Meagre effects of disuse on the human fibula are not explained by bone size or geometry

IRELAND, A.; CAPOZZA, R.F.; COINTRY, G.R.; NOCCIOLINO, L.; FERRETTI, J.L.; RITTWEGER, J.

OSTEOPOROSIS INTERNATIONAL

SPRINGER LONDON LTD

Año: 2017 vol. 28 p. 633 - 641

0937-941X

Summary: Fibula response to disuse is unknown; we assessed fibula bone in spinal cord injury (SCI) patients and able-bodied counterparts. Group differences were smaller than in the neighbouring tibia which could not be explained by bone geometry. Differential adaptation of the shank bones may indicate previously unknown mechanoadaptive behaviours of bone. Introduction: The fibula supports only a small and highly variable proportion of shank compressive load (−8 to +19 %), and little is known about other kinds of stresses. Hence, whilst effects of habitual loading on tibia are well-known, fibula response to disuse is difficult to predict. Methods: Therefore, we assessed fibular bone strength using peripheral quantitative computed tomography (pQCT) at 5 % increments from 5 to 90 % distal-proximal tibia length in nine participants with long-term spinal cord injury (SCI; age 39.2 ± 6.2 years, time since injury 17.8 ± 7.4 years), representing a cross-sectional model of long-term disuse and in nine able-bodied counterparts of similar age (39.6 ± 7.8 years), height and mass. Results: There was no group difference in diaphyseal fibula total bone mineral content (BMC) (P = 0.22, 95 % CIs -7.4 % to -13.4 % and +10.9 % to +19.2 %). Site by group interactions (P