Description
Background: Loss of bone stock as a response to the bone trauma and immobilization related to joint replacement can increase the risk of periprosthetic fracture and aseptic loosening. There are few previous studies with longterm follow-up of of tibia and femur bone loss after cementless total knee arthroplasty (TKA).Aim: The aim of this study was to investigate the short- term and long-term adaptive bone remodelling of the distal femur and the proximal tibia after cementless TKA.
Materials and Methods: 65 patients (mean age 61 years) were included and bone mineral density (BMD) mesassurements distal femur using dual energy x-ray (DEXA) were performed postoperatively and after 3, 6, 12, 24 and 84 months. We completed seven year follow up of 36 patients. Bone mineral density (g/cm2) was measured in three regions of interest in the periprosthetic bone of the distal femur and the proximal tibia. Also the BMD of distal tibia just above the ankles were meassured bilaterally as control.
Results: In the distal femur significant changes in bone mineral density were seen after 84 months of follow- up and bone mineral density decreased by 28.7% in the anterior region behind the anterior flange of the prosthesis, 16.2% in the posterior region and 10.3% in the proxiaml region. Most of the bone loss in the femur occured within the first 24 months. In the proximal medial region of the tibia bone mineral density decreased by 8.9% and in the proximal lateral tibia by 10.4%. During the first six months we found a temporary BMD increase in lateral proximal tibia. All the above BMD changes were statistically highly significant (PInterpretation / Conclusion: We found highly significant bone mineral change in the distal femur and proximal tibia after cementless total knee arthroplasty. Most of the BMD loss took place within the first 24 months. In the anterior femur region a decrease in bone mineral density of 28.7% during the seven year period. In the tibia we found less BMD loss and a temporary increase in lateral BMD which could be explained by correction of varus alignment. Taking the expected age related decay in this age group in to consideration the decrease was substantial and must be considered to predispose to periprosthetic fractures.
| Period | 2023 |
|---|---|
| Event title | Dansk Ortopædisk Selskab Kongres 2023 |
| Event type | Conference |