We used ultrasonographic heel measurements to compare the bone quality of patients who underwent total knee arthroplasty (TKA), age-matched controls and patients who suffered from hip fracture. The broadband ultrasound attenuation (BUA; dB/MHz) of the TKA (70), control (70) and hip fracture (107) groups was 42.2+/-15.5, 40.2+/-14.9 and 22.9+/-13.3, respectively. The hip fracture group was significantly different from both the TKA and control groups (P<0.0001). The TKA group had better BUA than the control group, although the difference was not significant (P=0.712). The increase in activity after artificial replacement of an arthritic joint might result in bone quality equivalent to that of controls. Considering that none of TKA patients suffered from hip fracture in the follow-up period, which ranged from 62 to 113 months, TKA might contribute to a decrease in the risk of later hip fracture, by allowing increased mobility and maintaining or improving bone quality.