Biological constraints that limit compensation of a common skeletal trait variant lead to inequivalence of tibial function among healthy young adults.

Although anecdotal evidence suggests functional inequivalence is tolerated under normal loading conditions, our concern is that the functional deficit of slender tibiae may contribute to fracture susceptibility under extreme loading conditions, such as intense exercise during military training or falls in the elderly. Thus, we show the natural variation in bone robustness was associated with predictable functional deficits that were attributable to cellular constraints limiting the amount of compensation permissible in human long bone. Whether these cellular constraints can be circumvented prophylactically to better equilibrate function among individuals remains to be determined.  Jepsen KJ, Centi A, Duarte GF, Galloway K, Goldman H, Hampson N, Lappe JM, Cullen DM, Greeves J, Izard R, Nindl BC, Kraemer WJ, Negus CH, Evans RK. J Bone Miner Res. 2011 Aug 26. [Epub ahead of print] PMID: 21898595