Hip geometry and its role in fracture: what do we know so far?

As the number of hip fractures continues to rise, finding better ways to identify people at risk becomes crucial. In the past decade, several measures of hip geometry have been studied as possible risk factors for hip fracture. Among them, hip axis length (HAL) shows the greatest promise for enhancing fracture risk assessment in the clinical setting, followed by neck shaft angle (NSA) and femoral neck width (FNW). Studies have shown that both age and/or a loss of body weight are associated with changes in some of the geometric parameters, which subsequently indicate the decrease in hip strength. The greater hip strength in black women and men resulting in a lower incidence of fractures compared with white women is also attributed to more favorable geometric parameters. Asian women, who have a lower incidence of fractures than white women, have a shorter HAL and a smaller NSA. In general, a longer HAL and a greater NSA and FNW all increase the risk of fracture, though controversies exist due to the use of different subject populations and measurement tools. Overall evidence suggests assessing hip geometry para-meters can significantly improve the ability of identifying people at risk of fracture, but more development in measurement software and more research are necessary to make it applicable in clinical settings.