# Evaluating the Effect of Total Hip Arthroplasty on Bone Mineral Density in Postmenopausal Women Using an Artificial Intelligence-Assisted Osteoporosis Diagnostic System

## TL;DR

This study finds that total hip arthroplasty may slow bone density loss in postmenopausal women with hip osteoarthritis.

## Contribution

A novel AI-assisted diagnostic system estimates BMD changes in postmenopausal women after hip surgery.

## Key findings

- THA slowed annual BMD decline in lumbar spine and proximal femur compared to age-matched population trends.
- BMD decline rates were lower in patients who had THA at younger ages.
- AI-assisted system using chest radiographs effectively estimated BMD changes.

## Abstract

Background and aim: Total hip arthroplasty (THA) alleviates pain and improves walking ability and quality of life in patients with hip osteoarthritis (OA). However, its effect on systemic bone mineral density (BMD) remains unclear. In this study, we investigated the effect of THA on systemic BMD in postmenopausal women with hip OA using an artificial intelligence (AI)-assisted osteoporosis diagnostic support system that estimates BMD solely using posteroanterior chest radiographs.

Methods: This retrospective observational study included postmenopausal Japanese women aged 50-59 years who underwent bilateral THA on separate occasions at our institution between 2007 and 2023. BMD was estimated using our AI-assisted osteoporosis diagnostic system that uses posteroanterior chest radiographs obtained approximately one month before each THA. The rate of change was compared with age-specific BMD reference values for the Japanese population.

Results: A total of 59 patients were included, with a mean age of 54.9 years and an average interval between unilateral THA of 2.1 years. Among those who underwent an initial THA at ages 50-54 years, the estimated BMD decreased by 1.52% and 0.81% annually in the lumbar spine and proximal femur, respectively. For patients who underwent an initial THA at ages 55-59 years, the estimated BMD decreased by 0.00% and 0.80% annually in the lumbar spine and proximal femur, respectively. These rates were lower than the reported rates of annual BMD decline in Japanese women aged 50-54 years (1.77%, lumbar spine; 1.27%, proximal femur) and 55-59 years (1.28%, lumbar spine; 0.88%, proximal femur).

Conclusion: THA has the potential to attenuate age-related BMD decline in postmenopausal women with hip OA.