Relation of Temporal Asymmetry During Walking to Two-Year Knee Pain Outcomes in Those With Mild-to-Moderate Unilateral Knee Pain: An Exploratory Analysis From the Multicenter Osteoarthritis Study.

OBJECTIVE: We aimed to explore the cross-sectional relation of unilateral knee pain severity and temporal asymmetry during walking and to determine relations of temporal asymmetry during walking to 2-year changes in ipsilateral and contralateral knee pain in those with mild-to-moderate unilateral knee pain. METHODS: The Multicenter Osteoarthritis Study is a prospective cohort study of adults with or at risk for knee osteoarthritis. The current study included participants with unilateral knee pain. Gait was assessed during self-selected and fast walking at baseline. Knee pain was assessed at baseline and 2 years. We calculated limb symmetry indices (LSIs; nonpainful limb/painful limb × 100) for stance, single-limb support time, and double-limb support time, then examined their relations to unilateral knee pain severity, incident contralateral knee pain, and persistent ipsilateral knee pain. RESULTS: Unilateral knee pain severity was not associated with temporal asymmetry during self-selected or fast walking. At 2 years, 17.1% of participants had incident contralateral knee pain and 51.4% had persistent ipsilateral knee pain. For self-selected walking, greater LSIs (i.e., longer time on the nonpainful limb) for stance and single-limb support time were associated with decreased odds of incident contralateral knee pain. Measures of temporal asymmetry were not associated with persistent ipsilateral knee pain, except for single-limb support time during fast walking. CONCLUSION: For those with unilateral knee pain, temporal asymmetry during walking is not associated with pain severity. However, select measures of stance and single-limb support time during self-selected and fast walking relate to longitudinal knee pain outcomes.

Ground reaction force patterns in knees with and without radiographic osteoarthritis and pain: descriptive analyses of a large cohort (the Multicenter Osteoarthritis Study).

OBJECTIVE: To compare ground reaction force patterns (GRF) during walking among legs defined by presence or absence of knee pain and/or radiographic knee osteoarthritis (ROA). METHOD: Principal component analysis extracted major modes of variation (PCs) in GRF data from the Multicenter Osteoarthritis Study during self-paced walking. Legs were categorized as pain + ROA (n = 168), ROA only (n = 303), pain only (n = 476), or control (n = 1877). Relationships between group and GRF PCs were examined using Generalized Estimating Equations, adjusted for age, sex, body mass index, race, and clinic site with and without additional adjustment for gait speed. RESULTS: With or without speed adjustment, pain + ROA had flatter vertical GRF waveforms than control (speed adjusted PC2 difference [95%CI]: -66 [-113,-20]), pain + ROA and ROA only had higher lateral GRF at impact and greater mid-stance medial GRF than control (speed adjusted PC3 difference: 9 [3,16] and 6 [2,10], respectively), and ROA only had higher early vs late medial GRF than control (speed adjusted PC2 difference: 7 [2,13]). Pain only had flatter vertical GRF waveforms and a smaller difference between anterior and posterior GRF than control only without speed adjustment. CONCLUSION: In this large sample, sustained mid-stance loading and higher impact loads were identified in legs with ROA or ROA and pain, even when adjusting for differences in gait speed and other confounders. While it remains to be seen whether these features precede or result from ROA and pain, the presence of these patterns in the speed-adjusted models could have implications on gait interventions aimed to change joint loading.

Exerted running results in altered impact mechanics and footstrike patterns following gait retraining.

Exertion may alter running mechanics and increase injury risk. Effects of exertion following gait-retraining are unknown. OBJECTIVES: To determine how exertion effects load rates, footstrike, and cadence in runners following a transition to forefoot strike (FFS) or increased cadence (CAD) gait-retraining. METHODS: 33 (9 M, 24 F) healthy rearfoot strike runners were randomized into CAD or FFS groups. All runners received strengthening exercises and gait-retraining. 3D kinetic and kinematic motion analysis with instrumented treadmill at self-selected speed was performed at baseline & 1-week post-intervention, including an exerted run. Exertion was ≥17 on Borg's Rating of Perceived Exertion scale or voluntary termination of running. RESULTS: Within group comparisons between fresh and exerted running: Cadence not affected in either group. Foot angle at contact became less plantarflexed in FFS (-2.2°, ±0.4) and was unchanged in CAD. Both groups increased vertical average load rate (FFS +16.9%, CAD +13.6%). CAD increased vertical stiffness (+8.6 kN/m). FFS reduced ankle excursion (1.8°). (p ≤ 0.05 for all values listed). CONCLUSION: Both FFS and CAD exhibited increased load rates with exertion. Variables that may have increased load rates were different for each group. CAD runners had increased vertical stiffness while FFS runners had reduced plantarflexion at contact and reduced ankle dorsiflexion excursion.

Can Yoga or Physical Therapy for Chronic Low Back Pain Improve Depression and Anxiety Among Adults From a Racially Diverse, Low-Income Community? A Secondary Analysis of a Randomized Controlled Trial.

OBJECTIVE: To determine and compare the effect of yoga, physical therapy (PT), and education on depressive and anxious symptoms in patients with chronic low back pain (CLBP). DESIGN: Secondary analysis of a randomized controlled trial. SETTING: Academic safety net hospital and 7 community health centers. PARTICIPANTS: A total of 320 adults with CLBP. INTERVENTION: Yoga classes, PT sessions, or an educational book. OUTCOME MEASURE: Depression and anxiety were measured using the Patient Health Questionnaire and Generalized Anxiety Disorder 7-item Scale, respectively, at baseline, 12, and 52 weeks. We identified baseline and midtreatment (6-wk) factors associated with clinically meaningful improvements in depressive (≥3 points) or anxious (≥2 points) symptoms at 12 weeks. RESULTS: Participants (female=64%; mean age, 46.0±10.7 years) were predominantly non-White (82%), low-income (<$30,000/year, 59%), and had not received a college degree (71%). Most participants had mild or worse depressive (60%) and anxious (50%) symptoms. At 12 weeks, yoga and PT participants experienced modest within-group improvements in depressive symptoms (mean difference [MD]=-1.23 [95% CI, -2.18 to -0.28]; MD=-1.01 [95% CI, -2.05 to -0.03], respectively). Compared with the education group, 12-week differences were not statistically significant, although trends favored yoga (MD=-0.71 [95% CI, -2.22 to 0.81]) and PT (MD= -0.32 [95% CI, -1.82 to 1.18]). At 12 weeks, improvements in anxious symptoms were only found in participants who had mild or moderate anxiety at baseline. Independent of treatment arm, participants who had 30% or greater improvement in pain or function midtreatment were more likely to have a clinically meaningful improvement in depressive symptoms (odds ratio [OR], 1.82 [95% CI, 1.03-3.22]; OR, 1.79 [95% CI, 1.06-3.04], respectively). CONCLUSIONS: In our secondary analysis we found that depression and anxiety, common in this sample of underserved adults with CLBP, may improve modestly with PT and yoga. However, effects were not superior to education. Improvements in pain and function are associated with a decrease in depressive symptoms. More research is needed to optimize the integration of physical and psychological well-being in PT and yoga.

The Association of Parity with Greater Dynamic Pronation of the Feet.

BACKGROUND: Postpartum women are at increased risk for lower limb musculoskeletal disorders. Foot arch collapse following pregnancy has been reported as a mechanism for this increased risk. However, dynamic changes during gait in postpartum women have not been reported. Therefore, we assessed the association between parity and dynamic foot pronation during gait. OBJECTIVE: To determine (1) if there is an association between parity and dynamic foot pronation (center of pressure excursion index, CPEI) during gait; and (2) the extent to which there is a dose-effect of parity on foot pronation. DESIGN: The Multicenter Osteoarthritis Study (MOST) Study is a longitudinal cohort study of adults with or at risk for knee osteoarthritis (OA). SETTING: Two communities in the United States, Birmingham, Alabama and Iowa City, Iowa. INTERVENTIONS: Not applicable PARTICIPANTS: A population-based sample of 1177 MOST participants who were female, had complete CPEI and parity data and completed the baseline, 30- and 60-month visits. MAIN OUTCOME MEASURES: Odds of a one quintile decrease in CPEI by parity group and mean CPEI by parity group. RESULTS: In 1177 women, mean age was 67.7 years and mean body mass index (BMI) was 30.6 kg/m2 . As parity increased, there was significantly greater foot pronation, lower mean CPEI: 19.1 (18.2-20.1), 18.9 (18.4-19.4), 18 (17.5-18.6) to 17.5 (16.4-18.6) in the 0 to 4 and >5 children groups, respectively; (P = .002), which remained significant after adjusting for race and clinic site (P = .005). There was a positive linear trend (ß = 1.08, 1.03-1.14) in odds ratios of a one quintile decrease in CPEI (greater pronation) with increasing parity level (P = .004), which remained significant after adjusting for race and clinic site (P = .01). After adjusting for age and BMI, these two associations were no longer statistically significant. CONCLUSIONS: This study indicates a positive correlation between parity and greater dynamic pronation of the feet.

[Anesthesia in patients with dopa-responsive dystonia (Segawa syndrome) : Presentation of the pathophysiology, clinical picture and approach based on two case reports]. / Anästhesieführung bei Patienten mit Dopa-responsiver Dystonie (Segawa-Syndrom) : Darstellung der Pathophysiologie, Klinik und Vorgehensweise anhand zweier Fallberichte.

Segawa syndrome (dopa-responsive dystonia [DRD]) is a rare neurometabolic disorder characterized by progressive dystonia, diurnal variation and tremors. It is caused by an enzymatic defect (a mutation of the GTPCH1 gene located on chromosome 14q) in the synthesis of tetrahydrobiopterin, an important substrate for dopamine synthesis. In the case of early correct diagnosis, clinical symptoms are well-controlled by levodopa therapy. The disease has several features which may lead to organ dysfunctions (e.g. torticollis, scoliosis, dysphagia and immobilization), which may be of concern for the anesthesiologist. Presenting two case reports of female patients undergoing elective cesarean section and breast cancer surgery, the main principles of perioperative management are discussed. Either techniques of regional or general anesthesia can be performed safely. Preoperative medication with levodopa should not be interrupted. Pharmacological agents with an antidopaminergic mode of action have to be avoided as well as significant pain and emotional stress situations in the perioperative period. Surgery in an ambulatory setting may not be recommended.

Is Heel Height Associated with Pain Exacerbations in Hip Osteoarthritis Patients?-Results from a Case-Crossover Study.

The etiology of osteoarthritis (OA) pain exacerbations is not well understood. The purpose of this study is to evaluate the association of heel height and duration of wearing shoes with higher heels with pain exacerbations in people with hip OA. Eligible participants with symptomatic hip OA were instructed to complete online questionnaires every 10 days over a 90-day follow-up period. They were required to complete the questionnaire whenever they were experiencing hip pain exacerbation. Of 252 participants recruited, 137 (54.4%) contributed both case and control period data, and were included in the analysis. Wearing shoes with a heel height ≥ 2.5 cm during the past 24 h was associated with lower odds of pain exacerbations (OR: 0.54, 95% CI: 0.30 to 0.99). A longer duration (>6 h) of wearing shoes with heel height ≥ 2.5 cm was also associated with a lower risk of hip pain exacerbations (p for linear trend = 0.003). Wearing shoes with heel height ≥ 2.5 cm and longer duration in the past 24 h may be protective against hip pain exacerbations in people with symptomatic hip OA. Given the observational study nature, it would be prudent for this to be replicated in an independent data set.

Transition to forefoot strike reduces load rates more effectively than altered cadence.

BACKGROUND: Excessive vertical impacts at landing are associated with common running injuries. Two primary gait-retraining interventions aimed at reducing impact forces are transition to forefoot strike and increasing cadence. The objective of this study was to compare the short- and long-term effects of 2 gait-retraining interventions aimed at reducing landing impacts. METHODS: A total of 39 healthy recreational runners using a rearfoot strike and a cadence of ≤170 steps/min were randomized into cadence (CAD) or forefoot strike (FFS) groups. All participants performed 4 weeks of strengthening followed by 8 sessions of gait-retraining using auditory feedback. Vertical average load rates (VALR) and vertical instantaneous load rates (VILR) were calculated from the vertical ground reaction force curve. Both cadence and foot strike angle were measured using 3D motion analysis and an instrumented treadmill at baseline and at 1 week, 1 month, and 6 months post retraining. RESULTS: ANOVA revealed that the FFS group had significant reductions in VALR (49.7%) and VILR (41.7%), and changes were maintained long term. Foot strike angle in the FFS group changed from 14.2° dorsiflexion at baseline to 3.4° plantarflexion, with changes maintained long term. The CAD group exhibited significant reduction only in VALR (16%) and only at 6 months. Both groups had significant and similar increases in cadence at all follow-ups (CAD, +7.2% to 173 steps/min; and FFS, +6.1% to 172 steps/min). CONCLUSION: Forefoot strike gait-retraining resulted in significantly greater reductions in VALR and similar increases in cadence compared to cadence gait-retraining in the short and long term. Cadence gait-retraining resulted in small reductions in VALR at only the 6-month follow-up.

Step Rate and Worsening of Patellofemoral and Tibiofemoral Joint Osteoarthritis in Women and Men: The Multicenter Osteoarthritis Study.

OBJECTIVE: To determine the association of self-selected walking step rate with worsening of cartilage damage in the patellofemoral (PF) joint and tibiofemoral (TF) joint compartments at a 2-year follow-up visit. METHODS: The Multicenter Osteoarthritis Study (MOST) is a prospective cohort of men and women with or at risk of knee osteoarthritis. Self-selected step rate was measured using an instrumented GAITRite walkway (CIR Systems) at the 60-month visit. Cartilage damage was semiquantitatively graded on magnetic resonance images at the 60- and 84-month visits in the medial and lateral PF and TF compartments. Step rate was divided into quartiles, and logistic regression was used to determine the association of step rate with the risk of worsening cartilage damage in men and women separately. Analyses were adjusted for age, body mass index, and knee injury/surgery. RESULTS: A total of 1,089 participants were included. Mean ± SD age was 66.9 ± 7.5 years, mean ± SD body mass index was 29.6 ± 4.7 kg/m2 , and 62.3% of the participants were women. Women with the lowest step rate had increased risk of lateral PF (risk ratio [RR] 2.1 [95% confidence interval (95% CI) 1.1-3.8]) and TF (RR 1.8 [95% CI 1.1-2.9]) cartilage damage worsening 2 years later compared to those with the highest step rate. Men with the lowest step rate had increased risk of medial TF cartilage damage worsening 2 years later (RR 2.1 [95% CI 1.1-3.9]). CONCLUSION: Lower step rate was associated with increased risk of cartilage damage worsening in the lateral PF and TF compartments in women and worsening medial TF joint damage in men. Future research is necessary to understand the influence of step rate manipulation on joint biomechanics in women and men.

Association of Varus Knee Thrust During Walking With Worsening Western Ontario and McMaster Universities Osteoarthritis Index Knee Pain: A Prospective Cohort Study.

OBJECTIVE: To investigate the 2-year association of varus knee thrust observed during walking to the odds of worsening Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) knee pain in older adults with or at risk of osteoarthritis (OA). METHODS: Video recordings of self-paced walking trials of Multicenter Osteoarthritis Study participants were assessed for the presence of varus thrust at baseline. Knee pain was assessed using the WOMAC questionnaire at baseline and at 2 years. Logistic regression was used to estimate the odds of worsening knee pain (defined as either any increase in WOMAC score or as clinically important worsening), adjusting for age, sex, race, body mass index, clinic site, gait speed, and static knee alignment. Analyses were repeated, stratified by baseline radiographic OA status and among the subset of knees without baseline WOMAC pain. RESULTS: A total of 1,623 participants contributed 3,204 knees. Varus thrust was observed in 31.5% of knees. Knees with varus thrust had 1.44 times (95% confidence interval [95% CI] 1.19-1.73) the odds of any worsening and 1.37 times (95% CI 1.11-1.69) the odds of clinically important worsening WOMAC pain compared to knees without thrust. Knees with thrust without baseline WOMAC pain had 2.01 times (95% CI 1.47-2.74) the odds of incident total pain. CONCLUSION: Results indicate that varus thrust is a risk factor for worsening and incident knee pain. Targeting varus thrust through noninvasive therapies could prevent development or worsening of knee pain in older adults with or at risk for knee OA.

Analysis of the calcium paradox of renin secretion.

The secretion of the protease renin from renal juxtaglomerular cells is enhanced by subnormal extracellular calcium concentrations. The mechanisms underlying this atypical effect of calcium have not yet been unraveled. We therefore aimed to characterize the effect of extracellular calcium concentration on calcium handling of juxtaglomerular cells and on renin secretion in more detail. For this purpose, we used a combination of experiments with isolated perfused mouse kidneys and direct calcium measurements in renin-secreting cells in situ. We found that lowering of the extracellular calcium concentration led to a sustained elevation of renin secretion. Electron-microscopical analysis of renin-secreting cells exposed to subnormal extracellular calcium concentrations revealed big omega-shaped structures resulting from the intracellular fusion and subsequent emptying of renin storage vesicles. The calcium concentration dependencies as well as the kinetics of changes were rather similar for renin secretion and for renovascular resistance. Since vascular resistance is fundamentally influenced by myosin light chain kinase (MLCK), myosin light chain phosphatase (MLCP), and Rho-associated protein kinase (Rho-K) activities, we examined the effects of MLCK-, MLCP-, and Rho-K inhibitors on renin secretion. Only MLCK inhibition stimulated renin secretion. Conversely, inhibition of MCLP activity lowered perfusate flow and strongly inhibited renin secretion, which could not be reversed by lowering of the extracellular calcium concentration. Renin-secreting cells and smooth muscle cells of afferent arterioles showed immunoreactivity of MLCK. These findings suggest that the inhibitory effect of calcium on renin secretion could be explained by phosphorylation-dependent processes under control of the MLCK.

Common side closure type, but not stapler brand or oversewing, influences side-to-side anastomotic leak rates.

BACKGROUND: Anastomotic leak (AL) increases costs and cancer recurrence. Studies show decreased AL with side-to-side stapled anastomosis (SSA), but none identify risk factors within SSAs. We hypothesized that stapler characteristics and closure technique of the common enterotomy affect AL rates. METHODS: Retrospective review of bowel SSAs was performed. Data included stapler brand, staple line oversewing, and closure method (handsewn, HC; linear stapler [Barcelona technique], BT; transverse stapler, TX). Primary endpoint was AL. Statistical analysis included Fisher's test and logistic regression. RESULTS: 463 patients were identified, 58.5% BT, 21.2% HC, and 20.3% TX. Covidien staplers comprised 74.9%, Ethicon 18.1%. There were no differences between stapler types (Covidien 5.8%, Ethicon 6.0%). However, AL rates varied by common side closure (BT 3.7% vs. TX 10.6%, p = 0.017), remaining significant on multivariate analysis. CONCLUSION: Closure method of the common side impacts AL rates. Barcelona technique has fewer leaks than transverse stapled closure. Further prospective evaluation is recommended.

Varus thrust during walking and the risk of incident and worsening medial tibiofemoral MRI lesions: the Multicenter Osteoarthritis Study.

OBJECTIVE: To determine the association of varus thrust during walking to incident and worsening medial tibiofemoral cartilage damage and bone marrow lesions (BMLs) over 2 years in older adults with or at risk for osteoarthritis (OA). METHOD: Subjects from the Multicenter Osteoarthritis Study (MOST) were studied. Varus thrust was visually assessed from high-speed videos of forward walking trials. Baseline and two-year MRIs were acquired from one knee per subject and read for cartilage loss and BMLs. Logistic regression with generalized estimating equations was used to estimate the odds of incident and worsening cartilage loss and BMLs, adjusting for age, sex, race, body mass index (BMI), and clinic site. The analysis was repeated stratified by varus, neutral, and valgus alignment. RESULTS: 1007 participants contributed one knee each. Varus thrust was observed in 29.9% of knees. Knees with thrust had 2.17 [95% CI: 1.51, 3.11] times the odds of incident medial BML, 2.51 [1.85, 3.40] times the odds of worsening medial BML, and 1.85 [1.35, 2.55] times the odds of worsening medial cartilage loss. When stratified by alignment, varus knees also had significantly increased odds of these outcomes. CONCLUSION: Varus thrust observed during walking is associated with increased odds of incident and worsening medial BMLs and worsening medial cartilage loss. Increased odds of these outcomes persist in varus-aligned knees.

RF magnetron-sputtered coatings deposited from biphasic calcium phosphate targets for biomedical implant applications.

Bioactive calcium phosphate coatings were deposited by radio-frequency magnetron sputtering from biphasic targets of hydroxyapatite and tricalcium phosphate, sintered at different mass % ratios. According to Raman scattering and X-ray diffraction data, the deposited hydroxyapatite coatings have a disordered structure. High-temperature treatment of the coatings in air leads to a transformation of the quasi-amorphous structure into a crystalline one. A correlation has been observed between the increase in the Ca content in the coatings and a subsequent decrease in Ca in the biphasic targets after a series of deposition processes. It was proposed that the addition of tricalcium phosphate to the targets would led to a finer coating's surface topography with the average size of 78 nm for the structural elements.

The Association of Forefoot Varus Deformity with Patellofemoral Cartilage Damage in Older Adult Cadavers.

Forefoot alignment may contribute to patellofemoral joint (PFJ) osteoarthritis (OA) via its influence on the closed chain kinematics of the lower limb. The purpose of this cadaveric study was to investigate the relationship between forefoot varus and ipsilateral cartilage damage in the medial and lateral PFJ. Forefoot alignment measurements were obtained from the feet of 25 cadavers (n = 50). Cartilage damage in the medial and lateral PFJ of each knee was scored using the Outerbridge scale. The relative odds of medial and lateral PFJ cartilage damage in limbs with forefoot varus and valgus were determined using logistic regression. The relationship between increasing varus alignment and increasing odds of medial and lateral PFJ cartilage damage was assessed. Of the 51% of limbs with forefoot varus, 91.3% had medial, and 78.3% had lateral PFJ cartilage damage, compared with 54.6% and 68.2% of those with forefoot valgus. The former also had 3.0 times (95% CI 1.2, 7.7) the odds of medial PFJ damage; no association was found with lateral damage (OR 1.4, 95% CI 0.7, 3.0). Feet in the highest tertile of varus alignment had 3.9 times (95% CI 10, 15.3, P = 0.058) the odds of medial PFJ damage as those in the lowest tertile. The results of this study suggest a relationship between forefoot varus and medial PFJ cartilage damage in older adults. As forefoot varus may be modified with foot orthoses, these findings indicate a potential role for orthoses in the treatment of medial PFJ OA. Anat Rec, 300:1032-1038, 2017. © 2016 Wiley Periodicals, Inc.

Electrical conductivity of oxidized-graphenic nanoplatelets obtained from bamboo: effect of the oxygen content.

The large-scale production of graphene and reduced-graphene oxide (rGO) requires low-cost and eco-friendly synthesis methods. We employed a new, simple, cost-effective pyrolytic method to synthetize oxidized-graphenic nanoplatelets (OGNP) using bamboo pyroligneous acid (BPA) as a source. Thorough analyses via high-resolution transmission electron microscopy and electron energy-loss spectroscopy provides a complete structural and chemical description at the local scale of these samples. In particular, we found that at the highest carbonization temperature the OGNP-BPA are mainly in a sp(2) bonding configuration (sp(2) fraction of 87%). To determine the electrical properties of single nanoplatelets, these were contacted by Pt nanowires deposited through focused-ion-beam-induced deposition techniques. Increased conductivity by two orders of magnitude is observed as oxygen content decreases from 17% to 5%, reaching a value of 2.3 × 10(3) S m(-1) at the lowest oxygen content. Temperature-dependent conductivity reveals a semiconductor transport behavior, described by the Mott three-dimensional variable range hopping mechanism. From the localization length, we estimate a band-gap value of 0.22(2) eV for an oxygen content of 5%. This investigation demonstrates the great potential of the OGNP-BPA for technological applications, given that their structural and electrical behavior is similar to the highly reduced rGO sheets obtained by more sophisticated conventional synthesis methods.

Prospective change in daily walking over 2 years in older adults with or at risk of knee osteoarthritis: the MOST study.

OBJECTIVE: Radiographic disease and knee pain are thought to decrease physical activity in people with knee osteoarthritis (OA), but this has not been formally studied. We examined change in objectively measured daily walking over 2 years and evaluated the association of certain risk factors with reduced walking among adults with or at risk of knee OA. DESIGN: Steps/day over 7 days were collected at baseline and 2 years later in subjects with or at risk of knee OA from the Multicenter Osteoarthritis Study using a StepWatch. We evaluated the presence of radiographic knee osteoarthritis (ROA), knee pain, worsening of ROA and pain over 2 years, obesity, depressive symptoms, living situation, catastrophizing, fatigue, widespread pain and comorbidities with 2-year change in daily walking using regression models adjusted for potential confounders. RESULTS: 1318 met inclusion criteria (age 66.9 ± 7.7, 59% women, BMI 30.6 ± 5.9) and walked 126 ± 1700 steps/day fewer steps at 2 years (95% CI [-218, -35]). People with depressive symptoms at baseline walked 455 fewer steps/day [-872, -68], and there was a trend for people with ROA worsening to walk 183 fewer steps/day [-377.5, 11.7]. No other factors met statistical significance for change in daily walking. CONCLUSION: Adults with or at risk of knee OA experienced only minimal declines in daily walking over 2 years. Nonetheless, depressive symptoms and may be worsening ROA are associated with a decline in steps/day in adults with or at risk of knee OA.

Are Pressure Time Integral and Cumulative Plantar Stress Related to First Metatarsophalangeal Joint Pain? Results From a Community-Based Study.

OBJECTIVE: To examine the relationship between plantar stress over a step, cumulative plantar stress over a day, and first metatarsophalangeal (MTP) joint pain among older adults. METHODS: Plantar stress and first MTP pain were assessed within the Multicenter Osteoarthritis Study. All included participants were asked if they had pain, aching, or stiffness at the first MTP joint on most days for the past 30 days. Pressure time integral (PTI) was quantified as participants walked on a pedobarograph, and mean steps per day were obtained using an accelerometer. Cumulative plantar stress was calculated as the product of regional PTI and mean steps per day. Quintiles of hallucal and second metatarsal PTI and cumulative plantar stress were generated. The relationship between predictors and the odds ratio of first MTP pain was assessed using a logistic regression model. RESULTS: Feet in the quintile with the lowest hallux PTI had 2.14 times increased odds of first MTP pain (95% confidence interval [95% CI] 1.42-3.25, P < 0.01). Feet in the quintile with the lowest second metatarsal PTI had 1.50 times increased odds of first MTP pain (95% CI 1.01-2.23, P = 0.042). Cumulative plantar stress was unassociated with first MTP pain. CONCLUSION: Lower PTI was modestly associated with increased prevalence of frequent first MTP pain at both the hallux and second metatarsal. Lower plantar loading may indicate the presence of an antalgic gait strategy and may reflect an attempt at pain avoidance. The lack of association with cumulative plantar stress may suggest that patients do not limit their walking as a pain-avoidance mechanism.

Relation of Step Length to Magnetic Resonance Imaging-Detected Structural Damage in the Patellofemoral Joint: The Multicenter Osteoarthritis Study.

OBJECTIVE: To investigate the relationship of step length to the sex-specific prevalence and worsening of magnetic resonance imaging (MRI)-detected structural damage in the patellofemoral (PF) joint among a cohort of older women and men with or at risk of knee osteoarthritis (OA). METHODS: The Multicenter Osteoarthritis Study is a cohort study of persons ages 50-79 years with or at risk of knee OA. Step length was assessed using the GAITRite walkway (CIR Systems) at the 60-month visit, and cartilage damage and bone marrow lesions (BMLs) were graded on MRI at the 60- and 84-month visits. Step length was divided into sex-specific quintiles, and the relationship of step length to the prevalence and worsening of cartilage damage and BMLs in the PF joint was examined using logistic regression, adjusting for age, body mass index (BMI), leg length, and tibiofemoral joint structural damage. RESULTS: In 1,053 knees, 4,094 and 4,083 PF joint subregions were studied for the cartilage and BML analyses, respectively. Mean ± SD age was 65.6 ± 8.1 years and mean ± SD BMI was 29.1 ± 4.7 kg/m(2) ; 62% of participants were female. In women, compared to those with the shortest step length, those with the longest step length had 0.62 (95% confidence interval [95% CI] 0.43-0.88) and 0.59 (95% CI 0.40-0.87) times the odds of cartilage damage and BMLs, respectively. There was no cross-sectional association in men, and no longitudinal association in either sex. CONCLUSION: Women with PF joint structural damage may adapt their gait by shortening their step length, but this may not be sufficient to reduce the risk of worsening damage over time.