Physical Activity in Patients After Resurfacing and Total Hip Arthroplasty: an Observational Follow-up Study 15 Years After Surgery.
Conditions: Total Hip Arthroplasty (THA), Accelerometers, Resurfacing Hip Arthroplasty
Sponsor: Rijnstate Hospital

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TEMPLATE RESEARCH PROTOCOL 
(September 2018) 
 
- 
May 2015: adaptation section 11.5: text in accordance to old and new Measure 
regarding Compulsory Insurance for Clinical Research in Humans  
- 
Sept 2015: adaptation section 9.1, 9.2 and 12.5: text in accordance to WMO 
amendment on reporting SAE and temporary halt (section 10 of WMO) 
- 
Oct 2015: adaptation section 4.4 – comment [CCMO15], 8.2 and 10.1 with respect to 
methodology/statistics 
- 
Sept 2018: adaptation section 12.1 and comment [CCMO46] due to applicability 
GDPR as of May, 2018 
 
 
 

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PROTOCOL TITLE  
Physical activity in patients after resurfacing and total hip arthroplasty: an observational 
follow-up study 15 years after surgery. 
 
Protocol ID 
2025-2605 
Short title 
Triaxial Accelerometry Study 
EudraCT number  
N/A 
Version 
1 
Date 
11-02-2025 
Coordinating 
investigators/project leaders 
 
Dr. Lex D. de Jong 
Ziekenhuis Rijnstate  
Secretariaat Orthopedie (1191)  
Antwoordnummer 111  
6800 WC Arnhem 
 
Dr. Tim Lindsay and Dr. Milos Brkljac  
MSK-Lab, Imperial College London  
2nd Floor, Sir Michael Uren Hub 
86 Wood Lane, London W12 0BZ 
United Kingdom 
Principal investigators 
 
Dr. Job L.C. van Susante 
Ziekenhuis Rijnstate 
Secretariaat Orthopedie (1191) 
Antwoordnummer 111 
6800 WC Arnhem  
 
Professor Justin Cobb 
MSK-Lab, Imperial College London 

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2nd Floor, Sir Michael Uren Hub 
86 Wood Lane, London W12 0BZ 
United Kingdom 
Sponsor (Dutch: ‘Verrichter’) 
Stichting Rijnstate Ziekenhuis 
Afdeling Orthopedie (1191) 
Antwoordnummer 111 
6800 WC Arnhem 
Subsidising party 
N/A 
Independent expert (s) 
N/A 
 
 
Study Sites  
Department of Orthopedics, Rijnstate Hospital, 
Arnhem, The Netherlands. 
MSK Laboratory, Imperial College London, United 
Kingdom. 
Pharmacy 
N/A 
 

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TABLE OF CONTENTS 
 
1. INTRODUCTION AND RATIONALE ................................................................................. 8 
1.1 
Arthritis and physical activity ................................................................................... 8 
1.2 
Wearables and physical activity............................................................................... 9 
1.3 
Physical activity and common treatments for severe arthritis ..................................10 
2. OBJECTIVES ...................................................................................................................11 
2.1 Primary Objective: .......................................................................................................11 
2.2 Secondary Objective(s): ..............................................................................................11 
3. STUDY DESIGN ..............................................................................................................11 
4. STUDY POPULATION .....................................................................................................12 
5. TREATMENT OF SUBJECTS ..........................................................................................12 
6. INVESTIGATIONAL PRODUCT .......................................................................................12 
7. NON-INVESTIGATIONAL PRODUCT ..............................................................................12 
8. METHODS .......................................................................................................................13 
8.1 Study parameters/endpoints .......................................................................................13 
8.1.1 Main study parameter/endpoint ............................................................................13 
8.1.2 Secondary study parameters/endpoints ................................................................13 
8.2 Randomisation, blinding and treatment allocation .......................................................14 
8.3 Study procedures ........................................................................................................14 
8.3.1 Wearing GENEActiv Triaxial Accelerometer & Axivity AX3 Logging Triaxial 
Accelerometers .................................................................................................................14 
8.3.2 Instructions for wearing the accelerometers .............................................................14 
8.4 Withdrawal of individual subjects ................................................................................14 
8.5 Replacement of individual subjects after withdrawal ...................................................15 
8.6 Follow-up of subjects withdrawn from treatment ..........................................................15 
8.7 Premature termination of the study .............................................................................15 
9. SAFETY REPORTING .....................................................................................................15 
Temporary halt for reasons of subject safety ....................................................................15 
9.2 (Serious) Adverse events ............................................................................................15 
9.2.1 Adverse events (AEs) ...........................................................................................15 
9.2.2 Serious adverse events (SAEs) ............................................................................15 
9.3. Follow-up of adverse events ......................................................................................16 
9.4 Data Safety Monitoring Board (DSMB) / Safety Committee .........................................16 
10. STATISTICAL ANALYSIS ..............................................................................................16 
10.1 Primary study parameter(s) .......................................................................................16 
10.2 Secondary study parameter(s) ..................................................................................17 
11. ETHICAL CONSIDERATIONS .......................................................................................17 
11.1 Regulation statement ................................................................................................17 
11.2 Recruitment and consent ..........................................................................................17 
11.3 Benefits and risks assessment, group relatedness ....................................................18 
11.4 Incentives ..................................................................................................................18 
12. ADMINISTRATIVE ASPECTS, MONITORING AND PUBLICATION ..............................18 

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12.1 Handling and storage of data and documents ...........................................................18 
12.2 Monitoring and Quality Assurance.............................................................................19 
12.3 Amendments .............................................................................................................20 
12.4 Annual progress report ..............................................................................................20 
12.5 Temporary halt and (prematurely) end of study report...............................................20 
12.6 Public disclosure and publication policy ....................................................................20 
13. STRUCTURED RISK ANALYSIS ...................................................................................20 
13.1 Potential issues of concern .......................................................................................21 
13.2 Synthesis ..................................................................................................................21 
14. REFERENCES ...............................................................................................................21 

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LIST OF ABBREVIATIONS AND RELEVANT DEFINITIONS  
 
AE 
Adverse Event 
CCMO 
Central Committee on Research Involving Human Subjects; in Dutch: 
Centrale Commissie Mensgebonden Onderzoek 
DLW 
Doubly Labelled Water 
DSMB 
Data Safety Monitoring Board 
EU 
European Union 
EudraCT 
European drug regulatory affairs Clinical Trials  
GDPR 
General Data Protection Regulation; in Dutch: Algemene Verordening 
Gegevensbescherming (AVG) 
IC 
Informed Consent 
IPAQ-SF 
International Physical Activity Questionnaire - Short Form 
METC  
Medical research ethics committee (MREC); in Dutch: medisch-ethische 
toetsingscommissie (METC) 
MVPA 
Moderate-to-vigorous physical activity 
OHS 
Oxford Hip Score 
PA 
Physical Activity 
PAEE 
Physical activity energy expenditure 
RHA 
Resurfacing Hip Arthroplasty 
(S)AE 
(Serious) Adverse Event  
Sponsor 
The sponsor is the party that commissions the organisation or 
performance of the research, for example a pharmaceutical 
company, academic hospital, scientific organisation or investigator. A 
party that provides funding for a study but does not commission it is not 
regarded as the sponsor, but referred to as a subsidising party. 
SQUASH Short Questionnaire to Assess health-enhancing physical activity 
THA 
Total Hip Arthroplasty 
UCLA 
University of California at Los Angeles 
UK 
United Kingdom 
WMO 
Medical Research Involving Human Subjects Act; in Dutch: Wet Medisch-
wetenschappelijk Onderzoek met Mensen 
 
 

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SUMMARY 
Rationale:  
Arthritis significantly impacts patients' lives, affecting everything from pain and fatigue to daily 
activities and overall mortality. Physical activity (PA), particularly moderate-to-vigorous 
physical activity (MVPA), is crucial in managing arthritis symptoms and reducing mortality 
risks, with even minimal MVPA providing significant health benefits. Wearable technology 
has revolutionized the measurement of physical activity, offering accurate, large-scale data 
that informs treatment efficacy. Despite this, little is known about how common arthritis 
treatments affect physical activity levels, highlighting a critical gap in our understanding. Joint 
replacement, while effective in reducing pain and improving function, shows varying long-
term mortality outcomes, suggesting the need for further research into how different surgical 
procedures impact patients' activity levels and overall well-being. 
Objectives: i) To compare the volume and intensity of physical activity 15 years after surgery 
in patients after hip resurfacing and total hip replacement and ii) to explore the association 
between the participants’ physical activity and functional outcome scores. 
Study design: A cross-sectional observational (follow-up) study. 
Study population: We will approach patients that have previously participated in a 
randomised controlled trial during which they received either hip resurfacing (n = 34) or total 
hip replacement (n = 26). 
Intervention (if applicable): In this study there is no intervention, only observation using 
accelerometers. Participants will be asked to compete four physical activity questionnaires. 
Subsequently, they will wear a tri-alaxial accelerometer on their non-dominant wrist 
continuously for ten days and nights, and simultaneously wear a tri-axial accelerometer taped 
to the surgical thigh for a period of 48 hours.  
Main study parameters/endpoints: Using the accelerometers we will measure the 
participants’ physical activity energy expenditure (PAEE), the  intensity distribution of PAEE 
and step count. Secondary outcomes include self-reported physical activity, health status 
and the ability to perform specific activities. 
Nature and extent of the burden and risks associated with participation, benefit and 
group relatedness: There is no risk associated with participating in this study. Patients will be 
asked to complete four paper questionnaires at home (duration: 15 minutes). Patients will also 
be asked to wear an accelerometer on their wrist for ten days, and to simultaneously wear one 
accelerometer on their surgical thigh for 48 hours. The accelerometers collect physical activity 
data automatically. 
 
 

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1. INTRODUCTION AND RATIONALE 
1.1 Arthritis and physical activity  
The impact of arthritis is wide-ranging and patient specific. From traditional symptoms such as 
fatigue and pain to more holistic considerations like holiday destination and pragmatism over 
style(1), arthritis affects many patient life domains. Treatment strategies are similarly broad - 
spanning lifestyle changes, medicine, and surgery - as is the definition of what constitutes 
success in treatment. Surveys of arthritis sufferers have identified a reduction in fatigue, pain 
and a return to normal activities as core expectations of this patient group(1),(2), but again, 
answers are highly personal. Yet beyond commonly reported symptoms, some forms of 
arthritis are associated with a shortened life span. For example, a 15-year prospective study 
of rheumatoid arthritis patients in the Netherlands revealed significantly higher all-cause 
mortality in rheumatoid patients (3). Likewise, lower limb osteoarthritis is associated with 
increased cardiovascular mortality (4) and all-cause mortality (5). Further, gait speed, which 
commonly decreases with end-stage arthritis, independently predicts mortality in the elderly 
(6). Recent population-based studies suggest that a lack of physical activity may explain, at 
least in part, these findings. Physical activity researchers are ever more aware of the 
importance of physical activity volume and intensity in healthy ageing, both for all-cause 
mortality and intermediate disease states (7),(8),(9),(10),(11),(12). In a population-based study 
of over 96,000 participants, Strain et al. demonstrated that physical activity volume and 
intensity are independently associated with all-cause mortality (7). Figure 1 llustrates this 
relationship, but it also highlights the additional benefit of accumulating a greater fraction of 
physical activity energy expenditure (PAEE) from moderate-to-vigorous physical activity 
(MVPA). 
Figure 1. PAEE, intensity and all-cause mortality (7). 
 

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This study (7) demonstrated participants with the lowest levels of PAEE had almost double the 
mortality risk of those with average levels of physical activity. Even at low levels of physical 
activity, those with 20% MVPA had a 30% lower mortality rate than those with 10% MVPA. For 
context, this is the equivalent of a 12-minute stroll versus a brisk 7-minute walk. These findings 
are further supported by the results of a systematic review and meta-analysis of 30 million 
participants, confirming that significant protection against chronic disease is derived from just 
10 minutes of MVPA per day (9). Further population-based studies have demonstrated similar 
associations with intermediate disease states, including obesity and cardiometabolic risk 
score, along with depression and anxiety (8),(12),(13). Given the sweeping benefits of physical 
activity, it is perhaps not surprising that markers of physical activity such as ‘performing daily 
activities with ease’, frequently rate second to pain and/or fatigue in studies of patient hopes 
for arthritis treatment (1),(2),(14),(15). By logical extension, it is evident that for a notable 
proportion of arthritis patients, treatment can only be successful if it empowers that patient to 
achieve their desired level of activity. Despite this, relatively little is known about the effect of 
common arthritis treatments on levels of physical activity. Even less is known about the 
intensity distribution of patients following treatment. This represents a core knowledge gap in 
our evaluation of the treatments provided. 
 
1.2 Wearables and physical activity  
Until the introduction of wearables, physical activity was difficult to measure objectively or at 
scale. Traditionally, PA was studied using subjective measures such as surveys or diaries, or 
extremely expensive or intrusive objective measures such as doubly labelled water (DLW) or 
indirect calorimetry (16),(17),(18). The former methods can be applied in large population 
cohorts but are known to be subject to bias (17),(19). The latter provide highly accurate 
information about energy expenditure but provide no information about the underlying energy 
distribution (intensity) of that energy expenditure (20).  
 
The advent of wearable technology has revolutionised the study of physical activity at a 
population level. A variety of estimation techniques, ranging from uniaxial accelerometers to 
combined heart rate and movement sensors, have been used to study a diverse range of 
population cohorts (11),(21),(22),(23),(24). As a result, physical activity researchers have been 
able to look beyond simple metrics like time in MVPA to more biologically based phenomena. 
This has seen a shift from descriptive to aetiological studies that link an individual’s average 
daily PAEE, or their underlying intensity composition, with disease states (25),(26),(27). 
 
Of the methods currently available, triaxial accelerometers such as the GENEActive 
Device (Activinsights, UK; Figure 2) are emerging as a favoured device amongst physical 
activity researchers. Compared to other methods, the devices are well tolerated, can be placed 
on a variety of sites throughout the body, are worn 24 hours a day, are relatively inexpensive, 

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reusable, and are validated against the gold standard DLW in a British population (22),(28). 
Furthermore, as wrist-worn devices, they are suitable for use in orthopaedic patients with 
previous lower limb arthroplasty. Alternative devices include the thigh-worn Axivity AX3 3-Axis 
Logging Accelerometer (Axivity, UK; Figure 3). These are versatile, lightweight devices that 
have been validated against other monitors (29). 
 
 
 
 
 
 
 
 
Figure 2. GENEActive triaxial accelerometer (Activinsights, UK) 
 
 
 
 
 
 
 
 
 
Figure 3. Axivity AX3 3-Axis Logging Accelerometer (Axivity, UK) 
1.3 Physical activity and common treatments for severe arthritis 
Joint replacement is widely heralded as a safe and effective option for patients with end-stage 
arthritis, as patients report improved function and less pain. However, the statistic used to 
describe the success of the procedure is that of ‘implant survival’, which specifically ignores 
the more important metric of ‘patient survival’ (30). The two graphs below, from the National 
Joint Registry of England and Wales, illustrate this paradox: Figure 3A shows the unattractive 
higher mortality risks associated with total knee replacement, while Figure 3B shows the 
attractive low risk of revision surgery for the procedure. 
 

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Figure 3. Implant and patient survival post-knee replacement (30). 
 
In earlier work from our group, we have published the substantial differences in gait 
characteristics between patients with different types of surgical procedures (31),(32),(33). 
However, any extrapolation from these small laboratory-based studies would be theoretical. 
Our best explanation for the profound difference in mortality, in the longer term, between more 
and less radical procedures is that patients who are allowed to retain more of their own bodies 
feel more normal and thus enjoy more activity. Alternatively, patients with large stiff metal 
implants substituting large parts of their femur and tibia are not expected to feel ‘normal’ ever 
again. To test this explanation, we propose to study physical activity of two groups of patients 
who participated in a previous study (34). In the current study, we want to explore whether 
physical activity levels varies between these two groups 15 years after their index surgery. 
 
2. OBJECTIVES 
2.1 Primary Objective: 
To compare the volume and intensity of physical activity 15 years after surgery in patients after 
hip resurfacing and total hip replacement. 
 
2.2 Secondary Objective(s): 
To explore the association between the participants’ physical activity and functional outcome 
scores. 
 
3. STUDY DESIGN 
This is a cross-sectional observational (follow-up) study in which we will ask participants to 
complete four paper questionnaires, wear a tri-axial accelerometer on their non-dominant wrist 
continuously for ten days and nights, and simultaneously wear a tri-axial accelerometers taped 
to the surgical thigh for a period of 48 hours. 
 

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4. STUDY POPULATION 
We will only approach patients that have participated in a previous randomised controlled trial 
(34) that was conducted in Rijnstate hospital between 2007-2008. These include 34 patients 
after hip resurfacing and 26 patients after total hip replacement.  
 
5. TREATMENT OF SUBJECTS 
N/A. 
 
6. INVESTIGATIONAL PRODUCT  
N/A.  
 
7. NON-INVESTIGATIONAL PRODUCT 
During this study, the participants will be asked to continuously wear two different types of 
accelerometers that will measure their physical activity. 
 
GENEActiv triaxial accelerometer (wrist-worn) 
We will ask the participants to wear the GENEActiv triaxial accelerometer (Activinsights, UK) 
on their wrist for ten consecutive days and nights. The GENEActiv is currently a Class I self-
certified medical device under the MDD 93/42/EEC for CE Marking. GENEActiv is transitioning 
to the new Medical Device Regulation (EU) 2017/745 in 2023. Under the MDR the GENEActiv 
will become a Class IIa medical device. 
 
Axivity AX3 Logging tri-axial accelerometer (thigh-worn) 
We will also ask the participants to wear an Axivity AX3 Logging tri-axial accelerometer taped 
to the surgical thigh for a period of 48 hours. This accelerometer conforms to several EU 
regulation directives (89/336/EEC Electromagnetic Compatibility Directive, amended by 
92/31/EEC & 93/68/EEC 72/23/EEC Low Voltage Equipment Directive, amended by 
93/68/EEC). The product also meets the following standards: EN61326-1:2006 Electrical 
Equipment for Measurement, Control and Lab use, Radiated Emissions EN 55011:1998 A1 
A2, Electrostatic Discharge EN 61000/4/2:1995 A1 A2 and Radiated Immunity EN 
61000/4/3:2002. 
 
Both types of accelerometers have been deemed safe to use on the following basis: 
- They have a self enclosed, non-replaceable, 3.7V Lithium Polymer Cell.  
- The products have no sharp edges. 
- The products do not contain explosive, toxic or volatile parts.  
 

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All the relevant testing has been completed to ensure the device complies to the above 
standards. The technical documentation required to demonstrate that the product meets the 
requirements of the Low Voltage Directive is available for inspection by the relevant 
enforcement authorities. The Axivity AX3’s CE mark was first applied in December 2011. 
 
8. METHODS 
8.1 Study parameters/endpoints 
8.1.1 Main study parameter/endpoint 
In order to gain insight into the volume and intensity of physical activity, both the wrist-worn 
GENEActiv triaxial accelerometer and the thigh-worn Axivity AX3 Logging tri-axial 
accelerometers will measure physical activity energy expenditure (PAEE) (7) and the intensity 
distribution of PAEE (7),(8). The wirst worn GENEActiv triaxial accelerometer will additionally 
measure the participants’ step count (28),(35). 
8.1.2 Secondary study parameters/endpoints 
Prior to wearing the accelerometers we will ask the participants to complete a total of four 
questionnaires: 
 
1. A Dutch version of the International Physical Activity Questionnaire - Short Form (IPAQ-SF) 
(36),(37),(38),(39),(40). This is a self-reported physical activity questionnaire. This 
questionnaire can be found in Appendix A. 
2. A validated Dutch version of the Short Questionnaire to Assess health-enhancing physical 
activity (SQUASH). This is also a self-reported physical activity questionnaire. This 
questionnaire can be found in Appendix B. 
3. A psychometrically sound Dutch version of the EQ-5D-5L (41),(42),(43),(44),(45). This 
questionnaire evaluates health status in the five dimensions of mobility (ability to walk about), 
self-care (ability to take care of personal hygiene and activities of daily living), usual activities 
(ability to perform usual activities, such as work, study, housework, family or leisure activities), 
pain/discomfort and anxiety/depression. This questionnaire can be found in Appendix C. 
4. Finally, we will ask the participants to complete a validated Dutch version of the The Oxford 
Hip Score (OHS).(46),(47),(48),(49) This questionnaire includes 12 questions about the 
patient's ability to perform specific activities such as walking, climbing stairs, and putting on 
shoes and socks, as well as their experience of pain and limitations in daily activities due to 
their hip condition. This questionnaire can be found in Appendix D. 
 

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8.2 Randomisation, blinding and treatment allocation 
In this observational (follow-up) study participants will not be randomised, blinded or treated. 
The potential participants for this current study have previously participated in a randomised 
controlled trial. In this RCT (34), a total of 82 patients were randomly assigned to receive 
resurfacing hip arthroplasty (RHA, n = 34) with a 6-mm thick cobalt-chromium cup or 
conventional total hip arthroplasty (THA, n = 26) with a more conical threaded titanium cup. All 
participants of this previous RCT will be contacted to ask if they are willing to participate in this 
follow-up study. 
 
8.3 Study procedures 
8.3.1 Wearing GENEActiv Triaxial Accelerometer & Axivity AX3 Logging Triaxial 
Accelerometers 
Participants in this study will be sent both accelerometers by post. Participants will be asked 
to wear both the GENEActiv triaxial accelerometer for ten days and nights on their non-
dominant wrist and the Axivity AX3 Logging tri-axial accelerometer on their surgical thigh for 
48 hours, respectively. Both accelerometers are programmed to start at a certain time. The 
accelerometers are waterproof and should be worn continuously including during showering 
and sleeping. After use, the participants are requested to return both accelerometers to the 
researcher into a padded pre-paid envelope as soon as possible so the researcher can 
download the data. The envelope can be posted into a normal post box. 
 
8.3.2 Instructions for wearing the accelerometers 
We will provide all participants with an instruction leaflet explaining how the accelerometers 
should be used. This leaflet also contains a weblink to a video explaining how to wear the 
accelerometer: www.mrc-epid.cam.ac.uk/geneactiv1. Although this video is in English, in 
combination with the Dutch written instructions these should be easy to understand. The 
instruction leaflet also contains a phone number that participants can call in case they have 
questions or need assistance in placing or using the accelerometers. 
 
8.4 Withdrawal of individual subjects 
Subjects can leave the study at any time for any reason if they wish to do so without any 
consequences. The investigator can decide to withdraw a subject from the study for urgent 
medical reasons. 
 

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8.5 Replacement of individual subjects after withdrawal 
N/A 
8.6 Follow-up of subjects withdrawn from treatment 
N/A 
8.7 Premature termination of the study 
N/A 
 
 
9. SAFETY REPORTING 
Temporary halt for reasons of subject safety 
In accordance to section 10, subsection 4 of the WMO, the sponsor will suspend the study if 
there is sufficient ground that continuation of the study will jeopardise subject health or safety. 
The sponsor will notify the accredited METC without undue delay of a temporary halt including 
the reason for such an action. The study will be suspended pending a further positive decision 
by the accredited METC. The investigator will take care that all subjects are kept informed. 
 
9.2 (Serious) Adverse events 
9.2.1 Adverse events (AEs) 
Adverse events are defined as any undesirable experience occurring to a subject during the 
study that is related to wearing the GENEActiv or Axivity AX3 Logging tri-axial accelerometers.  
 
Wearing accelerometers may cause mild skin redness or irritation due to prolonged contact 
with the device. This is considered an expected adverse event of mild severity. Participants 
will be instructed to monitor their skin daily and only report signs of persisting irritation to the 
researcher. Mitigation strategies include the use of breathable hypoallergenic straps, 
participant instruction on proper device use, and how to treat the affected area with 
moisturising skin cream. Only severe or persistent irritation will be reported as an AE.  
9.2.2 Serious adverse events (SAEs) 
A serious adverse event is any untoward medical occurrence or effect that  
- results in death; 
- is life threatening (at the time of the event); 
- requires hospitalisation or prolongation of existing inpatients’ hospitalisation; 
- results in persistent or significant disability or incapacity; 
- is a congenital anomaly or birth defect; or 

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- any other important medical event that did not result in any of the outcomes listed above 
due to medical or surgical intervention but could have been based upon appropriate judgement 
by the investigator. 
 
Hospital admissions, that occur between the day of signing the Informed Consent and the day 
the participant starts wearing the accelerometers, will not be considered an SAE. 
 
Excessive, outside normally expected range complications will be considered as SAE as 
determined by the patient’s primary orthopaedic surgeon. The investigator will report all SAEs 
to the sponsor without undue delay after obtaining knowledge of the events, except for the 
following SAEs. The sponsor will report the SAEs through the web portal ToetsingOnline to the 
accredited METC that approved the protocol, within even days of first knowledge for SAEs that 
result in death or are life threatening followed by a period of maximum of eight days to complete 
the initial preliminary report. All other SAEs will be reported within a period of maximum 15 
days after the sponsor has first knowledge of the serious adverse events. 
 
9.3. Follow-up of adverse events 
All AEs will be followed until they have abated, or until a stable situation has been reached. 
Depending on the event, follow up may require additional tests or medical procedures as 
indicated, and/or referral to the general physician or a medical specialist. SAEs need to be 
reported till end of study within the Netherlands, as defined in the protocol. 
 
9.4 Data Safety Monitoring Board (DSMB) / Safety Committee 
N/A 
 
10. STATISTICAL ANALYSIS 
10.1 Primary study parameter(s) 
Following the devices' return to the researcher, the recorded data will be downloaded and 
stored securely in a dedicated study folder on Rijnstate’s digital network. The raw triaxial wrist 
and thigh acceleration data will be auto-calibrated to local gravitational acceleration (in g) and 
then converted to a Vector Magnitude (VM). VM, or Euclidean Norm, can be interpreted as the 
magnitude of acceleration the device was subjected to at each measurement, including 
gravitational acceleration. Non-wear detection procedures will be applied, and any such non-
wear periods will be excluded from these analyses. The acceleration signal will be summarised 
to a common time resolution of one observation per minute and subjected to prediction models 

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to calculate physical activity energy expenditure, time in moderate-to-vigorous physical activity, 
and step count. 
 
Raw accelerometry data will be processed using the R-project for Statistical Computing and 
open-source packages (R Foundation for Statistical Computing, Vienna, Austria). Statistical 
analysis will be conducted using STATA/SE version 17 (StataCorp, College Station, TX, USA).  
For descriptive statistics, we will report medians (interquartile ranges) or means (standard 
deviations) for continuous variables and proportions for categorical variables. To examine face 
validity and the performance of each multi-level linear regression model, we will conduct 
ANOVA repeat measures analysis to calculate Pearson’s coefficient and Root Mean Squared 
Error metrics. Differential bias will be assessed by age, sex, and BMI categories.  
 
10.2 Secondary study parameter(s)  
Descriptive analysis of participant demographics and outcomes will be conducted. Medians 
and interquartile ranges will be calculated for discrete data, such as scores from the 
questionnaires (IPAQ-SF, SQUASH, EQ-5D-5L, and OHS). These will be visualised through 
box plots. Mean and standard deviation will be calculated for continuous parameters. 
 
To conduct aetiological analysis based on sample size, we will perform univariate and 
multivariate regression to assess for statistically significant confounders in relation to the 
questionnaire outcomes, such as PAEE and patient characteristics. 
 
11. ETHICAL CONSIDERATIONS 
11.1 Regulation statement 
The study will be conducted according to the principles of the Declaration of Helsinki (Seoul, 
Korea, October 2008) and in accordance with the Dutch Medical Research Involving Human 
Subjects Act (WMO). 
 
11.2 Recruitment and consent 
Participants will be approached by their treating orthopedic surgeon using an introduction letter 
and a Patient Information Form (PIF) which includes the Informed Consent Form (IC, see 
Appendix E). One week after sending the PIF/IC, the coordinating researcher will contact the 
patient by phone to ask whether the patient has any questions about the study, and whether 
he/she is willing to participate. No pressure will be placed on any individual to participate; it will 
be made clear that participation is entirely voluntary and that participation can cease at any 
time. Participants who are will be asked to sign and date the Informed Consent form and return 
it to the researcher in a pre-paid envelope. 

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11.3 Benefits and risks assessment, group relatedness 
Benefits 
Participating in this study has no direct benefits for the participants, but it may provide 
participants some insight into their own physical activity. 
 
Risks 
Participants in this study will be asked to continuously wear a triaxial accelerometer for ten 
days and nights on their non-dominant wrist and for 48 hours on their thigh. In some instances, 
individuals may experience minor skin irritation or develop a localised rash from wearing the 
wrist strap. This is similar to cases where one starts to use a new (regular) watch or other wrist-
worn device. Leaving the monitor off for one night should alleviate this. If the strap is damp, 
drying both the skin and strap can also reduce irritations. However, if the irritation persists, 
participants are asked to remove the monitor and return it to the researcher in the prepaid 
padded envelope. If the irritation does not resolve on its own, a small amount of moisturising 
skin cream (e.g. Sudocrem, Nivea Soft, Bepanthen Zalf) may be applied to the affected area. 
This can be obtained without prescription from a pharmacist. The same treatment approach is 
recommended if minor skin irritation or a localised rash arises from using 3M Tegaderm Film 
strips (3M, UK), which will be used to secure the Axivity AX3 accelerometers on participants' 
thighs. 
 
11.4 Incentives 
Participants will not receive any incentives for their participation. 
 
12. ADMINISTRATIVE ASPECTS, MONITORING AND PUBLICATION 
12.1 Handling and storage of data and documents 
All data handling and storage will comply with the EU General Data Protection Regulation and 
the Dutch Act on Implementation of the General Data Protection Regulation (Dutch: 
Uitvoeringswet AVG). All data collected during this study will be managed according to the 
FAIR principles in order to enhance and improve Findability, Accessibility, Interoperability and 
Reuse of research data.  
All patient data will be handled confidentially. Each subject will be given an identification code 
and only the investigators involved in this study will have access to the subject identification 
code list which can be used to link the data to the patient. The code list and all raw patient data 
will be stored in a designated research folder on Rijnstate’s local computer mainframe.  

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The Rijnstate coordinating investigator/project leader will collect the patient source data from 
the electronic patient records. These data comprise the participant’s hospital identification 
number, age, gender, Body Mass Index (BMI), the presence and severity of any 
cardiovascular, pulmonary or neuromuscular diagnoses, and the use of medications for these 
diagnoses. After full data collection, data will be transferred to STATA/SE version 17 
(StataCorp, College Station, TX, USA). In this spreadsheet the participant data will be non-
identifiable/anonymous. All accelerometer and patient-related (questionnaire) data will be 
coded 
and 
securely 
shared 
with 
the 
UK 
investigators 
via 
Surf 
Filesender 
(https://www.surf.nl/en/services/surffilesender). All data collected during this study will be kept 
under secure conditions at Rijnstate Hospital for 15 years after the research has ended and 
then it will be destroyed. Any information collected will be treated as confidential and used only 
in this study unless otherwise specified. All source data relating to consented study participants 
will be stored and processed in line with Rijnstate Hospital requirements. All source data held 
in paper form (Informed Consents) will be scanned and securely stored as soon as possible 
after the participant has signed it. Paper copies will be stored in the secured research lockable 
cabinet at the department of Orthopaedics of Rijnstate. 
Before the study commences, the UK partner will sign a Data Transfer Agreement (Stichting 
Topklinische Ziekenhuizen template ‘Beschikbaarstelling persoonsgegevens/versie maart 
2021’) with Stichting Rijnstate Ziekenhuis. 
Privacy of the participants 
Both the GENEActiv triaxial accelerometer and Axivity AX3 triaxial accelerometer do not store 
any personal identifiable data. A code number on each monitor is matched with a participant 
ID number. The key to this code is known by the research team only. The participants’ personal 
details are stored separately. Other security mechanisms are also used to protect the 
participants’ privacy. For example, both types of accelerometer do not have GPS and do not 
measure the location of where the participant is. The accelerometers are only measuring body 
movement i.e. whether it moves up/down, forward/back and side-to-side. Once the movement 
data is uploaded, only the research team will be able to match the movement data to other 
patient information. 
12.2 Monitoring and Quality Assurance  
Monitoring of this study will take place during the total study duration according to guidelines 
set out by the Samenwerkende Topklinische Ziekenhuizen (STZ) and as described in Standard 
Operating Procedure ‘STZ SOP VC12 Monitoringplan’ (STZ version 21-02-2019; Rijnstate 
version 8-5-2019). Monitoring will be performed by Rijnstate’s local Research Ethics Office. 

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12.3 Amendments  
Amendments are changes made to the research after a favourable opinion by the accredited 
METC has been given. All amendments will be notified to the METC that gave a favourable 
opinion. Non-substantial amendments will not be notified to the accredited METC and the 
competent authority, but will be recorded and filed by the sponsor. 
 
12.4 Annual progress report 
The sponsor/investigator will submit a summary of the progress of the trial to the accredited 
METC once a year. Information will be provided on the date of inclusion of the first subject, 
numbers of subjects included and numbers of subjects that have completed the trial, serious 
adverse events/ serious adverse reactions, other problems, and amendments.  
 
12.5 Temporary halt and (prematurely) end of study report 
The investigator/sponsor will notify the accredited METC of the end of the study within a period 
of eight weeks. The end of the study is defined as the last patient’s last visit.  
The sponsor will notify the METC immediately of a temporary halt of the study, including the 
reason of such an action. In case the study is ended prematurely, the sponsor will notify the 
accredited METC within 15 days, including the reasons for the premature termination. 
Within one year after the end of the study, the investigator/sponsor will submit a final study 
report with the results of the study, including any publications/abstracts of the study, to the 
credited METC. 
 
12.6 Public disclosure and publication policy 
This study will be prospectively registered in a public trial registry before the first patient is 
recruited. All data will be the property of Rijnstate. Publication will be the responsibility of the 
coordinating and principal investigators. It is planned to publish the results of this study in a 
peer-reviewed journal and to present results at national and international meetings. It will not 
be possible to identify any individuals from any publication or presentation. 
 
13. STRUCTURED RISK ANALYSIS 
According to the Dutch Federation of University Medical Centers, the risk in this study is 
negligible (“verwaarloosbaar risico”) because there is only a small risk of minimal damage 
(“kleine kans op lichte schade”). Patients will be asked to wear an accelerometer on their wrist 
for ten days, and to simultaneously wear one accelerometer on their surgical thigh for 48 hours. 

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Both accelerometers collect physical activity data automatically. Additionally, participants will 
be asked to complete four paper questionnaires at home (duration: 15 minutes).  
 
13.1 Potential issues of concern 
N/A. 
 
13.2 Synthesis 
Participating in this study has no direct benefits for the participants. Participants who consent 
to participate will be asked to: 
1. Complete 4 paper questionnaires (duration: 15 minutes). 
2. Wear the GENEActiv tri-axial accelerometer on the wrist continuously for ten days and 
nights, and wear one Activity Ax3 Logging tri-axial accelerometers on the surgical thigh 
continuously for 48 hours. Wearing accelerometers is common, usually well tolerated and there 
are no documented risks of wearing in particular or physical activity monitors in general. 
 
 
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bicompartmental arthroplasty patients display more normal gait and improved satisfaction, 
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generates a more physiological gait than total hip replacement: A case-control study. Orthop 
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Gerhardt D, Mors TGT, Hannink G, Van Susante JLC. Resurfacing hip 
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Vandelanotte C, De Bourdeaudhuij I, Philippaerts R, Sjöström M, Sallis J. 
Reliability and Validity of a Computerized and Dutch Version of the International Physical 
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Gottschalk S, Konig HH, Nejad M, Dams J. Measurement properties of the 
EQ-5D in populations with a mean age of >/= 75 years: a systematic review. Qual Life Res. 
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Devlin N, Pickard S, Busschbach J. The Development of the EQ-5D-5L and 
its Value Sets. In: Devlin N, Roudijk B, Ludwig K, editors. Value Sets for EQ-5D-5L: A 
Compendium, Comparative Review & User Guide. Cham (CH)2022. p. 1-12. 
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Versteegh MM, Vermeulen KM, Evers SMAA, de Wit GA, Prenger R, Stolk 
EA. Dutch Tariff for the Five-Level Version of EQ-5D. Value Health. 2016;19(4):343-52. 
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Stolk E, Ludwig K, Rand K, van Hout B, Ramos-Goni JM. Overview, 
Update, and Lessons Learned From the International EQ-5D-5L Valuation Work: Version 2 of 
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Gosens T, Hoefnagels NH, de Vet RC, Dhert WJ, van Langelaan EJ, 
Bulstra SK, et al. The "Oxford Heup Score": the translation and validation of a questionnaire 
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49. 
Haverkamp D, Breugem SJM, Sierevelt IN, Blankevoort L, Dijk CNv. 
Translation and validation of the Dutch version of the Oxford 12-item knee questionnaire for 
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Appendix: Participant Information Form 
(English translation; original form will be in Dutch) 
2. 
Title of the Study: 
Physical Activity in Patients After Resurfacing and Total Hip Arthroplasty: An Observational 
Follow-up Study 15 Years After Surgery. 
3. 
Introduction 
Dear Sir/Madam, 
 
This information letter is to ask whether you would like to participate in medical-scientific 
research. Participation is voluntary. 
 
You are receiving this letter because you participated in the sports hip and/or treadmill test 
study at Rijnstate approximately 15 years ago. This document explains the nature of the current 
study, what it entails for you, and the potential benefits and risks. Please review the information 
carefully before deciding whether you want to participate. If you decide to participate, you can 
complete the form included in Appendix B. 
4. 
Questions? 
You can make your decision based on the information in this letter. Additionally, we recommend 
that you: 
- Ask the physician or researcher any questions you may have. 
- Discuss the study with your partner, family, or friends. 
- Read the information on www.rijksoverheid.nl/mensenonderzoek. 
5. 
General Information 
The Rijnstate Hospital Foundation has set up this study in collaboration with researchers from 
Imperial College London. In this document, we will refer to Rijnstate as the 'sponsor.' 
Researchers, including doctors and investigators, will conduct the study. The costs of the study 
are covered by the researchers at Imperial College London. 
 
This study invites all participants who took part in the sports hip and/or treadmill test study 
approximately 15 years ago. 
6. 
What is the purpose of the study? 
This study aims to examine how much you move and how physically active you are. We will 
measure the energy you expend during movement, the intensity of your activities, and the 
number of steps you take per day. This will be done using two motion sensors 
('accelerometers'). By collecting this information, we hope to better understand how much 
people move after receiving a total hip prosthesis or a resurfacing hip prosthesis. 
7. 
Background of the Study 
Hip osteoarthritis can cause significant pain, often leading to reduced movement. For many 
individuals, this is a reason to undergo hip replacement surgery. 
Hip prostheses usually reduce pain, but little is known about how active people remain after 

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surgery. Staying active is important for recovery and overall health post-surgery. 
By researching how much people move after hip replacement surgery, doctors can better 
understand patient needs. This can help improve treatment and rehabilitation programs and 
provide better support for a healthier lifestyle. Furthermore, comparing different types of hip 
prostheses, such as total hip prostheses and resurfacing prostheses, can help doctors and 
patients make better-informed decisions. 
8. 
How is the study conducted? 
The study will last a total of 10 days. Participants will wear two different motion sensors and 
complete questionnaires from home. 
9. 
Potential Side Effects, Discomfort, or Risks 
Some individuals may experience mild skin irritation from wearing the motion sensors. This can 
be managed by using a moisturizer or removing the sensor temporarily. 
10. 
Benefits and Drawbacks of Participation 
There is no direct benefit to participation, but it may provide insight into your movement 
patterns. Data collected will help improve understanding of post-surgical mobility. 
11. 
Withdrawal from the Study 
You may withdraw at any time without providing a reason. This will not affect your medical care 
at Rijnstate. 
12. 
Data Handling and Privacy 
Your data will be coded to protect your privacy. Some data will be securely transferred to 
Imperial College London for analysis. 
13. 
Compensation 
No financial compensation is provided for participation in this study. 
14. 
Contact Information 
For study-related inquiries: 
Dr. J.L.C. van Susante, Orthopedic Surgeon (Email: JvanSusante@rijnstate.nl) 
 
For complaints: 
Contact the Rijnstate complaints officer at: klachtenbureau@rijnstate.nl 
15. 
Thank you 
Thank you for your time and consideration. 
 
 
 
 

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Appendix: Informed Consent Form for the Study "Physical Activity of Patients with a Total 
Hip Prosthesis or a Resurfacing Hip Prosthesis: An Observational Follow-up Study 15 Years After 
Surgery." 
(English translation; original form will be in Dutch) 
 
• 
I have read the information letter. I was given the opportunity to ask questions. My 
questions have been sufficiently answered. I had enough time to decide whether I wanted to 
participate. 
• 
I understand that participation is voluntary. I also understand that I can withdraw from 
this study at any time or revoke my participation without having to provide an explanation. 
• 
I give permission to the researcher to collect and use my data. The researchers will do 
this solely to answer the questions in the study. 
• 
I agree that my research data will be stored at Rijnstate for a period of 15 years after this 
study. 
• 
I am aware that my coded data will also be sent to the United Kingdom, where EU privacy 
regulations do not apply. However, this is essential for the study. The data will be shared in 
coded form, without my name being disclosed. I consent to this. 
• 
I want to participate in this study. 
Please check "Yes" or "No" in below: 
I give permission for my data to be used for other scientific research on physical activity, as 
described in the information letter. 
☐ Yes 
☐ No 
First and Last Name of Participant (in block letters): ……….…………………………………… 
Signature: …………………………………………….. 
Date:      /       /         (DD / MMM / YYYY) 
________________________________________ 
Declaration by the Researcher: 
I declare that I have fully informed this participant about the study. 
If any new information arises during the study that could influence the participant’s consent, I 
will inform the participant in a timely manner. 
Name of Researcher (or their representative): ……….…………………………………………… 
Signature: …………………………………………….. 

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Date:      /       /         (DD / MMM / YYYY) 
The participant will receive a full information letter and a copy of the fully signed consent form.