Outcome
Type |
Measure |
Description |
Time frame |
Safety issue |
Primary |
Moderate/Severe persistent postsurgical pain |
The main outcome is the number of patients with moderate or severe persistent postsurgical pain in the operated knee, defined as patients with a numerical rating scale (NRS) score higher than 3. The NRS score was dichotomised for the primary outcome because this is more intuitively understood by patients and clinicians. This outcome will be reported as percentage of all patients with 95% confidence interval, which is calculated with assumed binomial distribution as p ± 1.96 v( (p (1 - p) ) / n) |
11-15 months postsurgically |
|
Secondary |
How satisfied are you with the outcome of your knee replacement surgery? Very satisfied, Satisfied, Neither satisfied nor dissatisfied, Dissatisfied, Very dissatisfied |
Reported as n (%) for each response option. The 1st question assesses overall satisfaction with surgery and have been translated directly from the questionnaire used by the Swedish Arthroplasty Register. |
11-15 months postsurgically |
|
Secondary |
Knowing what your knee replacement surgery did for you, if you could go back in time, would you still have undergone this surgery? Yes, No, Uncertain |
Reported as n (%) for each response option. |
11-15 months postsurgically |
|
Secondary |
Pain frequency: Do you still have pain in the operated knee? Yes, constantly; Yes, daily; Yes, a few times a week; Yes, more rarely; No |
Reported as n (%) for each response option. |
11-15 months postsurgically |
|
Secondary |
Numerical Rating Scale (NRS) pain: Please rate your pain in the operated knee by indicating the number that best describes your pain on average during the last week. 0 means 'No pain' and '10' means 'Pain as bad as you can imagine'. |
Reported as median (interquartile range [IQR]) and number of respondents |
11-15 months postsurgically |
|
Secondary |
Pain domain of the likert-scale version 3.1 of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). |
The five questions in the WOMAC pain domain can be scored 0-4, where 0 is 'none' and 4 is 'extreme'. This results in an overall score of 0-20, which will be reported as median (IQR). Moreover, each response option of the individual questions are reported as n (%). |
11-15 months postsurgically |
|
Secondary |
Pain interference: In total, how much does the pain in the operated knee bother you in your everyday life? Not at all, A little, Some, Much, Very Much |
Reported as n (%) for each response option |
11-15 months postsurgically |
|
Secondary |
Douleur Neuropathique 4 questions (DN4) interview |
Each of the seven questions in the DN4 interview can be scored 0/1 (no/yes), which results in an overall score of 0-7. A score =3 constitutes 'possible' neuropathic pain. Both the median (IQR) DN4 interview score and number of patients (% of all patients) with possible neuropathic pain will be reported. |
11-15 months postsurgically |
|
Secondary |
Other pain: Do you have chronic pain, other than from your operated knee? Yes; No. [If yes] -> Please describe your pain condition |
Pain conditions will be categorised independently by two authors and reported as n (%). |
11-15 months postsurgically |
|
Secondary |
Analgesic use: Do you take analgesic medication(s) daily or almost daily? Yes; due to pain in the operated knee; Yes, due to other pain; No. [If yes] -> Which medication(s)?: |
Reported as n (%). |
11-15 months postsurgically |
|
Secondary |
Height (cm) |
|
11-15 months postsurgically |
|
Secondary |
Weight (kg) |
|
11-15 months postsurgically |
|