Minimum Performance on Clinical Tests of Physical Function to Predict Walking 6,000 Steps/Day in Knee Osteoarthritis: An Observational Study

Effects of Long-Term Walking Exercise on Structural Progression, Symptoms, and Extensor Muscle Strength in Patients With Mild or at High Risk of Knee Osteoarthritis: Data From the Osteoarthritis Initiative

OBJECTIVE

The aim of the study is to assess the relationship between walking exercise and medial joint space narrowing progression, symptoms, and knee extensor muscle strength in early knee osteoarthritis patients.

METHODS

This nested cohort study within the Osteoarthritis Initiative included participants aged 50 yrs and older with knee osteoarthritis (Kellgren-Lawrence grades 0-2). Walking exercisers were identified using a modified Historical Physical Activity Survey Instrument. Differences in medial joint space narrowing, Knee Injury and Osteoarthritis Outcome Score, and knee extensor muscle strength were evaluated through the three-way analysis of variance.

RESULTS

Among 896 participants, 83.4% reported walking exercise. Female walkers showed significant improvements in symptoms (Knee Injury and Osteoarthritis Outcome Score-pain: P < 0.001; Knee Injury and Osteoarthritis Outcome Score-symptom: P < 0.001; Knee Injury and Osteoarthritis Outcome Score-quality of life: P < 0.001; Knee Injury and Osteoarthritis Outcome Score-function, sports, and recreational activities: P = 0.007). Similar results were observed in male walkers (Knee Injury and Osteoarthritis Outcome Score-pain: P < 0.001; Knee Injury and Osteoarthritis Outcome Score-symptom: P < 0.001; Knee Injury and Osteoarthritis Outcome Score-quality of life: P = 0.001; Knee Injury and Osteoarthritis Outcome Score-function, sports, and recreational activities: P = 0.009). Walkers showed significantly increased knee extensor muscle strength at 24 mos (female: P < 0.001; male: P = 0.003). Female nonwalkers had significantly decreased knee extensor muscle strength at 24 mos ( P < 0.001). Walkers showed significant improvement in medial joint space narrowing (odds ratio = 1.1, 95% confidence interval = 1.0-1.2) and Kellgren-Lawrence grade (OR = 1.0, 95% CI = 1.0-1.1) compared with nonwalkers.

CONCLUSIONS

Walking exercise prevents structural progression and improves symptoms. Meanwhile, the increased knee extensor muscle strength in all walkers further supports the validity of recommending walking exercises for early-stage knee osteoarthritis patients.

A Systematic Review of Physical Activity and Sedentary Behavior Patterns in an Osteoarthritic Population

OBJECTIVE

To explore physical activity (PA) and sedentary behaviors (SB) in individuals with lower limb (LL) Osteoarthritis (OA) and the influence of age, sex, and body mass index (BMI) on these behaviors.

DESIGN

Systematic review search: PubMed, Cochrane Library, ScienceDirect, and CINAHL databases were searched from inception until July 2023. Study criteria: Studies that reported quantifiable device-based or self-reported data for PA and SB variables in adults clinically diagnosed with LL OA were included.

DATA SYNTHESIS

A synthesis of PA and SB levels for those diagnosed with LL OA and the influence age, sex, and BMI have on these behaviors.

RESULTS

From the 1930 studies identified through the electronic search process, 48 met the inclusion criteria. PA guidelines were met by 33% of the sample population that measured moderate and moderate to vigorous PA. No studies reported 75 minutes per week or more of vigorous PA. Additionally, 58% of the population reporting SB were sedentary for 8 hours per day or more. Also, increasing age, BMI, and the female sex were identified as negative influences on PA levels. There were numerous methodological inconsistencies in how data were collected and reported, such as various activity monitor cut points for PA and SB bout duration.

CONCLUSION

Adults with LL OA may be at an increased risk of noncommunicable diseases due to low PA and high SB levels. It is important to consider age, sex, and BMI when investigating behavior patterns in those with LL OA.

Clinical mobility metrics estimate and characterize physical activity following lower-limb amputation

Background

Regular physical activity following a lower-limb amputation is essential for maintaining health and a high quality of life. Most adults with a lower-limb amputation, however, participate in insufficient daily physical activity, and thus, are predisposed to poor health outcomes. Estimating physical activity after lower-limb amputation via common mobility metrics may aid in clinical decisions regarding treatment prioritization and prosthesis prescription. The objectives of this study were (a) to examine associations between daily physical activity and patient-reported and performance-based mobility metrics among adults with lower-limb amputation, and (b) to determine whether patient-reported and performance-based mobility metrics can distinguish between physical activity status [i.e., sedentary (< 5000 steps/day) or non-sedentary (≥ 5000 steps/day)] of adults with lower-limb amputation.

Methods

A cross-sectional study involving 35 adults with a unilateral transtibial (N = 23; 63.0 ± 10.4 years) or transfemoral amputation (N = 12; 58.8 ± 9.5 years) was conducted. Participants completed patient-reported (Prosthesis Evaluation Questionnaire-Mobility Subscale) and performance-based mobility metrics (L-Test, 10-m Walk Test, 6-min Walk Test). Physical activity, i.e., average steps/day, was measured with an accelerometer.

Results

Patient-reported and performance-based mobility metrics were associated with daily physical activity (p < 0.050). Prosthesis Evaluation Questionnaire-Mobility Subscale scores, L-Test time, 10-m Walk Test speed and 6-min Walk Test distance independently explained 11.3%, 31.8%, 37.6% and 30.7% of the total variance in physical activity. Receiver operating characteristic curves revealed patient-reported and performance-based mobility metrics significantly distinguish between physical activity status, i.e., sedentary (< 5000 steps/day) versus non-sedentary (≥ 5000 steps/day). Preliminary cut-points for mobility metrics to classify physical activity status were determined.

Conclusions

Following a lower-limb amputation, patient-reported and performance-based mobility metrics may estimate daily physical activity, thereby aiding clinical decisions regarding treatment prioritization as well as prosthesis selection.

Total Knee Arthroplasty Assessments Should Include Strength and Performance-Based Functional Tests to Complement Range-of-Motion and Patient-Reported Outcome Measures

Range of motion (ROM) and pain often define successful recovery after total knee arthroplasty (TKA), but these routine clinical outcomes correlate poorly or not at all to functional capacity after TKA. The purpose of this Perspective is to underscore the importance of muscle strength and performance-based functional tests in addition to knee ROM and patient-reported outcome (PRO) measures to evaluate outcomes after TKA. Specifically: (1) muscle strength is the rate-limiting step for recovery of function after TKA; (2) progressive rehabilitation targeting early quadriceps muscle strengthening improves outcomes and does not compromise ROM after TKA; (3) ROM and PROs fail to fully capture functional limitations after TKA; and (4) performance-based functional tests are critical to evaluate function objectively after TKA. This Perspective also addresses studies that question the need for or benefit of physical therapy after TKA because their conclusions focus only on ROM and PRO measures. Future research is needed to determine the optimal timing, delivery, intensity, and content of physical therapy.

Relationship of Patellofemoral Osteoarthritis to Changes in Performance-based Physical Function Over 7 Years: The Multicenter Osteoarthritis Study

OBJECTIVE

To determine the relationship of patellofemoral osteoarthritis (PFOA) to changes in performance-based function over 7 years.

METHODS

There were 2666 participants (62.2 ± 8.0 yrs, BMI 30.6 ± 5.9 kg/m2, 60% female) from the Multicenter Osteoarthritis Study with knee radiographs at baseline who completed repeated chair stands and a 20-meter walk test (20MWT) at baseline, 2.5, 5, and 7 years. Generalized linear models assessed the relation of radiographic PFOA and radiographic PFOA with frequent knee pain to longitudinal changes in performance-based function. Analyses were adjusted for age, sex, BMI, tibiofemoral OA, and injury/surgery.

RESULTS

Linear models demonstrated a significant group-by-time interaction for the repeated chair stands (P = 0.04) and the 20MWT (P < 0.0001). Those with radiographic PFOA took 1.01 seconds longer on the repeated chair stands (P = 0.02) and 1.69 seconds longer on the 20MWT (P < 0.0001) at 7 years compared with baseline. When examining the relation of radiographic PFOA with frequent knee pain to performance-based function, there was a significant group-by-time interaction for repeated chair stands (P = 0.05) and the 20MWT (P < 0.0001). Those with radiographic PFOA with frequent knee pain increased their time on the repeated chair stands by 1.12 seconds (P = 0.04) and on the 20MWT by 1.91 seconds (P < 0.0001) over 7 years.

CONCLUSION

Individuals with radiographic PFOA and those with radiographic PFOA with frequent knee pain have worsening of performance-based function over time. This knowledge may present opportunities to plan for early treatment strategies for PFOA to limit functional decline over time.

Linking physical activity with clinical, functional, and structural outcomes: an evidence map using the Osteoarthritis Initiative

Physical activity is consistently recommended across clinical practice guidelines for managing knee osteoarthritis, yet prescription rates are low. Evidence mapping uses a systematic approach to visually illustrate and summarize published evidence, highlight gaps in the literature, and formulate research questions. The purpose of this study was to review and summarize evidence published from the Osteoarthritis Initiative (OAI) linking physical activity with clinical, functional, and structural knee osteoarthritis outcomes. Electronic databases were searched until June 2021. Studies from the OAI reporting subjective (Physical Activity Scale for the Elderly, PASE) or objective (accelerometry) physical activity data were included. Scatter plots were created to represent each outcome group (clinical, functional, structural) and physical activity measure (PASE, accelerometry) to map the evidence by the directional effect (positive, interaction, negative, or no effect) associated with physical activity. Forty-two articles were included in this review. Physical activity was quantified using PASE (n = 21), accelerometry (n = 20), or both (n = 1). Studies reported consistently positive physical activity effects on clinical (n = 22) and functional (n = 20) outcomes, with few exceptions. Structural (n = 15) outcomes were largely reported as interaction effects by physical activity intensity or sex, or as no significant effect. A network of interconnected outcomes emerged, with clinical and functional outcomes often reported together, and structural outcomes reported individually. This study provides an overview of current evidence linking physical activity to multiple interrelated knee osteoarthritis outcomes using an OAI-driven model. These evidence maps can be used as a framework to guide future investigations of the effects of physical activity on knee osteoarthritis.

Role of psychosocial factors on the effect of physical activity on physical function in patients after lumbar spine surgery

Background

The purpose of this study was to investigate the longitudinal postoperative relationship between physical activity, psychosocial factors, and physical function in patients undergoing lumbar spine surgery.

Methods

We enrolled 248 participants undergoing surgery for a degenerative lumbar spine condition. Physical activity was measured using a triaxial accelerometer (Actigraph GT3X) at 6-weeks (6wk), 6-months (6M), 12-months (12M) and 24-months (24M) following spine surgery. Physical function (computerized adaptive test domain version of Patient-Reported Outcomes Measurement Information System) and psychosocial factors (pain self-efficacy, depression and fear of movement) were assessed at preoperative visit and 6wk, 6M, 12M and 24M after surgery. Structural equation modeling (SEM) techniques were utilized to analyze data, and results are represented as standardized regression weights (SRW). Overall SRW were computed across five imputed datasets to account for missing data. The mediation effect of each psychosocial factor on the effect of physical activity on physical function were computed [(SRW for effect of activity on psychosocial factor X SRW for effect of psychosocial factor on function) ÷ SRW for effect of activity on function]. Each SEM model was tested for model fit by assessing established fit indexes.

Results

The overall effect of steps per day on physical function (SRW ranged from 0.08 to 0.19, p<0.05) was stronger compared to the overall effect of physical function on steps per day (SRW ranged from non-existent to 0.14, p<0.01 to 0.3). The effect of steps per day on physical function and function on steps per day remained consistent after accounting for psychosocial factors in each of the mediation models. Depression and fear of movement at 6M mediated 3.4% and 5.4% of the effect of steps per day at 6wk on physical function at 12M, respectively. Pain self-efficacy was not a statistically significant mediator.

Conclusions

The findings of this study suggest that the relationship between physical activity and physical function is stronger than the relationship of function to activity. However, future research is needed to examine whether promoting physical activity during the early postoperative period may result in improvement of long-term physical function. Since depression and fear of movement had a very small mediating effect, additional work is needed to investigate other potential mediating factors such as pain catastrophizing, resilience and exercise self-efficacy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-021-04622-w.

Joint Association of Moderate-to-vigorous Intensity Physical Activity and Sedentary Behavior With Incident Functional Limitation: Data From the Osteoarthritis Initiative

OBJECTIVE

To examine the joint association of moderate-to-vigorous intensity physical activity (MVPA) and sedentary behavior with the risk of developing functional limitation 4 years later in adults with knee osteoarthritis (OA).

METHODS

Using 48-month (baseline) accelerometry data from the Osteoarthritis Initiative, we classified participants as Active-Low Sedentary (≥ 1 10-min bout/week of MVPA, lowest tertile for standardized sedentary time), Active-High Sedentary (≥ 1 10-min bout/week of MVPA, top 2 tertiles for standardized sedentary time), Inactive-Low Sedentary (zero 10-min bouts/week of MVPA, lowest tertile for standardized sedentary time), and Inactive-High Sedentary (zero 10-minute bouts/week of MVPA, top 2 tertiles for standardized sedentary time) groups. Functional limitation was defined as > 12 seconds for the 5-repetition sit-to-stand test (5XSST) and < 1.22 m/s gait speed during the 20-meter walk test. To investigate the association of exposure groups with risk of developing functional limitation 4 years later, we calculated adjusted risk ratios (aRR; adjusted for potential confounders).

RESULTS

Of 1091 and 1133 participants without baseline functional limitation, based on the 5XSST and 20-meter walk test, respectively, 15% and 21% developed functional limitation 4 years later. The Inactive-Low Sedentary and Inactive-High Sedentary groups had increased risk of developing functional limitations compared to the Active-Low Sedentary and Active-High Sedentary groups. The Inactive-Low Sedentary group had 72% (aRR 1.72, 95% CI 1.00-2.94) and 52% (aRR 1.52, 95% CI 1.03-2.25) more risk of developing functional limitation based on the 5XSST and 20-meter walk test, respectively, compared to the Active-Low Sedentary group.

CONCLUSION

Regardless of sedentary category, being inactive (zero 10-min bouts/week in MVPA) may increase the risk of developing functional limitation in adults with knee OA.

Physical activity thresholds for predicting longitudinal gait decline in adults with knee osteoarthritis

OBJECTIVE

To investigate the longitudinal relationship between physical performance (via real-life accelerometry) and physical capacity (laboratory measurement of gait speed) in patients with knee osteoarthritis (KOA), and to derive accelerometry measured thresholds associated with gait speed decline in KOA that may provide targets for disease-specific physical activity guidelines.

DESIGN

Longitudinal data from the Osteoarthritis Initiative (OAI) accelerometer sub-study was extracted from 1,229 participants assessed 2 years apart. Extracted data include functional capacity, demographic and anthropometric characteristics, patient-reported outcome measures, and accelerometry-based physical activity measures. A "poor capacity" group was defined based on the gait speed quintile decline between baseline and the 2-yr follow-up. A Random Forest classifier was trained to classify individuals' capacity status, and the impact of each extracted factor on the prediction outcome was analyzed using a novel machine learning interpretation algorithm.

RESULTS

The most impactful predicting feature for gait decline is low minutes in the performance of moderate-vigorous activity (count per min 2,500+). Slower sit-to-stand performance, higher age and self-reported knee pain, and lower minutes in performance light activities (count per min 350-2499) also contributed to the model prediction. The overall classification accuracy is 76.3% (75.4% sensitivity, 76.5% specificity).

CONCLUSIONS

We investigated the impact magnitude and direction of each predicting feature on the longitudinal capacity status among KOA patients. Using novel data interpretation method, we established feature thresholds that may increase the probability of gait decline. These identified thresholds may provide meaningful information for establishing specific physical activity guidelines for KOA.

The association of objectively measured physical activity and sedentary behavior with skeletal muscle strength and muscle power in older adults: A systematic review and meta-analysis

BACKGROUND

Engaging in physical activity (PA) and avoiding sedentary behavior (SB) are important for healthy ageing with benefits including the mitigation of disability and mortality. Whether benefits extend to key determinants of disability and mortality, namely muscle strength and muscle power, is unclear.

AIMS

This systematic review aimed to describe the association of objective measures of PA and SB with measures of skeletal muscle strength and muscle power in community-dwelling older adults.

METHODS

Six databases were searched from their inception to June 21^st, 2020 for articles reporting associations between objectively measured PA and SB and upper body or lower body muscle strength or muscle power in community dwelling adults aged 60 years and older. An overview of associations was visualized by effect direction heat maps, standardized effect sizes were estimated with albatross plots and summarized in box plots. Articles reporting adjusted standardized regression coefficients (β) were included in meta-analyses.

RESULTS

A total of 112 articles were included representing 43,796 individuals (range: 21 to 3726 per article) with a mean or median age from 61.0 to 88.0 years (mean 56.4 % female). Higher PA measures and lower SB were associated with better upper body muscle strength (hand grip strength), upper body muscle power (arm curl), lower body muscle strength, and lower body muscle power (chair stand test). Median standardized effect sizes were consistently larger for measures of PA and SB with lower compared to upper body muscle strength and muscle power. The meta-analyses of adjusted β coefficients confirmed the associations between total PA (TPA), moderate-to-vigorous PA (MVPA) and light PA (LPA) with hand grip strength (β = 0.041, β = 0.057, and β = 0.070, respectively, all p ≤ 0.001), and TPA and MVPA with chair stand test (β = 0.199 and β = 0.211, respectively, all p ≤ 0.001).

CONCLUSIONS

Higher PA and lower SB are associated with greater skeletal muscle strength and muscle power, particularly with the chair stand test.

Everyday Physical Activity and Sedentary Behavior After Total Joint Arthroplasty: Do Patients and Partners Develop an Active Lifestyle?

Background

Osteoarthritis (OA) is a frequent cause of pain and disability, affecting half of the world’s population aged 65 years or older. Due to experienced pain and limitations, OA patients generally spend most of their waking hours sedentary and fail to adhere to physical activity (PA) recommendations. As a result of living together with OA patients, their partners might adopt a sedentary lifestyle. This study investigates the change in habitual PA and sedentary behavior (SB) in patients and their partners one year after the patients’ total joint replacement (arthroplasty) and inpatient rehabilitation.

Methods

This is a follow-up of a prospective cohort study including 24 older couples (69.3±7.8 years, gender ratio 11:13) consisting of OA patients (17 hip OA, 7 knee OA) and their partners. The participants’ habitual PA and SB were assessed by means of synchronous accelerometry (16h per day, 4–7 days) and additional self-report.

Results

Although the partners (~6300 steps per day) were significantly more active than the patients (~4800 steps per day) before arthroplasty, their lifestyle was still classified “low active”. Irrespective of the method used, the PA and SB parameters of patients and partners were significantly correlated before arthroplasty (accelerometry: r≥0.333, p≤0.001; self-report: r≥0.569, p≤0.004). Following the patients’ arthroplasty, no improvement in PA or SB was observed either in the patients or their partners. A detailed evaluation of accelerometric data on hourly basis revealed no change in behavior for both groups. Furthermore, their everyday activities remained correlated (accelerometry: r≥0.418, p≤0.001; questionnaire: r≥0.554, p≤0.005).

Conclusion

One year post-arthroplasty and inpatient rehabilitation neither the OA patients nor their partners had changed their PA or SB. Their everyday physical activity was still strongly intertwined. Further research is needed to determine why behavior change does not occur even though the prerequisites are in place.

Does the 1-year Decline in Walking Speed Predict Mortality Risk Beyond Current Walking Speed in Adults With Knee Osteoarthritis?

OBJECTIVE

To investigate whether walking speed at 1 timepoint, decline over the past 12 months, or both predict mortality risk over 11 years in adults with, or at risk of, knee osteoarthritis (OA).

METHODS

Using the data from the Osteoarthritis Initiative, we defined slow versus adequate walking speed as walking < 1.22 versus ≥ 1.22 m/s on a 20m walk test during the 12-month follow-up visit. We defined meaningful decline (yes/no) as slowing ≥ 0.08 m/s over the past year. At the 12-month visit, we classified adequate sustainers as those with adequate walking speed and no meaningful decline, slow sustainers as slow walking speed and no meaningful decline, adequate decliners as adequate walking speed and meaningful decline, and slow decliners as slow walking speed and meaningful decline. Mortality was recorded over 11 years. To examine the association of walking speed with mortality, HR and 95% CI were calculated using Cox regression, adjusted for potential confounders.

RESULTS

Of 4229 participants in the analytic sample (58% female, age 62 ± 9 yrs, BMI 29 ± 5 kg/m²), 6% (n = 270) died over 11 years. Slow sustainers and slow decliners had 2-times increased mortality risk compared to adequate sustainers (HR 1.96, 95% CI 1.44-2.66 for slow sustainers, and HR 2.08, 95% CI 1.46-2.96 for slow decliners). Adequate decliners had 0.43 times the mortality risk compared with adequate sustainers (HR 0.57, 95% CI 0.32-1.01).

CONCLUSION

In adults with, or at risk of, knee OA, walking slower than 1.22 m/s in the present increased mortality risk, regardless of decline over the previous year.

The association between walking speed from short- and standard-distance tests with the risk of all-cause mortality among adults with radiographic knee osteoarthritis: data from three large United States cohort studies

OBJECTIVE

Adults with radiographic knee OA (rKOA) are at increased risk of mortality and walking difficulty may modify this relation. Little is known about specific aspects of walking difficulty that increase mortality risk. We investigated the association of walking speed (objective measure of walking difficulty) with mortality and examined the threshold that best discriminated this risk in adults with rKOA.

METHODS

Participants with rKOA from the Johnston County Osteoarthritis Project (JoCoOA, longitudinal population-based cohort), Osteoarthritis Initiative and Multicenter Osteoarthritis Study (OAI and MOST, cohorts of individuals with or at high risk of knee OA) were included. Baseline speed was measured via 2.4-meter (m) walk test (short-distance) in JoCoOA and 20-m walk test (standard-distance) in OAI and MOST. To examine the association of walking speed with mortality risk over 9 years, hazard ratios (HR) and 95% confidence intervals (CI) were calculated from Cox regression models adjusted for potential confounders. A Maximal Likelihood Ratio Chi-square Approach was utilized to identify an optimal threshold of walking speed predictive of mortality.

RESULTS

Deaths after 9 years of follow-up occurred in 23.3% (290/1244) of JoCoOA and 5.9% (249/4215) of OAI + MOST. Walking 0.2 m/s slower during short- and standard-distance walk tests was associated with 23% (aHR [95%CI]; 1.23 [1.10, 1.39]) and 25% (1.25 [1.09, 1.43]) higher mortality risk, respectively. Walking <0.5 m/s on short-distance and <1.2 m/s standard-distance walk tests, best discriminated those with and without mortality risk.

CONCLUSION

Slower walking speed measured via short- and standard-distance walk tests was associated with increased mortality risk in adults with rKOA.

Physical Performance Tests Provide Distinct Information in Both Predicting and Assessing Patient-Reported Outcomes Following Lumbar Spine Surgery

STUDY DESIGN

Secondary analysis of randomized controlled trial data.

OBJECTIVE

The aim of this study was to examine whether preoperative physical performance is an independent predictor of patient-reported disability and pain at 12 months after lumbar spine surgery.

SUMMARY OF BACKGROUND DATA

Patient-reported outcome measures (PROMs) are commonly used to assess clinical improvement after lumbar spine surgery. However, there is evidence in the orthopedic literature to suggest that PROMs should be supplemented with physical performance tests to accurately evaluate long-term outcomes.

METHODS

A total of 248 patients undergoing surgery for degenerative lumbar spine conditions were recruited from two institutions. Physical performance tests (5-Chair Stand and Timed Up and Go) and PROMs of disability (Oswestry Disability Index: ODI) and back and leg pain (Brief Pain Inventory) were assessed preoperatively and at 12 months after surgery.

RESULTS

Physical performance tests and PROMs significantly improved over 12 months following lumbar spine surgery (P < 0.01). Weak correlations were found between physical performance tests and disability and pain (ρ = 0.15 to 0.32, P < 0.05). Multivariable regression analyses controlling for age, education, preoperative outcome score, fusion, previous spine surgery, depressive symptoms, and randomization group found that preoperative 5-Chair Stand test was significantly associated with disability and back pain at 12-month follow-up. Each additional 10 seconds needed to complete the 5-Chair Stand test were associated with six-point increase in ODI (P = 0.047) and one-point increase in back pain (P = 0.028) scores. The physical performance tests identified an additional 14% to 19% of patients as achieving clinical improvement that were not captured by disability or pain questionnaires.

CONCLUSION

Results indicate that physical performance tests may provide distinct information in both predicting and assessing clinical outcomes in patients undergoing lumbar spine surgery. Our findings suggest that the 5-Chair Stand test may be a useful test to include within a comprehensive risk assessment before surgery and as an outcome measure at long-term follow-up.

LEVEL OF EVIDENCE

3.

A Narrative Review on Measurement Properties of Fixed-distance Walk Tests Up to 40 Meters for Adults With Knee Osteoarthritis

Knee osteoarthritis (OA) is a serious disease and has no cure to date. Knee OA is a leading cause of functional limitation (e.g., difficulty walking). Walking speed is 1 method of quantifying difficulty with walking and should be assessed in clinical practice for adults with knee OA because it has prognostic value and is modifiable. Specifically, slow walking speed is associated with increased risk of adverse health outcomes, including all-cause mortality in adults with knee OA and can be modified by engaging in physical activity or exercise. However, at present, there is little consensus on the distance and instructions used to conduct the walk test. Distance is often selected based on space availability, and instruction varies, from asking the participants to walk at a comfortable pace versus as fast as possible. Therefore, the purpose of this narrative review is to summarize the measurement properties, strengths, and limitations of a fixed-distance walk test ≤ 40 meters in adults with knee OA. Good measurement properties in terms of reliability and validity were observed across the different testing protocols for fixed-distance walk test (i.e., any distance ≤ 40 m and fast- or self-paced). Therefore, clinicians and researchers can select a testing protocol that can safely and consistently be performed over time, as well as provide a practice trial to acclimatize the patients to the fixed-distance walk test.

A Decline in Walking Speed Is Associated With Incident Knee Replacement in Adults With and at Risk for Knee Osteoarthritis

OBJECTIVE

To determine if a 1-year change in walking speed is associated with receiving an incident knee replacement during the following year in adults with and at risk for knee osteoarthritis (OA).

METHODS

Using data from the Osteoarthritis Initiative, we determined a 1-year change in the 20-meter walk speed from 3 observation periods (i.e., 0-12, 12-24, and 24-36 months). We operationally defined 1-year change in walking speed as either (1) decline: ≤ -0.1 m/s change, (2) no change: between -0.1 and 0.1 m/s change, and (3) increase: ≥ 0.1 m/s change. Incident knee replacement was defined using each subsequent 1-year period (i.e., 12-24, 24-36, and 36-48 months). Combining data from the 3 observation periods, we performed a Poisson regression with robust error variance to determine the relative risk between a change in walking speed (exposure) and incident knee replacement over the following year (outcome).

RESULTS

Of the 4264 participants included within this analysis (11,311 total person visits), 115 (3%) adults received a knee replacement. Decline in walking speed was associated with a 104% increase in risk [adjusted relative risk (RR) 2.04, 95% CI 1.40-2.98], while an increase in walking speed associated with a 55% decrease in risk (RR 0.45; 95% CI 0.22-0.93) of incident knee replacement in the following year compared to a person with no change in walking speed.

CONCLUSION

A 1-year decline in walking speed is associated with an increased risk, while a 1-year increase in walking speed is associated with a decreased risk of future incident knee replacement.

Patient-specific reference values for objective physical function tests: data from the Osteoarthritis Initiative

INTRODUCTION/OBJECTIVE

We aimed to establish sex-specific reference values of objective physical function tests among individuals with or at risk for knee osteoarthritis (KOA) across subsets of age, radiographic KOA severity, and body mass index (BMI).

METHOD

We included Osteoarthritis Initiative participants with data for objective physical function tests, sex, age, BMI, and radiographic KOA severity (Kellgren-Lawrence [KL] grade) at baseline. Objective physical function was quantified with 20-m walk speed, chair-stand speed, 400-m walk time, and knee extension and flexion strength. We created participant characteristic subsets for sex, age, KL grade, and BMI. Reference values were created as percentiles from minimum to maximum in 10% increments for each combination of participant characteristic subsets. Previously established clinically important differences for 20-m walk speed and knee extension strength were used to highlight clinically relevant differences.

RESULTS

Objective physical function reference values tables and an interactive reference value table were created across all combinations of sex, age, KL grade, and BMI among 3860 individuals with or at risk for KOA. Clinically relevant differences exist for 20-m walk speed and knee extension strength between males and females across age groups, KL grades, and BMI categories.

CONCLUSIONS

Establishing an individual's relative level of objective physical function by comparing their performance to individuals with similar sex, age, KL grade, or BMI may help improve interpretation of physical function performance. The interactive reference value table will provide clinicians and researchers a clinically accessible avenue to use these reference values.Key Points• Since greater age, radiographic knee osteoarthritis severity, and body mass index are all associated with worse objective physical function, reference values should consider the complex inter-play among these patient characteristics.• This study provides objective physical function reference values among subsets of individuals across the spectrum of sex, age groups, radiographic knee osteoarthritis severity, and body mass index categories.• These reference values offer a more patient-centered approach for interpreting an individual's relative level of objective physical function by comparing them to a more homogeneous group of individuals with similar participant characteristics.• We have provided a clinically accessible interactive table that will enable clinicians and researchers to input their patient's data to quickly and efficiently determine a patient's relative objective physical function compared to individual's with similar characteristics.

Osteoarthritis physical activity care pathway (OA-PCP): results of a feasibility trial

BACKGROUND

To obtain information on feasibility and acceptability, as well as preliminary data on efficacy, of an Osteoarthritis Physical activity Care Pathway (OA-PCP).

METHODS

This was a single group pilot study involving 60 participants with symptomatic, physician diagnosed knee or hip OA, recruited from primary care clinics. Participants self-reported completing less than 150 min per week of moderate-to-vigorous physical activity (MVPA) at baseline. The 3-month OA-PCP intervention involved 3 physical activity (PA) coaching calls (focused on goal setting), three check-in emails and linkage with community-based or online resources to support PA. Efficacy outcomes were collected at baseline and 4-month follow-up. The primary efficacy outcome was minutes of MVPA, assessed via accelerometer. Secondary outcomes included minutes of light intensity activity, sedentary minutes, step counts, and Western Ontario and McMaster Universities (WOMAC) pain and function subscales. Participants were also asked to rate the helpfulness of the OA-PCP intervention on a scale of 0-10. Differences in efficacy outcomes between baseline and 4-month follow-up were assessed using paired t-tests.

RESULTS

Among participants beginning the study, 88% completed follow-up assessments and ≥ 90% completed each of the intervention calls. Average daily minutes of MVPA was 8.0 at baseline (standard deviation (SD) = 9.9) and 8.9 at follow-up (SD = 12.1, p = 0.515). There were no statistically significant changes in light intensity activity, sedentary time or step counts. The mean WOMAC pain score improved from 8.1 (SD = 3.6) at baseline to 6.2 (SD = 3.8) at follow-up (p < 0.001); the mean WOMAC function score improved from 26.2 (SD = 13.2) to 20.2 (SD = 12.5; p < 0.001). The mean rating of helpfulness was 7.6 (SD = 2.5).

CONCLUSIONS

Results supported the feasibility and acceptability of the study, and participants reported clinically relevant improvements in pain and function. PA metrics did not improve substantially. Based on these results and participant feedback, modifications including enhanced self-monitoring are being made to increase the impact of the OA-PCP intervention on PA behavior.

TRIAL REGISTRATION

NCT03780400, December 19, 2018.

The Role of Cohabitating Partner and Relationship Characteristics on Physical Activity among Individuals with Osteoarthritis

BACKGROUND

Most individuals with knee or hip osteoarthritis do not meet recommendations for physical activity. The Social Cognitive Theory suggests that the social environment (e.g., spouses/partners) may influence the physical activity of individuals with osteoarthritis. The purpose of this study was to examine whether the physical activity of insufficiently active, coupled adults with osteoarthritis was associated with received partner support for physical activity, partner's engagement in physical activity, and relationship satisfaction.

METHODS

Cross-sectional data from 169 couples were collected. Accelerometers estimated moderate-to-vigorous physical activity and daily steps for participants with osteoarthritis and their partners. Participants with osteoarthritis reported total received partner support for physical activity and relationship satisfaction.

RESULTS

Participants with osteoarthritis were on average 65 years old, 65% female, 86% non-Hispanic white, and 47% retired. Receiving total partner support more frequently was associated with more minutes of moderate-to-vigorous physical activity but not with steps. Relationship satisfaction moderated the association of partner's physical activity on the daily steps of individuals with osteoarthritis such that having a partner who accomplished more daily steps was associated with participants with osteoarthritis accomplishing more daily steps themselves when they reported greater relationship satisfaction.

CONCLUSIONS

Partners and relationship satisfaction may play an important role in the physical activity of individuals with osteoarthritis. Interventions seeking to increase physical activity in this population may be enhanced by promoting partner support. Additional research is needed to further explain these associations within the context of relationship satisfaction.

Exercise prescription in patients with cirrhosis: Recommendations for clinical practice

Exercise in cirrhosis of the liver is an emerging topic in hepatology. Despite the known benefits of exercise in the general population, there are currently few studies addressing that issue in relation to cirrhosis and more evidence is still needed. Even though some studies have reported an acute, exercise-induced increase in the hepatic venous pressure gradient (HVPG), the opposite (a decrease in the HVPG) has been shown by recent data after an exercise program carried out for>14 weeks. In addition to that benefit, improvement has been described in the metabolic profile, quality of life, muscle mass, cardiopulmonary function, and nutritional status. Together, those features make exercise in cirrhosis a very attractive intervention. However, certain aspects must be taken into account before prescribing exercise in that population and they include cardiovascular risk, musculoskeletal disorders, and complications related to cirrhosis. After considering those factors, an individually tailored exercise program should be developed for each patient, according to the points stated above and the desired goal. Information about exercise-limiting factors, type of exercise prescribed, monitoring methods, and concomitant nutritional therapy is provided in the present review.

Minimal Detectable Change for Motor Function Tests in Patients with Knee Osteoarthritis

Objective:

Improvement in a subject’s motor function is clinically evaluated by comparing measurements of the motor function tests taken before and after an intervention. Consequently, it is important to increase the accuracy of the determination of the intervention effect by confirming the minimal detectable change (MDC), which is an index representing the limits of measurement errors in motor function tests. This study aimed to examine the MDC of the five-time sit-to-stand test (FTSST) and the 5-m walk test (5mWT) in patients with knee osteoarthritis (OA).

Methods:

In this cross-sectional study, 83 patients (63 women and 20 men, mean age: 73.7±8.0 years) with knee OA were subjected to two trials of the FTSST and 5mWT. The maximum walking speed was calculated using the walking time in the 5mWT, and the intraclass correlation coefficients (ICCs) were determined.

Results:

The ICCs (1,1) of the FTSST, the walking time in the 5mWT, and the walking speed were 0.90, 0.83, and 0.81, respectively. The MDC₉₅ for the FTSST time, walking time in the 5mWT, and walking speed were 1.71 s, 0.99 s, and 0.36 m/s, respectively.

Conclusion:

If the observed changes in the motor function tests exceed 1.71 s for FTSST time, 0.99 s for walking time in the 5mWT, or 0.36 m/s for walking speed, then an improvement in function is indicated. Such an improvement would reflect the effectiveness of the intervention. These findings may aid in clinical decision making when using motor function tests in patients with knee OA.