Changes In Gait Biomechanics Research Articles

Feasibility of predicting changes in gait biomechanics following muscle strength perturbations using optimal control in patients with transfemoral amputation

Bone-anchored limbs (BALs) are socket prosthesis alternatives, directly fixing to residual bone via osseointegrated implant. There is a need to quantify multi-level effects of rehabilitation for transfemoral BAL users (i.e. changes in joint loading and movement patterns). Our primary objective was determining feasibility of using optimal control to predict gait biomechanics compared to ground-truth experimental data from transfemoral BAL users. A secondary objective was examining biomechanical effects from estimated changes in hip abductor muscle strength. We developed and validated a workflow for predicting gait biomechanics in four transfemoral BAL users and investigated the biomechanical effects of altered hip abductor strengths.

Gait kinematics and kinetics in patients with chronic ankle instability and healthy controls: A statistical parametric mapping analysis

BackgroundChronic ankle instability (CAI) is associated with changes in gait biomechanics which may be related to chronic dysfunction. Traditional statistical models may be limited in their ability to assess the complex 3D movement of the lower extremity during gait. Multivariate analysis of the lower extremity kinematics may reveal unique biomechanical differences associated with CAI. Research Question: Do patients with CAI differ from healthy controls in their lower extremity biomechanics and GRF when comparing 3D biomechanics? MethodsThirty-nine young, active adults participated in this study. Data was collected using a 3D motion analysis system while patients walked and jogged. Statistical parametric mapping (SPM) was used to explore 3D GRF, kinematics and kinetics of the of the lower extremity of CAI and healthy patients. ResultsDuring walking, patients with CAI had greater inversion from 68–100% of gait cycle (p < 0.001, mean difference=3.2°). During jogging, patients with CAI had greater inversion from 20–92% (p < 0.001, mean difference=4.6°). Greater plantar flexion moments were found from 65–71% (p = 0.05, mean difference=347.4Nm/kg) and greater eversion moments were found from 95–100% (p = 0.03, mean difference=74.6Nm/kg) in the CAI group. No differences in GRF were found.Significance:Greater inversion may present a potentially injurious position. A faulty position of the rearfoot may require greater muscle function in order to correct the position of the joint resulting in greater eversion moments at the ankle. However, this kinetic change does not appear to correct the ankle position.

Fatigue Effects on Peak Plantar Pressure and Bilateral Symmetry during Gait at Various Speeds

Fatigue-related changes in gait biomechanics, specifically plantar pressures, are well documented in the general population. However, research is generally confined to unilateral measures across a limited range of speeds, while changes in more well-trained populations remain largely unknown. Therefore, we sought to assess the impact of fatigue on bilateral peak plantar pressure (PP) and plantar pressure symmetry angle (SA) in well-trained runners across a range of speeds. Data from 16 (females, n = 9) well-trained runners were collected using in-sole pressure sensors pre- and post-fatigue at the following speeds: walking (1.3 m/s), jogging (2.7 m/s), running (3.3 m/s), and sprinting (4.5 m/s). Pre-fatigue PP significantly increased from walking to jogging (p &lt; 0.001) and from jogging to running (p &lt; 0.005) with no difference between running and sprinting (p &gt; 0.05). Post-fatigue PP for walking was less than jogging (p &lt; 0.002), running (p &lt; 0.001), and sprinting (p &lt; 0.001), with no other significant differences (p &gt; 0.05). Post-fatigue PP was significantly greater when compared to pre-fatigue PP at all speeds (p &lt; 0.001 for all). Though SA was not significantly different pre- to post-fatigue across speeds (p’s &gt; 0.05) at the cohort level, noteworthy changes were observed at the individual level. Overall, fatigue effects are present at all running speeds but isolating these effects to a single side (left or right) may be inadequate.

Ankle-targeted exosuit resistance increases paretic propulsion in people post-stroke

BackgroundIndividualized, targeted, and intense training is the hallmark of successful gait rehabilitation in people post-stroke. Specifically, increasing use of the impaired ankle to increase propulsion during the stance phase of gait has been linked to higher walking speeds and symmetry. Conventional progressive resistance training is one method used for individualized and intense rehabilitation, but often fails to target paretic ankle plantarflexion during walking. Wearable assistive robots have successfully assisted ankle-specific mechanisms to increase paretic propulsion in people post-stroke, suggesting their potential to provide targeted resistance to increase propulsion, but this application remains underexamined in this population. This work investigates the effects of targeted stance-phase plantarflexion resistance training with a soft ankle exosuit on propulsion mechanics in people post-stroke.MethodsWe conducted this study in nine individuals with chronic stroke and tested the effects of three resistive force magnitudes on peak paretic propulsion, ankle torque, and ankle power while participants walked on a treadmill at their comfortable walking speeds. For each force magnitude, participants walked for 1 min while the exosuit was inactive, 2 min with active resistance, and 1 min with the exosuit inactive, in sequence. We evaluated changes in gait biomechanics during the active resistance and post-resistance sections relative to the initial inactive section.ResultsWalking with active resistance increased paretic propulsion by more than the minimal detectable change of 0.8 %body weight at all tested force magnitudes, with an average increase of 1.29 ± 0.37 %body weight at the highest force magnitude. This improvement corresponded to changes of 0.13 ± 0.03 N m kg− 1 in peak biological ankle torque and 0.26 ± 0.04 W kg− 1 in peak biological ankle power. Upon removal of resistance, propulsion changes persisted for 30 seconds with an improvement of 1.49 ± 0.58 %body weight after the highest resistance level and without compensatory involvement of the unresisted joints or limb.ConclusionsTargeted exosuit-applied functional resistance of paretic ankle plantarflexors can elicit the latent propulsion reserve in people post-stroke. After-effects observed in propulsion highlight the potential for learning and restoration of propulsion mechanics. Thus, this exosuit-based resistive approach may offer new opportunities for individualized and progressive gait rehabilitation.

Changes in biomechanics, strength, physical function, and daily steps after extended-release corticosteroid injections in knee osteoarthritis: a responder analysis.

To determine changes in gait biomechanics, quadricep strength, physical function, and daily steps after an extended-release corticosteroid knee injection at 4 and 8weeks post-injection in individuals with knee osteoarthritis as well as between responders and non-responders based on changes in self-reported knee function. The single-arm, clinical trial included three study visits (baseline, 4weeks, and 8weeks post-injection), where participants received an extended-release corticosteroid injection following the baseline visit. Time-normalized vertical ground reaction force (vGRF), knee flexion angle (KFA), knee abduction moment (KAM), and knee extension moment (KEM) waveforms throughout stance were collected during gait biomechanical assessments. Participants also completed quadricep strength, physical function (chair-stand, stair-climb, 20-m fast-paced walk) testing, and free-living daily step assessment for 7days following each visit. All participants demonstrated increased KFA excursion (i.e., greater knee extension angle at heel strike and KFA at toe-off), increased KEM during early stance, improved physical function (all p < 0.001), and increased quadricep strength at 4 and 8weeks. KAM increased throughout most of stance at 4 and 8weeks post-injection (p < 0.001) but appears to be driven by gait changes in non-responders. Non-responders demonstrated lesser vGRF during late stance and lesser KEM and KFA throughout stance compared to responders at baseline. Extended-release corticosteroid injections demonstrated short-term improvements in gait biomechanics, quadricep strength, and physical function for up to 4weeks. However, non-responders demonstrated gait biomechanics associated with osteoarthritis progression prior to the corticosteroid injection, suggesting that non-responders demonstrate more deleterious gait biomechanics prior to corticosteroid injection. Key Points • Individuals with knee osteoarthritis who were treated with extended-release corticosteroid injections demonstrated improvements in gait biomechanics and physical function for 8weeks. • Individuals with knee osteoarthritis, who walked with aberrant walking biomechanics before treatment, failed to respond to extended-release corticosteroid treatment. • Future research should determine the mechanisms contributing to the short-term changes in gait biomechanics and physical function such as reduced inflammation.

Gait analysis and knee kinematics before, and 6 and 18 months after corrective valgus osteotomy

BackgroundThe study objective was to assess clinical outcomes and gait biomechanics in patients after 6 and 18 months after varus deformity (VD) surgical correction at knee joint (KJ). MethodThe study included 20 patients with medial osteoarthritis (OA) of the knee of grade 2–3 and a VD of >4°. A total of 21 surgeries were performed on the patients. Full length weight bearing (FLWB) X-ray and KJ assessments were done using the KSS, KOOS and VAS scoring systems were obtained from all the patients. Biomechanical gait parameters were captured using an inertial sensor system at timepoints before, and 6 and 18 months after surgery. Temporal and kinematic parameters of walking were analyzed. ResultsThe radiological parameters showed a stable VD correction. According to the KOOS, KS and VAS scores, there was a moderate dynamic improvement in the operated knee function during the study. The biomechanical parameters remained virtually unchanged throughout the entire follow-up period. In the following year, there were some subjective improvements but without any significant changes in gait biomechanics or knee kinematics. ConclusionsThus, the main changes in the joint clinical condition and function occur in the first 6 months after surgery. According to the study data—assessments by VAS, KOOS, and KSS—there was a moderate clinical improvement during the long-term follow-up period, however, the biomechanical changes were minor.

Change in functional biomechanics following a targeted exercise intervention in patients with acetabular retroversion and femoroacetabular impingement syndrome

BackgroundAcetabular retroversion is a form of hip dysplasia that may cause femoroacetabular impingement syndrome (FAIS), leading to pain and restricted hip range of motion. An exercise intervention aiming at altering pelvis tilt and related functional biomechanics may be a useful first-line intervention for patients who are not eligible for surgical repositioning. Research questionDoes squat and gait biomechanics change following an 8-week targeted exercise program in individuals with symptomatic acetabular retroversion and FAIS? MethodsThis prospective intervention study used participants as their own controls. Examinations were conducted at three time-points: T1 baseline; T2 following an 8-week control period; T3 after 8 weeks’ intervention. At each time-point, three-dimensional motion analysis of a deep squat and level gait was performed, and pain intensity was recorded using a numerical rating scale (NRS 0–10). The intervention consisted of a home-exercise program to improve core stability and pelvic movement. Differences in waveforms between time-points across pelvis and lower-limb biomechanics were evaluated using statistical parametric mapping. Delta (Δ, differences between T1-T2 and T2-T3) was used to evaluate changes in spatiotemporal gait parameters and pain. ResultsNineteen patients (18 females), mean age 22.6 (SD 4.5) years, BMI (kg/m2) 23.0 (SD 4.1), were included. Changes (Δ T1-T2 vs. Δ T2-T3) in squat biomechanics were observed as: (i) decreased anterior pelvic tilt, (ii) deeper vertical pelvis position, and (iii) increased knee flexion angle. Contrary, no significant changes in gait biomechanics, Δ walking speed, Δ step length, or NRS for pain were found. SignificanceFollowing a targeted exercise intervention, participants were able to squat deeper, potentially allowing better hip function. The deepened squat position was accompanied by increased knee flexion and reduced anterior pelvic tilt. Gait biomechanics and patient-reported pain remained unchanged post-intervention. These findings are important for future design of exercise interventions targeting pelvic tilt in symptomatic individuals.

Changes In Gait Biomechanics One-year Following Osseointegration In People With Transfemoral Amputation

Changes In Gait Biomechanics One-year Following Osseointegration In People With Transfemoral Amputation

Gait biomechanics after proximal femoral nailing of intertrochanteric fractures.

Proximal femur fractures in the elderly are associated with significant loss of independence, mobility, and quality of life. This prospective study aimed to: (1) investigate gait biomechanics in intertrochanteric fracture (ITF) patients (A1 and A2 AO/OTA) managed via femoral nailing at 6 weeks and 6 months postoperative and how these compared with similarly aged elderly controls; and (2) investigate whether femoral offset shortening (FOS) and lateral lag screw protrusion (LSP) were associated with changes in gait biomechanics at postoperative time points. Hip radiographs and gait data were collected for 34patients at 6 weeks and 6 months postoperatively. Gait data were also collected from similarly aged controls. FOS and LSP were measured from radiographs. Joint angles, external moments, and powers were calculated for the hip, knee, and ankle and compared between time points in ITF patients and healthy controls using statistical parametric mapping. The relationship between radiographic measures with gait speed, step length, peak hip abduction, and maximum hip abduction moment was assessed using a Pearson correlation. External hip adduction moments and hip power generation improved in the first 6 months postoperative, but differed significantly from healthy controls during single limb stance. LSP showed a moderate correlation with maximum hip abduction moment at 6 weeks postoperative (r = -0.469, p = 0.048).These results provide new detail on functional outcomes after ITF and potential mechanisms that functional deficiencies may stem from. Lag screw prominence may be an important factor in maintaining functional independence and minimizing the risk of secondary falls after ITF in the elderly.

Gait analysis and knee joint kinematics before a and 6month after of corrective valgus osteotomy at patients with medial knee arthritis.

A varus deformity (VD) of the lower limbs results in greater loading of the medial compartment of the knee joint (KJ), leading to its degenerative changes and, eventually, to progressive osteoarthritis (OA) of the joint. The aim of the study was to investigate the mid-term changes in gait biomechanics and clinical symptoms in patients with VD of KJ and OA before and sixmonths after surgical correction. The study enrolled 25 patients with medial OA of grade 2-3 according to Kellgren-Lawrence and a VD of > 3°, who underwent arthroscopic lavage and debridement of the knee joint followed by corrective osteotomy. The control group included 20 healthy adults. Clinical and biomechanical assessments were done twice: immediately prior to and sixmonths after the surgical treatment. Biomechanical parameters of gait were recorded using an inertial sensor system. According to our findings, there was a statistically significant post-operative increase in the knee extension amplitude by 1.4° in female patients and an insignificant extension increase in male patients. The mean postoperative KOOS score was 66.7 points (46 to 91) in the patient group, 67.1 points (54 to 91) in males, and 59.5 points (46 to 64) in females. As early as sixmonths after a valgus osteotomy, we already observed improved biomechanics of the KJ motions compared to pre-operative data. By that time, the swing flexion amplitude of the affected KJ had increased and became symmetrical, which had not been the case before surgery. We observed a total of three changes in the KJ kinematics after surgery: increased swing flexion amplitudes in both KJs, a decreased extension amplitude in the affected KJ, and increased first flexion amplitudes in both KJs. According to our study, the midterm outcomes after a valgus osteotomy showed clinical improvements based on the VAS and KOOS scores, which were however less pronounced than in similar studies with a longer assessment term after surgery. We also found a significant increase in the amplitude of joint extension, but only in females. As the function of the operated joint is concerned, valgus osteotomy restored the kinematics of walking movements to a nearly normal gait with increased first and second flexion amplitudes. The function of KJ becomes symmetric though the non-operative side. Thus, the healthy and functionally more capable side is copying the movement pattern of the affected side. Hence, the non-operative leg is functioning less efficiently than it is required by the walking pace.

ASSOCIATION OF CHANGES IN GAIT BIOMECHANICS AFTER HIGH TIBIAL OSTEOTOMY WITH SUBSEQUENT TOTAL KNEE REPLACEMENT

ASSOCIATION OF CHANGES IN GAIT BIOMECHANICS AFTER HIGH TIBIAL OSTEOTOMY WITH SUBSEQUENT TOTAL KNEE REPLACEMENT

Biomechanical Characteristics of the Typically Developing Toddler Gait: A Narrative Review

Simple SummaryThis narrative review clarified the gait biomechanics of typically developing toddlers and revealed the changes of gait characteristics at different age stages till independent walking. The remarkable gait characteristics and developmental nature of toddlers indicate that the gait pattern of the junior independent walkers differs from the senior and experienced cohort. Gait patterns are associated with neuromuscular maturation. Changes in gait biomechanics are age-dependent. Therefore, it is necessary for pediatric clinicians to understand the characteristics and stages of normal or abnormal development. Developmental neuromotor control suggests that early identification and intervention may expedite treatment and optimize outcomes.Independent ambulation is one of the most important motor skills in typically developing toddlers. Gait analysis is a key evaluation method in basic and clinical research. A narrative review on the literature of toddler gait development was conducted following inclusion criteria, explicitly including the factors of English article, age range, no external intervention during the experimental process of studies involved, the non-symptomatic toddler, and no pathological gait. Studies about toddlers’ morphological, physiological, and biomechanical aspects at this developmental stage were identified. Remarkable gait characteristics and specific development rules of toddlers at different ages were reported. Changes in gait biomechanics are age and walking experience-dependent. Gait patterns are related to the maturation of the neuro and musculoskeletal systems. This review thus provides critical and theoretical information and the nature of toddler walking development for clinicians and other scientific researchers. Future studies may systematically recruit subjects with more explicit criteria with larger samples for longitudinal studies. A particular design could be conducted to analyze empirically before practical application. Additionally, the influence of external interventions on the development of toddler gait may need consideration for gait development in the toddler cohort.

Impact loading in female runners with single and multiple bone stress injuries during fresh and exerted conditions

BackgroundBone stress injuries (BSIs) are common in female runners, and recurrent BSI rates are high. Previous work suggests an association between higher impact loading during running and tibial BSI. However, it is unknown whether impact loading and fatigue-related loading changes discriminate women with a history of multiple BSIs. This study compared impact variables at the beginning of a treadmill run to exertion and the changes in those variables with exertion among female runners with no history of BSI as well as among those with a history of single or multiple BSIs. MethodsWe enrolled 45 female runners (aged 18–40 years) for this cross-sectional study: having no history of diagnosed lower extremity BSI (N-BSI, n = 14); a history of 1 lower extremity BSI (1-BSI, n = 16); and diagnosed by imaging, or a history of multiple (≥3) lower extremity BSIs (M-BSI, n = 15). Participants completed a 5-km race speed run on an instrumented treadmill while wearing an Inertial Measurement Unit. The vertical average loading rate (VALR), vertical instantaneous loading rate (VILR), vertical stiffness during impact via instrumented treadmill, and tibial shock determined as the peak positive tibial acceleration via Inertial Measurement Unit were measured at the beginning and the end of the run. ResultsThere were no differences between groups in VALR, VILR, vertical stiffness, or tibial shock in a fresh or exerted condition. However, compared to N-BSI, women with M-BSI had greater increase with exertion in VALR (–1.8% vs. 6.1%, p = 0.01) and VILR (1.5% vs. 4.8%, p = 0.03). Similarly, compared to N-BSI, vertical stiffness increased more with exertion among women with M-BSI (–0.9% vs. 7.3%, p = 0.006) and 1-BSI (–0.9% vs. 1.8%, p = 0.05). Finally, compared to N-BSI, the increase in tibial shock from fresh to exerted condition was greater among women with M-BSI (0.9% vs. 5.5%, p = 0.03) and 1-BSI (0.9% vs. 11.2%, p = 0.02). ConclusionWomen with 1-BSI or M-BSIs experience greater exertion-related increases in impact loading than women with N-BSI. These observations imply that exertion-related changes in gait biomechanics may contribute to risk of BSI.

Changes in pain, function and gait biomechanics 10 years after high tibial osteotomy for medial compartment knee osteoarthritis

Purpose: 1) To evaluate change in patient-reported outcome measures, including OMERACT-OARSI responder criteria, at 2, 5 and 10 years after medial opening high tibial osteotomy (HTO); 2) to evaluate change in gait biomechanics at 2, 5 and 10 years after HTO; 3) to investigate the association between baseline gait biomechanics and changes in pain and function over time.

Changes In Gait Biomechanics Between Level And Downhill Walking Do Not Differ Between Those With Anterior Cruciate Ligament Reconstruction And Controls

Conflicting evidence exists regarding the presence of aberrant gait biomechanics after the first year post-anterior cruciate ligament reconstruction. Overground walking may not elucidate differences in those further removed from surgery due to the unexacting nature of the task. Deleterious gait biomechanics following ACLR are partly attributable to quadriceps dysfunction. Downhill walking may exacerbate aberrant gait biomechanics, as this task places greater demands on the quadriceps compared to level walking. PURPOSE: To compare gait biomechanics between individuals with ACLR and healthy controls during level and downhill walking conditions. METHODS: 24 individuals more than 1 year removed from primary ACLR (83% female, age= 21 ± 3 yr, time since ACLR 44 ± 26 mo, BMI= 23 ± 3 kg/m2) and 24 healthy controls (79% female, age= 21 ± 1 yr, BMI= 24 ± 3 kg/m2) completed both level and downhill (10°grade) gait biomechanics assessments on an instrumented split-belt treadmill at their preferred walking speed. Peak variables were evaluated over the first 50% of stance including the vertical ground reaction force (vGRF), internal knee abduction moment, internal knee extension moment, knee flexion angle, and knee abduction angle. Moments were normalized to %body weight∗height (%BW∗Ht) and vGRF was normalized to %body weight. Dependent variables were compared across groups and conditions via two-way repeated measures ANCOVA controlling for gait speed. RESULTS: There were no significant condition∗group interaction effects nor group main effects for any outcomes. However, there were significant condition main effects for peak internal knee extension moment (p = 0.020, level to downhill mean increase of 0.042 %BW∗Ht) and peak knee flexion angle (p = 0.018, level to downhill mean increase of 13.2&#176;). CONCLUSIONS: Downhill walking necessitates a larger internal extension moment and knee flexion angle compared to level gait. Our results suggest that changes in gait biomechanics between level and downhill conditions do not differ between individuals with ACLR > 1 year post reconstruction and controls. These results suggest that aberrant gait biomechanics may be mitigated over time in those with ACLR.

Tibiofemoral joint space narrowing: can dynamic joint stiffness 2 years after anterior cruciate ligament injury years predict narrowing 5 years after injury?

Purpose: Patients with anterior cruciate ligament (ACL) injury experience higher rates of knee osteoarthritis (OA) compared with non-injured individuals. Changes in gait biomechanics are one proposed mechanism for OA development, as small changes in load bearing position shift cartilage loading to regions not adapted to ambulatory loading resulting in gradual degradation. Dynamic joint stiffness (DJS) is a biomechanical measure that captures contributions of both active muscle contraction and passive tissue tension. People with severe knee OA ambulate with higher DJS compared to healthy controls. It is unknown if DJS is predictive of radiographic changes in people after ACL injury. The purpose of this study was to evaluate if DJS measured 2 years after ACL injury predicts minimal joint space width (mJSW) 5 years after ACL injury. We hypothesized that higher DJS 2 years after injury will predict less joint space width (JSW) 5 years after injury. Methods: As part of a larger longitudinal study, 37 subjects (13 females, age 28.1 ± 11.9 yrs,) completed gait assessment 2 years after injury and radiographs at 5 years after injury. We analyzed participants' walking patterns using an eight-camera motion capture (VICON, Oxford, UK) at 120 Hz and embedded force platform (Bertec Corp, Columbus, OH) at 1080 Hz. We used 39 retroreflective markers on bilateral lower extremities and pelvis. Participants walked overground at a self-selected gait speed maintained ± 5% across trials. Data were processed using commercial software (Visual3D; C-Motion, Germantown, MD). DJS was analyzed during loading response, defined as from the first increase in external knee flexion moment to peak knee flexion. Knee flexion angle was plotted on the X-axis and an increase in the joint angle represents an increase in knee flexion. Knee extension joint moment was plotted along the Y-axis and an increase in moment represents an increase in the net external flexion moment. A larger positive slope indicates higher DJS. Weightbearing posteroanterior (PA) bent knee (30°) radiographs were read by one researcher (JLJ) for mJSW in each compartment. Tibiofemoral JSW in the medial compartment measured from plain radiographs has been shown to be a surrogate for articular cartilage thickness, of particular concern in knee OA. Linear regression was used to test if DJS at 2 years predicted mJSW at 5 years, adjusting for sex, body mass index (BMI), and meniscal involvement. Results: The median mJSW in this study was 4.6 mm and 5.7 mm in the medial and lateral compartment respectively. Using the IKDC scale for joint space narrowing, 8 subjects had mJSW of less than 4.0 mm, and 1 subject had mJSW less than 2.0 mm in the medial compartment. In the lateral compartment, 5 subjects had mJSW less than 4.0 mm and 1 subject had mJSW less than 2.0 mm. Average DJS of the involved limb at 2 years was 0.050 ± 0.009 and was not predictive of medial or lateral mJSW at 5 years, with unadjusted R2 = 0.033 and 0.022 respectively. Adjusting for sex, BMI, and meniscal involvement, the model remained not significant (R2 = 0.107 and 0.112). Conclusions: DJS was not a predictor of mJSW in subjects 5 years after ACL injury. Previous studies found a relationship only between severe OA and DJS; we had only 2 subjects with severe OA. Additionally, our cohort had a DJS range of 0.034–0.073, less stiff than previous literature. Limitations of this study included a lack of baseline DJS or JSW measurement. Additionally, our cohort had a very wide age range at time of initial injury (14.1–49.6 years old); previous research was on older adults. It is unknown what affect age has on DJS of the knee during gait. Further research at future time points (for OA progression) or with a more homogenous age sample may provide more insight to the relationship of DJS and JSW.

Effects of sex and obesity on gait biomechanics before and six months after total knee arthroplasty: A longitudinal cohort study

BackgroundGait biomechanics, sex, and obesity can contribute to suboptimal outcomes from primary total knee arthroplasty. The aims of this study were to i) determine if sex and/or obesity influence the amount of change in gait biomechanics from pre-surgery to six months post-surgery and; ii) assess if gait returns to normal in men and women. MethodsThree-dimensional gait analysis was performed on 43 patients undergoing primary total knee arthroplasty for knee osteoarthritis (pre- and six months post-operative) and 40 asymptomatic controls. Mixed linear regression models were fit to assess which factors influenced change in gait biomechanics within the arthroplasty cohort, and interaction terms were included to assess if biomechanics returned to normal following surgery. FindingsMale peak knee adduction moment (p < 0.001) and impulse (p < 0.001) decreased six months following arthroplasty, whilst gait in women remained unchanged after surgery. Obesity did not influence gait changes in men or women. Gait of female arthroplasty participants did not differ from female controls after surgery except for sagittal plane knee range of motion (p = 0.003), whilst men differed from controls for peak knee adduction moment (p = 0.011), knee range of motion (p < 0.001), and peak knee flexion moment (p < 0.001). InterpretationSex, but not obesity, influenced changes in gait biomechanics after arthroplasty. Men retained abnormal gait patterns after surgery, whilst women did not. Further research should determine the long-term implications of gait abnormalities seen in men after arthroplasty.

Identifying changes in gait waveforms following a strengthening intervention for women with knee osteoarthritis using principal components analysis

Lower limb strengthening exercise is pivotal for the management of symptoms related to knee osteoarthritis (OA). Though improvement in clinical symptoms is well documented, concurrent changes in gait biomechanics are ill-defined. This may occur because discrete analyses miss changes following an intervention, analyses limited to the knee undermine potential mechanical trade-offs at other joints, or strengthening interventions not been designed based on biomechanical principles. The purpose of this study was to characterize differences in entire gait waveforms for sagittal plane ankle, knee, and hip angles and external moments; the knee adduction moment; and frontal plane hip angle and moment following 12-weeks of a previously designed novel lower limb strengthening program. Forty women with knee OA completed two laboratory visits: one at baseline and one immediately following intervention (follow-up). Self-report measures, strength, and gait analyses were completed at each visit. Principal components analyses were completed for sagittal angles and external moments at the ankle, knee, and hip joints, as well as frontal plane angle and moment for the hip. Participants improved self-report and strength (p≤0.004). Two significant, yet subtle differences in principal components were identified between baseline and follow-up waveforms (p<0.05) pertaining to the knee and hip sagittal external moments. The subtle changes in concert with the lack of differences in other joints and planes suggest the lower limb strengthening program does not translate to changes in the gait waveform. It is likely this program is improving symptoms without worsening mechanics.

Ankle and knee biomechanics during normal walking following ankle plantarflexor fatigue

The purpose of this study was to investigate the immediate effects of unilateral ankle plantarflexor fatigue on bilateral knee and ankle biomechanics during gait. Lower leg kinematics, kinetics, and muscle activation were assessed before and after an ankle plantarflexor fatiguing protocol in 31 healthy individuals. Fatigue (defined as >10% reduction in maximal isometric ankle plantarflexor torque production and a downward shift in the median power frequency of both heads of the gastrocnemius muscle of the fatigued limb) was achieved in 18 individuals, and only their data were used for analysis purposes. Compared to pre-fatigue walking trials, medial gastrocnemius activity was significantly reduced in the study (fatigued) limb. Other main changes following fatigue included significantly more knee flexion during loading, and an associated larger external knee flexion moment in the study limb. At the ankle joint, participants exhibited significantly less peak plantarflexion (occurring at toe-off) with fatigue. No significant differences were observed in the contralateral (non-fatigued) limb. Findings from this study indicate that fatigue of the ankle plantarflexor muscle does not produce widespread changes in gait biomechanics, suggesting that small to moderate changes in maximal ankle plantarflexor force production capacity (either an increase or decrease) will not have a substantial impact on normal lower limb functioning during gait.

Changes in gait biomechanics are associated with long-term clinically important improvements in patient-reported outcomes

Purpose: Aberrant gait biomechanics are consistently shown to be associated with knee osteoarthritis (OA) progression and are therefore the targets of numerous interventions. However, the ability to produce sustained long-term improvements in gait biomechanics remains elusive, and the potential effect of improvements in gait on long-term patient-reported outcomes is unclear. The purpose of this study was to investigate the 5-year change in gait biomechanics after limb realignment surgery in order to test the hypothesis that these long-term changes are associated with long-term clinically important improvements in patient-reported outcomes. Methods: Three-dimensional gait analysis, full-limb standing radiographs and Knee injury and Osteoarthritis Outcome Scores (KOOS) were evaluated before and 5-years after medial opening wedge high tibial osteotomy (HTO). The changes from baseline to 5 years were calculated and patients were categorized as having a clinically important improvement in the KOOS4 (≥10 points) or not. Predictors of clinically important change (dependent variable) were then evaluated using multivariate logistic regression. We tested two models. The first model included the 5-year change in mechanical axis angle and BMI, while controlling for baseline age, sex, disease severity (KLG) and KOOS4 (independent variables). The second model added the 5-year change in peak external knee adduction and flexion moments and gait speed as independent variables. Receiver operating characteristic (ROC) curves assessed the ability of each model (i.e. with and without gait biomechanics) to correctly discriminate between patients achieving a long-term clinically important improvement or not. The area under the curve (AUC) and 95% confidence intervals were calculated for each model. Results: 170 patients (135 males, 35 females) with medial knee OA participated (age: 46±9 years; BMI: 29.5±4.9 kg/m2; KLG: 1 = 10, 2 = 46, 3 = 64, 4 = 50). ROC curves are shown in Figure 1. The AUC was 0.67 (95%CI: 0.59-0.76; p<0.001) for the first model (i.e. without changes in gait biomechanics), and increased to 0.74 (95%CI: 0.66-0.81, p<0.001) for the second model (i.e. with changes in gait biomechanics). Conclusions: This is the first study we are aware of to show that long-term changes in gait biomechanics are significantly associated with long-term clinically important improvements in patient-reported outcomes. Moreover, assessing changes in gait biomechanics improves the ability to discriminate between patients with medial knee OA achieving a long-term clinically important improvement or not.