Validation of a novel activity monitor in impaired, slow-walking, crutch-supported patients

Disability and physical activity in people with chronic disease receiving physiotherapy. A prospective cohort study

Chronic disease affects patients' disability and participation in activities of daily living. Longitudinal information on disability and physical activity is generally scarce in patients with chronic disease. The current study aimed to investigate if self-reported disability and physical activity changed in patients with chronic disease receiving physiotherapy. Furthermore, the aim was to assess if an improvement in self-reported disability was related to an increase in objectively measured physical activity and if an aggravation in self-reported disability was related to a decrease in physical activity. Seventy patients with either multiple sclerosis, Parkinson's disease, rheumatoid arthritis or stroke receiving free of charge physiotherapy were tested at baseline and 1 year later. Disability was measured with the self-reported modified Ranking Scale-9 Questionnaire and physical activity was objectively measured using tri-axial accelerometry. Neither self-reported disability nor physical activity changed among patients receiving 1 year of free of charge physiotherapy at group level. Furthermore, self-reported change of disability was not expressed with changes in objectively measured physical activity, indicating that the two measures represent two different constructs.

Only limited correlations between patient-reported outcomes and objectively monitored physical activity 10-years after THA

In orthopaedics, patient reported outcomes (PROMs) are designed to quantify changes in pain and to assess physical function, most often after joint arthroplasty. However, PROMs have some disadvantages, most important is their subjective nature. The aim was to investigate how patient-self-reported-outcomes of general health, disease-specific outcome and physical function, joint-awareness and self-perceived activity- levels are correlated with objectively-measured physical-activity (PA) parameters derived from wearable activity-monitors (AM) in subjects with a hip-arthroplasty. A prospective cohort study was conducted in a group of 32 patients, with a mean follow-up of 10 years after total hip arthroplasty. To assess different domains, the SF-36 (general health), HOOS-PS (pain/functional outcome), FJS-12 (joint awareness) and SQUASH (physical activity) were chosen. Activity-monitoring was performed using a 3-axis accelerometer, gyroscope and magnetometer. No significant correlations between PA-parameters and the FJS-12 and SQUASH were found. The HOOS- PS was significant correlated with BMI, the daily time walking and total-time active and the amount of daily steps. The physical functioning-subscale of the SF-36 was significant negative correlated with BMI and time sitting, but significant positive correlated with time walking, total-time active and the amount of daily steps. Considering the value of PA for maintaining general health, the value of using sensor-based AMs to assess efficacy of treatments in this health related dimension or use it as a tool for patient education, awareness and communication, seems very high.

Developing and validating an accelerometer-based algorithm with machine learning to classify physical activity after acquired brain injury

Purpose: To develop and validate an accelerometer-based algorithm classifying physical activity in people with acquired brain injury (ABI) in a laboratory setting resembling a real home environment.Materials and methods: A development and validation study was performed. Eleven healthy participants and 25 patients with ABI performed a protocol of transfers and ambulating activities. Activity measurements were performed with accelerometers and with thermal video camera as gold standard reference. A machine learning-based algorithm classifying specific physical activities from the accelerometer data was developed and cross-validated in a training sample of 11 healthy participants. Criterion validity of the algorithm was established in 3 models classifying the same protocol of activities in people with ABI.Results: Modeled on data from 11 healthy and 15 participants with ABI, the algorithm had a good precision for classifying transfers and ambulating activities in data from 10 participants with ABI. The weighted sensitivity for all activities was 89.3% (88.3-90.4%) and the weighted positive predictive value was 89.7% (88.7-90.7%). The algorithm differentiated between lying and sitting activities.Conclusion: An algorithm to classify physical activities in populations with ABI was developed and its criterion validity established. Further testing of precision in home settings with continuous activity monitoring is warranted.

Quality, but not quantity of physical activity is associated with metal ion concentrations in unilateral hip resurfacing

Little is known about the influence of physical activity (PA) on metal ion concentrations in subjects with metal-on-metal hip arthroplasty. Implant wear is thought to be a function of use and thus of patient activity levels. It is hypothesized that daily habitual PA of patients with hip resurfacing arthroplasty (HRA) is associated with metal ion concentrations. Therefore a study was conducted in patients with a unilateral HRA at 10-years follow-up. Blood metal ion concentrations were determined. An acceleration-based activity monitor was used to measure PA in daily life. The cohort consisted of 12 males (75%) and 4 females (25%) with a median age at surgery of 55.5 ± 9.7 years [43.0-67.9] and a 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 association between sit-stand transfers and high-intensity peaks with cobalt ion concentrations were found. Regarding PA and metal ion concentrations as a proxy of wear in HRA, specific activities like transfers or qualitative aspects of activity behavior like intensity, seem to matter more than the quantity of low-intensity activities like walking or cycling. This suggests that patients may safely engage in such activities to achieve important general health benefits and quality of life.

Use of accelerometer-based activity monitoring in orthopaedics: benefits, impact and practical considerations

Studies of the effectiveness of orthopaedic interventions do not generally measure physical activity (PA). Applying accelerometer-based activity monitoring in orthopaedic studies will add relevant information to the generally examined physical function and pain assessment.Accelerometer-based activity monitoring is practically feasible in orthopaedic patient populations, since current day activity sensors have battery time and memory to measure continuously for several weeks without requiring technical expertise.The ongoing development in sensor technology has made it possible to combine functional tests with activity monitoring.For clinicians, the application of accelerometer-based activity monitoring can provide a measure of PA and can be used for clinical comparisons before and after interventions.In orthopaedic rehabilitation, accelerometer-based activity monitoring may be used to help patients reach their targets for PA and to coach patients towards a more active lifestyle through direct feedback. Cite this article: EFORT Open Rev 2019;4:678-685. DOI: 10.1302/2058-5241.4.180041.

Predicting physical activity recovery after hip and knee arthroplasty? A longitudinal cohort study

BACKGROUND

Recovery of physical activity (PA) after telerehabilitation following knee and hip arthroplasty (TKA-THA) has rarely been studied. An improved understanding of PA recovery is needed, as it could be influenced by many factors such as age, gender or pre-operative physical function.

OBJECTIVES

To assess PA recovery weekly for 3 months after TKA-THA and to determine perioperative factors that could help predict PA recovery at 3 months.

METHODS

From one week before until 3 months after surgery, 132 patients wore a fitness tracker continuously. Each patient received personalized and daily exercises and feedback through a tablet. Before and after surgery, patient-reported outcome measures of symptoms, pain, activities of daily living and quality of life were recorded. A one-way repeated-measure ANOVA was used to assess the time effect on step count for each post-operative week. To predict the absolute step count at 3 months post-surgery, a backward multiple linear regression was used.

RESULTS

Patients reached their pre-operative PA level at week 7, with no significant additional improvement by 3 months post-surgery. Pre-operative step count, the number of days using crutches and pre-operative symptoms explained 35% of the variability of step count at 3 months.

CONCLUSION

This patient population receiving telerehabilitation reached their pre-operative PA level at 7-week post-surgery with no further improvement over the subsequent 5 weeks. The PA level at 3 months could be predicted by pre-operative step count, duration of crutches use, and pre-operative symptoms.

Metal ion concentrations after metal-on-metal hip arthroplasty are not correlated with habitual physical activity levels

INTRODUCTION

Metal-on-metal (MoM) hip arthroplasties have shown high clinical failure rates with many patients at risk for a revision and under surveillance for high metal ion concentrations. Implant wear releasing such ions is assumed to be a function of use, i.e. the patient's physical activity. This study aimed to assess whether habitual physical activity levels of MoM patients are correlated with metal ion concentrations and are higher in patients with high (at risk) than in patients with low (safe) metal ion concentrations.

METHODS

A cohort study was conducted of patients with any type of MoM hip prosthesis. 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.

RESULTS

In total, 62 patients were included. Mean age at surgery was 60.8 ± 9.3 years and follow-up was 6.3 ± 1.4 years. Cobalt concentrations were highly elevated overall (112.4 ± 137.9 nmol/L) and significantly more in bilateral (184.8 ± 106.5 nmol/L) than in unilateral cases (87.8 ± 139.4 nmol/L). No correlations were found between physical activity parameters and metal ion concentrations. Subgroup analysis of patients with low versus high cobalt concentration showed no significant differences in habitual physical activity.

DISCUSSION

No correlation was found between physical activity levels and metal ion concentrations. Implant use by normal habitual activities of daily living seems not to influence metal ion concentrations.

Does the physical activity profile change in patients with hip dysplasia from before to 1 year after periacetabular osteotomy?

Background and purpose - Knowledge of physical activity profiles among patients with hip dysplasia is lacking. We investigated whether patients with hip dysplasia change physical activity profile from before to 1 year after periacetabular osteotomy. Furthermore, we investigated associations between change in accelerometer-based physical activity and change in self-reported participation in preferred physical activities (PA). Patients and methods - Physical activity was objectively measured at very low to high intensity levels with accelerometer-based sensors. Subjectively, PA was recorded with Copenhagen Hip and Groin Outcome Score (HAGOS) in 77 patients. Associations between the 2 were analyzed with simple linear regression analyses. Results - Changes in accelerometer-based physical activity ranged from -2.2 to 4.0% points at all intensity levels from baseline to 1-year follow-up. These changes represent very small effect sizes (-0.16 to 0.14). In contrast, self-reported PA showed a statistically and clinically relevant increase of 22 (CI 14-29) HAGOS PA points 1 year post-surgery. Associations between change in accelerometer-based physical activity and change in self-reported PA were, however, not statistically significant and correspond to a percentage change in physical activity of only -0.87% to 0.65% for a change of 10 HAGOS PA points. Interpretation - Patients with hip dysplasia do not seem to change physical activity profile 1 year post-surgery if measured with objective accelerometer-based sensors. This is interesting as self-reported PA indicates that patients' ability to participate in physical activity increases, suggesting that this increased self-reported participatory capacity is not manifested as increased objectively measured physical activity.

Are patients with knee osteoarthritis and patients with knee joint replacement as physically active as healthy persons?

Background

It is well documented that patients with knee osteoarthritis (KOA) suffer from reduced physical function and that function of the affected knee is improved after knee joint replacement (KJR). However, it remains uncertain whether patients with KOA are less physically active than healthy people and whether patients increase their level of physical activity after surgery to a level comparable with that of healthy people. The aim of this study was to examine whether patients with KOA are less physically active than healthy participants and whether patients who have undergone KJR show an increased activity and achieve the same level of physical activity as healthy participants 5 years postoperatively.

Methods

Fifty-four patients with KOA (29 women; mean age 62 ± 8.6; mean body mass index (BMI) 27 ± 5), 52 patients who had KJR due to KOA 5 years earlier (26 women; mean age 66 ± 7.2; mean BMI 30 ± 5) and 171 healthy participants (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 period of 5.5 days with a triaxial accelerometer mounted on the thigh. Number of daily steps, number of daily short walking bouts of <10 s duration and number of daily transfers from sitting to standing position were recorded. Data were analysed using two sample t tests and were adjusted for age, gender and BMI.

Results

Patients with KOA did not differ significantly from healthy participants regarding daily steps (+321, p = 0.50) or daily transfers from sitting to standing (+1.9, p = 0.52) but performed significantly less daily short walking bouts <10 s (-11.9, p = 0.02). Patients after KJR did not differ significantly from healthy participants regarding daily steps (-281, p = 0.60) of transfers from sitting to standing position (-3.2, p = 0.32) but performed significantly less daily short walking bouts <10 s (-21.7, p = 0.001).

Conclusion

Patients with KOA and KJR showed no significant reduction in number of daily step counts and transfers from sitting to standing position when compared with matched healthy controls. However, the number of short walking bouts was reduced in patients with KOA and by twice as much in patients with KJR. This indicates that KOA and treatment with KJR hardly affect health-related general activity but do affect specific physical activity behaviour potentially indicative of KOA or post-KJR functional limitations.

The translational potential of this article

Activity monitoring with an accelerometer-based method gives insights into health-related general activity levels such as total daily steps and specific parameters such as short walking bouts, which may serve as an objective outcome measure in clinical practice.