The Impact of Pinless Navigation in Conventionally AlignedTotal Knee Arthroplasty

Restoration of the mechanical axis is a main objective in total knee replacement (TKR). Aim of this study was to analysethe verification tool of a pinless navigation system in conventional TKR (cTKR).Methods.Inaprospectivestudy,147TKRwereperformed by conventional technique. Using the “pinless verification” mode of a smartphone based navigation system, the cuttingblock position and final resection plane for distal femur and proximal tibial resection were measured. If necessary, the block positionor resection level were optimized, corrections were protocolled. Postoperatively, standardized radiographs were performed.Results.In 65.3%, intraoperative measurements changed the surgical procedure (corrections: 20.4% femoral, 25.9% tibial, 19% both). Theadditional time for surgery compared to cTKR averaged 6 minutes (79±15 versus 73±17 minutes). Using navigation data, thefinal femoral and tibial axes were in 93% within a range of±2∘. A mean difference of 1.4∘and 1.6∘could be shown between the finalmeasurement of the navigation system and the postoperative mLDFA and mMPTA.Conclusion.Intraoperativepinlessnavigationhas impact on the surgical procedure in the majority of cTKR. It represents a less time-consuming tool to improve implant positionwhile maintaining the routine of conventional technique