Kim 2009a.

Methods	RCT stated Randomisation technique not stated Duration of study: 2.6 years
Participants	Inclusion: bilateral cases with degenerative osteoarthritis with prior non‐operative therapy Exclusion: rheumatoid arthritis, septic arthritis history Korea: 92 participants (184 knees) 85 female, 7 male, age 69.5 (± 7.92) years
Interventions	Fixed: Medial Pivot (Wright Medical) Mobile: PFC Sigma, rotating platform (DePuy) Routine patellar resurfacing All components cemented Flexion space with various bone referenced techniques
Outcomes	KSS, HSS, range of motion, satisfaction Only final follow‐up (2.6 years) given Point estimates and ranges given
Notes	No commercial association of any of the study authors Study authors reported no conflict of interest
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Randomised allocation
Allocation concealment (selection bias)	Low risk	Sealed envelopes
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Participant blinding not described; surgeon not blinded
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Outcome assessor blinding unclear
Incomplete outcome data (attrition bias) All outcomes	High risk	Drop‐out rate given and acceptable; no intention‐to‐treat analysis
Selective reporting (reporting bias)	Unclear risk	No protocol available
Other bias	Low risk	Homogeneity in participant groups on prognostic factors; co‐interventions described in sufficient detail