Abstract
Objective
In this study, we aim to compare total bone amount extracted in total knee arthroplasty in implant design and the bone amount extracted through intercondylar femoral notch cut.
Material and Method
In this study, we implemented 10 implants on a total of 50 sawbones from 5 different total knee arthroplasty implant brands namely Nex-Gen Legacy (Zimmer, Warsaw, IN, USA), Genesis 2 PS (Smith&Nephew, Memphis, TN, USA), Vanguard (Biomet Orthopedics Inc., Warsaw, IN, USA), Sigma PS (De Puy, Johnson&Johnson, Warsaw, IN, USA), Scorpio NRG PS (Stryker Co., Kalamazoo, USA). Equal or the closest sizes of each brand on anteroposterior plane were selected, and cuts were made following standard technique(see Fig 1 and 2). Extracted bone pieces were measured in terms of volume and length on three planes, and statistically analysed. The volume of all pieces available after each femoral incision was measured according to Archimedes’ principles. Furthermore, the volume of each intercondylar femoral notch pieces was measured separately from other pieces but with the same method. The measurement of intercondylar femoral notch pieces on 3 planes (medial-lateral, anterior-posterior, superior-inferior) was made using Kanon slide gauge (Ermak Ltd, Istanbul, TR). Femoral notch incision pieces were scanned with CAD/CAM technology using three-dimensional scanner 1 SeriesTM (Dental Wings Inc, Montreal, QC, Canada), and the measurements were confirmed with DWOS CAD 4.0.1 software (Dental Wings Inc, Montreal, QC, Canada)(see figure 3a-e). The volume of 10 intercondylar femoral notch pieces performed through the set of each brand was averaged, and considered as the incision volume of that particular brand.
Results
The comparison made by excluding femoral notch cuts did not produce any statistically significant difference between the amounts of bone extracted. The least volumetric value measured in extracted intercondylar femoral notch cut was obtained using Vanguard (3,6±0,4 cm3). The gradually increasing volumes were obtained from Nex-Gen (3,7±0,5 cm3), Sigma (5,7±0,4 cm3), Genesis 2 (6,3±0,3 cm3) and Scorpio NRG (6,7±0,7 cm3), respectively. There was no statistical difference between Genesis 2 and Scorpio NRG, and between Nex-Gen and Vanguard.
Conclusion
There are significant differences among implant designs in terms of preserving bone stock, and much of these differences stems from intercondylar femoral notch incision.
