Abstract. Objectives. The aim of this study was to investigate whether mechanical loading induced by physical activity can reduce risk of sarcopenia in middle-aged adults. Methods. This was a longitudinal study based on a subset of UK Biobank data consisting of 1,918 participants (902 men and 1,016 women, mean age 56 years) who had no sarcopenia at baseline (assessed between 2006 and 2010). The participants were assessed again after 6 years at follow-up, and were categorized into no sarcopenia, probable sarcopenia, or sarcopenia according to the definition and algorithm developed in 2018 by European Working Group on Sarcopenia in Older People (EWGSOP). Physical activity was assessed at a time between baseline and follow-up using 7-day acceleration data obtained from wrist worn accelerometers. Raw acceleration data were then analysed to study the mechanical loading of physical activity at different intensities (i.e. very light, light, moderate-to-vigorous). Multinominal logistic regression was employed to examine the association between the incidence of sarcopenia and physical activity loading, between baseline and follow up, controlled for other factors at baseline including age, gender, BMI, smoking status, intake of alcohol, vitamin D and calcium, history of rheumatoid arthritis, osteoarthritis, secondary osteoporosis, and type 2 diabetes. Results. Among the 1918 participants with no sarcopenia at baseline, 230 (69 men and 161 women) developed probable sarcopenia and 37 (14 men and 23 women) developed sarcopenia at follow-up. Physical activity loading at moderate-to-vigorous intensity was higher in men (p<0.05), while women had higher physical activity loading at very light intensity (p<0.05). No significant difference was found in physical activity loading at light intensity between men and women (p>0.05). Logistic regression models showed that increase in physical activity loading at moderate-to-vigorous intensity significantly reduced the risk of sarcopenia (odds ratio = 0.368, p<0.05), but not probable sarcopenia (odds ratio = 0.974, p>0.05), while loading at light or very light activity intensity were not associated with the risk of sarcopenia or probable sarcopenia (p>0.05). Conclusion. Loading of physical activity at moderate-to-vigorous intensity could reduce risk of sarcopenia in middle-aged adults. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project

Pediatric patients with lower extremity sarcoma often experience long lasting restrictions concerning physical activity and walking due to the required off-loading of the limb and other consequences of surgeries. Activity promotion during treatment in addition to physiotherapy could improve patients’ activity levels and walking capabilities. In the present study we investigated the ambulatory activity of 31 pediatric patients (13.7 ± 3.1 years, 1.63 ± 0.15 m, 51.9 ± 15 kg, 19.3 ± 3.7 kg/m2) with Osteosarcoma or Ewing sarcoma at the lower limb using the StepWatch™ Activity monitor (SAM; Orthocare Innovations, USA). Sixteen patients regularly underwent supervised exercise interventions during inpatient stays, 15 did not receive any additional intervention. Step activities were measured for seven consecutive days during home stays at five different points in time, to determine a possible transfer of activity to everyday life. Patients without intervention assembled considerably less steps than those in the intervention group. Before surgery they reached 25.4% of the intervention group (total n=16), six weeks after surgery 40% (total n= 8), after three months 46% (total n=10), after six months 72% (total n=13) and after one year 90%. However differences only reached significance at the first measurement. Data presented must be considered as preliminary. Not all patients could be measured at all appointments due to impaired walking ability. Nevertheless activity promoting interventions during inpatient stays seem to have a positive influence on patients’ daily walking activity. Though the differences between the groups are not significant they are considerable. Especially during treatment – as reflected by the first three measurements- patients could benefit from additional interventions exceeding typical therapy regimes. Interventions should be individualized to the patients’ capabilities. Conclusions concerning tumor location or surgical procedures are not yet possible. Future research should furthermore concentrate on the effects of activity promotion on other fields of well-being

Abstract. Aims. Whilst short and mid-term activity levels after a Total Knee Replacement (TKR) have been reported in the literature; there is an over simplification of the reporting and longer-term activity levels are unknown. The aim of this study was to map the long-term trajectories of patients’ physical activity levels postoperatively to identify meaningful subgroups and explore associations with preoperative variables. Methods. This was a secondary analysis of a single centre longitudinal cohortstudy using group-based trajectory modelling (GBTM) of the University of California, Los Angeles (UCLA) physical activity score over ten years. Multinomial logistic regression models (both adjusted and unadjusted) were used to test associations between preoperative variables and trajectory group membership. Results. 266 of the 904 eligible patients were recruited (29%). Data from 260 patients was available for analysis. Four trajectory groups were identified with good fit of the model (average posterior probability 0.79 to 0.93). Of the four groups, the two more active groups had a peak activity level between two-three years postoperatively; the less active groups had a peak activity level at between three months and one year. Preoperative UCLA, participation in sports in the three years prior to surgery and male gender showed trends towards association with a higher activity group. Conclusions. Four trajectory groups were identified giving a more detailed understanding of temporal trends in physical activity levels post TKR. There was weak evidence to show an association between patient expectation, preoperative UCLA score and participation in sports in the prior three years and group membership

Abstract. INTRODUCTION. This study aimed to examine how physical activity and health-related quality of life (HRQoL) evolved over the first year after total knee replacement (TKR) for patients with and without post-operative chronic knee pain. METHODS. 83 adults participating in the PEP-TALK, a RCT testing the effectiveness of a behaviour change physiotherapy intervention versus usual rehabilitation post-primary TKR, were analysed. UCLA Activity Score and EQ-5D-5L values for participants with and without chronic knee pain (14 points or lower in the Oxford Knee Score Pain Subscale at six months post-TKR) were compared at six and 12 months post-TKR. We evaluated recovery trajectory those with or without chronic pain at these time points. RESULTS. Participants with chronic knee pain, UCLA Activity Score remained unchanged between baseline to six months (mean: 3.8 to 3.8), decreasing at 12 months (mean: 3.0). Those without post-operative chronic knee pain reported a improvement in physical activity from baseline to six months (mean: 4.0 vs 4.9), plateauing at 12 months (mean: 4.9). Participants with chronic knee pain reported lower baseline HRQoL, although both groups improved mean health utility over one year. Of participants who were not defined as being in chronic pain at six months, 8.5% returned to a chronic pain categorisation by 12 months. CONCLUSION. People with chronic knee pain post-TKR report poorer physical activity and HRQoL scores post-operatively. Monitoring outcomes longer than six months may be indicated as those without chronic knee pain initially post-TKR remain at risk of reverting to chronic knee pain 12 months post-TKR

Hip resurfacing arthroplasty (HRA) became a popular procedure in the early 90s because of the improved wear characteristic, preserving nature of the procedure and the optimal stability and range of motion. Concerns raised since 2004 when metal ions were seen in blood and urine of patients with a MoM implant. Design of the prosthesis, acetabular component malpositioning, contact-patch-to-rim distance (CPR) and a reduced joint size all seem to play a role in elevated metal ion concentrations. Little is known about the influence of physical activity (PA) on metal ion concentrations. Implant wear is thought to be a function of use and thus of patient activity levels. Wear of polyethylene acetabular bearings was positively correlated with patient's activity in previous studies. It is hypothesized that daily habitual physical activity of patients with a unilateral resurfacing prosthesis, measured by an activity monitor, is associated with habitual physical activity. A prospective, explorative study was conducted. Only patients with a unilateral hip resurfacing prosthesis and a follow-up of 10 ± 1 years were included. Metal ion concentrations were determined using ICP-MS. Habitual physical activity of subjects was measured in daily living using an acceleration-based activity monitor. Outcome consisted of quantitative and qualitative activity parameters. In total, 16 patients were included. 12 males (75%) and 4 females (25%) with a median age at surgery of 55.5 ± 9.7 years [43.0 – 67.9] and median follow-up of 9.9 ± 1.0 years [9.1 – 10.9]. The median cobalt and chromium ion concentrations were 25 ± 13 and 38 ± 28 nmol/L. A significant relationship, when adjusting for age at surgery, BMI, cup size and cup inclination, between sit-stand transfers (p = .034) and high intensity peaks (p = .001) with cobalt ion concentrations were found (linear regression analysis). This study showed that a high number of sit-stand transfers and a high number of high intensity peaks is significantly correlated with high metal ion concentrations, but results should be interpreted with care. For patients it seems save to engage in activities with low intensity peaks like walking or cycling without triggering critical wear or metal ions being able to achieve important general health benefits and quality of life, although the quality (high intensity peaks) of physical activity and behaviour of patients (sit-stand-transfers) seem to influence metal ion concentrations

Introduction: Both physical activity and inactivity have been suggested as risk factors for LBP, but the current evidence is conflicting. In this study we evaluated how the level of leisure time physical activity and amount of sitting are associated with LBP in a general population of adolescents. Methods: The study population consisted of 5999 boy and girl members of the Northern Finland 1986 Birth Cohort who responded to mailed questions at the age of 15–16 years. LBP during the past six months was classified as “No LBP”, “Reporting LBP” (not seeking medical help), or “Consultation for LBP”. Odds ratios and 95% confidence intervals obtained by multinomial logistic regression were adjusted for smoking and BMI. Results: Being physically very active (more than six hours of brisk physical activity per week) was associated with increased prevalence of “Consultation for LBP” in both genders, and with “Reporting LBP” in girls, compared to being moderately active (2–3 hours of brisk physical activity per week). High amount of sitting associated with “Consultation for LBP” and “Reporting LBP” in girls, but not in boys. Discussion: Very active participation in physical activities in both genders and high amount of sitting in girls, irrespective of the level of physical activity, were associated with reported LBP. Perhaps encouraging adolescents to physically moderately active lifestyle could diminish LBP. In addition, avoiding excessive sitting-based activities such as television watching and playing video games may be recommendable among girls

Background. Metal-on-metal hip implants can produce adverse tissue reactions to wear debris. Increased metal ion concentrations in the blood are measured as a proxy to wear and the complications it can trigger. Many studies have examined various factors influencing the metal ion concentrations. This is the first study to investigate the effect of physical activity level, as objectively measured in daily life, on blood ion levels, expecting higher concentrations for higher patient activity. Methods. Thirty-three patients (13F/20M, 55.8 ± 6.2 years at surgery) with a unilateral resurfacing hip prosthesis were included. At last follow-up (6.8 ± 1.5 years) cobalt and chromium concentrations in the blood were determined by inductively coupled plasma mass spectrometry. Physical activity was measured during 4 successive days using a 3D-acceleration-based activity monitor. Data was analysed using validated algorithms, producing quantitative and qualitative parameters. Acetabular cup position was measured radiographically. Correlations were tested with Pearson's r'. Results. Wide ranges in cobalt (10-833nmol/l) and chromium (16-592nmol/l) concentrations were measured. No correlations were found between metal ion concentrations and patient characteristics. The mean time of walking per day of was 5475 ± 2730 seconds (≈ 91 minutes) per day, with 6953 ± 3104 steps made during the day. The cadence, the number of steps per minute, was 99.5 ± 7.4. The subjects performed 41 ± 13 sit-stand transfers per day. The number of peak intensity declines when peaks where more intense. No correlations were found between quantitative or qualitative parameters and metal ion concentrations. Conclusions. Higher metal ion concentrations were not correlated with higher activity levels contrary to original expectations. Based on the results the orthopaedic surgeons is able to reassure his or her patients that physical activity in daily living is presumably safe en does not influence metal ion concentrations. Level of Evidence. 2b. Approval. the ethics committee of the Atrium MC, Heerlen approved this study

The purpose of this study was to evaluate and assess the sporting and physical activities of patients who have undergone hip resurfacing. One hundred and seventeen patients who underwent hip resurfacing between 2003–2007 were reviewed. Demographic data such as age, sex and comorbidities were recorded. University of California and Los Angeles (UCLA) activity level ratings and Oxford hip scores were collected pre-and postoperatively for each patient. The sporting and physical activities of all patients were pre-and post-operatively recorded. The mean age of patients at surgery was 54 yrs and 56 yrs at review. The mean follow up time was 19 months. Following surgery there was a significant improvement in UCLA activity level scores from 4.4 to 6.8 (Wilcoxon Matched-pairs Signed rank test, p< 0.05). Oxford hip scores significantly improved from 43.4 to 17.7 following surgery. Eighty six patients regularly participated in sport before they became symptomatic with significant hip pain, and 75 regularly participated in sports after surgery. In total 87% of patients successfully returned to their regular sporting and physical activities following surgery. Many patients were returning to high impact sports including football, tennis, cricket and squash. The published medium-term survivorship of the Birmingham hip has given surgeons increasing confidence to use the prosthesis on a younger generation of patients. Our study has demonstrated that hip resurfacing can allow patients to remain extremely active

Introduction. This analysis determined whether the type and level of physical activity changes during the initial 24 months post-total hip (THR) or total knee replacement (TKR) compared to pre-operative levels, and how this change compares to people without arthroplasty or osteoarthritis. Patients/Materials & Methods. Data from a prospective cohort dataset (Osteoarthritis Initiative dataset) of community-dwelling individuals who had undergone a primary THR or TKR were identified. These were compared to people who had not undergone an arthroplasty and who did not have a diagnosis of hip or knee osteoarthritis during the follow-up period (control). Data were analysed comparing between-group and within-group differences for physical activity (gardening, domestic activities, sports, employment, walking) within the first 24 months post-arthroplasty. Results. In total, 116 participants were analysed in the TKR group, 105 in the THR group. These cohorts were compared to 3441 (control) participants. Whilst physical activity largely increased from pre-operative levels during the first 12 months post-operatively, this change reverted at the 24 month assessment to pre-operative levels in people who underwent THR. There appeared limited change (increase nor decrease) in physical activity at 12 or 24 months post-operatively compared to pre-operative levels in people who underwent TKR. Compared to the non-arthroplasty cohorts, physical activity was consistently greater in the non-arthroplasty group at 12 and 24 months post-pre-operative/baseline measures. Discussion. There is limited change in the level or type of physical activity undertaken between people before or after THR or TKR in the first 24 post-operative months. Physical activity levels are lower in people following THR and TKR compared to people with similar characteristics who have not undergone arthroplasty or have osteoarthritis. Conclusion. Health strategies are warranted to address the limited increase in post-operative physical activity, to encourage this post-arthroplasty population to engage and maintain physical activity pursuits for wider health benefits

Introduction. Osteoarthritis (OA) of the hip and knee causes pain and functional limitations which lead to decreased physical activity level (1,2). Half of all male, and two thirds of all female, patients with early knee OA do not fulfill the recommendations for physical activity level (30 min/day of at least 5 days/week) (1). We tested the hypothesis that Scandinavian patients prior to total joint replacement had reduced actual physical activity and intensity levels compared with matched controls and that most patients did not fulfill the recommendations for physical activity. Methods. Physical activity and intensity were measured during 5 consecutive days with SenseWearTM Armband (SWA; BodyMedia, Inc., Pittsburgh, PA) in 53 patients with severe knee (n = 26) or hip (n = 27) OA prior to total joint replacement (51% women, age: 68 ± 5 years, BMI: 29.8 ± 10.2) and compared with data from 15 age-matched population-based controls (53% women, age: 68 ± 5 years, BMI: 26.9 ± 3.3). Sedentary, moderate, vigorous and very vigorous intensities were equivalent to Sense Wear Armband recordings of 3 MET, >36 MET, >69 MET, >9MET, respectively. In addition, total energy expenditure, average MET, numbers of steps/day, and the combined activity of moderate, vigorous, and very vigorous activity were calculated (min/day). Unpaired students t-test was used for between group comparisons (p < 0.05). Results. Participants wore the device for a mean ± SD of 98.5 ± 1.5% of the time. Patients spent significant less time being vigorously physically active (0.093 ± 0.082 vs. 0.156 ± 0.099 hours/day) and very vigorously active (0.015 ± 02 vs.0.028 ± 0.035 hours/day) than controls. However, no differences were observed for total energy expenditure, average MET, time spend being sedentary, and time spend being moderately physically active. The average activity of combined moderate, vigorous, and very vigorous activity for patients were 185 ± 1 min/day and 11.3% did not reach the recommended activity level. Finally, a tendency (p = 0.059) towards less steps/day was observed for patients (6778 ± 3196 vs. 8576 ± 2872 steps/day). Conclusions. Since Scandinavian OA patients prior to joint replacement show no or little decrease in physical activity, and that the majority fulfills recommendations for physical activity an increase in actual physical activity cannot be expected from surgery. This unexpected finding needs to be confirmed

Introduction. Early functional recovery following total hip arthroplasty (THA) has the potential to increase patient satisfaction and reduce resource utilization. The direct anterior approach (DA) has been shown to provide earlier recovery compared to the direct lateral (DL) approach based on functional tests and outcome scores. There are limited studies that objectively evaluate functional recovery comparing the two approaches in the early post-operative period. Activity trackers have emerged as a valid tool to objectively quantify physical activity levels and potentially better assess functional status compared to commonly reported functional questionnaires. The purpose of this study is to measure physical activity levels in patients undergoing THA with the DA approach and compare these to THA with the direct lateral approach in the immediate postoperative period. Methods. In a tertiary academic center we prospectively enrolled patients with primary OA that were eligible for a primary THA undergoing either the DA or the DL approach using the same prosthesis. Patients with comorbidities precluding them from ambulation, diagnoses of AVN or RA or undergoing bilateral THA were excluded. The number of steps walked per day were measured using wristband activity tracking technology for one week preoperatively, the first 2 weeks postoperatively and for 1 week leading up to their 6-week follow-up appointment. The University of California, Los Angeles (UCLA) activity score was also collected at the same two time points. Demographics were analyzed with descriptive statistics. A non-parametric Mann Whitney U test was used to determine whether a difference in physical activity levels exist between the DA and DL approach groups in the first 2 weeks and 6 weeks postoperatively. Results. One hundred and thirty-nine patients with primary OA were enrolled. Seventeen were withdrawn prior to beginning the study (7 – patient requested, 5 – could not work the activity tracker, 5 – health issues). Following enrolment 29 patients were withdrawn due to lack of data available for analysis. There were 53 patients in the DA group and 40 patients in the DL group. Patient demographics including age and gender were similar in both groups. Body mass index was higher in the DL group (32.4 ± 6.9) compared to the DA group (28.2 ± 3.9) (p=0.001). There was no difference in the average steps taken per day or the UCLA score between the two groups preoperatively. The UCLA score and the overall average steps walked collected at 2 weeks postoperatively were significantly higher in the DA group compared to the DL group (median 4(1–6) vs. 3(2–6), p<0.001 and median 1641(329 – 8678) vs. 890(87 – 4347), p<0.001) respectively. When each postoperative day was evaluated individually, the DA group had a greater number of steps per day for the entire two weeks. At 6 weeks, the average number of steps taken by the DA group (median 4734 (1703 – 16605) () were greater than those taken by the DL group (median 3534 (462–8665) ± 2263) (p=0.007). A similar finding was demonstrated for the UCLA with the DA having greater self-reported activity levels (median 6 vs. 4, p<0.001). Discussion/Conclusions. The DA approach provided faster functional recovery in the immediate postoperative period compared to the DL approach as measured by a wristband activity tracker. DA approach patients walked a greater number of steps at both 2 weeks and 6 weeks. Further examination regarding the economic implications of the improved early function from the perspective of the patient, caregiver, and care payer is indicated

Introduction. A smartphone-based care platform allows a customizable educational and exercise interface with patients, allowing many to recover after surgery without the need for formal physical therapy (PT). Furthermore, advances in wearable technology to monitor physical activity (PA) provides patients and physicians quantifiable metrics of the patient's recovery. The purpose of this study is to determine the feasibility of a smartphone-based exercise educational platform after primary knee arthroplasty as well as identifying factors that may predict the need for formal physical therapy. Methods. This study is part of a multi-institution, prospective study of patients after primary total knee arthroplasty (TKA) and partial knee arthroplasty (PKA) enrolled in a smartphone with smartwatch-based episode of care platform that recorded multimodal PA (steps, kcal, stairs). Postoperatively, all patients initially followed the smartphone-based exercise program. At the surgeon's discretion, patients were prescribed therapy if needed. The outcome of this study was the need for PT outside the app-based exercise program as well as time to return to preoperative step count. Variables assessed were preoperative weekly step counts (steps/day), weekly postoperative activity level (weekly step count compared to preoperative level), compliance with the exercise program (>75% completion) and patient demographic data including gender, age, BMI and narcotic use. One hundred eighty-eight patients were included in analysis: 45 PKA (24%) and 143 TKA (76%). Step count data was available on 135 patients and physical therapy data on 174. Results. Overall educational compliance was 91% and exercise compliance 34%. By 4-weeks postop, 45.6% of patients reached or exceeded their preoperative step count, including 60% of PKA and 41% of TKA (p=0.05). There was no significant difference in reaching step count based on gender (p=0.7), BMI <40kg/m2 (p=0.9) or age <65-years old (p=0.67). Sixty-three percent of patients that were compliant with the exercise program reached the step count compared to 40% of patients that weren't complaint (p=0.01). One hundred thirty-three patients (76.4%) completed the app-based exercise program without the need for PT, which included 81.4% of PKA patients and 75% of TKA patients (p=0.38). Weekly compliance with the exercise program (>75%) was significantly associated with not needing PT (p<0.001). Other factors that were significantly associated with the need for PT were a high physical activity level in postoperative week 1 (p<0.001) and a low physical activity level in postoperative week 2 (p=0.002). Conclusion. A high percentage of patients after primary knee arthroplasty were able to successfully complete the smartphone-based exercise program without the need for PT. Compliance with the exercise program was an important predictor of success. Postoperative activity level may also indicate the need for therapy as patients who were very active in the first postoperative week and then saw a decline in activity in the second week were more likely to be prescribed PT. With this platform, surgeons can monitor a patient's exercise compliance and postoperative activity level allowing many to recover at home, while being able to identify those within the first few weeks who may need structured physical therapy. For figures, tables, or references, please contact authors directly

Introduction. Previous systematic reviews have shown that patients experience low physical activity levels following total hip replacement (THR). However no previous systematic reviews have examined the changes between pre- and post-operative physical activity levels. Methods. AMED, MEDLINE, EMBASE, CENTRAL, CINHAL, openSIGLE, . ClinicalTrials.gov. and UK Clinical Trials Gateway databases were searched to 19. th. May 2015. All study designs presenting data on physical activity at pre- and up to one-year post-operatively were included. Eligible studies were critically appraised using the Cochrane risk of bias tool (for randomised controlled trials (RCTs)) and the CASP tool (non-RCTs). Where possible, mean differences (MD) and 95% confidence intervals (CI) were calculated through meta-analyses. Results. From 3850 citations, 16 met the eligibility criteria; nine included in the meta-analysis. The quality of the evidence was graded low to moderate. There was no statistically significant difference in physical activity pre- to one year post-THR when assessed using: movement-related activity (MD: −0.08; 95% CI:- 1.60 to 1.44; I. 2. =0%; n=77), percentage of 24 hours spent walking (MD: −0.21; 95% CI: −1.36 to 0.93; I. 2. =12%; n=65), six minute walk test (MD: −60.85; 95% CI: −122.41 to 0.72; I. 2. =84%; n=113) or the cardiopulmonary exercise test (MD: −0.24; 95% CI: −1.36 to 0.87; I. 2. =0%; n=76). Discussion. There is no evidence to suggest that physical activity changes pre- compared to post-THR. The low methodological quality of the included papers means this finding should be viewed with caution. Further research is warranted to better understand the relationship between physical activity pre- and post-THR, as greater consideration may be needed to increase physical activity in this population post-operatively. Conclusion. Surprisingly, there is no significant change in physical activity following THR. Surgeons, physiotherapists and patients should consider how to increase and maintain physical activity levels to maximise the potential for wider-health benefits following THR

Introduction: Previous studies have reported controversial associations between exercise and neck or shoulder pains in adolescents. In this study we evaluated the relationships between physical activity or sedentary activities and neck or occipital pain (NOP) or shoulder pain (SP) in a representative sample of adolescents. Methods: The study population consisted of adolescents belonging to the Northern Finland Birth Cohort 1986 (n=5993). Associations of physical activity level, total sitting time, and different kinds of sedentary activities with NOP and SP were analyzed at 15–16 years of age using logistic regression. “Reporting NOP and SP” (not seeking medical help) and “Consultation for NOP and SP” were assessed separately in girls, but were combined in boys because of low prevalence of “Consultations”. Results: Almost half of the girls and one third of the boys reported NOP or SP, and 5% of girls and 2% of boys reported “Consultation for NOP or SP” during the past six months. High level of physical activity associated with increased prevalence of both “Consultation for NOP” and “Consultation for SP” in girls, but not in boys. Prolonged sitting was associated with high prevalence of NOP and SP in girls, and NOP in boys. Of various sedentary activities, TV watching and reading books associated with NOP in girls, whereas playing or working with a computer associated with NOP in boys. In girls, TV watching also associated with “Reporting SP”. Discussion: Both prolonged sitting and high level of physical activity seem to be related to NOP and SP among adolescents

Introduction: Despite growing awareness of the beneficial effects of physical activity on health, little is known about the amount of physical activity after THA. Although the WOMAC does not give direct information about the amount of physical activity it can be hypothesized that when patients experience limitations this will have an adverse effect on the amount of physical activity they are involved in. In this way the WOMAC can be predictive for the amount of physical activity. The aim of this study is to determine the correlation between the WOMAC and the amount of physical activity and to determine the predictive value of the WOMAC on meeting the (inter-) national guidelines of health -enhancing physical activity. Materials and Methods: 364 patients with a THA (minimal one year postoperative) were included. Self-reported physical functioning was assessed by means of the WOMAC and the amount of physical activity by means of the SQUASH. Correlations between the WOMAC and SQUASH-scores were assessed using Pearson’s correlation coefficient. Binary logistic regression modelling was used to determine to which extent the score on the WOMAC was predictive in meeting the (inter-)national guidelines. Results: A significant, low correlation between the WOMAC and SQUASH-scores (range 0.14 – 0.24) was found. Although the WOMAC was a significant predictor to meet the (inter-) national guidelines of physical activity (p< 0.001), the odds-ratio was low (1.022, 95%CI 1.0121.033). The Nagelkerke R2 was 0.069, implicating that 6.9% of the variance could be explained. Conclusion: The WOMAC is not suitable to predict the amount of physical activity after THA, necessitating the use of additional quantitative outcome measures

Summary. Physical activity monitoring using a single accelerometer works reliably in clinical practice and is of added value as clinical outcome tool, as it provides objective and more precise information about a patient's activity compared to currently used questionnaires. Introduction. Standard clinical outcome tools do not comply with the new generation of patients who are younger and more active. To capture the high functional demands of these patients, current outcome scales have been optimised (e.g. New-Knee Society Score: New-KSS), new outcome scales have been developed (e.g. Knee disability and Osteoarthritis Outcome score: KOOS). Also objective measurement tools (e.g. activity monitors) have become increasingly popular. This study evaluates the pre- and postoperative TKA status of patients using such optimised and new outcome tools. Patients and Methods. Physical activity of 18 preoperative (68 ± 6yrs) and 16 postoperative (72 ± 7yrs, follow up range 9–10 yrs) TKA patients was assessed using a most recommended patient reported questionnaire, SQUASH (high value=more active) and a body-fixed 3D-accelerometer based activity monitor (AM). The AM was worn for 4–7 successive days at the lateral side of the nonaffected upper leg. Activity parameters (e.g. # steps, # transfers, # walking bouts of short/long duration, cadence) were derived using validated algorithms. Function was measured using patient reported questionnaires: KOOS-PS (range 0–100=worse) and New-KSS (higher score=better). Independent t-test, Mann-Whitney test and Pearson's r were used to compare groups and to investigate correlations (p<0.05). Results. All AMs and questionnaires were returned (response rate 100%) and showed similar or higher completion rates for the AM (100%) than questionnaires (range 82–100%). At 10yrs follow-up, the function of TKA patients was significantly improved with regards to preoperative showing lower KOOS-PS and higher New-KSS subscores. Also physical activity was higher at 10yrs showing significantly more steps/day (+39%). Other activity parameters like walking bouts and transfers were also higher in the postoperative group (resp.8% and 21%), but not significantly. Most walking bouts were short taking 10–30s (pre: 63%, post: 59% of the bouts) and consisting of 10–15 steps (pre: 78%, post: 75% of the bouts). The only correlation found between activity and functional outcomes was between AM data (amount steps, sitting, walking time) and the New-KSS Function walking & standing subscale (r-range 0.37–0.54). No correlation was found between AM data and SQUASH. Moderate to high correlations were found between functional outcomes (KOOS-PS vs. New-KSS, r-range −0.56 – −0.81). Discussion/Conclusion. At 10yr follow up, TKA patients continue to have higher functional scores and also maintain higher activity levels than preoperative, as is mainly shown in steps/day. The fact that only the New-KSS Function Walking & Standing subscale correlated with AM data indicates that function and activity are two widely independent outcome dimensions. This suggests that patients are active largely independent of their functional limitations (e.g. high activity, worse KOOS). The lack of correlation between objectively measured and patient reported physical activity indicates patients are less reliable in estimating their actual activity. The correlations between functional outcomes indicate redundancy. AM meets and exceeds response and completion rates of questionnaires. AM seems to be more objective, precise and sensitive to measure physical activity than questionnaires and adds a largely independent outcome dimension to clinical assessments

Introduction. Knee osteoarthritis (KOA) causes impairment through pain, stiffness and malalignment and knee joint replacement (KJR) may be necessary to alleviate such symptoms. There is disagreement whether patients with KJR increases their level of physical activity after surgery. The aim of this study is to investigate whether patients with KJR have a higher level of physical activity than patients with KOA, as measured by accelerometer-based method. Furthermore, to investigate whether patients achieve the same level of activity as healthy subjects five years post TJR. Material and method. 54 patients with KOA (29 women, mean age 62±8.6, mean BMI 27±5), 53 patients who had KJR five years earlier (26 women, mean age 66±7.2, mean BMI 30±5) and 171 healthy subjects (76 women, mean age 64±9.7, mean BMI 26±5) were included in this cross sectional study. The level of physical activity was measured over a mean of 5.5 days with a tri-axial accelerometer mounted on the thigh. Number of daily short walking bouts of. Results. Patients with KJR had 10.1 fewer short walking bouts (p=0.04), 745 fewer steps (p=0.19) and 6.2 fewer transfers (p=0.09) per day than patients with KOA. In addition, patients with KJR performed 21.7 fewer short walking bouts (p=0.001), 281 fewer steps (p=0.60) and 3.2 fewer transfers (p=0.32) per day than healthy subjects. Conclusion. Patients with KJR do not seem to be more physically active than patients with KOA. Neither do the seem to be as active as healthy subjects, However, the results may suffer from selection bias and thus the results ought to be confirmed in a bigger cohort study

Introduction. Limited physical activity (PA) is one indication for orthopaedic intervention and restoration of PA a treatment goal. However, the objective assessment of PA is not routinely performed and in particular the effect of spinal pathology on PA is hardly known. It is the purpose of this study using wearable accelerometers to measure if, by how much and in what manner spinal stenosis affects PA compared to age-matched healthy controls. Patients & Methods. Nine patients (m/f= 5/4, avg. age: 67.4 ±7.7 years, avg. BMI: 29.2 ±3.5) diagnosed with spinal stenosis but without decompressive surgery or other musculoskeletal complaints were measured. These patients were compared to 28 age-matched healthy controls (m/f= 17/11, avg. age: 67.4 ±7.6 years, avg. BMI: 25.3±2.9). PA was measured using a wearable accelerometer (GCDC X8M-3) worn during waking hours on the lateral side of the right leg for 4 consecutive days. Data was analyzed using previously validated activity classification algorithms in MATLAB to identify the type, duration and event counts of postures or PA like standing, sitting, walking or cycling. In addition, VAS pain and OSWESTRY scores were taken. Groups were compared using the t-test or Mann-Whitney U-test where applicable. Correlations between PA and clinical scores were tested using Pearson”s r. Results. Spinal stenosis patients showed much lower PA than healthy controls regarding all parameters like e.g. daily step count (2946 vs 8039, −63%, p<0.01) or the relative daily time-on-feet (%) (8.6% vs 28.3%, −70%, p<0.01) which is matched with increased sitting durations (80.3% vs 58.8%, p<0.01). Also qualitative parameters such as walking cadence was reduced in stenosis patients (83.7 vs 97.8 steps/min). With stenosis no patient ever walked >1000 steps without interruption. Also the number of walking bouts between 250–1000 steps was 4.5 times lower than in healthy controls (p<0.01). When the relative distribution of walking bout length was calculated, it became visible that stenosis patients showed more short walking bouts of 10–50 steps (p<0.05). There were no strong and significant correlations between the clinical scores and PA parameters. Discussion & Conclusions. Spinal stenosis greatly reduced physical activity to levels below WHO guidelines (e.g. <5000 steps= sedentary lifestyle) where the risk for general health (overall mortality), cardiovascular or endocrinological health is significantly increased. Activity levels are lower than reported for end-stage hip or knee osteoarthritis. Therefore, spinal stenosis patients should not only receive pain medication, but be made aware of their limited PA and its detrimental health effects, participate in activation programs, or be considered for surgical intervention. The absence of long walking bouts and the relatively more frequent short walking bouts seem indicative of intermittent claudication as typical in spinal stenosis

Objective of the study is to determine to what extent patients experience more limitations 1–5 years after revision total hip arthroplasty (THA) compared to patients after primary THA, and if this is accompanied by a reduction in physical activity behavior. Five hundred and six patients were included: 372 primary and 134 revision THA. Questionnaires were used to measure limitations and physical activity. Linear regression analysis showed that patients after revision surgery report significantly more, clinically relevant limitations compared with primary THA patients, but did not show a significant difference in mean total minutes of physical activity per week. Physical activity behavior appeared to be similar for primary and revision THA patients. The results stress the importance of determining different aspects of recovery after THA

Purpose: Section of the anterior cruciate ligament (ACL) is classically used to induce experimental joint degeneration in animal models (dog, rabbit, rat…), but the contribution of physical activity to the course of the cartilage damage observed in this model remains unknown. We studied the influence of moderate physical activity on the course of experimental knee joint degeneration induced by section of the ACL in the rat. Material and methods: The right knee ACL was sectioned with and arthrotome in 60 male Wistar rats (180 g) under general anaesthesia. Full section of the ACL, performed with a fine lancet, was verified clinically by demonstrating anterior drawer. The non-operated knee served as a control. The rats were separated at random into two groups, with or without exercise. Exercise was calibrated on a treadmill running at constant speed (30 cm/s for 30 min, i.e. 15 km for 28 days). Rats were sacrificed on days 7, 14 and 28. Macroscopic inspection, histological analysis and immunohistochemistry tests (Caspase 3) were performed on each knee segment. NO was also assayed in the synovial fluid. Results: No cartilage damage was observed in the non-operated knees after running 15 km. Marked synovitis was observed in the knees with a sectioned ACL starting on day 7, associated with fibrillary surface formations. The severity of the cartilage damage increased from day 14 to day 28, predominantly on the medial tibial plateau and to a lesser extent on the adjacent femoral condyle, in the weight-bearing zone. Damage was minimal on the patella. Chondrocyte apoptotic phenomena were also observed, reaching maximum on day 7 and sustained thereafter. Physical activity had a significant effect on these parameters showing an improvement in the macroscopic and histological lesions from day 14 to day 28, and improvement in chondrocyte apoptosis from day 7 to day 14 and to day 28. Discussion: This novel work confirms the beneficial effect of moderate physical activity in an experimental joint degeneration rat model. Elsewhere, it has been well established experimentally that intense joint activity has a deleterious effect on chondral lesions after meniscectomy and/or section of the ACL. This unfavourable effect of intense physical activity has also been observed clinically in high-level athletes. Our experimental data suggest that moderate physical activity does not increase the risk of joint degeneration and could, under certain conditions, have a beneficial effect, as has been suggested by certain recent clinical data