Longitudinal assessment of bone loss using quantitative ultrasound in a blood‐induced arthritis rabbit model

Introduction Osteoporosis is common in haemophilic arthropathy. Quantitative ultrasound ( QUS ) can be a suitable alternative for dual‐energy x‐ray absorptiometry for diagnosing osteoporosis in haemophiliacs due to its lack of ionizing radiation, and ease to use. Aim We investigated the intra‐ and inter‐operator reliability of QUS , its responsiveness to bone growth, its ability to differentiate bone adjacent to blood‐injected vs. control joints, and the effect of soft tissues on the speed of sound ( SOS ) QUS values in a juvenile white New Zealand rabbit model of blood‐induced arthritis. Methods Eight of 16 rabbits were injected with autologous blood (0.1 mL kg −1 ) 8 times over a 17‐week period, the remaining eight rabbits served as controls. SOS was measured at baseline, weeks 8 and 17 in vivo and after the bones were excised on week 17. Results Intra‐ and inter‐operator coefficients of variation for QUS data were <5% and intraclass correlation coefficients were >60% for 22/27 (81.5%) of bones assessed. The level of interval increase in SOS values from baseline to week 17 was significantly different in tibiae of injected, contralateral to injected and non‐injected knee groups by anova ( P = 0.01). In vivo (mean ± SD , 4147.17 ± 96.27 m s −1 ) and postmortem (4457.85 ± 104.00 m s −1 ) measurements on week 17 differed ( P < 0.01) indicating an effect of soft tissues on SOS . Conclusion In conclusion, QUS ' acceptable reliability, its responsiveness to growth‐related changes and its ability to discriminate injected and non‐injected joints make this technique a plausible candidate as a diagnostic tool for osteoporosis in the paediatic haemophilic population if these results are confirmed upon animal–human translation.