Cognitive interviews

As described above, the questionnaire was compiled predominantly from validated questionnaires with a few additional items added and amended where necessary. To ensure that the questionnaire was simple to follow, retained content validity and was understood by the target population, the draft amalgamated questionnaire was first iteratively developed by expert review as described above and secondly by think-aloud cognitive interviews with participants demographically matched to the target population.

These participants, suffered from pain in their hip or experienced in THR, were over 18 years old, and comprehended English, were invited to interview by email. The interviews were completed during two cycles throughout July-August and November 2012.

3.1.3.1 Method

Potential participants were contacted via the pain psychology research panel. The participants were received an invitation email with the participants’ information sheet (Appendix 10) for the inclusion, exclusion criteria, and other details of the study, and participation form (Appendix 11). Interested parties who replied email of invitation were contacted for an interview arranged. Interviews took place on the University premises or the participant’s own home. At the start of the interviews, participants gave written informed consent (Appendix 12). During the interviews, participants read the questions out loud and verbalised what they were thinking with their answer, including their thought processes in reaching that answer. Interviews were audio recorded and notes taken.

Subsequent analysis identified difficulties with completion or comprehension and these were addressed through adaptations to the questionnaire, without altering the structure of validated components wherever possible.

3.1.3.2 Result

Interviews of around an hour using a think aloud technique were conducted with 9 individuals in two series. Seven participants took part in the initial round of interviews, after which, the questionnaire was revised with iterative expert review. The second round was conducted in two other participants. Their experiences of hip pain varied from mild

hip pain to around a ten-year recovery from hip replacement or resurfacing displayed in Table 5.

Table 5: Demographic data of participants in cognitive interviews

No. Age Sex Hip history Numbers of

co-morbidities

Surgery history

1 73 Male Mild pain, unknown cause 3 No

2 68 Female Osteoarthritis 4 No

3 61 Female Osteoarthritis 1 No

4 53 Female Osteoarthritis 9 No

5 73 Male Osteoarthritis 8 Shoulder: 5 months ago

6 67 Female Pain caused by accident 5 No

7 73 Female Osteoarthritis 1 Hip: 1 year ago

8* 90 Male Osteoarthritis 1 Hip: 1.5 year ago

9* 88 Male Osteoarthritis 3 Hip: 10 years ago

*Two participants took part for the second round of cognitive interviews.

In amalgamating the questionnaires, the format and instructions were changed to create a clear and coherent structure. Following the first round of cognitive interviews, clarification footnotes were added. The final version of the questionnaire was further improved through iterative expert review. The original format and structure of the validated questionnaires was retained as much as possible throughout this process. Seven elements of the questionnaire were refined following the cognitive interviews. All improvements are listed in Table 6. In addition, questions relating to numbers of floors in participants’ home, date of surgery, and date of completing questionnaire were added to obtain more details about participants. A list of questions about co-morbidities were changed to two open questions, they were: ‘Do you have any other diagnosed medical conditions?’ OR ‘Have you been diagnosed with any new condition(s) since you complete the last questionnaire?’ and ‘Please tell us about how the listed condition(s) affect your pain or movement (if they do)’.

The revised questionnaire was also subject to two final think-aloud cognitive interviews in the second round to confirm that issues had been adequately addressed. The final version of the questionnaire took around 30 minutes to complete in a cognitive interview, suggesting that this would be the maximum time taken, and participants did not report any further issues. Finally, four different versions of the questionnaire were prepared from

the final version of master questionnaire to reflect the differences relating to the four time points of administration throughout the study. These final questionnaires were submitted to obtain ethical approval from the NRES Committee.

Table 6: Refinement from cognitive interviews comments

Domain Comments Amendments

PCS  Most of participants asked for the exact time of instructions.

 ‘In the past week’ was added.

 Two subjects raised an issue of other painful events in an item of ‘I keep thinking of other painful events’

 An item was explained at footnote as

‘This refers to other situations involving pain other than at your hip’

Fear VAS  A patient who had undergone shoulder surgery asked for specific surgery.

 ‘Surgery’ was identified as ‘Hip surgery’.

ASES-11  The instruction was not quite clear in three participants ‘How certain are you when you will cope before the surgery’.

 This instruction was changed to ‘How you will cope until now’ for pre-operative period and ‘How you will cope with your pain’ for post-operative period.

 There were two doubted questions which were ‘You can decrease your pain quite a bit’ and ‘You can manage arthritis pain during your daily activities as

compared with other people with arthritis like yours’.

 They were explained at footnote as ‘This refers to being able to reduce pain using treatment or techniques’ and ‘This question asks how you think you managed compared to other people – are you better, worse or the same as others?’

respectively.

HOOS  Some subjects confused nearby adjectival choices.

 Between differently adjectival scales, more spaces were added.

 Three participants asked the definition of ‘Straightening your hip fully’.

 Footnote was added as ’This means making your hip joint straight, such as when stretching out on a bed’.

 Four participants asked for more explanation of ‘twisting/pivoting on loaded leg’

 This was then defined as “This means turning on your foot, whilst putting weight on it” at footnote.

Expectation  Format of this part was quite difficult to complete and understand.

 A gap between preoperative and postoperative period was added.

 A subject undergoing hip replacement mentioned that ‘running’ and

‘Twisting/pivoting on your loaded leg’

have not been permitted to do.

 These questions would the participant like to imagine their function in the future in all difficult levels of mobility.

Demographic data

 ‘What is your usual transport?’ and ‘Has anyone helped you with daily activity during the last week?’ were unclear.

 Both ‘usual’ and ‘during the last week’

were emphasized by bold and underline to clarify the question.

After provisional opinion from the other NRES Committee (Liverpool Central), two further amendments were made by adding a sentence on the cover page to clarify the fact of voluntary participation for a further questionnaire and a question listing the medication of participants in the demographic data part.