Moment Impulse Research Articles

Effects of increasing walking cadence on gait biomechanics in adults with knee osteoarthritis

Gait retraining is a strategy to manage altered loading patterns and pain characteristic of knee osteoarthritis. Lower walking cadence is associated with higher knee joint loading, vertical ground reaction forces, and risk for cartilage worsening. Therefore, we determined the acute effects of increasing walking cadence on measures of lower extremity loading and knee pain in knee osteoarthritis. Twenty-five participants with knee osteoarthritis (age = 62.5 ± 7.2; 76.0 % female) walked at fixed speed on an instrumented treadmill from which baseline cadence was measured. Five, randomized experimental cadence conditions (2 %, 4 %, 6 %, 8 %, or 10 % over baseline cadence) were completed. Real-time auditory and visual feedback on cadence was provided while kinematics and ground reaction forces were sampled. Linear mixed effects models evaluated the effect of cadence on knee adduction and flexion moment peaks and impulses, impact loading metrics (vertical ground reaction force impact peak, vertical average and instantaneous loading rates), and knee pain. Increasing cadence by 2–10 % did not significantly change knee adduction moment peaks or impulse. Peak knee flexion moment increased by 3–32 % and knee flexion moment impulse reduced by 2–9 % with increases in cadence, but these results were not significant (peak knee flexion moment, p = 0.070; knee flexion moment impulse, p = 0.085). Increasing cadence significantly increased the vertical impact peak (p < 0.001), and the vertical average (p = 0.010), and instantaneous (p = 0.007) loading rates. Small increases in cadence at a fixed gait speed does not significantly change surrogate measures of knee joint loading or pain, but does increase measures of impact loading.

Poster 365: Impact of Graft Type and Meniscal Status on Patellofemoral Cartilage Early after ACL Reconstruction

Objectives: Anterior cruciate ligament reconstruction (ACLR) restores passive knee stability but does not reduce the rate of osteoarthritis (OA). Meniscal status, requiring repair or meniscectomy, is a known component of degenerative progression. Regarding the patellofemoral joint (PFJ) specifically, traditional imaging modalities have shown some evidence that patellar tendon autograft (BPTB) is associated with an increased risk of OA. T2 relaxation time using quantitative MRI (qMRI) is an established method to identify early cartilage changes. However, T2 relaxation in the PFJ as a function of graft type and meniscal status has not been previously evaluated. We aimed to evaluate the effect of autograft type (BPTB, hamstring [HT] and quadriceps tendon [QT]) as well as concomitant meniscal surgery (repair or meniscectomy) at the time of ACLR on T2 relaxation time in PFJ cartilage. We hypothesized that BPTB grafts, concomitant meniscal repair, and meniscectomy would result in higher (worse) T2 relaxation times at 6 months after ACLR. We also evaluated the effect of abnormal joint loading during gait on the PFJ cartilage. We hypothesized that T2 relaxation times would not differ in any group after controlling for knee joint loading during walking. Methods: Thirty-four participants aged 15-35 years were enrolled prospectively within 1 month of ACL injury. Exclusion criteria included prior knee injury or surgery, concomitant grade III tear to other knee ligaments that was symptomatic or required surgical intervention and presence of chondral damage. Sagittal qMRIs were obtained within 1 month of injury (but prior to ACLR) and 6 months after ACLR. Articular cartilage of the PFJ was manually segmented using ITK-SNAP software (Penn Image Computing and Science Laboratory, University of Pennsylvania) and was confirmed for accuracy by a board-certified, fellowship-trained musculoskeletal radiologist (Figure 1). Mean T2 relaxation times were extracted from the trochlear and patellar cartilage. Non-physiological T2 relaxation times less than 10 ms and greater than 90 ms were excluded. Gait biomechanics were captured using two in-ground force plates (Bertec Corporation, Columbus, OH) sampled at 1,080 Hz and retroreflective markers with an 8-camera motion capture system (Qualisys, Göteborg, Sweden) sampled at 120 Hz. Data was processed using Visual 3D software (C-motion, Bethesda, MD). Using an inverse dynamic approach, joint angle and force plate data were used to calculate the knee flexion moment (KFM) impulse normalized to mass and height during the stance phase. Separate one-way ANOVAs were used to evaluate the relationship between graft type and concomitant meniscus surgery with the percent change in T2 relaxation time in PFJ cartilage from baseline to 6 months after ACLR. To determine the influence of gait biomechanics on T2 relaxation time across groups, general linear models were used with the interlimb ratio (involved/uninvolved) of KFM impulse as a covariate. Results: The 34 participants had a mean age of 19.0±4.7 years, and 21 (61.8%) were female. Grafts used during ACLR included 22 BPTB, 4 HT and 8 QT. Seventeen participants (50.0%) had a concomitant meniscus repair and 3 (8.8%) had a meniscectomy. Overall, T2 relaxation time increased 8.7±7.3% in the patellar cartilage (pre-ACLR: 39.1±2.6 ms, 6 months: 42.4±3.6 ms, p&lt;0.001) and 7.1±7.3% in the trochlear cartilage (pre-ACLR: 46.3±2.6 ms, 6 months: 49.5±2.7 ms, p&lt;0.001). The change in T2 relaxation time 6 months after ACLR did not differ based on graft type in either the patellar (p=0.729) or trochlear cartilage (p=0.525) (Figure 2). Group differences remained insignificant after controlling for knee loading (KFM impulse) during gait (patellar: p=0.594; trochlear: p=0.222). Meniscal status was also not associated with a change in T2 relaxation time in either the patellar (p=0.392) or trochlear cartilage (p=0.190) (Figure 3) although there was a trend toward higher T2 relaxation times in those with a concomitant meniscus repair or meniscectomy. Group differences remained statistically insignificant after controlling for the KFM impulse during gait (patellar: p=0.400; trochlear: p=0.197). Conclusions: Our findings provide insufficient evidence that graft type is associated with worse quantitative chondral changes within the PFJ at 6 months following ACLR. While meniscal status is a known risk factor for increased contact pressure in the involved compartment and subsequent degenerative progression, our data does not demonstrate statistically significant changes to the PFJ cartilage when meniscal tears were present, likely due to the limited sample size and large variation within groups. Future work with larger cohorts is needed to confirm our findings and further investigate the role that graft type and meniscal status may play within the PFJ after ACLR. [Figure: see text][Figure: see text][Figure: see text]

Knee contact forces of individuals with osteoarthritis and those with lower limb amputation: A systematic review.

Osteoarthritis (OA) is a major cause of impairment. Research has shown that individuals with unilateral lower limb amputation (ULLA) are 17 times more likely to develop OA on their sound side limb. Therefore, this review aimed to describe similarities and differences in the biomechanical loading variables of individuals with OA and those with ULLA. Researchers systematically searched PubMed-Medline, EBSCOhost and Web of Science for articles published between January 1990 and February 2022. Included studies investigated the biomechanical profiles (peak external knee adduction moment (KAM); peak external knee flexion moment (KFM); ground reaction force; external knee adduction moment loading rate; external knee adduction moment impulse) of both population groups. A total of 31 articles were included in this review. Only KAM and KFM presented similar profiles in both groups, whilst all other variables were dissimilar. The use of advanced prostheses reduced the loading on the sound side of individuals with ULLA. As both KAM and KFM are surrogate measures for knee contact forces, interventions need to target these variables to help manage and prevent the development of OA. Interventions, particularly for addressing these variables in individuals with ULLA, should be further investigated in future research.

The effect of foot orientation modifications on knee joint biomechanics during daily activities in people with and without knee osteoarthritis

BackgroundAltered gait could influence knee joint moment magnitudes and cumulative damage over time. Gait modifications have been shown to reduce knee loading in people with knee osteoarthritis during walking, although this has not been explored in multiple daily activities. Therefore, this study investigated the effect of different foot orientations on knee loading during multiple daily activities in people with and without knee osteoarthritis. MethodsThirty people with knee osteoarthritis and twenty-nine without (control) performed walking, stair ambulation and sit-to-stand across a range of foot progression angles (neutral, toe-in, toe-out and preferred). Peak knee adduction moment, knee adduction moment impulse and knee pain were compared across a continuous range of foot orientations, between activities, and groups. FindingsIncreased foot progression angle (more toe-in) reduced 1st peak knee adduction moment across all activities in both knee osteoarthritis and control (P < 0.001). There was a greater reduction in knee adduction moment in the control group during walking and stair ambulation (P ≤ 0.006), where the knee osteoarthritis group already walked preferably less toe-out than the control group. Under preferred condition, stair descent had the greatest knee loading and knee pain compared to other activities. InterpretationAlthough increased foot progression angle (toward toe-in) appeared to be more effective in reducing knee loading for all activities, toe-in modification might not benefit stair ambulation. Future gait modification should likely be personalised to each patient considering the individual difference in preferred gait and knee alignment required to shift the loading medially or laterally.

The biomechanical influence of transtibial Bone-Anchored limbs during walking

Individuals with unilateral transtibial amputation (TTA) using socket prostheses demonstrate asymmetric joint biomechanics during walking, which increases the risk of secondary comorbidities (e.g., low back pain (LBP), osteoarthritis (OA)). Bone-anchored limbs are an alternative to socket prostheses, yet it remains unknown how they influence multi-joint loading. Our objective was to determine the influence of bone-anchored limb use on multi-joint biomechanics during walking. Motion capture data (kinematics, ground reaction forces) were collected during overground walking from ten participants with unilateral TTA prior to (using socket prostheses) and 12-months after bone-anchored limb implantation. Within this year, each participant completed a rehabilitation protocol that guided progression of loading based on patient pain response and optimized biomechanics. Musculoskeletal models were developed at each testing timepoint (baseline or 12-months after implantation) and used to calculate joint kinematics, internal joint moments, and joint reaction forces (JRFs). Analyses were performed during three stance periods on each limb. The between-limb normalized symmetry index (NSI) was calculated for joint moments and JRF impulses. Discrete (range of motion (ROM), impulse NSI) dependent variables were compared before and after implantation using paired t-tests with Bonferroni-Holm corrections while continuous (ensemble averages of kinematics, moments, JRFs) were compared using statistical parametric mapping (p < 0.05). When using a bone-anchored limb, frontal plane pelvic (residual: pre = 9.6 ± 3.3°, post = 6.3 ± 2.5°, p = 0.004; intact: pre = 10.2 ± 3.9°, post = 7.9 ± 2.6°, p = 0.006) and lumbar (residual: pre = 15.9 ± 7.0°, post = 10.6 ± 2.5°, p = 0.024, intact: pre = 17.1 ± 7.0°, post = 11.4 ± 2.8°, p = 0.014) ROM was reduced compared to socket prosthesis use. The intact limb hip extension moment impulse increased (pre = -11.0 ± 3.6 Nm*s/kg, post = -16.5 ± 4.4 Nm*s/kg, p = 0.005) and sagittal plane hip moment impulse symmetry improved (flexion: pre = 23.1 ± 16.0 %, post = -3.9 ± 19.5 %, p = 0.004, extension: pre = 29.2 ± 20.3 %, post = 8.7 ± 22.9 %, p = 0.049). Residual limb knee extension moment impulse decreased compared to baseline (pre = 15.7 ± 10.8 Nm*s/kg, post = 7.8 ± 3.9 Nm*s/kg, p = 0.030). These results indicate that bone-anchored limb implantation alters multi-joint biomechanics, which may impact LBP or OA risk factors in the TTA population longitudinally.

Characteristics of Acute Cartilage Response After Mechanical Loading in Patients with Early-Mild Knee Osteoarthritis.

This study determined whether the acute cartilage response, assessed by cartilage thickness and echo intensity, differs between patients with early-mild knee osteoarthritis (OA) and healthy controls. We recruited 56 women aged ≥ 50years with Kellgren-Lawrence (KL) grade ≤ 2 (age, 70.6 ± 7.4years; height, 153.7 ± 5.2cm; weight, 51.9 ± 8.2kg). Based on KL grades and knee symptoms, the participants were classified into control (KL ≤ 1, asymptomatic, n = 27) and early-mild knee OA groups (KL 1 and symptomatic, KL 2, n = 29). Medial femoral cartilage thickness and echo intensity were assessed using ultrasonographic B-mode images before and after treadmill walking (15min, 3.3km/h). To investigate the acute cartilage response, repeated-measures analysis of covariance (groups × time) with adjusted age, external knee moment impulse, steps during treadmill walking, and cartilage thickness at pre-walking was performed. A significant interaction was found at the tibiofemoral joint; after walking, the cartilage thickness was significantly decreased in the early-mild knee OA group compared to the control group (p = 0.002). At the patellofemoral joint, a significant main effect of time was observed, but no interaction was detected (p = 0.802). No changes in cartilage echo intensity at either the tibiofemoral or patellofemoral joints, and no interactions were noted (p = 0.295 and p = 0.063). As acute cartilage response after walking, the thickness of the medial tibiofemoral joint in the early-mild knee OA was significantly reduced than that in the control group. Thus, greater acute deformation after walking might be a feature found in patients with early-mild knee OA.

Control of Reverse Flow over Cantilevered Swept Blades Using Passive Camber Morphing

High-speed rotorcraft experience a region of reversed flow over the retreating blade at high advance ratios. This reverse flow region results in multiple unfavorable effects, including negative lift, increased drag, and a large pitching moment impulse. The effect of the sweep angle on a rotor blade in reverse flow was explored, and it was demonstrated that the introduction of a trailing edge reflex camber could mitigate the adverse effects seen in this regime. A cantilevered, finite-span NACA 63-218 blade was examined at a Reynolds number Rec=2.38×105 both with and without a 10° trailing edge reflex camber. Three blades were tested: one with 20° forward sweep, one with 20° backward sweep, and one with no sweep. The experiments consisted of load measurements across a range of angles of attack, as well as volumetric flowfield measurements using stereoscopic particle image velocimetry on the two swept models at 10° angle of attack in reverse flow. The flowfields exhibited a highly three-dimensional separation bubble that existed on the blades in both backward and forward sweep conditions. Cambering of the trailing edge led to almost complete flow attachment on the backward swept model and a significant reduction in separation over the forward swept model. Cambering also led to a large reduction in drag in the entire reverse flow regime in both swept and unswept conditions. A large reduction in pitching moment and a smaller reduction in negative lift were also observed at moderate angles of attack.

Relationship between ankle–foot-complex mobility during static loading and frontal moment impulses of knee and hip joints during the stance phase

BackgroundAnkle–foot-complex mobility impairments, which can be assessed by the difference between the sitting and standing positions, are related to an increase in the load on the knee and hip joints during the stance phase of the gait. Research questionWhat is the relationship between the ankle–foot-complex mobility during static weight bearing and the mechanical stresses on the knee and hip joints throughout the stance phase? MethodsAnkle–foot-complex mobility and gait data were collected from 26 healthy adults. The complex mobility was established by comparing the foot indices, measured using a three-dimensional foot scanner, in sitting and standing positions. The gait data were acquired using eight cameras (recording at 100 Hz) and three force plates (recording at 1000 Hz). Stance phase data were collected via ground reaction forces. The stance phase was dissected into shock absorption and propulsion phases, during which the external knee and hip adduction moment impulses (KAMi, HAMi) were recorded. The correlation between the ankle–foot-complex mobility during static weight bearing and KAMi and HAMi during the stance phase was examined using Pearson's product–moment correlation coefficients. ResultsThis study revealed that KAMi correlated with medial malleolus mobility (r = −0.44) throughout the stance phase. Furthermore, in the propulsive phase, KAMi correlated with calcaneus (r = 0.51) and navicular (r = −0.50) mobilities, whereas HAMi correlated with calcaneus mobility (r = −0.40). SignificanceThe study provides insights into the relationship between the static mobility of the ankle–foot complex in healthy individuals and mechanical stress during the stance phase. Calcaneus and navicular mobilities were related to efficient push-off in the propulsive phase. Medial malleolus mobility was related to the control of the lateral tilt of the lower limb and ankle dorsiflexion motion throughout the stance phase.

Understanding muscle coordination during gait based on muscle synergy and its association with symptoms in patients with knee osteoarthritis.

We aimed to investigate the muscle coordination differences between a control group and patients with mild and severe knee osteoarthritis (KOA) using muscle synergy analysis and determine whether muscle coordination was associated with symptoms of KOA. Fifty-three women with medial KOA and 19 control patients participated in the study. The gait analyses and muscle activity measurements of seven lower limb muscles were assessed using a motion capture system and electromyography. Gait speed and knee adduction moment impulse were calculated. The spatiotemporal components of muscle synergy were extracted using non-negative matrix factorization, and the dynamic motor control index during walking (walk-DMC) was computed. The number of muscle synergy and their spatiotemporal components were compared among the mild KOA, severe KOA, and control groups. Moreover, the association between KOA symptoms with walk-DMC and other gait parameters was evaluated using multi-linear regression analysis. The number of muscle synergies was lower in mild and severe KOA compared with those in the control group. In synergy 1, the weightings of biceps femoris and gluteus medius in severe KOA were higher than that in the control group. In synergy 3, the weightings of higher tibial anterior and lower gastrocnemius lateralis were confirmed in the mild KOA group. Regression analysis showed that the walk-DMC was independently associated with knee-related symptoms of KOA after adjusting for the covariates. Muscle coordination was altered in patients with KOA. The correlation between muscle coordination and KOA may be attributed to the knee-related symptoms. Key points • Patients with knee osteoarthritis (OA) experienced a deterioration in muscle coordination when walking. • Loss of muscle coordination was associated with severe knee-related symptoms in knee OA. • Considering muscle coordination as a knee OA symptom-related factor may provide improved treatment.

Exploring relationships among multi-disciplinary assessments for knee joint health in service members with traumatic unilateral lower limb loss: a two-year longitudinal investigation

Motivated by the complex and multifactorial etiologies of osteoarthritis, here we use a comprehensive approach evaluating knee joint health after unilateral lower limb loss. Thirty-eight male Service members with traumatic, unilateral lower limb loss (mean age = 38 yr) participated in a prospective, two-year longitudinal study comprehensively evaluating contralateral knee joint health (i.e., clinical imaging, gait biomechanics, physiological biomarkers, and patient-reported outcomes); seventeen subsequently returned for a two-year follow-up visit. For this subset with baseline and follow-up data, outcomes were compared between timepoints, and associations evaluated between values at baseline with two-year changes in tri-compartmental joint space. Upon follow-up, knee joint health worsened, particularly among seven Service members who presented at baseline with no joint degeneration (KL = 0) but returned with evidence of degeneration (KL ≥ 1). Joint space narrowing was associated with greater patellar tilt (r[12] = 0.71, p = 0.01), external knee adduction moment (r[13] = 0.64, p = 0.02), knee adduction moment impulse (r[13] = 0.61, p = 0.03), and CTX-1 concentration (r[11] = 0.83, p = 0.001), as well as lesser KOOSSport and VR-36General Health (r[16] = − 0.69, p = 0.01 and r[16] = − 0.69, p = 0.01, respectively). This longitudinal, multi-disciplinary investigation highlights the importance of a comprehensive approach to evaluate the fast-progressing onset of knee osteoarthritis, particularly among relatively young Service members with lower limb loss.

Study on suppression of violent sloshing in a multiple tuned liquid column damper by porous media layers

Multiple tuned liquid multi-column damper (MTLCD) is a passive damping device that is used to suppress the motion of semisubmersible floating offshore wind turbine (FOWT). However, the violent sloshing within the MTLCD under extreme sea environments reduces the anti-pitch motion effect. Thus, this study employed an innovative MTLCD with porous media layers, which can increase the flow energy dissipation, suppress the violent sloshing and enhance the damping moment (Mdamping). The OpenFOAM is used to simulate the hydrodynamic force in MTLCD, where the numerical method is validated by the decay test of a scaled model. The numerical natural period of the MTLCD shows good agreement with the experimental and analytical results. The sloshing characteristics, including pressure, damping moment impulse and work of the MTLCD without porous media, are analyzed firstly under simple harmonic rotation amplitudes (θ0) of 2°–20°. Subsequently, porous media layers are installed in the MTLCD with different heights (hp), including immersion and suspension, in order to improve the MTLCD's damping moment. Wavelet transform and wavelet-based bicoherence are utilized to analyze the nonlinear behaviors of the damping moment under violent sloshing. The breaking, surging and converging in the MTLCD are captured by the numerical method. The analyses show that the porous layers can suppress the violent sloshing by dissipating the fluid kinetic energy, and the damping moment work can be significantly improved when θ0 >6°. The liquid surging with bubbles leads to the nonlinear behaviors in the MTLCD, the sloshing energy transfer to the frequency doubling by three-wave interaction.

The Relationship Between Knee Moments and Function with Western Ontario and McMaster Universities in Moderate Knee Osteoarthritis

Introduction: The knee is the most affected weight-bearing joint by osteoarthritis. The kinetics parameters are correlated with the progression of knee osteoarthritis (KOA). This study was done to investigate the relationship between kinetics parameters and functional tests with Western Ontario and McMaster Universities osteoarthritis index (WOMAC) scores in people with moderate KOA.&#x0D; Materials and Methods: Twenty- three participants with moderate KOA participated in this study. Gait analysis involved the measurement of the external peak knee adduction moment (PKAM), peak knee flexion moment (PKFM), knee adduction moment impulse (KAM impulse), and knee flexion moment impulse (KFM impulse) during level walking. Functional tests included timed up and go (TUG) and figure of eight walkings (FO8W) tests. Pearson’s correlation coefficient was used to investigate the correlation between kinetics parameters and functional test scores with WOMAC total scores and sub-scores.&#x0D; Results: There was a significant inverse correlation between the first PKAM and WOMAC total score and pain sub-score (r=-0.43 P=0.03 and r=-0.6 P=0.002, respectively). Also, there was a significant inverse correlation between the second PKAM and pain sub-score (r=-0.46 P=0.02). There was no significant correlation between functional tests and WOMAC scores.&#x0D; Conclusion: The low score of the WOMAC in the moderate KOA should not be attributed to the low level of joint knee moments.

Hip adduction angle during wider step-width gait affects hip adduction moment impulse

BackgroundDecreasing an external hip adduction moment (HAM) impulse during stance is important to prevent the progression of hip osteoarthritis. A hip adduction angle (HAA) during walking influences the HAM impulse. Although a wider step-width (WS) gait is a gait modification to decrease a peak HAM, no study has reported the HAM impulse and HAA. Research questionWe investigated whether the HAA influences the peak HAM and HAM impulse during WS gait. MethodsTwenty-six healthy young adults walked with normal step-width (NS) and WS comfortably. They were not instructed about hip adduction motion during gait, and the peak HAM, HAM impulse, HAA, and other gait parameters were evaluated using a 3D motion capture system. The participants were divided into two groups according to the HAA size during WS gait. The percentage reduction of HAM variables (the WS condition relative to the NS condition) and other gait parameters were compared between the groups. ResultsNo difference in gait parameters was found between the groups. The percentage reduction of the HAM impulse in participants with smaller HAA was significantly higher than that in participants with larger HAA (14.5 % vs. 1.6 %, p < 0.01). Also, during normal step-width gait, the large HAA group showed a significantly larger HAA compared to the small HAA group (about 3°). SignificanceParticipants with smaller HAA could decrease the HAM impulse more effectively during WS gait compared with those with larger HAA. Thus, the HAA would influence the HAM impulse reduction effect on the WS gait. We recommend paying attention to the HAA to decrease the HAM with the WS gait.

Inter-joint coordination variability is associated with pain severity and joint loading in persons with knee osteoarthritis.

As the lower extremity is a linked-joint system, the contribution of movements at the hip and ankle, in addition to the knee, to gait patterns should be considered for persons with knee osteoarthritis (OA).However, the relationships of joint coordination variability to OA symptoms, particularly knee pain, and joint loading is unknown. The purpose of this study was to determine the relationship of joint coordination variability to knee pain severity and joint loading in persons with knee OA. Thirty-fourparticipants with knee OA underwent gait analysis. Vector coding was used to assess coordination variability during the early, mid, and late stance phase. Hip-knee coupling angle variability (CAV)during midstance was associated with Knee Injury and Osteoarthritis Outcome Score (KOOS)pain (r = -0.50, p = 0.002) and Visual Analog Scalepain (r = 0.36, p = 0.04). Knee-ankle CAV during midstance was associated with KOOS pain (r = -0.34, p = 0.05). Hip-knee CAV during early and midstance were associated with knee flexion moment (KFM)impulses (r = -0.46, p = 0.01). Knee-ankle CAV during early and midstance were associated with peak KFM (r = -0.51, p < 0.01; r = -0.70, p < 0.01). Moreover, knee-ankle CAV during early, mid, and late stance phase were associated with KFM impulses (r = -0.53, p < 0.01; r = -0.70, p < 0.01; r = -0.54, p < 0.01). These findings suggest that joint coordination variability may be a factor that influences pain and knee joint loading in persons with knee OA. Statement of Clinical Significance: Movement coordination of the hip, knee, and ankle should be considered in the clinical management and future research related to knee OA.

Single-Legged Triple-Hop Propulsion Strategies in Females With and Those Without a History of Anterior Cruciate Ligament Reconstruction.

The single-legged triple hop is a commonly used functional task after anterior cruciate ligament reconstruction (ACLR). Recently, researchers have suggested that individuals may use a compensatory propulsion strategy to mask underlying quadriceps dysfunction and achieve symmetric hop performance. To evaluate the performance and propulsion strategies used by females with and those without ACLR during a single-legged triple hop. Cross-sectional study. Laboratory. A total of 38 females, 19 with ACLR (age = 19.21 ± 1.81 years, height = 1.64 ± 0.70 m, mass = 63.79 ± 7.59 kg) and 19 without ACLR (control group; age = 21.11 ± 3.28 years, height = 1.67 ± 0.73 m, mass = 67.28 ± 9.25 kg). Hop distance and limb symmetry index (LSI) were assessed during a single-legged triple hop for distance. Propulsion strategies were evaluated during the first and second hops of the single-legged triple hop. Separate 2-way analysis-of-variance models were used to examine the influence of ACLR, joint, and their interaction on mechanical joint work, moment impulse, and the relative joint contributions to total work and moment impulse in females with and those without a history of ACLR. Despite achieving a mean LSI of approximately 96%, the ACLR group produced less total work in the reconstructed than the uninvolved limb during single-legged triple-hop propulsion (first hop: t18 = -3.73, P = .002; second hop: t18 = -2.55, P = .02). During the first and second hops, the reconstructed knee generated 19.3% (t18 = -2.33, P = .03) and 27.3% (t18 = -4.47, P < .001) less work than the uninvolved knee. No differences were identified between the involved and uninvolved limbs of the ACLR group in moment impulse (first hop: t18 = -0.44, P = .67; second hop: t18 = -0.32; P = .76). Irrespective of limb or group, the ankle was the largest contributor to both work and moment during both the first and second hops (P < .001). Clinicians should exercise caution when using a single-legged triple hop as a surrogate for restored lower extremity function in females post-ACLR. This recommendation is driven by the compelling findings that knee-joint deficits persisted in the reconstructed limb despite an LSI of approximately 96% and, regardless of previous injury status, single-legged triple-hop propulsion was predominantly driven by the ankle.

High tibiofemoral contact and muscle forces during gait are associated with radiographic knee OA progression over 3 years

BackgroundThe objective of this study was to investigate differences in tibiofemoral joint contact forces between individuals with moderate medial OA who exhibit radiographic knee OA progression within 3 years versus those who do not, and to understand the relationship between model-predicted contact forces and net external moments for this population. Methods27 individuals with moderate medial compartment knee OA underwent baseline instrumented gait analysis. OA progressors were defined as those who experienced at least a one grade increase in medial joint space narrowing at three years. An electromyography-driven musculoskeletal model was used to estimate muscle and tibiofemoral contact forces at baseline, which were compared between progressors and non-progressors using t-tests. ResultsSeven individuals experienced radiographic OA progression by 3 years. Progressors walked with significantly higher peaks of medial and total tibiofemoral contact forces, and higher impulse of medial contact forces. Significant and high correlations were found between: first peaks of medial and total contact forces with first peak of the knee adduction moment (R2 = 0.74; R2 = 0.59); second peaks of medial and total knee contact forces with second peaks of knee adduction and flexion moments (R2 = 0.71; R2 = 0.68); medial knee contact force impulse with knee adduction moment impulse (R2 = 0.76). ConclusionsHigher tibiofemoral joint contact forces during walking were associated with three-year radiographic knee OA progression based on medial joint space narrowing. These results support the need for strategies that reduce compressive knee contact forces through the reduction of adduction and flexion moments during walking.

Gait biomechanical analysis of unaffected knee before and 6 months after total knee arthroplasty

Abstract Study aim: This study aimed to compare gait biomechanical data on the unaffected side before and six months after total knee arthroplasty (TKA) and determine the postoperative changes in medial knee loading on the unaffected side. Material and methods: Three-dimensional gait analysis was performed on 19 female patients who had underwent TKA. Gait parameters were extracted at each time point using the maximum value of the backward (braking phase) and forward components (propulsion phase) of the ground reaction force on the unaffected side, while the knee adduction moment impulse (KAM impulse) was used as an index of medial knee loading. The pre – and post-TKA values of these parameters were compared. The relationship between KAM impulse and gait biomechanical factors on the unaffected side was examined using partial correlation analysis with gait speed as a control factor. Results: KAM impulse was not significantly different on the unaffected side compared to preoperatively. In the braking phase, there were significant differences in hip adduction moment (p = 0.033) and ankle dorsiflexion moment (p = 0.013), and hip flexion angle (p=0.011) in the propulsive phase. The relationship between KAM impulse and gait biomechanical factors on the unaffected side showed a positive correlation between KAM impulse and knee adduction angle (braking phase, propulsion phase; r = 0.671, 0.689) and KAM (braking phase, propulsion phase; r = 0.715, 0.745). Conclusions: There was no significant difference in KAM impulse on the unaffected side before and after TKA, suggesting that TKA did not influence medial knee loading increase on the unaffected side even six months post-TKA.

Effects of Kettlebell Load on Joint Kinetics and Global Characteristics during Overhead Swings in Women.

This study sought to identify the changes in ankle, knee, and hip joint kinetics with increasing load while performing the kettlebell overhead swing (OHS). Women (n = 18, age: 29.4 ± 5.3 years, 69.7 ± 8.9 kg) with a minimum of 6 months of kettlebell swing training experience performed fifteen repetitions of the kettlebell OHS with three different kettlebell masses (8 kg, 12 kg, 16 kg) in a counterbalanced order. Ankle, knee, and hip joint kinematics were captured within a 12-camera infrared motion capture space, while standing atop two force plates collecting ground reaction force (GRF) data. Post hoc results of statistically significant joint by mass interactions (p &lt; 0.05) of the net joint moment impulse, work, and peak power revealed the hip demonstrating the greatest increase in response to load, followed by the ankle (p &lt; 0.05). The knee joint kinetics changed very little between the masses. Pairwise post hoc comparisons between the joints at each mass level support the kettlebell OHS as being a hip dominant exercise, with the knee making the second largest contribution, despite contributions not changing across kettlebell masses. Collectively, these results provide practitioners with objective evidence regarding the mechanical demands and effects of load changes on the kettlebell OHS.

Exacerbating patellofemoral pain alters trunk and lower limb coordination patterns and hip-knee mechanics

The exacerbation of patellofemoral pain (PFP) may lead to compensatory trunk and lower limb movement patterns in order to minimize patellofemoral joint loading. However, joint kinematics are often analysed in isolation, which limits the understanding of how the underlying segments were coordinated to produce limb postures and distribute load across the limb. In this study we used a dynamical systems approach to investigate how women with PFP coordinate trunk, hip, and knee motion and distribute hip-knee moment demands following symptom exacerbation. Coordination patterns and coordination variability of the trunk, hip, and knee from 61 women with PFP were obtained during stair descent, ascent, and step down tasks, before and after a pain exacerbation protocol. Hip-knee extensor moment impulse ratio was also calculated. Following the exacerbation of PFP, women utilized knee dominant coordination patterns less often (p = 0.039–0.027; d = 0.51–0.53), while coordination patterns with the trunk leaning forward were utilized more during stair negotiation (p = 0.043-<0.001; d = 0.52–0.96). Although no significant differences in hip-knee coordination patterns were found, there was an increase in the hip-knee impulse ratio during stair negotiation (p = 0.014-<0.001; d = 0.27–0.36). These findings seem to display a movement strategy utilized by women with PFP in order to distribute more load to the hip joint and less to the knee joint, possibly in an attempt to avoid/manage pain.

Effects of Walking With a Cane on Frontal Plane Hip Joint Loading in Patients With Late-Stage Unilateral Hip Osteoarthritis

ObjectiveTo investigate the effects of walking with a cane on frontal plain bilateral hip joint loading in patients with late-stage unilateral hip osteoarthritis (OA). DesignNonrandomized experimental design. SettingUrban inpatient hospital. ParticipantsAdults (men, n=10; women, n=17) with osteoarthritis who were scheduled for total hip arthroplasty (N=27). InterventionGait with and without a T-cane was assessed using a 3-dimensional motion analysis system. Main Outcome MeasuresPeak hip adduction moment and hip adduction moment impulse, vertical ground reaction force, and ground reaction force impulse were assessed under 4 different conditions: OA side vs non-OA side with non-cane gait, OA side vs non-OA side with cane gait, non-cane vs cane gait on OA side, and non-cane vs cane gait on non-OA side. The lateral trunk lean angle in the stance phase on both sides was compared between with and without a cane. Pain during walking with and without a cane was also determined using a visual analog scale (0=no pain; 100=most painful). ResultsWalking with a cane reduced the peak hip adduction moment from an average of 0.76 to 0.57 Nm/kg (reduction approximately 25%) and the mean hip adduction moment impulse from 50.58 to 42.78 Nm/kg (reduction approximately 15%) on the affected side. Walking with a cane reduced the peak ground reaction force from an average of 10.15 to 9.20 N/kg but did not markedly affect the mean ground reaction force impulse on the affected side. The mean impulse of vertical ground force and hip adduction moment on the nonaffected side with a T-cane was larger than that without a cane (940.4 vs 899.2, 73.7 vs 68.8, respectively), albeit without statistical significance. The mean lateral trunk lean angle on the affected side was 5.85±3.95 degrees with a non-cane gait and 4.46±2.66 degrees with a T-cane gait, showing a significant difference. Furthermore, walking with a cane was associated with a significant decrease in the visual analog scale of pain from 42.1 to 26.4. ConclusionThese findings indicate that walking with a cane reduces the load and pain on the affected hip joint. The effect of the cane on the trunk lean was small, but it is worth noting that walking with a cane may increase the load on the healthy side.