Are the Effects of Resistance Exercise on Pain and Function in Knee and Hip Osteoarthritis Dependent on Exercise Volume, Duration, and Adherence? A Systematic Review and Meta-Analysis.

OBJECTIVE: The purpose of this study was to determine dose parameters for resistance exercise associated with improvements in pain and physical function in knee and hip osteoarthritis (OA) and whether these improvements were related to adherence. METHODS: We searched six databases, from inception to January 28, 2023, for randomized controlled trials comparing land-based, resistance exercise-only interventions with no intervention, or any other intervention. There were four subgroups of intervention duration: 0 to <3 months, 3 to 6 months, >6 to <12 months, ≥12 months. The between-group effect was calculated for immediate postintervention pain and physical function (activities of daily living [ADL] and sports/recreation [SPORT]). RESULTS: For both knee and hip, data from 280 studies showed moderate benefit for pain, physical function ADL, and physical function SPORT in favor of interventions 3 to 6 months. For the knee, there was also a moderate benefit for physical function ADL in favor of interventions >6 to <12 months. From 151 knee and hip studies that provided total exercise volume data (frequency, time, duration), there was no association between volume with the effect size for pain and physical function. A total of 74 studies (69 knee, 5 hip) reported usable adherence data. There was no association between adherence with the effect size for pain and physical function. CONCLUSION: In knee and hip OA, resistance exercise interventions 3 to 6 months (and for the knee >6 to <12 months) duration improve pain and physical function. Improvements do not depend on exercise volume or adherence, suggesting exercise does not require rigid adherence to a specific dose.

Improving muscle capacity utilization with a 12-week strengthening program for females with symptomatic knee osteoarthritis.

BACKGROUND: Strengthening exercise improves symptoms in knee osteoarthritis (OA), but it remains unclear if biomechanical mechanisms contribute to this improvement. Muscle capacity utilization, which reflects the proportion of maximum capacity required to complete tasks, may provide insight into how strengthening exercise improves clinical outcomes in painful knee OA. PURPOSE: The purpose of this secondary analysis was to determine if a 12-week strengthening intervention reduced muscle capacity utilization during walking, squat and lunge tasks in females with painful knee OA. METHODS: Data from 28 females (age 59.6 ± 6.2 years old; body mass index 29.1 ± 4.7 kg/m2) with clinical knee OA were included. Participants completed a strengthening intervention 3 times per week for 12 weeks. Knee extensor isometric torque was measured on a commercial dynamometer; peak values from three exertions were averaged. Peak KFM was extracted and averaged from five walking trials. Mean KFM was extracted and averaged from three trials for each of static lunges and squats. Muscle capacity utilization was the ratio of mean peak KFM to peak extensor torque for walking; and mean KFM to peak extensor torque for squats and lunges. Paired t-tests determined differences between peak extensor torque, peak KFM and muscle capacity utilization from pre to post intervention (p < 0.05). RESULTS & SIGNIFICANCE: Peak extensor torque increased at follow up (p = 0.02). Peak KFM during walking decreased (p = 0.005). Muscle capacity utilization during walking (p = 0.008) and squat (p = 0.002) decreased. Mean KFM and muscle capacity utilization during lunge remained unchanged from pre to post intervention. The reduction in muscle capacity utilization at follow up indicates the strengthening intervention produced a decrease in proportion of the maximal capacity a participant used to complete walking and squat tasks. Strengthening both increases maximal muscle capacity and decreases the net moment required during daily tasks in knee OA.

Scoping Review of Curricula and Pedagogical Approaches for Physiotherapist Performed Point of Care Ultrasonography.

Purpose: This study collates and maps physiotherapy pre- and post-licensure curricula and pedagogical approaches for point of care ultrasonography (POCUS). Method: We used a standardized scoping review methodology and reporting framework. A total of 18,217 titles and abstracts, and 1,372 full text citations were screened, with 209 studies classified as physiotherapist performed POCUS. Results: Of the 209 studies, 15 evaluated pre- and post-licensure curricula and pedagogical approaches. Seventy-two to 98% of pre-licensure programs reported including theoretical knowledge of POCUS and 44-45% reported practical teaching or competency assessment. In post-licensure studies of POCUS, 0-61% of physiotherapists reported training for POCUS. All studies of post-licensure pedagogical approaches included an assessment of theoretical knowledge of POCUS, but only one study included a practical assessment of competency. There was considerable variability in POCUS methods and duration of pedagogical approaches. Except for one study, all pedagogical approaches reported improvement in theoretical knowledge. Conclusion: Progress in physiotherapy-specific, standardized, competency-based curricula and pedagogical approaches in POCUS has been limited, with minimal research available, and considerable variability both pre- and post-licensure. These findings could be used to advocate for the inclusion of POCUS in pre- and post-licensure physiotherapy curriculum, and suggest a need for clear guidelines from regulatory colleges and licensing bodies, and a common terminology for physiotherapist performed POCUS. Future directions for research include a systematic review of the psychometric properties of physiotherapist performed POCUS within and across anatomical areas, an assessment of value of different forms of training, and an evaluation of the impact of physiotherapist performed POCUS on patient outcomes.

Objectif: compiler et cartographier les programmes et les approches pédagogiques avant et après l'obtention du permis d'exercer à l'égard de l'échographie au point d'intervention (ÉPI). Méthodologie: analyse environnementale standardisée et cadre référentiel. Les chercheurs ont examiné un total de 18 217 titres et résumés et de 1 372 citations complètes, et 209 études ont été classées comme des ÉPI effectuées par des physiothérapeutes. Résultats: des 209 études, 15 évaluaient des programmes et des approches pédagogiques avant et après l'obtention du permis d'exercer. De 72 % à 98 % des programmes avant l'obtention du permis d'exercer présentaient des connaissances théoriques sur l'ÉPI, et de 44 % à 45 % traitaient de l'enseignement pratique ou de l'évaluation des compétences. Pour ce qui est des études sur l'ÉPI après l'obtention du permis d'exercer, de 0 % à 61 % des physiothérapeutes ont déclaré avoir suivi une formation sur l'ÉPI. Toutes les études sur les approches pédagogiques après l'obtention du permis d'exercer contenaient une évaluation des connaissances théoriques sur l'ÉPI, mais une seule incluait une évaluation pratique de la compétence. Les modes d'ÉPI et la durée des approches pédagogiques étaient très variables. Sauf dans une étude, toutes les approches pédagogiques entraînaient une amélioration des connaissances théoriques. Conclusion: les programmes et approches pédagogiques des ÉPI fondés sur les compétences, standardisés et propres à la physiothérapie ont peu évolué, on fait l'objet de très peu de recherches et sont très variables tant avant et qu'après l'obtention du permis d'exercer. Ces résultats pourraient être utilisés pour revendiquer l'inclusion des ÉPI dans les programmes de physiothérapie avant et après l'obtention du permis d'exercer et démontrent la nécessité de directives claires de la part des ordres de réglementation et des organismes d'attribution de permis, de même que d'une terminologie commune sur les ÉPI effectuées par des physiothérapeutes. Les futures orientations de la recherche comprennent une analyse systématique des propriétés psychométriques des ÉPI effectuées par un physiothérapeute dans les zones anatomiques et entre elles, une évaluation de la valeur de divers types de formation et une évaluation des effets des ÉPI effectuées par des physiothérapeutes sur les résultats cliniques des patients.

Muscle-driven simulations and experimental data of cycling.

Muscle-driven simulations have provided valuable insights in studies of walking and running, but a set of freely available simulations and corresponding experimental data for cycling do not exist. The aim of this work was to develop a set of muscle-driven simulations of cycling and to validate them by comparison with experimental data. We used direct collocation to generate simulations of 16 participants cycling over a range of powers (40-216 W) and cadences (75-99 RPM) using two optimization objectives: a baseline objective that minimized muscle effort and a second objective that additionally minimized tibiofemoral joint forces. We tested the accuracy of the simulations by comparing the timing of active muscle forces in our baseline simulation to timing in experimental electromyography data. Adding a term in the objective function to minimize tibiofemoral forces preserved cycling power and kinematics, improved similarity between active muscle force timing and experimental electromyography, and decreased tibiofemoral joint reaction forces, which better matched previously reported in vivo measurements. The musculoskeletal models, muscle-driven simulations, simulation software, and experimental data are freely shared at https://simtk.org/projects/cycling_sim for others to reproduce these results and build upon this research.

Barriers and strategies for recruiting participants who identify as racial minorities in musculoskeletal health research: a scoping review.

Objective: Visible minorities are disproportionately affected by musculoskeletal disorders (MSD) and other diseases; yet are largely underrepresented in health research. The purpose of this scoping review was to identify barriers and strategies associated with increasing recruitment of visible minorities in MSD research. Methods: Electronic databases (MEDLINE, EMBASE, CINAHL, and PsycInfo) were searched. Search strategies used terms related to the concepts of 'race/ethnicity', 'participation', 'research' and 'musculoskeletal'. All research designs were included. Two reviewers independently screened titles and abstracts, completed full-text reviews, and extracted data. Papers that did not focus on musculoskeletal research, include racial minorities, or focus on participation in research were excluded. Study characteristics (study location, design and methods; sample characteristics (size, age, sex and race); MSD of interest) as well as barriers and strategies to increasing participation of visible minorities in MSD research were extracted from each article and summarized in a table format. Results: Of the 4,282 articles identified, 28 met inclusion criteria and were included. The majority were conducted in the United States (27 articles). Of the included studies, the groups of visible minorities represented were Black (25 articles), Hispanic (14 articles), Asian (6 articles), Indigenous (3 articles), Middle Eastern (1 article), and Multiracial (1 article). The most commonly cited barriers to research participation were mistrust, logistical barriers (e.g., transportation, inaccessible study location, financial constraints), and lack of awareness or understanding of research. Strategies for increasing diversity were ensuring benefit of participants, recruiting through sites serving the community of interest, and addressing logistical barriers. Conclusion: Understanding the importance of diversity in MSD research, collaborating with communities of visible minorities, and addressing logistical barriers may be effective in reducing barriers to the participation of visible minorities in health research. This review presents strategies to aid researchers in increasing inclusion in MSD-related research.

Muscle Architecture and Subcutaneous Fat Measurements of Rectus Femoris and Vastus Lateralis at Optimal Length Aided by a Novel Ultrasound Transducer Attachment.

Purpose: This cross-sectional study determines the sensitivity of muscle architecture and fat measurements of the rectus femoris (RF) and vastus lateralis (VL) muscles from ultrasound images acquired with varying transducer tilt, using a novel transducer attachment, in healthy adults. Secondary objectives were to estimate intrarater and interrater reliability of image measurement and acquisition, respectively. Methods: Thirty healthy adults participated (15 women and 15 men; 25 [SD 2.5] y). Ultrasound image acquisition was conducted by two raters at different transducer tilts relative to the skin: estimated perpendicular, and five measured angles (80°, 85°, 90°, 95°, 100°) using the transducer attachment. Muscle thickness (MT), subcutaneous fat thickness (FT), pennation angle (PA), and fascicle length (FL) were measured. Sensitivity and reliability were assessed using intra-class correlation coefficients (ICCs) and standard error of measurements (SEMs). Results: MT and FT for RF and VL were not sensitive to transducer tilt. However, PA and FL were sensitive to transducer tilt. MT and FT for both muscles showed high ICCs and low SEMs for intrarater and interrater reliability. For PA of both muscles, standardizing transducer tilt improved interrater ICCs and lowered SEMs. Conclusion: MT and FT measurements of RF and VL acquired at 60° knee flexion are robust to varying transducer tilt angles. PA measurements benefit from standardizing transducer tilt.

Objectif : étude transversale pour déterminer la sensibilité de l'architecture musculaire et des mesures lipidiques du muscle droit antérieur de la cuisse (MDAC) et du muscle vaste externe (MVE) à partir des images échographiques acquises chez des adultes en santé par diverses inclinaisons du transducteur, au moyen d'un nouveau dispositif. Les objectifs secondaires consistaient à évaluer la fiabilité intraévaluateurs et interévaluateurs des mesures et de l'acquisition des images, respectivement. Méthodologie: au total, 30 adultes en santé ont participé (15 femmes et 15 hommes de 25 [ÉT 2,5 ans]). Deux évaluateurs ont acquis des images échographiques à des inclinaisons différentes du transducteur par rapport à la peau : mesure perpendiculaire estimative et mesure à cinq angles (80°, 85°, 90°, 95°, 100°) au moyen du dispositif du transducteur. Ils ont mesuré l'épaisseur des muscles (ÉM), l'épaisseur de la graisse sous-cutanée (ÉG), l'angle de pennation (AP) et la longueur des fascicules (LF). Ils ont aussi évalué la sensibilité et la fiabilité au moyen de coefficients de corrélation intraclasse (CCI) et de l'écart-type des mesures (ÉTM). Résultats: l'ÉM et l'ÉG du MDAC et du MVE n'étaient pas sensibles à l'inclinaison du transducteur, mais l'AP et la LF l'étaient. La fiabilité intraévaluateur et interévaluateur de l'ÉM et de l'ÉG des deux muscles présentait un CCI élevé et un ÉTM faible. Pour ce qui est de l'AP des deux muscles, la standardisation de l'inclinaison du transducteur améliorait la CCI et réduisait l'ÉTM interévaluateurs. Conclusion: les mesures de l'ÉM et de l'ÉG du MDAC et du MVE acquises à une flexion du genou de 60° sont probantes à des angles d'inclinaison variables du transducteur. Les mesures de l'AP tirent profit d'une inclinaison du transducteur standardisée.

Physiotherapist performed Point of Care Ultrasonography (POCUS): a scoping review of 209 studies.

BACKGROUND: Point of care ultrasonography (POCUS) is a non-ionizing imaging technique that is emerging in physiotherapy practice. OBJECTIVE: To systematically map the research literature on physiotherapist performed POCUS. DATA SOURCES: Following PRISMA-ScR guidelines, OVID Medline, CINAHL, AMED, and EMBASE were searched. ELIGIBILITY CRITERIA: Peer-reviewed publications of physiotherapist performed POCUS were included. DATA EXTRACTION AND DATA SYNTHESIS: Data collected included: title, author(s), journal, year of publication, design of included studies, sample size, age category of the sample, anatomical area of POCUS, geographical location of research, study setting, and disease condition/patient population. Data analysis consisted of descriptive statistics for the key characteristics of each research question. RESULTS: A total of 18 217 titles and abstracts and 1 372 full-text citations were screened, with 209 studies included. Most included studies were measurement studies that assessed the psychometric properties of POCUS in adult patients, were published in the United States of America and imaged the abdominal lumbo-pelvic region. Eighty-two percent of studies were published in the last 10 years. LIMITATIONS: Non-English language, review articles and grey literature were excluded for feasibility. Studies were excluded if it was not clearly reported that a physiotherapist performed the POCUS. CONCLUSION: This review identified a wide variety of practice settings and a diverse number of patient conditions in which physiotherapists are performing POCUS. This breadth and depth of this review highlighted the need for improved reporting of study methodology and key areas of future research in physiotherapy performed POCUS. CONTRIBUTION OF THE PAPER.

Integrating MR imaging with full-surface indentation mapping of femoral cartilage in an ex vivo porcine stifle.

The potential of MRI to predict cartilage mechanical properties across an entire cartilage surface in an ex vivo model would enable novel perspectives in modeling cartilage tolerance and predicting disease progression. The purpose of this study was to integrate MR imaging with full-surface indentation mapping to determine the relationship between femoral cartilage thickness and T2 relaxation change following loading, and cartilage mechanical properties in an ex vivo porcine stifle model. Matched-pairs of stifle joints from the same pig were randomized into either 1) an imaging protocol where stifles were imaged at baseline and after 35 min of static axial loading; and 2) full surface mapping of the instantaneous modulus (IM) and an electromechanical property named quantitative parameter (QP). The femur and femoral cartilage were segmented from baseline and post-intervention scans, then meshes were generated. Coordinate locations of the indentation mapping points were rigidly registered to the femur. Multiple linear regressions were performed at each voxel testing the relationship between cartilage outcomes (thickness change, T2 change) and mechanical properties (IM, QP) after accounting for covariates. Statistical Parametric Mapping was used to determine significance of clusters. No significant clusters were identified; however, this integrative method shows promise for future work in ex vivo modeling by identifying spatial relationships among variables.

The relationship between muscle capacity utilization during gait and pain in people with symptomatic knee osteoarthritis.

BACKGROUND: Muscle capacity utilization reflects the percentage of maximal knee extensor strength required to complete physical activities. RESEARCH QUESTION: Is pain associated with muscle capacity utilization during walking in older adults with knee osteoarthritis? Secondarily, is muscle capacity utilization in older adults with knee osteoarthritis sex-specific? METHODS: Twenty-three participants (15 females) with symptomatic knee OA completed this study [age 67 ( ± 8) years, body mass index 29.7 ( ± 3.9) kg/m2, gait speed during the Six Minute Walk test 1.25 ( ± 0.25) m/s]. Pain was measured using the Knee injury and Osteoarthritis Outcome Score. Muscle capacity utilization was quantified as the peak external knee flexor moment during level walking normalized to knee extensor maximum voluntary isometric contraction. The knee flexor moment was calculated from kinematic and kinetic data during barefoot level walking at a self-selected speed and at 1.1 m/s. Knee extensor maximum voluntary isometric contraction was measured on a dynamometer. Multiple linear regressions were used to determine the relationship between pain and muscle capacity utilization after adjusting for age, sex, body mass index, and gait speed. Independent sample t-tests examined sex differences. RESULTS: Pain was not associated with muscle capacity utilization during self-selected and standardized walking speeds (p = 0.38 and p = 0.36, respectively). Females did not require a greater muscle capacity utilization than males to complete gait at self-selected and standardized speeds (p = 0.28, and p = 0.40, respectively). SIGNIFICANCE: Muscle capacity utilization was not associated with pain during walking in people with knee osteoarthritis. Future work should explore more challenging activities of daily living in knee OA.

Investigating acute changes in osteoarthritic cartilage by integrating biomechanics and statistical shape models of bone: data from the osteoarthritis initiative.

OBJECTIVE: This proof-of-principle study integrates joint reaction forces (JRFs) and bone shape to assess acute cartilage changes from walking and cycling. METHODS: Sixteen women with symptomatic knee osteoarthritis were recruited. Biomechanical assessment estimated JRFs during walking and cycling. Subsamples had magnetic resonance imaging (MRI) performed before and after a 25-min walking (n = 7) and/or cycling (n = 9) activity. MRI scans were obtained to assess cartilage shape and composition (T2 relaxation time). Bone shape was quantified using a statistical shape model built from 13 local participants and 100 MRI scans from the Osteoarthritis Initiative. Statistical parametric mapping quantified cartilage change and correlations between cartilage change with JRFs and statistical shape model features. RESULTS: Cartilage thickness (interior lateral, Δ - 0.10 mm) and T2 (medial, Δ - 4 ms) decreased on the tibial plateau. On the femur, T2 change depended on the activity. Greater tibiofemoral JRF was associated with more cartilage deformation on the lateral femoral trochlea after walking (r - 0.56). Knees more consistent with osteoarthritis showed smaller decreases in tibial cartilage thickness. DISCUSSION: Walking and cycling caused distinct patterns of cartilage deformation, which depended on knee JRFs and bone morphology. For the first time, these results show that cartilage deformation is dependent on bone shapes and JRFs in vivo.

Equations to Prescribe Bicycle Saddle Height based on Desired Joint Kinematics and Bicycle Geometry.

Overuse knee injuries are common in bicycling and are often attributed to poor bicycle-fit. Bicycle-fit for knee health focuses on setting saddle height to elicit a minimum knee flexion angle of 25-40°. Equations to predict saddle height include a single input, resulting in a likely suboptimal bicycle-fit. The purpose of this work was to develop an equation to predict saddle height from anthropometrics, bicycle geometry, and user-defined joint kinematics.Methods: Forty healthy adults (17 women, 23 men; mean (SD): 28.6 (7.2) years; 24.2 (2.6) kg/m2) participated. Kinematic analyses were conducted for 18 three-minute bicycling bouts including all combinations of 3 horizontal and 3 vertical saddle positions, and 2 crank arm lengths. For both minimum and maximum knee flexion, predictors were identified using Least Absolute Shrinkage and Selection Operator (LASSO) regression, and final models were fit using linear regression. Secondary analyses determined if saddle height equations were sex dependent.Results: The equation to predict saddle position from minimum knee flexion angle (R2=0.97; root mean squared error (RMSE) = 1.15 cm) was: Saddle height (cm) = 7.41 + 0.82(inseam cm) - 0.1(minimum knee flexion °) + 0.003(inseam cm)(seat tube angle °). The maximum knee flexion equation (R2=0.97; RMSE=1.15 cm) was: Saddle height (cm) = 41.63 + 0.78(inseam cm) - 0.25(maximum knee flexion °) + 0.002(inseam cm)(seat tube angle °). The saddle height equations were not dependent on sex.Conclusions: These equations provide a novel, practical strategy for bicycle-fit that accounts for rider anthropometrics, bicycle geometry and user-defined kinematics.Highlights This work developed simple equations to prescribed bicycle saddle height that elicits desired knee kinematics.Separate equations are presented for prescribing minimum or maximum knee flexion angle.Equations can be generalized to riders of both sexes, and a breadth of anthropometrics and ages.

Nutrition risk, physical activity and fibre intake are associated with body composition in OA: analysis of the Canadian Longitudinal Study on Aging.

Objective: Sarcopenic obesity is a key feature in osteoarthritis (OA). While ideal OA treatment involves physical activity and diet, how diet influences OA pathophysiology is unclear. We explored the associations between diet, nutrition risk and physical activity with body composition in older adults with OA. Methods: Baseline data from the Canadian Longitudinal Study on Aging data set were analysed. Participants with hip, knee, hand or multiple forms of OA were included in this cross-sectional analysis. Body composition measures (lean, fat and total masses (kg) and body fat percentage) were separate dependent variables. Regression analyses were conducted to explore associations between body composition with dietary intake (high calorie snack, fibre), nutrition risk (SCREEN II) and physical activity (Physical Activity Scale for the Elderly). Results: 1596 participants were 66.5 (9.0) years old with a body mass index of 28.2 (5.3) kg/m2. Higher fibre cereal intake was associated with higher lean mass (unstandardised beta coefficient 0.5 (0.1, 0.9), p=0.02) and lower body fat percentage (-0.3 (-0.6, 0.0), p=0.046). Lower nutrition risk was associated with higher lean mass (0.1 (0.0, 0.1), p=0.03), lower fat mass (-0.05 (-0.1, 0.0), p=0.009) and lower body fat percentage (-0.1 (-0.1, 0.0), p<0.001). Higher physical activity was associated with higher lean mass (0.01 (0.01, 0.02), p<0.001), lower fat mass (-0.01 (0.0, 0.0), p=0.005) and lower body fat percentage (-0.01 (0.0, 0.0), p<0.001). Conclusion: Greater physical activity and lower nutrition risk were associated with better body composition. While fibre intake was also associated body composition, the CIs were wide suggesting weak associations.

Daily cumulative load and body mass index alter knee cartilage response to running in women.

BACKGROUND: It is unknown whether a greater accumulation of knee load over a typical day is related to how cartilage responds to an acute bout of loading. This information may clarify the role of habitual activity on cartilage function. RESEARCH QUESTION: Is there a relationship between change in tibial and femoral cartilage thickness, volume, and T2 relaxation time following running with daily cumulative knee load in women? Secondarily, is there a relationship between cartilage change following running and the statistical interaction of body mass index (BMI) and daily steps? METHODS: Participants (n = 15) completed gait analyses and wore an accelerometer over a week. Daily cumulative knee load was the statistical interaction between tibial compressive joint reaction force (JRF) impulse with the average number of daily steps measured using accelerometry. Magnetic resonance imaging scans were acquired before and immediately after 15-min of treadmill running. Changes in tibial and femoral cartilage thickness, volume, and T2 relaxation time were calculated. Multiple linear regressions tested the associations of cartilage change outcomes with: baseline (thickness, volume, T2), JRF impulse, steps, and the interaction JRF impulse*steps. Secondarily, BMI was substituted for JRF impulse. RESULTS AND SIGNIFICANCE: Tibial volume change was explained by baseline volume, JRF impulse, steps, and JRF impulse*steps (R2 = 0.50, p = 0.013). Additionally, tibial volume change was explained by baseline volume, BMI, steps, and BMI*steps (R2 = 0.43, p = 0.002). Those who were more physically active with lower JRF impulse (or lower BMI) showed less change in tibial cartilage after a running exposure. This may suggest cartilage conditioning.

Automatic knee cartilage and bone segmentation using multi-stage convolutional neural networks: data from the osteoarthritis initiative.

OBJECTIVES: Accurate and efficient knee cartilage and bone segmentation are necessary for basic science, clinical trial, and clinical applications. This work tested a multi-stage convolutional neural network framework for MRI image segmentation. MATERIALS AND METHODS: Stage 1 of the framework coarsely segments images outputting probabilities of each voxel belonging to the classes of interest: 4 cartilage tissues, 3 bones, 1 background. Stage 2 segments overlapping sub-volumes that include Stage 1 probability maps concatenated to raw image data. Using six fold cross-validation, this framework was tested on two datasets comprising 176 images [88 individuals in the Osteoarthritis Initiative (OAI)] and 60 images (15 healthy young men), respectively. RESULTS: On the OAI segmentation dataset, the framework produces cartilage segmentation accuracies (Dice similarity coefficient) of 0.907 (femoral), 0.876 (medial tibial), 0.913 (lateral tibial), and 0.840 (patellar). Healthy cartilage accuracies are excellent (femoral = 0.938, medial tibial = 0.911, lateral tibial = 0.930, patellar = 0.955). Average surface distances are less than in-plane resolution. Segmentations take 91 ± 11 s per knee. DISCUSSION: The framework learns to automatically segment knee cartilage tissues and bones from MR images acquired with two sequences, producing efficient, accurate quantifications at varying disease severities.

Muscle strength gains after strengthening exercise explained by reductions in serum inflammation in women with knee osteoarthritis.

Background Individuals with knee osteoarthritis have elevated circulating inflammatory markers and altered cartilage properties but it is unclear if these features adapt to exercise. We aimed to determine (1) whether inflammatory markers, cartilage transverse relaxation time and thickness mediate the effect of body mass index (BMI) on quadriceps strength at baseline; and (2) whether these changes explain variance in quadriceps strength improvements after 12 weeks of exercise in women with knee osteoarthritis. Methods This secondary analysis (17 women with clinical knee osteoarthritis) of a randomized control trial compared supervised group interventions, 3 times/week for 12 weeks (36 sessions): (a) weight-bearing progressive resistive quadriceps exercise or (b) attention control. (1) From baseline, separate linear regressions were conducted with strength (Nm/kg) as the dependent, BMI as the predictor, and c-reactive protein, tumor necrosis factor, interleukin-6, cartilage transverse relaxation time or thickness as potential mediators. (2) Multiple linear regression analyses were completed with 12-week strength change (post-pre) as the dependent, change in serum inflammatory markers and cartilage measurements as predictors, and age, BMI and adherence as covariates. Findings (1) At baseline, there was no mediation. (2) A decrease in each of interleukin-6 (ß = -0.104 (95% confidence intervals: -0.172, -0.036), R2 = 0.51, P < 0.007) and tumor necrosis factor (ß = -0.024 (-0.038, -0.009), R2 = 0.54, P < 0.005) was associated with strength gains. Interpretation At baseline, inflammatory markers and cartilage measurements do not act as mediators of BMI on quadriceps strength. After 12 weeks of exercise, reduced interleukin-6 and tumor necrosis factor were associated with increased quadriceps strength in women with knee osteoarthritis.

Association of Machine Learning-Based Predictions of Medial Knee Contact Force With Cartilage Loss Over 2.5 Years in Knee Osteoarthritis.

OBJECTIVE: The relationship between in vivo knee load predictions and longitudinal cartilage changes has not been investigated. We undertook this study to develop an equation to predict the medial tibiofemoral contact force (MCF) peak during walking in persons with instrumented knee implants, and to apply this equation to determine the relationship between the predicted MCF peak and cartilage loss in patients with knee osteoarthritis (OA). METHODS: In adults with knee OA (39 women, 8 men; mean ± SD age 61.1 ± 6.8 years), baseline biomechanical gait analyses were performed, and annualized change in medial tibial cartilage volume (mm3 /year) over 2.5 years was determined using magnetic resonance imaging. In a separate sample of patients with force-measuring tibial prostheses (3 women, 6 men; mean ± SD age 70.3 ± 5.2 years), gait data plus in vivo knee loads were used to develop an equation to predict the MCF peak using machine learning. This equation was then applied to the knee OA group, and the relationship between the predicted MCF peak and annualized cartilage volume change was determined. RESULTS: The MCF peak was best predicted using gait speed, the knee adduction moment peak, and the vertical knee reaction force peak (root mean square error 132.88N; R2 = 0.81, P < 0.001). In participants with knee OA, the predicted MCF peak was related to cartilage volume change (R2 = 0.35, ß = -0.119, P < 0.001). CONCLUSION: Machine learning was used to develop a novel equation for predicting the MCF peak from external biomechanical parameters. The predicted MCF peak was positively related to medial tibial cartilage volume loss in patients with knee OA.

A new technique to evaluate the impact of running on knee cartilage deformation by region.

OBJECTIVES: When measuring changes in knee cartilage thickness in vivo after loading, mean values may not reflect local changes. The objectives of this investigation were: (1) use statistical parametric mapping (SPM) to determine regional deformation patterns of tibiofemoral cartilage in response to running; (2) quantify regional differences in cartilage thickness between males and females; and (3) explore the influence of sex on deformation. MATERIALS AND METHODS: Asymptomatic males (n = 15) and females (n = 15) had MRI imaging of their right knee before and after 15 min of treadmill running. Medial and lateral tibial, and medial and lateral weight-bearing femoral cartilage were segmented. SPM was completed on cartilage thickness maps to test the main effects of Running and Sex, and their interaction. F-statistic maps were thresholded; clusters above this threshold indicated significant differences. RESULTS: Deformation was observed in all four compartments; the lateral tibia had the largest area of deformation (p < 0.0001). Thickness differences between sexes were observed in all four compartments, showing females have thinner cartilage (p ≤ 0.009). The lateral tibia had small clusters indicating an interaction of sex on deformation (p ≤ 0.012). DISCUSSION: SPM identified detailed spatial information on tibiofemoral cartilage thickness differences observed after running, and between sexes and their interaction.

Hip and ankle kinematics are the most important predictors of knee joint loading during bicycling.

OBJECTIVES: To assess the effect of ankle, knee, and hip kinematics on patellofemoral and tibiofemoral joint reaction forces (JRF) during bicycling. Secondarily, to assess if sex, horizontal saddle position, or crank arm length were related to JRFs, after accounting for kinematics. DESIGN: Experimental cross-sectional study. METHODS: Forty healthy adults (mean (SD); 28.6 (7.2) years, 24.2 (2.6)kg/m2, 17 women) bicycled under 18 bicycling positions. One position used commercial guidelines and 17 randomly deviated from commercial. Resultant patellofemoral as well as compressive and shear tibiofemoral JRFs were calculated. Linear mixed-effects models with a random intercept of leg-nested-in-participant were used. RESULTS: Patellofemoral resultant forces were most sensitive to all joint kinematics (i.e., sensitivity was defined as the slope of single predictor models); all JRFs were least sensitive to minimum knee flexion. Tibiofemoral compression was predicted by minimum hip flexion and maximum ankle dorsiflexion (R2=0.90). Tibiofemoral shear (R2=0.86) and the resultant patellofemoral JRF (R2=0.90) were predicted by minimum hip flexion, maximum ankle dorsiflexion, minimum knee flexion, and the interaction between minimum hip flexion and minimum knee flexion. Adding sex as a factor improved fit of all models. This sex-effect was driven by differences in cycling intensity, reflected by the tangential crank arm force. Horizontal saddle position and crank arm length were not related to JRFs. CONCLUSIONS: Optimizing joint kinematics should be the primary goal of bicycle-fit. JRFs were least sensitive to the current gold standard for assessing bicycle-fit, minimum knee flexion. Bicycle-fit is of particular importance for those working at high intensities.

Design and Preliminary Implementation of an Air Microfluidics Enabled Soft Robotic Knee Brace Towards the Management of Osteoarthritis.

A dynamic and low-profile unloader tibiofemoral knee brace is designed and prototyped by synergizing concepts from the fields of microfluidics and soft robotics. Microfluidics provides strategies for miniaturization and multiplexing while soft robotics afford the tools to create soft fluidic actuators and allow compliant and inherently safe robotic assistance as part of clothing. The unloader knee brace provides dynamic response during the gait cycle, where a three-point leverage torque is provided only during the stance phase to contribute to joint stability when required and enhance comfort and compliance.Clinical Relevance- This novel soft robotic brace has the potential to reduce device abandonment due to aesthetics, user non-compliance and discomfort due to a constant three-point leverage torque during the gait cycle. Also, this air microfluidics enabled soft robotic knee brace could be expanded upon to improve the efficacy of braces in general and augment the effects of physical therapy, rehabilitation and treatment of musculoskeletal conditions.