whether the measured spatiotemporal and kinematic alterations are associated with disease progression or merely a result of reduced walking speed.Research question: The purpose of this study was to investigate the effect of walking speed on kinematic parameters in patients with knee OA using statistical parametric mapping (SPM).MethodsTwenty-three patients with unilateral knee OA scheduled for a total knee replacement and 28 age matched control subjects were included in this study. Spatiotemporal parameters and sagittal plane kinematics were measured in the hip, knee, and ankle using the inertial sensors system RehaGait® while walking at a self-selected normal (patients and controls) and slow walking speed (controls) for a distance of 20 m. Gait parameters were compared between groups for self-selected walking speed and for matched walking speed using SPM with independent sample t tests.ResultsAt self-selected walking speed, patients had significantly lower knee flexion during stance (maximum difference, -6.8°) and during swing (-11.0°), as well as higher ankle dorsiflexion during stance phase (+12.5°) and lower peak hip extension at the end of stance compared to controls (+4.2°). At matched speed, there were no significant differences in joint kinematics between groups.SignificanceDifferences in sagittal plane gait kinematics between patients with knee OA and asymptomatic controls appear to be mainly a result of reduced walking speed. These results emphasize the importance of considering walking speed in research on gait kinematics in patients with knee OA and in clinical trials using gait parameters as outcome measures.     

The influence of external knee moments on the outcome of total meniscectomy. A comparison of radiological and 3-D gait analysis measurements

Twenty one individuals who had undergone unilateral total meniscectomy, and had no significant antero-posterior (AP) laxity underwent three dimensional (3-D) gait analysis, bilateral radiological assessment of varus/valgus alignment and tibio-femoral osteoarthritis (TFOA). Average foot progression angle during the stance phase of gait was not related to knee adduction moment. The findings support the previously noted correlation between varus/valgus alignment and TFOA. The dynamic gait parameter of the adduction moment in early stance did not correlate with either hip–knee–ankle angle or TFOA, thus the expected influence of external moments on outcome after meniscectomy was not found. Thus the correlation between varus/valgus alignment and TFOA can not be explained by a simple loading algorithm.     

The anterior cruciate ligament-deficient knee with varus alignment. An analysis of gait adaptations and dynamic joint loadings.

Thirty-two patients with an ACL-deficient knee and lower limb varus alignment and 16 healthy controls were analyzed during level walking using a force-plate and optoelectronic system. The forces and moments of the lower limb and knee joint were measured and knee joint loads and ligament tensile forces were calculated using a mathematical model. The majority of patients (20 of 32) had an abnormally high adduction moment at the affected knee. The adduction moment showed a statistically significant correlation to high medial tibiofemoral compartment loads and high lateral soft tissue forces, but not to the degree of varus alignment on standing roentgenograms. Fifteen of 32 knees had abnormally high lateral soft tissue forces. We interpreted these gait findings as indicative of a medial shift in the center of maximal joint pressure and an increase in lateral soft tissue forces to achieve coronal plane stability. Further, there is the likelihood of separation of the lateral tibiofemoral joint and "condylar lift-off" during periods of the stance phase. If this occurs, all of the load-bearing forces would shift to the medial tibiofemoral joint and relatively large tensile forces would occur in the lateral soft tissue restraints. The flexion moment, as related to the quadriceps muscle force, was significantly lower than the control knees in 40% of the involved knees, and the extension moment, as related to the hamstring muscle force, was significantly higher in 50% of the involved knees. We interpret this finding as a gait adaptation tending to diminish quadriceps muscle activity and enhance hamstring muscle activity to provide dynamic anteroposterior stability of the knee joint. The fundamental assumption of this paper is that any combination of conditions leading to higher medial joint forces is associated with factors leading to more rapid degeneration of the medial compartment in patients with ACL deficiency, varus deformity, and lax lateral ligaments.     

Hip joint mechanics during walking in individuals with mild-to-moderate hip osteoarthritis

The purpose of this case-control study was to characterise hip joint kinematics and moments during gait in people with mild-to-moderate hip osteoarthritis (OA). Eligible participants were allocated to the hip OA group (n = 27) or the age-matched control group (n = 26) based on radiographic and symptomatically defined inclusion criteria. Participants walked barefoot along a 10-m walkway at their self-selected gait speed. Trajectories of 43 markers attached to the trunk, pelvis, upper and lower limbs were recorded using a 12-camera motion capture system. Ground reaction force data were simultaneously collected. Individuals in the hip OA group had a 10% higher body mass, 13% slower self-selected walking speed, 10% shorter step length, 2% and 9% longer relative stance and double support duration (% stride) respectively, 41% lower sagittal plane hip range of motion, and 28% and 45% lower peak sagittal and transverse plane hip joint moments respectively during gait compared to controls (p < 0.05). The finding that individuals with mild-to-moderate hip OA experienced less net hip joint loading over a reduced range of hip motion for a longer proportion of the gait cycle when walking at their preferred gait speed suggest that the mechanics of the hip joint are altered in hip OA, and could have implications for disease progression through altered mechano-biological processes within the joint.     

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.     

Trunk flexion during walking in people with knee osteoarthritis

BackgroundOver 50% of the body’s mass is concentrated within the head, arms and trunk. Thus, small deviations in the orientation of the trunk, during normal walking, could influence the position of the centre of mass relative to the lower limb joint centres and impact on lower limb biomechanics. However, there are minimal data available on sagittal kinematics of the trunk in people with knee osteoarthritis (OA) during walking.Research questionDo people with knee OA have altered kinematic patterns of the trunk, pelvis or hip compared with healthy control participants during walking?MethodsStatistical parametric mapping was used to compare sagittal and frontal plane kinematic patterns, during walking, between a healthy group and cohort of people with knee OA.ResultsIndividuals with knee OA walked with a mean increase in trunk flexion of 2.6°. Although this difference was more pronounced during early stance, it was maintained across the whole of stance phase. There were no differences, between the groups, in sagittal plane pelvic or hip kinematics. There were also no differences in trunk, pelvic or hip kinematics in the frontal plane.SignificanceMost previous gait research investigating trunk motion in people with knee OA has focused on the frontal plane. However, our data suggest that an increase in sagittal trunk flexion may be a clinical hallmark of people with this disease. Altered trunk flexion could affect joint moments and muscle patterns and therefore our results motivate further research in this area.