Finite element analysis of effects of nail holes on tibial plateau stress distribution in unicompartmental knee arthroplasty

Abstract

Objective To investigate the effect of different nail holes of osteotomy guide plate on the tibial plateau stress distribution. Methods Dicom data of 10 full-length CT scans of adult tibia with lower extremity angiography and no bone disease were collected from the Imaging Center of Guangdong Second Hospital of Traditional Chinese Medicine. A three-dimensional reconstruction of Mimics 20.0 was performed to obtain a normal full-length humeral model, then import the model into the Abaqus for simulated surgery. The nail holes remains after the temporary fixation of the K-wire with a diameter of 3 mm at different positions 15 mm below the tibial osteotomy surface. The model is divided into four groups according to the position of the nail holes, namely: group A (no nail hole) group B (the nail hole was located directly below the vertical osteotomy line); group C (the nail hole was located directly below the keel groove); group D (the nail hole was located 3 mm outside the keel groove). Two regions of interest (ROI) were set: ROI1 was the corner of the vertical osteotomy and the plane osteotomy, and ROI2 was the bottom of the keel. Analyze the stress distribution of the tibial plateau under different conditions. One -way ANOVA was used to compare the differences between four groups, and SNK or Dunnett ’s T3 was used to compare means between groups in pairs. Results Compared with group A, the maximum stress of ROI1 in group B increased, and the difference was statistically significant (P 0.05). The maximum stress of ROI2 in group D was slightly lower than that without nail hole, and the difference was statistically significant (t=0.34, P <0.05). Conclusions In UKA, the nail hole under the tibial plateau will affect the distribution of platform stress. When the position of the nail hole is located under the vertical osteotomy and the keel groove, the maximum stress at ROI1 and ROI2 will increase significantly, and the risk of tibial plateau fracture will be increased. During the operation, the osteotomy template fixation nails should be avoided to avoid dangerous areas. Key words: Knee; Osteoarthritis; Arthroplasty; Fractures; Finite element analysis