Table 1.

Summary of beliefs broken down by TDF domain

Domain	Specific Belief	Sample quote
Knowledge	25% not aware of Randomised Controlled Trials or NICE guidance	Based on Questionnaire data
Skills	Resisting pressure of patients who want an arthroscopy	Sometimes useful as a delaying tactic when under pressure from patient with minimal change but very symptomatic. (Questionnaire Participant 1)
	Diagnosis of OA knee (WB film rather than non-WB or MRI)	“it [non-weight bearing radiographs and MRI] give you some leeway to offer what you want” (Interview participant 3)
Social/Professional Role and Identity	Resisting pressure of patients who want an arthroscopy (Professional confidence)	“Pressure from patients who do not want major surgery but want “something” done.’ (Questionnaire participant 6)
		“Expectation of patients to have a treatment/procedure prior to receiving arthroplasty.”(Questionnaire participant 7)
	Junior under pressure from seniors	“He is the boss” (interview participant 1)
		“It’s…. Commonly instigated by a senior surgeon” Interview participant 3)
Beliefs about Capabilities	Resisting pressure of patients who want an arthroscopy	“Pressure from patients who do not want major surgery but want “something” done.’ (Questionnaire participant 6)
		“Expectation of patients to have a treatment/procedure prior to receiving arthroplasty.”(Questionnaire participant 7)
	Belief that some surgeons better than average at arthroscopy, and will therefore have better results	“some surgeons do feel that they are better than average” (Interview participant 1)
Beliefs about Consequences	10% of respondents disagreed with NICE Guidance (most common in patients with mechanical symptoms); widely held belief that arthroscopy delays the need for TKR, and improves outcome in patients with knee OA	Delay in treatment:
		“Sometimes useful as a delaying tactic when under pressure from patient with minimal change but very symptomatic.” . (Questionnaire Participant 1)
		“It makes it look like the knee replacement was delayed” (Interview participant 1)
		Subgroups of patients that may benefit:
		“The guidelines restrict treatment for the sub-group of patients who DO benefit from arthroscopic treatment in OA, or are unfit or do not wish to have more major interventions.” (Questionnaire participant 5)
Reinforcement	Financial and regulatory factors (restrictions from commissioning groups and private insurance companies)	“I think BUPA are getting independent reviews on private patients.”(Questionnaire participant 2)
		“Diagnostic arthroscopy alone is not a sufficient indication for surgery in the trust and it is not funded by the PCT. Therefore the patient is removed from the waiting list.” (Questionnaire participant 3)
Intentions	Disagreement with guidelines result in no intention to adhere to them Stable	“Patients cannot … be rigidly boxed into a protocol and clinicians, especially at consultant level, should have the freedom to assess patients on an individual basis.” (Interview participant 5)
Goals	Returns to beliefs about outcome	“Treat patients, not NICE guidelines. NICE guidelines assume patients are similar to machines, with no emotional input.” (Questionnaire participant 4)
Environmental Context and Resources	Financial and regulatory factors	“If all my peers stop doing it I would think twice, thrice, before offering it so yes, it would make me less likely to offer it.” (Interview participant 4)
	Enabler is if other surgeons in department are not doing it
	Resource issue	“We essentially cant offer anything in the intermediate stage”(Interview participant 2)
	Time pressure	“You need more time to explain to patients what the option are if you are not doing arthroscopy”(Interview participant 1)
Social Influences	Enabler if other surgeons in department are not doing it	“It is harder to do a treatment none of your peers are.” (Interview participant 2)
	Financial and regulatory factors	As above
Emotion	Desire to help – wanting to list even though might not be best thing (wanting to do something)	“You do not want to dismiss their concerns” (Interview participant 1)
		“You want to help” (Interview participant 2)
Behavioural Regulation	Just habit and learned behaviour that is driving the high arthroscopy rate	“its been an established kind of solution for a long time … that is still a bit of a problem” (Interview participant 2)
		“Different consultants have different ways of managing … it would be a treatment they still would offer” (interview participant 1)