Proximal tibia bone mineral density correlates more closely with hip density in men with knee osteoarthritis

Abstract

Purpose

Achieving biological fixation of the often loosened tibia is increasingly important for total knee arthroplasty (TKA), with one key factor being the bone density of the proximal tibia. This study examined whether hip bone mineral density (BMD), the most common diagnostic tool for osteoporosis, can estimate tibial BMD in both sexes.

Methods

This retrospective study included patients who underwent primary TKA with hip and tibial BMD measurement. Tibial BMD was measured 10 ​mm distal to the lateral tibial articular surface, separately for the medial (BMD_m) and lateral (BMD_l) sides. Additionally, the association between BMD and lower limb alignment was evaluated.

Results

In total, 1012 knees were included (79.3% in women). The mean patient age at surgery was 73.3 ​± ​7.5 years. The mean total hip BMD for women and men was 0.79 ​± ​0.13 ​g/cm² and 0.95 ​± ​0.16 ​g/cm², respectively. The mean BMD_m and BMD_l was, respectively, 0.75 ​± ​0.16 ​g/cm² and 0.63 ​± ​0.13 ​g/cm² in women and 0.92 ​± ​0.18 ​g/cm² and 0.89 ​± ​0.18 ​g/cm² in men. Both BMD_m and BMD_l showed a moderate correlation with hip BMD (r ​= ​0.67 and 0.66, respectively) in men. In women, BMD_m showed a weak correlation (r ​= ​0.47). Regarding lower limb alignment, BMD_m was significantly higher in varus alignment than in neutral or valgus alignment. BMD_l did not change with lower limb alignment.

Conclusions

BMD_m and BMD_l were moderately correlated with hip BMD in men, while BMD_m showed a low correlation in women.