title: Higher Rate of Revision in PFC Sigma Primary Total Knee Arthroplasty With Mismatch of Femoro-Tibial Component Sizes.
abstract: Total knee arthroplasty (TKA) systems permit a degree of femoro-tibial component size mismatch. The effect of mismatched components on revision rates has not been evaluated in a large study. We reviewed 21,906 fixed-bearing PFC Sigma primary TKAs using the Australian Orthopaedic Association National Joint Replacement Registry, dividing patients into three groups: no femoro-tibial size mismatch, tibial component size > femoral component size, and femoral component > tibial component. Revision rates were higher when the femoral size was greater than the tibia, compared to both equal size (HR = 1.20 (1.00, 1.45), P = 0.047) and to tibial size greater than femoral (HR = 1.60 (1.08, 2.37), P = 0.019). Potential mechanisms to explain these findings include edge loading of polyethylene and increased tibial component stresses.
authors.affiliation: Mayo Clinic, Scottsdale, Arizona.
authors.forename: Simon W
authors.initials: SW
authors.lastname: Young
authors.affiliation: Mayo Clinic, Scottsdale, Arizona.
authors.forename: Henry D
authors.initials: HD
authors.lastname: Clarke
authors.affiliation: Australian Orthopaedic Association National Joint Replacement Registry, Discipline of Public Health, School of Population Health, University of Adelaide, Adelaide, SA, Australia.
authors.forename: Stephen E
authors.initials: SE
authors.lastname: Graves
authors.affiliation: Data Management and Analysis Centre, University of Adelaide, Adelaide, SA, Australia.
authors.forename: Yen-Liang
authors.initials: YL
authors.lastname: Liu
authors.affiliation: Australian Orthopaedic Association National Joint Replacement Registry, Discipline of Public Health, School of Population Health, University of Adelaide, Adelaide, SA, Australia.
authors.forename: Richard N
authors.initials: RN
authors.lastname: de Steiger
mesh_terms: D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects* / Q000379:methods*; D001315:Australia; D005269:Femur / Q000601:surgery*; D006801:Humans; D015994:Incidence; D007719:Knee Joint / Q000601:surgery*; D007720:Knee Prosthesis / Q000009:adverse effects*; D009985:Orthopedics / Q000592:standards; D020959:Polyethylene; D016016:Proportional Hazards Models; D012042:Registries; D012086:Reoperation / Q000706:statistics & numerical data*; D015203:Reproducibility of Results; D013977:Tibia / Q000601:surgery*
chemical_list: D020959:Polyethylene
keywords: component size; registry; revision rates; size mismatch; total knee arthroplasty