This study is a systematic literature review of outcomes following total knee arthroplasty with implants specifically designed to enable increased knee flexion. English language comparative studies without date restriction were identified through a computerised literature search and bibliography review. Nine studies met the inclusion criteria representing a total of 399 high-flexion knee arthroplasties in 370 patients. Five studies reported greater flexion or range of motion; however, the methodological rigour was questionable with inadequate blinding, flawed participant selection, short follow-up periods and functional outcomes which lacked sensitivity. There was insufficient evidence of improved range of motion or functional performance after high-flexion knee arthroplasty.