Reduce Joint Loading Research Articles

The dynamic progression of temporomandibular joint osteoarthritis-like lesions elicited by mandibular shift in a rat model

BackgroundTemporomandibular joint osteoarthritis (TMJ-OA) presents significant challenges due to its complex etiology, often insidious onset, high incidence, and progressive structural deterioration. While research has explored genetic and molecular factors, treatment outcomes remain suboptimal, emphasizing the need for a deeper understanding of disease progression. ObjectiveThis study employs a specific mandibular shift rat model to explore the dynamic progression of TMJ-OA-like lesions and evaluate the potential for self-repair at different stages, aiming to inform early diagnosis and preventative strategies. MethodsSeventy-two female Sprague-Dawley rats were randomized into three groups: a control group (n=24; average weight: 157.23±1.63 g) receiving sham surgery. an experimental group (n=24; average weight: 157.78±1.88 g) subjected to mandibular shift induction, and a removal group (n=24; average weight: 158.11±2.20 g) experiencing mandibular shift for one, two, or four weeks followed by a one-month recovery period (designated as 1w Removal, 2w Removal and 4w Removal, respectively). Histomorphological and molecular analyses were conducted at designated time points. ResultsRats in the 1-week removal group exhibited substantial recovery in condylar morphology, cartilage thickness, extracellular matrix composition, and expression of OA-related genes. Conversely, the 4-week removal group mirrored the experimental group, indicating limited self-repair capacity at later stages. The 2-week removal group presented with variable outcomes, with some animals showing signs of recovery and others resembling the experimental group, indicating a potential transitional phase in the disease process. ConclusionRecovery from early-stage TMJ-OA involves eliminating provoking factors such as occlusal interference or reducing joint loading. However, advanced stages exhibit diminished self-repair capabilities, necessitating additional therapeutic interventions. These findings emphasize the importance of early diagnosis and intervention in TMJ-OA management.

Metabolic Profiles of Encapsulated Chondrocytes Exposed to Short-Term Simulated Microgravity.

The mechanism by which chondrocytes respond to reduced mechanical loading environments and the subsequent risk of developing osteoarthritis remains unclear. This is of particular concern for astronauts. In space the reduced joint loading forces during prolonged microgravity (10-6 g) exposure could lead to osteoarthritis (OA), compromising quality of life post-spaceflight. In this study, we encapsulated human chondrocytes in an agarose gel of similar stiffness to the pericellular matrix to mimic the cartilage microenvironment. We then exposed agarose-chondrocyte constructs to simulated microgravity (SM) using a rotating wall vessel (RWV) bioreactor to better assess the cartilage health risks associated with spaceflight. Global metabolomic profiling detected a total of 1205 metabolite features across all samples, with 497 significant metabolite features identified by ANOVA (FDR-corrected p-value < 0.05). Specific metabolic shifts detected in response to SM exposure resulted in clusters of co-regulated metabolites, as well as key metabolites identified by variable importance in projection scores. Microgravity-induced metabolic shifts in gel constructs and media were indicative of protein synthesis, energy metabolism, nucleotide metabolism, and oxidative catabolism. The microgravity associated-metabolic shifts were consistent with early osteoarthritic metabolomic profiles in human synovial fluid, which suggests that even short-term exposure to microgravity (or other reduced mechanical loading environments) may lead to the development of OA.

A framework based on subject-specific musculoskeletal models and Monte Carlo simulations to personalize muscle coordination retraining

Excessive loads at lower limb joints can lead to pain and degenerative diseases. Altering joint loads with muscle coordination retraining might help to treat or prevent clinical symptoms in a non-invasive way. Knowing how much muscle coordination retraining can reduce joint loads and which muscles have the biggest impact on joint loads is crucial for personalized gait retraining. We introduced a simulation framework to quantify the potential of muscle coordination retraining to reduce joint loads for an individuum. Furthermore, the proposed framework enables to pinpoint muscles, which alterations have the highest likelihood to reduce joint loads. Simulations were performed based on three-dimensional motion capture data of five healthy adolescents (femoral torsion 10°–29°, tibial torsion 19°–38°) and five patients with idiopathic torsional deformities at the femur and/or tibia (femoral torsion 18°–52°, tibial torsion 3°–50°). For each participant, a musculoskeletal model was modified to match the femoral and tibial geometry obtained from magnetic resonance images. Each participant’s model and the corresponding motion capture data were used as input for a Monte Carlo analysis to investigate how different muscle coordination strategies influence joint loads. OpenSim was used to run 10,000 simulations for each participant. Root-mean-square of muscle forces and peak joint contact forces were compared between simulations. Depending on the participant, altering muscle coordination led to a maximum reduction in hip, knee, patellofemoral and ankle joint loads between 5 and 18%, 4% and 45%, 16% and 36%, and 2% and 6%, respectively. In some but not all participants reducing joint loads at one joint increased joint loads at other joints. The required alteration in muscle forces to achieve a reduction in joint loads showed a large variability between participants. The potential of muscle coordination retraining to reduce joint loads depends on the person’s musculoskeletal geometry and gait pattern and therefore showed a large variability between participants, which highlights the usefulness and importance of the proposed framework to personalize gait retraining.

Attitude of Physical Therapy Students Towards Fat People

Weight management is becoming more widely recognized as a part of physiotherapists' scope of practice in order to enhance patient outcomes by reducing joint load or alleviating chronic pain, for example. Interactions with patients about weight, on the other hand, might lead to a patient's perception of a negative judgment from health professionals, which can lead to poorer health outcomes. The current study aimed to evaluate the attitude of physical therapy students towards fat people. A cross-sectional study design was used, 377 questionnaires were filled out by undergraduate DPT students from different universities in Karachi. The sample size was 377.According to the data majority of the participants had a positive attitude towards fat people while a few participants had weight-based stereotypes. This impression should be recognized by physical therapy students since it may lead to lower patient outcomes and avoidance of physiotherapy consultations.

Differences in Muscle Demand and Joint Contact Forces Between Running and Skipping

Skipping has been proposed as a viable cross-training exercise to running due to its lower knee contact forces and higher whole-body energy expenditure. However, how individual muscle forces, energy expenditure, and joint loading are affected by differences in running and skipping mechanics remains unclear. The purpose of this study was to compare individual muscle forces, energy expenditure, and lower extremity joint contact forces between running and skipping using musculoskeletal modeling and simulations of young adults (n = 5) performing running and skipping at 2.5m·s-1 on an instrumented treadmill. In agreement with previous work, running had greater knee and patella contact forces than skipping which was accompanied by greater knee extensor energetic demand. Conversely, skipping had greater ankle contact forces and required greater energetic demand from the uniarticular ankle plantarflexors. There were no differences in hip contact forces between gaits. These findings further support skipping as a viable alternative to running if the primary goal is to reduce joint loading at the commonly injured patellofemoral joint. However, for those with ankle injuries, skipping may not be a viable alternative due to the increased ankle loads. These findings may help clinicians prescribe activities most appropriate for a patient's individual training or rehabilitation goals.

Muscle coordination retraining inspired by musculoskeletal simulations reduces knee contact force

Humans typically coordinate their muscles to meet movement objectives like minimizing energy expenditure. In the presence of pathology, new objectives gain importance, like reducing loading in an osteoarthritic joint, but people often do not change their muscle coordination patterns to meet these new objectives. Here we use musculoskeletal simulations to identify simple changes in coordination that can be taught using electromyographic biofeedback, achieving the therapeutic goal of reducing joint loading. Our simulations predicted that changing the relative activation of two redundant ankle plantarflexor muscles—the gastrocnemius and soleus—could reduce knee contact force during walking, but it was unclear whether humans could re-coordinate redundant muscles during a complex task like walking. Our experiments showed that after a single session of walking with biofeedback of summary measures of plantarflexor muscle activation, healthy individuals reduced the ratio of gastrocnemius-to-soleus muscle activation by 25 ± 15% (p = 0.004, paired t test, n = 10). Participants who walked with this “gastrocnemius avoidance” gait pattern reduced late-stance knee contact force by 12 ± 12% (p = 0.029, paired t test, n = 8). Simulation-informed coordination retraining could be a promising treatment for knee osteoarthritis and a powerful tool for optimizing coordination for a variety of rehabilitation and performance applications.

MECHANICAL INTERVENTIONS IN THE MANAGEMENT OF KNEE OSTEOARTHRITIS: AN OA TRIAL BANK INDIVIDUAL PARTICIPANT DATA META-ANALYSIS INITIATIVE STATUS UPDATE

Purpose: Treatment for knee osteoarthritis (OA) may aim to alter biomechanics and reduce joint loads through the application or wear of mechanical interventions like bracing, taping, insoles, footwear, or mobility aids. The OARSI guidelines conditionally recommend use of mobility aids and wedged insoles for knee OA management, but conditionally to strongly recommend against taping and bracing, based on a lack of clear efficacy from low quality evidence. However, knee OA is a heterogeneous condition, and it may be that clearly defined subgroups of patients may be more likely to respond to mechanical interventions.We are conducting a systematic review with individual participant data (IPD) meta-analysis of randomized controlled trials (RCTs) investigating mechanical interventions to treat painful knee OA.

Preliminary biomechanical cadaver study investigating a new load-sharing knee implant

PurposeOne of the major contributors to the progression of knee osteoarthritis (OA) is the condition of loading in the knee joint. Innovatively designed load-sharing implants may be effective in terms of reducing joint load. The effects of these implants on contact joint mechanics can be evaluated through cadaver experiments. In this work, a case study is carried out with cadaver knee specimens to carry out a preliminary investigation into a novel load-sharing knee implant, in particular to study the surgical procedures required for attachment, and to determine the contact pressures in the joint with and without the implant.MethodsContact pressure in the tibiofemoral joint was measured using pressure mapping sensors, with and without the implant, and radiographs were conducted to investigate the influence of the implant on joint space. The implant was designed from a 3D model of the specimen reconstructed by segmenting MR images of the knee, and it was manufactured by CNC machining.ResultsIt was observed that attachment of the implant does not affect the geometry of the hard/soft tissues. Radiographs showed that the implant led to an increase in the joint space on the medial side. Contact pressure measurements showed that the implant reduced the load on the medial side by approximately 18% under all tested loading conditions. By increasing the load from 800 to 1600 N, the percentage of load reduction in the lateral side was decreased by 8%. After applying 800, 1200, and 1600 N load it was observed that the peak contact pressures were 3.7, 4.6, and 5.5 MPa, respectively.ConclusionsThis new knee implant shows some promise as a treatment for OA, through its creation of a conducive loading environment in the knee joint, without sacrificing or damaging any of the hard or soft tissues. This device could be as effective as, for example, the Atlas® system, but without some complications seen with other devices; this would need to be validated through similar results being observed in an appropriate in vivo study.

Are Medial and Lateral Tibiofemoral Compressive Forces Different in Uphill Compared to Level Walking for Patients Following Total Knee Arthroplasty?

The purpose of this study was to determine how tibiofemoral joint compressive forces and knee joint-spanning muscle forces during uphill walking change compared to level walking in patients with total knee arthroplasty (TKA). A musculoskeletal model capable of resolving total (TCF), medial (MCF), and lateral (LCF) tibiofemoral compressive forces was used to determine compressive forces and muscle forces during level and uphill walking on a 10 deg incline for twenty-five post-TKA patients. A 2 × 2 (slope: level and 10 deg × limb: replaced and nonreplaced) repeated measures analysis of variance was used to detect differences in knee contact forces between slope and limb conditions and their interaction. Peak loading-response TCF, MCF, and LCF were greater during uphill walking than level walking for nonreplaced limbs. During uphill walking, peak loading-response TCF was smaller in replaced limbs compared to nonreplaced limbs with no change in MCF or LCF. Peak knee extension moment and knee extensor muscle force were smaller in replaced limbs compared to nonreplaced limbs during uphill walking. During level walking, replaced and nonreplaced limbs experienced rather equal joint loading; however, replaced limb experienced reduced joint loading during uphill walking. Differences in joint loading between replaced and nonreplaced limbs were not present during level walking, suggesting compensation from the replaced limb during the more difficult task. Uphill walking following TKA promotes more balanced loading of replaced limbs during stance; however, these benefits may come at the expense of increased loading on nonreplaced limbs.

Effect of Footwear on the Biomechanics of Loaded Back Squats to Volitional Exhaustion in Skilled Lifters.

Brice, SM, Doma, K, and Spratford, W. Effect of footwear on the biomechanics of loaded back squats to volitional exhaustion in skilled lifters. J Strength Cond Res 36(10): 2676-2684, 2022-This study examined whether footwear influences the movement dynamics of barbell back squats to volitional exhaustion in experienced lifters. Eleven men (1 repetition maximum [1RM] = 138 ± 19 kg; 1RM % body mass = 168 ± 18%) performed 3 sets (5-12 ± 4 repetitions per set) of loaded barbell back squats to volitional exhaustion using raised-heel and flat-heel footwear. Barbell motion as well as moments, angles, angular velocity, and power in the sagittal plane at the ankle, knee, hip, and lumbopelvis were examined during the second repetition of the first set (T second ) and the final repetition of the third set (T final ). There were significant reductions ( p < 0.05) in lower-limb concentric angular velocity and power output for both footwear conditions. For the raised-heel condition at T final , hip and knee concentric angular velocities were significantly slower ( p < 0.05), and knee concentric power output was significantly less ( p < 0.05) compared with the flat-heel condition. A reduction in barbell velocity was not observed for the raised-heel condition despite there being reduction in hip and knee angular velocities. Furthermore, no differences were identified in lower-limb joint moments or any of the biomechanical characteristics of the lumbopelvis between the footwear conditions. The findings of this study suggest that neither type of footwear reduced joint loading or improved joint range-of-motion.

The Influence of Load Carriage on Knee Joint Loading and Metabolic Cost on Walking with Lower-Limb Amputation: A Preliminary Modeling Study

ABSTRACT Introduction For able-bodied individuals, the mechanical output from the ankle muscles is modulated to meet the altered demands of load carriage. However, for individuals with a lower-limb amputation, the stiffness properties of standard-of-care prosthetic feet do not change with varying load conditions. Thus, individuals with amputation often develop gait asymmetries during load carriage that increase their risk for developing overuse injuries such as in the intact knee and increase the metabolic cost of walking relative to able-bodied individuals. The purpose of this preliminary study was to assess the influence of load carriage technique on knee joint loading and metabolic cost during gait of an individual with a below-knee amputation using a forward dynamics simulation framework. Methods Simulations were generated to track the experimental walking data of individuals with amputation for 3 loading conditions (unloaded, front load, and back load). Results These simulations showed that individuals with amputation rely on their intact limb as a compensatory strategy to meet the increased demands of carrying a load. Carrying a back load was found to increase intact knee joint loading relative to carrying a front load but reduced metabolic cost. Conclusion The tradeoff between joint loading and metabolic cost should be considered when determining the appropriate load carriage technique. Future work should focus on improving prosthetic foot designs to help reduce joint loading asymmetry and elevated metabolic cost during different loading conditions for individuals with lower-limb amputation.

Effects of overground surfaces on running kinematics and kinetics in habitual non-rearfoot strikers

ABSTRACT This study aimed to investigate the effects of different overground surfaces on running biomechanics of non-rearfoot strikers. Thirty-one male habitual non-rearfoot strikers were required to run at 3.3 ± 0.2 m/s on a customized runway with artificial grass, concrete, or synthetic rubber surfaces in a random order. Vertical loading rates, three-dimensional ground reaction forces (GRFs), and lower-limb joint angles and moments were compared among surfaces. Regarding kinematics, significances were only detected in maximum knee flexion angle, with greater values when running on artificial grass compared to synthetic rubber or concrete. Regarding kinetics, changes were demonstrated in GRF peaks and lower-limb joint moments. GRF peaks were significantly greater when running on synthetic rubber or artificial grass compared to concrete; lower-limb joint moments were significantly lower when running on synthetic rubber compared to concrete; these changes were inconsistent when running on artificial grass compared to concrete. Significant differences were demonstrated in running kinetics when habitual non-rearfoot strikers ran on different overground surfaces. Running on artificial grass or synthetic rubber caused greater GRFs than running on concrete. However, only synthetic rubber could reduce joint loads.

A biomechanical field testing approach in snow sports: Case studies toward a detailed analysis of joint loading

In this study, kinematic and kinetic measurements were combined to assess the effects of removing the stiff shaft from a ski boot. It was hypothesized that joint flexion at the ankle, knee and hip increase and reduce joint loading specifically at the knee. A previously developed force sensor was combined with a high-speed camera system for data collection of 6 degrees of freedom ground reaction forces and three-dimensional marker data in the field on a wave slope. The collected data were used as input to a musculoskeletal model for the estimation of joint kinematics and joint moments and contact forces in the ankle and knee. The force sensor, which was previously used for skiing, had experienced wear and tear and was thus prone to breakage. As a result, joint loading could only be analyzed for two skiers. These two skiers did not use the added range of ankle flexion to its full extent, but showed substantial reductions in joint moments and joint contact forces (e.g. knee compression force from 85 to 57 N/kg). Only one of the five experienced skiers tested was able to adopt the anticipated movement pattern by substantially increased maximum ankle joint flexion angle (from 10° to 37°) and knee joint flexion angle (from 93° to 105°) and the respective ranges of motion when skiing through a wave course. The study provides information on possible individual adaptations to ski boot modifications. The mechanical construction of the force sensor will need to be modified to withstand the high forces expected during freestyle skiing. The study also supports the future use of this measurement setup for comprehensive studies in snow sports, provided that a sufficient training period is given.

Cooperative Walking Equipment for the Elderly

With the accelerated aging of our country and the increasing proportion of the elderly population, the health problems and quality of life of the elderly population in our country are receiving more and more attention from the society. Due to the aging of physiological function, the old people’s exercise ability is getting weaker and weaker, and the deterioration of exercise function causes various kinds of exercise difficulties, thus making the old people have different degrees of assistance needs in standing, walking and balancing. Based on this, we plan to design a walking aid device to maintain the walking function of the elderly. The device meets the walking requirements of the elderly through the coordination and cooperation of a multi-rod mechanism, a damping mechanism and a slider mechanism. Mainly to reduce the weight of the knee joint of the elderly, while assisting in regular exercise, exercise stimulates physiological activity and reduces physical decline. The device assists the elderly to walk and has three main functions of reducing joint load, increasing balance ability and assisting walking.

Muscle recruitment strategies can reduce joint loading during level walking

Joint inflammation, with consequent cartilage damage and pain, typically reduces functionality and affects activities of daily life in a variety of musculoskeletal diseases. Since mechanical loading is an important determinant of the disease process, a possible conservative treatment is the unloading of joints. In principle, a neuromuscular rehabilitation program aimed to promote alternative muscle recruitments could reduce the loads on the lower-limb joints during walking. The extent of joint load reduction one could expect from this approach remains unknown. Furthermore, assuming significant reductions of the load on the affected joint can be achieved, it is unclear whether, and to what extent, the other joints will be overloaded. Using subject-specific musculoskeletal models of four different participants, we computed the muscle recruitment strategies that minimised the hip, knee and ankle contact force, and predicted the contact forces such strategies induced at the other joints. Significant reductions of the peak force and impulse at the knee and hip were obtained, while only a minimal effect was found at the ankle joint. Adversely, the peak force and the impulse in non-targeted joints increased when aiming to minimize the load in an adjacent joint. These results confirm the potential of alternative muscle recruitment strategies to reduce the loading at the knee and the hip, but not at the ankle. Therefore, neuromuscular rehabilitation can be targeted to reduce the loading at affected joints but must be considered carefully in patients with multiple joints affected due to the potential adverse effects in non-targeted joints.

Effects of body weight support and pedal stance width on joint loading during pinnacle trainer exercise

BackgroundA pinnacle trainer is a stair climber that has a biplane exercise trajectory and an adjustable pedal stance width (PSW). A pinnacle trainer integrated with a body weight support (BWS) system can help overweight individuals or individuals with poor balance exercise safely by reducing excessive or improper joint loads, preventing training-related injuries. However, few studies have investigated the biomechanical features of the lower extremities during pinnacle trainer exercise with and without partial BWS for various PSWs. Research questionWe aimed to investigate the effects of partial BWS and PSW on the joint loading of the lower extremities during stepping on a pinnacle trainer. MethodsSeventeen healthy adults exercised on the pinnacle trainer with or without BWS using various PSWs. The joint resultant forces and joint moments of the lower extremities were calculated according to the kinematic and kinetic data measured via a motion capture system and force transducers on the pedals, respectively. ResultsThe joint resultant forces and joint moments of the lower extremities significantly decreased with increasing percentage of BWS. The internal knee adduction moment and internal hip abduction moment significantly increased with increasing PSW. For every kilogram of BWS, the joint loading of the lower extremities decreased by approximately 1% of the joint resultant forces of body weight during exercise with the pinnacle trainer. SignificanceExercise on the pinnacle trainer with partial BWS significantly reduced joint loading. Exercise with a wider pedal stance may be helpful for knee osteoarthritis rehabilitation as it produces greater internal hip abduction and internal knee adduction moments.

Gait mechanics contribute to exercise induced pain flares in knee osteoarthritis

BackgroundExercise-induced pain flares represent a significant barrier for individuals with knee osteoarthritis to meet physical activity recommendations. There is a need to understand factors that contribute to pain flares and the potential for the motor system to adapt and reduce joint loading should a flare occur. The study aim was to examine the impact of a bout of exercise on self-reported pain, walking mechanics and muscle co-contraction for participants with knee osteoarthritis.MethodsThirty-six adults (17 healthy older and 19 knee osteoarthritis) participated in this study. Self-reported pain, joint mechanics and muscle co-activation during gait at two self-selected speeds were collected before and after a 20-min preferred pace treadmill walk (20MTW).ResultsEight of nineteen osteoarthritis participants had a clinically significant pain flare response to the 20MTW. At baseline the participants that did not experience a pain flare had smaller knee flexion and total reaction moments compared to both the participants with pain flares (p = 0.02; p = 0.05) and controls (p < 0.001; p < 0.001). In addition, the 2nd peak knee adduction (p = 0.01) and internal rotation (p = 0.001) moments were smaller in the no flares as compared to controls. The pain flare participants differed from controls with smaller knee internal rotation moments (p = 0.03), but greater relative hamstrings (vs. quadriceps) and medial (vs. lateral) muscle activation (p = 0.04, p = 0.04) compared to both controls and no flare participants (p = 0.04, p = 0.007). Following the 20MTW there were greater decreases in the 1st and 2nd peak knee adduction (p = 0.03; p = 0.02), and internal rotation (p = 0.002) moments for the pain flare as compared to the no flare group. In addition, for the pain flare as compared to controls, greater decreases in the knee flexion (p = 0.03) and internal rotation (p = 0.005) moments were found.ConclusionsIndividuals who adapt their gait to reduce knee joint loads may be less susceptible to exercise-induced pain flares. This highlights a potential role of gait biomechanics in short-term osteoarthritis pain fluctuations. The results also suggest that despite the chronic nature of osteoarthritis pain, the motor system’s ability to respond to nociceptive stimuli remains intact.

Basic study on assistance force in the standing assistance device with reduced joint loading

Basic study on assistance force in the standing assistance device with reduced joint loading

Force during functional exercises on land and in water in older adults with and without knee osteoarthritis: Implications for rehabilitation

BackgroundClosed kinetic chain and plyometric exercises are commonly used in aquatic rehabilitation because they are believed to reduce joint loading whilst replicating functional tasks. However, the forces and relationship to land-based functional movement is unknown. This study aims to compare vertical ground reaction force during squats, calf raises and jumping in older adults with and without knee osteoarthritis on land and in water. MethodsForty one participants (Healthy n = 21; Knee osteoarthritis n = 20; Age 68.5 (4.4) years) completed squats and calf raises at slow, medium and maximal speeds and jumping at maximal speed on land and in waist and chest depth water. Vertical ground reaction force and pain rating was measured in each environment. ResultsForce in all exercises was significantly greater on land than in chest depth water (p < 0.005). Peak force was significantly greater at maximal speed compared to slow speed (p < 0.001). The pattern of force in squats at slow speed in water was different to on land, with force highest at the start and end of the exercise and decreasing in the central phase. Pain ratings were significantly lower (p < 0.001) in water compared to on land in squats. ConclusionsClosed kinetic chain exercises offer inherently different loading in an aquatic environment. Body weight squats and calf raises in water could be defined as either neuromotor or low load, high velocity training. Maximal speed exercise in water produces higher relative load compared to slow speed and minimal pain providing an opportunity for clinicians to use greater speed to address power deficits.

Weight loss changed gait kinematics in individuals with obesity and knee pain

BackgroundObesity is a mechanical risk factor for osteoarthritis. In individuals with obesity, knee joint pain is prevalent. Weight loss reduces joint loads, and therefore potentially delays disease progression; however, how the knee joint responds to weight loss in individuals with obesity and knee pain is not clear. Research questionTo assess the effect of weight loss on knee joint kinematics during gait in individuals with obesity and knee pain. MethodsWe recruited individuals with obesity (BMI ≥ 35) and knee pain who were participating in a weight loss program which included bariatric surgery or medical management. At baseline and 1 year follow-up, participants walked on a treadmill, and their knee joint kinematics were assessed using a dual-fluoroscopic imaging system and subject-specific magnetic resonance imaging knee joint models. Gait changes were represented by change in range of tibiofemoral motion, i.e., excursions in flexion-extension, adduction-abduction, internal-external rotation, anterior-posterior translation, medial-lateral translation, and superior-inferior translation during gait. ResultsTwelve individuals with obesity and knee pain completed the gait analysis at baseline and 1 year follow-up. Participants lost on average 10.4% (standard deviation: 17.2%) of their baseline body weight. Reduction in body weight was associated with increased range of flexion-extension (r = -0.75, p < 0.01) and decreased range of adduction-abduction (r = 0.60, p = 0.04) during gait. The reduction in body weight was also associated with self-reported pain decrease (r = 0.62, p = 0.04); however, the change in pain was not significantly associated with kinematic changes. SignificanceWeight loss was associated with improved gait kinematics in the sagittal and frontal planes. The change in gait pattern in individuals with obesity and knee pain was not associated with the change in pain given a reduction in body weight.