Kim 2009b.

Methods	RCT stated Randomisation based on sequential pool derived from a table of randomised numbers Duration of study: 10‐12 years
Participants	Inclusion: patients younger than 55 requiring bilateral TKA Exclusion: criteria not mentioned Korea: 61 participants (122 knees) 45 female, 16 male, age 48.3 (34‐55) years
Interventions	Fixed: AMK (DePuy) Mobile: LCS, meniscal bearing (DePuy) Routine patellar resurfacing All components cemented
Outcomes	KSS total, KSS functional, KSS pain, ROM, HSS total, HSS pain, alignment, radiolucent lines Assessments preoperative and at final follow‐up 10 to 12 years postoperative Average given
Notes	No benefits or funds received in support of the study No declarations of interest reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Sequential pool based on a table of randomised numbers
Allocation concealment (selection bias)	Unclear risk	Not described
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	Low risk	Observer blinded for radiographic findings
Incomplete outcome data (attrition bias) All outcomes	Low risk	Drop‐out rate given and acceptable; 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