Impact of target joint and FVIII inhibitor οn bone properties in children with haemophilia A: A peripheral quantitative computed tomography study.

BACKGROUND: Haemophilic children are prone to low bone mass accrual.

OBJECTIVE: To assess bone properties in haemophilic children, using peripheral quantitative computed tomography (pQCT) and to correlate findings with clinical data.

SUBJECTS/METHODS: Peripheral quantitative computed tomography scan of both radii and tibiae were performed in 31 haemophilic A children (severe 24, mean age 11.2 years). Seven subjects had a history of inhibitors. Five children had an upper extremity target-joint and 12 had at least one lower extremity target-joint. The following parameters were measured: trabecular, total and cortical bone density and content (TBD, ToBD, CBD, TbC, CC), strength-stress index (SSI), and tibial cross-sectional area (CA), outer and inner bone contour length (PERI, ENDO) and cortical thickness (CTHC).

RESULTS: Mean right radius TBD was significantly higher than the left one (P = 0.015). In subjects with arm target-joint, radius TBD was significantly lower in the target than in non-target arm (186.6 ± 60.4 vs 218.6 ± 39.8, P = 0.032). Left arm target-joint subjects had significantly lower left radius TBD in comparison to subjects without arm target-joint (155.4 ± 50.3 vs 215.7 ± 37.9, P = 0.019). There were no similar differences in leg target-joint. Bone quality and geometry parameters in cortical compartment were significantly lesser in inhibitor group, with statistically significant side-to-side differences for legs and arms and left side predominance.

CONCLUSION: In children with haemophilia A and a history of target-joint and/or FVIII inhibitor, abnormalities may occur in the long bones as were revealed by pQCT, where low trabecular density and weak cortical bone quality in upper and lower extremities, respectively, were confirmed.