Creating Perforations in the Sclerotic Region of the Proximal Tibia During Total Knee Arthroplasty to Enhance Prosthesis Stability.

Objective: In patients with varus deformity of the knee, the redistribution of the subchondral bone mineral density (BMD) of the tibia leads to sclerotic zones that may cause osteoarthritis. Drilling the sclerotic area of the tibia prior to cementing during total knee arthroplasty is advisable practice. However, the extent of the sclerotic area and the effect of drilling on the tibial component are not well defined. We aimed to quantify the BMD and sclerotic bone distribution of the knee to clarify the effect of drilling on the stability of the prosthesis.

Methods: Our retrospective cohort study enrolled a total of 97 patients from December 2018 to December 2019, categorized into drilled and nondrilled groups, with their computed tomography (CT) knee joint images documented. The proximal tibia image was divided into nine regions, the BMD of each region calculated, and CT values compared between the affected and normal sides. We established finite element models to analyze the drilling and stress distribution. The differences in CT values were assessed using the paired t test and Wilcoxon signed-rank test.

Results: The mean thickness of sclerotic bone was 7.7 ± 1.4 mm, and the surface area was 441.9 ± 89.4 mm². The CT values of the affected anteromedial, anterolateral, mediomedial, mediolateral, posteromedial, posteromedian, and posterolateral tibial areas were significantly higher than their normal counterparts. Stress concentration around the boreholes in all finite element models is minimal, with stress values ranging from 0.01 to 3.73 MPa, markedly lower than the 13.93 MPa observed in the undrilled model.

Conclusion: Abnormal stress in the proximal tibia alters the distribution pattern of BMD, and drilling in the sclerotic area is associated with improved prosthesis stability.