The optional depth of screw for the treatment of tibial plateau defect in total knee arthroplasty: A finite element analysis

Background: The cement-screw technique is an effective method for repairing tibial plateau defects in total knee arthroplasty (TKA). However, it is unknown which depth for the screw is better. This study aimed to perform a finite element analysis (FEA) to determine the advantage of a cement-screw technique and confirm the optimal screw depth. Results: : Four FEA models were set to represent the cement-screw or cement-only techniques. In the cement-screw technique, screws were inserted into the defect area obliquely with an angle of 45 degrees from the mechanical axis with 3 different depths. The FEA models showed that cement-only technique had more stress-shielding areas in the tibial plateau and medullary cervicitis, while higher stress areas were in the defect and medullary cervicitis. For the cement-screw technique, stresses were lower on the surface of cancellous bone around screw when it was inserted below the upper surface of tibia. Conclusion: From the FEA data, we found that cement-screw technique is superior to cement-only technique for repairing a tibial plateau defect in TKA; for the former, it may be more beneficial to insert the screw below the upper surface of tibia plateau.