Investigating the primary stability of the transversal support tibial plateau concept to retain both cruciate ligaments during total knee arthroplasty

Purpose: The important roles of the anterior cruciate ligament regarding knee stability, physiologic kinematics, and proprioception are unquestioned. Thus, various efforts have been made to retain the ACL during total knee arthroplasty (TKA). Neither of the existing solutions to this problem, i.e. bicruciate retaining prostheses and implantation of two unicondylar prostheses, has been successful because of concept-specific problems as well as general difficulties with implant fixation.
The new transversal support tibial plateau concept is a prosthesis of two individual joint surfaces reinforced beneath the articular line by joint surface supports and buttressed by a single transversal support. This configuration, which enables retention of both cruciate ligaments, should provide good bone fixation and ensure long-term alignment of the individual joint surfaces. Methods: In the current study, four prototypes based on this novel concept were developed and the resulting primary stability was analyzed using adapted load testing. The test set-up, with the model-loading of specially prepared Sawbones® and a sinusoidal oscillating load transmission with 25 000 cycles over 10 increasing load levels, achieved subsidence, which enabled comparison of the four different model variants regarding primary stability in view of bone anchoring.Results: The model variant (TSmobile) that allowed transverse glide of the joint surface supports along the transversal support revealed the largest subsidence.Conclusions: A rigid attachment of the joint surface supports of the transversal support tibial plateau thus appears to offer increased primary stability regarding bone anchoring.