Weight Change and the Risk of Chronic Pain Following Hip and Knee Arthroplasties

Study Overview
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Brief Summary
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The study is a nationwide, register-based cohort survey study. The objective of this study is to investigate whether weight change is associated with the incidence of persistent postoperative pain following total hip arthroplasty and knee arthroplasty across non-obese and obese and patients.

Official Title
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Weight Change and the Risk of Chronic Pain Following Hip and Knee Arthroplasties: A Nationwide Registry-based Cohort Survey Study.

Conditions
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Persistent Postsurgical Pain, Arthritis Knee, Arthropathy of Knee, Arthropathy of Hip, Weight Loss, Weight Gain, Obesity

Intervention / Treatment
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* Other: Weight gain
* Other: Weight loss
* Other: Weight unchanged


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: - Patients operated with primary hip or knee arthroplasty for osteoarthritis 11-15 months before survey distribution Exclusion Criteria: Legally incompetent citizens, i.e., persons with a legal guardian, will not be asked to participate.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 99 Years

Sexes Eligible for Study
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All

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Weight gainers<br>Weight gain 11-15 months after arthroplasty | Other: Weight gain<br>* ≥5% weight gain<br>|
| Weight losers<br>Weight loss11-15 months after arthroplasty | Other: Weight loss<br>* ≥5% weight loss after arthroplasty<br>|
| Weight unchanged<br>Weight unchanged 11-15 months after arthroplasty | Other: Weight unchanged<br>* <5% weight change after arthroplasty<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Moderate/Severe Persistent Postoperative Pain | The primary outcome is the number of patients with moderate or severe persistent postsurgical pain in the operated hip or knee, defined as patients with a numerical rating scale (NRS) score higher than 3. The outcome will be presented as Odd Ratio (OR) with its' corresponding 95% Confidence Interval (CI) | 11-15 months postsurgically | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Satisfaction | Answering with satisfied or very satisfied in satisfaction question The outcome will be presented as Odd Ratio (OR) with its' corresponding 95% Confidence Interval (CI) | 11-15 months postsurgically | 
| Willingness to repeat the surgery | Answering yes in willlingness question The outcome will be presented as Odd Ratio (OR) with its' corresponding 95% Confidence Interval (CI) | 11-15 months postsurgically | 
| Frequent pain | Experiencing pain constantly, daily or few times a week The outcome will be presented as Odd Ratio (OR) with its' corresponding 95% Confidence Interval (CI) | 11-15 months postsurgically | 
| Use of analgaesic | The outcome will be presented as Odd Ratio (OR) with its' corresponding 95% Confidence Interval (CI) | 11-15 months postsurgically | 
| Interference with daily activities | Answering some, much and very much in the interference question The outcome will be presented as Odd Ratio (OR) with its' corresponding 95% Confidence Interval (CI) | 11-15 months postsurgically | 
| WOMAC pain score | mean (standard deviaiton [SD]). We will report the mean difference (MD) and the corresponding 95% CI | 11-15 months postsurgically |