Early to Midterm Clinical and Radiographic Survivorship of the All-Polyethylene Versus Modular Metal-Backed Tibia Component in Primary Total Knee Replacement

The purpose of this study was to compare the all-polyethylene tibial component with the modular metal-backed component in primary total knee arthroplasty. A retrospective review of 1064 patients recorded clinical failure, as determined by need for revision surgery, range of motion, and impending radiographic loosening, as evaluated by the presence of radiolucent lines. Mean follow-up was 1.2 and 3 years, respectively. Survival in the all-polyethylene group was 100%, with 95.5% (95% CI: 85.8–98.6) survival in the metal-backed component group at 4.3 years. Thin (<4 mm) radiolucent lines were present in one patient (0.7%) with an all-polyethylene implant and 24 (16.9%) patients with the metalbacked component (p < .001), while one (0.7%) and two (1.4%) patients had evidence of osteolysis, respectively (p = .621). While there were fewer radiolucent lines noted around the all-polyethylene implant on radiographs, the clinical implications of the finding are unknown. In this study population, the all-polyethylene tibial component appears appropriate. (Journal of Surgical Orthopaedic Advances 28(2):108–114, 2019) Key words: all-polyethylene, metal-backed, osteolysis, primary knee arthroplasty