Do High-Flexion Total Knee Arthroplasty Have More Adverse Events™

INTRODUCTION: High-flexion knee prosthesis was proposed to result in better outcomes after knee arthroplasty. However, latest meta-analysis revealed that this implant indeed only produced better range of motion (ROM) and no benefits in other functional outcomes, including weight-bearing flexion. Moreover, recent studies suggested that more complications occurred in high-flexion total knee arthroplasty (TKA) instead. OBJECTIVES: This study focuses on the adverse events of high-flexion TKA compared to standard TKA in mid to long term of follow-up. METHODS: Systematic search was done in online databases, i.e. Pubmed, ScienceDirect, ClinicalKey. We only included studies with a minimum follow-up duration of 5 years, expecting that this mid to long term follow-up could provide a better picture of the outcomes. RESULTS: Seven studies were included in the final quantitative analyses, involving a total of 2,693 knees in high-flexion TKA and 3,892 knees in standard TKA. High-flexion TKA significantly had higher revision surgery compared to standard TKA (p = 0.03), 41(1.52%) and 53 (1,36%) knees, respectively. Loosening was not statistically different between those groups. Generally, radiolucent line was also more frequently observed in high-flex TKA (p = 0.01), 7.43% V 3.83% at femoral side and 5.69% V 4.41% at tibial side. Although infection and instability were higher in high-flexion knee, only a few studies found the occurrence of these parameters. Four studies evaluated the incidence of osteolysis and none was found in both groups. CONCLUSION: Considering that high-flexion TKA may only yield on better ROM but carry a bigger risk of adverse events, one has to cautiously weighing up the benefits and risks when planning of delivering a high-flexion TKA.