Contribution of total knee arthroplasty to increased bone mineral density

Although several studies describe a significant decrease in postoperative bone mineral density of up to 44% adjacent to the implants after total knee arthroplasty, most reports demonstrated that the decrease in bone mineral density did not continue after 2 years. Most patients may show a reduction in activity levels in the first 6 months after surgery, gradually returning to the preoperative level within the next 6 months, and then show an improvement over the preoperative level by 2 years postoperatively. Namely, although bone density initially decreases after total knee arthroplasty, this procedure contributes to increased bone mineral density approximately 1–2 years postoperatively. Our results suggest that total knee arthroplasty may contribute to a reduction of the risk of later hip fractures. In addition, it may reduce the risk of lifestyle-related diseases, including diabetes mellitus, hypertension and hyperlipemia, by allowing increased mobility, resulting in better bone quality.