Finite element analysis of three reconstruction strategies for AORI IIA tibial bone defects in TKA.

BACKGROUND

AORI IIA-type bone defects are frequently encountered during total knee arthroplasty (TKA), posing a challenge for achieving durable and stable fixation. Although various reconstruction strategies have been proposed, the optimal method balancing mechanical stability and biological integration remains unclear.

OBJECTIVE

This study aimed to evaluate and compare the biomechanical performance of three reconstruction techniques-locking plate fixation (LP Group), screw-assisted bone cement filling (SC Group), and metal block augmentation (MB Group)-for managing AORI IIA tibial defects using finite element analysis.

METHODS

A finite element model of a medial AORI IIA tibial defect was constructed. Three reconstruction strategies were simulated, and the deformation and Von Mises stress distribution were analyzed under two loading conditions: (1) a vertical load of 800 N, and (2) a combined load of 600 N vertical force and 6000N・mm internal torsional moment.

RESULTS

Under vertical loading, the MB group showed the smallest maximum deformation of the graft material (0.299 mm) and the lowest maximum fixation stress (1.688 MPa), while the SC and LP groups exhibited similar maximum deformation (∼3.4 mm) with higher maximum internal stresses. Under combined loading, the MB group again had the lowest maximum deformation (0.227 mm) and fixation stress (1.153 MPa); the LP group showed the highest maximum fixation stress (62.841 MPa). The graft material in the MB and SC groups experienced higher maximum stress, suggesting improved load transfer, whereas the LP group showed stress shielding effects. Across both conditions, the MB group demonstrated the lowest residual stress in the cancellous bone.

CONCLUSION

The metal block technique offers superior biomechanical performance by combining structural stability with effective load sharing. The screw-assisted bone cement method provides moderate support and potential for bone integration, while the locking plate technique offers rigid initial fixation and preserves bone stock, it limits stress transmission. Selection of reconstruction strategy should be tailored to patient-specific bone quality, defect morphology, and functional demands.