Henricson 2006.

Methods	RCT stated Randomisation based on sealed envelopes opened during surgery Duration of study: 2 years
Participants	Inclusion: primary gonarthrosis grade III‐IV; age between 60 and 85 years; body weight < 120 kg; no gonarthrosis secondary to arthritis or trauma; no previous knee surgery Sweden: 47 participants (52 knees) Fixed: n = 26, 14 female, age 72 (62‐83) years Mobile: n = 26, 16 female, age 72 (62‐84) years
Interventions	Fixed: NexGen (Zimmer) Mobile: MBK, meniscal bearing (Zimmer) Some participants with patellar component All components cemented
Outcomes	RSA, KSS, HSS Assessments: preoperative and at 3, 12 and 24 months Average, range or 95% CI given
Notes	One of the study authors received funding from Zimmer Scandinavica
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 opened during operation
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 not described
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