Influence of intrinsic and extrinsic conditions on the knee joint loading during double-leg landing using a musculoskeletal model in the sagittal plane.

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

Quantitative assessments of prostheses performances rely more and more frequently on gait analysis focusing on prosthetic knee joint forces and moments computed by inverse dynamics. However, this method is prone to errors, as demonstrated in comparison with direct measurements of these forces and moments. The magnitude of errors reported in the literature seems to vary depending on prosthetic components. Therefore, the purposes of this study were (A) to quantify and compare the magnitude of errors in knee joint forces and moments obtained with inverse dynamics and direct measurements on ten participants with transfemoral amputation during walking and (B) to investigate if these errors can be characterised for different prosthetic knees. Knee joint forces and moments computed by inverse dynamics presented substantial errors, especially during the swing phase of gait. Indeed, the median errors in percentage of the moment magnitude were 4% and 26% in extension/flexion, 6% and 19% in adduction/abduction as well as 14% and 27% in internal/external rotation during stance and swing phase, respectively. Moreover, errors varied depending on the prosthetic limb fitted with mechanical or microprocessor-controlled knees. This study confirmed that inverse dynamics should be used cautiously while performing gait analysis of amputees. Alternatively, direct measurements of joint forces and moments could be relevant for mechanical characterising of components and alignments of prosthetic limbs.

Antero-posterior ground reaction forces are the driving forces affecting walking speed. This study examined the relation between hip, knee, and ankle joint moment and the production of antero-posterior ground reaction forces during walking in the elderly and younger individuals. Forty elderly people, ≥65 years old, and 40 younger people, 20 to 29 years old, participated in this study. Gait analyses involved measurement of the ground reaction forces as well as calculation of hip, knee, and ankle joint moment. A stepwise linear regression analysis determined joint moment that can predict the amplitude of the antero-posterior ground reaction force. Extension moment during early stance of the knee was related to the posterior component of ground reaction force in elderly men, whereas hip and knee joint moments were related to the generation of the antero-posterior ground reaction forces in younger men. Moment of the hip and ankle were related to these forces in the elderly women. On the other hand, moment of the knee was related to generation of these forces in young women. Our results suggest differences between the elderly and the younger individuals with regard to the joints used for production of the antero-posterior ground reaction forces.

A large number of injuries to the lower extremity occur in skiing and snowboarding. Due to the difficulty of collecting 3D kinematic and kinetic data with high accuracy, a possible relationship between injury statistic and joint loading has not been studied. Therefore, the purpose of the current study was to compare ankle and knee joint loading at the steering leg between carved ski and snowboard turns. Kinetic data were collected using mobile force plates mounted under the toe and heel part of the binding on skies or snowboard (KISTLER). Kinematic data were collected with five synchronized, panning, tilting, and zooming cameras. An extended version of the Yeadon model was applied to calculate inertial properties of the segments. Ankle and knee joint forces and moments were calculated using inverse dynamic analysis. Results showed higher forces along the longitudinal axis in skiing and similar forces for skiing and snowboarding in anterior-posterior and mediolateral direction. Joint moments were consistently greater during a snowboard turn, but more fluctuations were observed in skiing. Hence, when comparing joint loading between carved ski and snowboard turns, one should differentiate between forces and moments, including the direction of forces and moments and the turn phase.

Limited data exists on knee biomechanics in alpine ski turns despite the high rate of injuries associated with this maneuver. The purpose of the current study was to compare knee joint loading between a carved and a skidded ski turn and between the inner and outer leg. Kinetic data were collected using Kistler mobile force plates. Kinematic data were collected with five synchronized, panning, tilting, and zooming cameras. Inertial properties of the segments were calculated using an extended version of the Yeadon model. Knee joint forces and moments were calculated using inverse dynamics analysis. The obtained results indicate that knee joint loading in carving is not consistently greater than knee joint loading in skidding. In addition, knee joint loading at the outer leg is not always greater than at the inner leg. Differentiation is required between forces and moments, the direction of the forces and moments, and the phase of the turn that is considered. Even though the authors believe that the analyzed turns are representative, results have to be interpreted with caution due to the small sample size.

A Method to Measure the Accuracy of Loads in Knee-Ankle-Foot Orthoses Using Conventional Gait Analysis, Applied to Persons With Poliomyelitis

Joint loading asymmetries in knee replacement patients observed both pre- and six months post-operation

PURPOSE Our purpose was to compare knee joint moments and forces between older adults with knee osteoarthritis and an age, gender, and mass matched healthy cohort. METHODS This study was designed to provide preliminary data that would identify trends to justify further investigation. The subjects for this investigation were 10 older adults (74.1± 1.49 yrs) with tibiofemoral and/or patellofemoral radiographic evidence and pain (ranged from mild to severe) and disability attributed to knee OA, and 10 age (73.0± 1.61 yrs), gender (9 female, 1 male, and mass(OA,65.1± 2.61 kg; H, 58.3± 2.74 kg) matched healthy (H) adults. Three dimensional gait analysis was used to calculate peak knee joint forces and moments. EMG data were obtained to verify our interpretation of the knee joint moment data. An analysis of covariance was used to adjust for differences in walking velocity between the groups (OA: 109.7 ±3.59 cm/s; H: 129.6± 8.42 cm/s). RESULTS The OA group had between 7% and 8% greater knee joint compressive (OA: 3.67± 0.24 BW; H: 3.40± 0.24 BW) and shear (OA: 0.47± 0.04 BW; H:0.44± 0.04 BW) forces, and 33% higher knee extension moments (OA:0.32± 0.07 Nm/kg; H: 0.24± 0.07Nm/kg) and 24% lower knee internal abduction (OA:0.25 ± 0.06Nm/kg; H:0.33± 0.06 Nm/kg) moments than the H group. CONCLUSION The trends in our data provide insight that may prove significant in a subsequent study using a larger sample size. Specifically, the chronic application of the slightly larger loads found in the OA group may increase cartilage degradation and present a possible pathway to knee OA. The 24% greater internal abduction moment in the H group is in contrast to the greater internal abduction moment that several authors have found differentiates patients with severe medial compartment knee OA from healthy cohorts. Hence, it appears the greater internal abduction moment may pertain only to patients with severe medial compartment knee OA.

INTRODUCTION: Approximately 66% of the United States is overweight or obese. Obesity is associated with many negative health conditions including osteoarthritis. Research has investigated the effects of increased mass on gait biomechanics, however weight-related changes stair locomotion biomechanics are less understood. PURPOSE: to assess changes in lower extremity joint moments associated with acutely added body mass during stair ascent. METHODS: Ten college aged participants performed 5 stair ascent trials in each of 5 loading conditions: body weight (BW), BW+5%, BW+10%, BW+15%, and BW+20%. Mass was added using a weighted vest. An 18-camera motion capture system (240 Hz) and embedded force platform (1200 Hz) were used to collect kinematics and ground reaction forces simultaneously. Commercial software was used to calculate ankle, knee and hip joint moments during the stance phase of second step of a five-step stairway. Univariate ANOVAs with Tukey’s post-hoc tests were used to compare peak ankle, knee and hip joint moments from each weighting condition. RESULTS: Ankle plantarflexion and knee extension moments increased with added load (Table 1). Hip extension moments were not altered with added load. DISCUSSIONS/CONCLUSION: The ankle joint is the primary contributor to increased lower extremity joint moments in response to added load during stair ascent. Though an omnibus effect of added load was observed at the knee, only one post-hoc comparison was statistically different (BW vs. BW+15%) suggesting that the knee is not responsible for increased propulsion in response to added load during stair ascent. Interestingly, no changes in peak joint moments were observed at the hip joint. A limitation of this study was that the acutely added load was not similar in location or physical properties to the increased load associated with obesity which may limit the generalizability of these findings to obese individuals.Table 1: Mean ankle, knee and hip joint moments during stair ascent in the control and added load conditions. P-value represents omnibus findings of the univariate ANOVA.

BackgroundThe aim of this study was to investigate the kinetic characteristics of compensatory backward descending movement performed by patients with osteoarthritis of the knee.MethodsUsing a three-dimensional motion analysis system, we investigated lower extremity joint angles, joint moments, joint force of the support leg in forward and backward descending movements on stairs, and joint force of the leading leg at landing in 7 female patients with osteoarthritis of the knee.ResultsCompared with the forward descending movement, knee joint angle, joint moment and joint force of the support leg all decreased in the backward descending movement. Joint force of the leading leg at landing was also reduced in the backward descending movement. In addition, we confirmed that the center of body mass was mainly controlled by the knee and ankle joints in the forward descending movement, and by the hip joint in the backward descending movement.ConclusionsSince it has been reported that knee flexion angle and extensor muscle strength are decreased in patients with osteoarthritis of the knee, we believe that backward descending movement is an effective method to use the hip joint to compensate forthese functional defects. In addition, due to the decreased knee joint force both in the leading and support legs in backward descending movement, the effectiveness of compensatory motion for pain control and knee joint protection was also suggested.

The aim of this study was to determine external and internal loads on the knee joint during downhill walking with and without hiking poles. Kinematic, kinetic and electromyographic data were collected from eight males during downhill walking on a ramp declined at 25 o . Planar knee joint moments and forces were calculated using a quasi-static knee model. The results were analysed for an entire pole-cycle as well as differentiated between single and double support phases and between each step of a pole-cycle. Significant differences between downhill walking with and without hiking poles were observed for peak and average magnitudes of ground reaction force, knee joint moment, and tibiofemoral compressive and shear forces (12-25%). Similar reductions were found in patellofemoral compressive force, the quadriceps tendon force and the activity of the vastus lateralis; however, because of a high variability, these differences were not significant. The reductions seen during downhill walking with hiking poles compared with unsupported downhill walking were caused primarily by the forces applied to the hiking poles and by a change in posture to a more forward leaning position of the upper body, with the effect of reducing the knee moment arm.

Kinetic gait analysis using inertial motion capture : new tools for knee osteoarthritis

The purposes of this study were to investigate effects of conditions on knee joint load during cutting movement, and to compare them during experiment, and to examine what condition pose a risk for knee injury. Three experiments were performed by 6 male graduate students: control, slow and fast speed, 45 degree direction, toe in and toe out cutting .Knee joint forces and moments were calculated by Inverse dynamics. During fast speed, peak posterior force was greater than low speed. During toe-out, peak abduction moment was lower than toe-out and control cutting. It was suggested that in toe out cutting, the risk of knee injury is decreased by greater peak abduction moment with comparison of toe in and control cutting.

Influence of light handrail use on the biomechanics of stair negotiation in old age

Independently ambulatory children with spina bifida experience near-typical knee and ankle joint moments and forces during walking