Effect of low-dose amitriptyline on reducing pain in clinical knee osteoarthritis compared to benztropine: study protocol of a randomised, double blind, placebo-controlled trial

Table 1 Schedule of study flow and assessments

	Enrolment	Baseline	2 weeks	6 weeks	12 weeks
ENROLMENT:
Eligibility screen	x
Informed consent	x
Clinical assessment		x
Randomisation		x
INTERVENTION:
Amitriptyline, 25 mg nocte		Alternate	Nightly	Nightly	Nightly
Benztropine, 1 mg, nocte		Alternate	Nightly	Nightly	Nightly
ASSESSMENTS
Primary and secondary outcomes
WOMAC (pain, stiffness, function, total)		x			x
Other measures of knee pain
Pain severity (NRS, 0–10)		x	x	x	x
Pain severity (VAS, 100 mm), pain diagram		x			x
PainDETECT		x			x
Functional status and severity
ACR functional class I, II or III		x			x
Investigator assessed global assessment of OA status (Likert, 0 very well–4 very poor)		x			x
General health status (AQOL-8D)		x			x
Leg muscle strength (in triplicate)		x			x
Xray – KL score, osteophytes, JSN		x
Other measures of response
Pain acceptability (48 h)		x			x
Patient global impression of change (Likert, 0–7)			x	x	x
Other measures
Inclusion criteria: pain & 1 of age > 50, stiff <30mins, Crepitus, osteophytes and KOA		x
Age, height, weight, bp, smoking		x
Medical conditions		x			x
Education (category), Employment current status, type of work (manual, office, NA)		x
Medications – analgesics, NSAID, opioid		x			x
Fear of movement (TSK)		x			x
Mood disorder (HADS)		x			x
Physical activity (IPAQ, 7 days)		x			x
Sleep quality and disturbance (PSQI)		x			x
Treatment and safety issues
Medications – analgesics, NSAID, opioid		x			x
Treatment belief: study drug or placebo					x
Rating of medication and side effects (Scale, excellent, good, fair, poor, unacceptable)					x
UKU		x	x	x	x
Adverse events			x	x	x
Adherence, pill count					x

WOMAC Western Ontario and McMaster Arthritis Index. NRS Numerical rating scale VAS visual analogue scale, AQOL-8D Assessment of quality of life. TSK Tampa Scale of Kinesiophobia HADS Hospital anxiety and depression scale IPAQ International physical activity questionnaire PSQI Pittsburgh sleep quality index UKU: UKU Side effect rating scale for psychotropic drugs

ISSN: 1471-2474