3D templating and patient-specific instrumentation in primary total knee arthroplasty with retained internal fixation hardware: Two case reports.

Two elderly female patients with Kellgren-Lawrence grade 4 knee osteoarthritis (KOA) having varus knee deformity and retained hardware for internal fixation in either femur or tibia underwent total knee arthroplasty (TKA) using 3D templating and patient-specific instrumentation (PSI). TKA was performed to treat KOA by minimally removing or without removing the retained hardware for the internal fixation of distal femoral or tibial diaphyseal fractures. Throughout a 2-year follow-up period, no superficial or deep infection was observed. In additions, no radiological symptoms of suspected component loosening were observed. Furthermore, both patients can currently walk without using crutches. 3D templating and PSI in primary TKA for patients with retained hardware for internal fixation of femoral or tibial fractures are considered suitable treatment options for reducing surgical invasion.