Lizaur‐Utrilla 2012.

Methods	RCT Randomisation based on computer‐generated random numbers table Duration of the study: 2.5 years
Participants	Inclusion: osteoarthritic patients with primary TKA, aged 70 years or older, without prior infection in the knee and with severe angular deformity or severe instability that required grafting, modular augmentation or a constrained design Spain: 119 participants Fixed: n = 58, 47 female, age 73.9 (± 3.2) years Mobile: n = 61, 47 female, age 74.6 (± 3.3) years
Interventions	Fixed: Trekking MB (Samo) Mobile: Multigen Plus FB (Lima) Patella resurfaced if there was degeneration Cementless femoral component design and a cemented tibial component
Outcomes	Maximum knee flexion assessments preoperative and at 3 months, 6 months, 12 months and 24 months KSS function, WOMAC, SF‐12, VAS, radiolucent lines assessments preoperative and at 3 months, 6 months and 12 months, and yearly thereafter, but only final follow‐up results given Average, standard deviation and range given
Notes	No funding stated Study authors reported no conflict of interest
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated random number tables
Allocation concealment (selection bias)	Low risk	Office staff
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Participant blinded; surgeon not blinded
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Observers blinded
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