2016 年 28 巻 2 号 p. 155-161
Bony atrophy around the components following total knee arthroplasty (TKA) is often observed by radiography. To investigate the underlying cause of this incidence, we sought to quantitatively evaluate postoperative bone changes around the total knee components using dual-energy X-ray absorptiometry (DXA) over time. A retrospective study was conducted to compare bone mineral density (BMD) around the components in 22 patients pre-operatively and at 1, 3, 6, 12, and 24 months after cementless TKA for the treatment of osteoarthritis. In the coronal view, the medial tibia showed that a significant decrease in BMD at 12 months compared with 1 month after surgery (P<0.05), while the sagittal view showed that a significant decrease in BMD only at the anterior femoral condyle at 24 months compared with 1 month postoperatively (P<0.05). TKA improved the leg alignment and load-bearing axis in all patients, but we found that BMD tended to decrease on the medial side of the tibia and the anterior femoral condyle area over time following surgery. Our results suggest that recreating proper valgus alignment of the knee joint provides physiological balancing and condition. A larger prospective study is warranted.
