Z-scorización original de curvas de referencia de “distribución/masa” y de “distribución/calidad” obtenidas por pQCT en la tibia humana para evaluar la eficiencia del mecanostato óseo en la clínica

GUSTAVO ROBERTO COINTRY; PAOLA REINA; LAURA NOCCIOLINO; IRENE GRAPPIOLO; SARA FELDMAN; JOSÉ LUIS FERRETTI; RICARDO FRANCISCO CAPOZZA

Buenos Aires

Congreso; XXIX REUNIÓN DE LA AAOMM; 2012

The efficiency of bone mechanostat to control bone stiffness/strength could be assessed as the adequacy of the spatial distribution of bone tissue as a function of its stiffness at any given skeletal site. With that purpose we determined pQCT indicators of cortical tissue distribution (d, bending and torsion moments of inertia, MIs) and quality (q, vDMO -CtD-, a correlate of tissue stiffness) at every 5% of the tibia height in 42 normal men and women. The analysis of the highly-significant d/q curves obtained at every studied site allowed selecting the standard, 38% site as adequate to test the d/q relationship for clinical applications. Aiming to obtain suitable reference d/q curves for comparative diagnosis, we measured the same indicators at the 38% site in a larger sample of healthy men and pre- and post-MP women (n=60, 80, 120) aged 25-85 years, and Z-scored the observed d/q relationships for each group. Then we plotted d/q data obtained in 36 chronic cirrhotic and 60 dialyzed men and women with reference to their sex controls. The healthy post-MP women showed significantly lower d/q Z-scores (similar MIs for lower CtD values) than the reference pre-MP women. Both cirrhotic and dialyzed patients showed significantly lower d/q Z-scores (lower values of both MIs and CtD) than their respective references. Results show that cortical tissue distribution (i.e. the efficiency of cortical modeling drifts modulation in response to local strains induced by mechanical usage) tends to decay as a function of tissue deformability in post-MP women and in patients with metabolic osteopenias (i.e. under the effect of non-mechanical, metabolic disturbances) as expected according to the Mechanostat Theory.