Femoral Neck Stress in Older Adults During Stair Ascent and Descent

Abstract

A detailed understanding of the hip loading environment is needed to help prevent hip fractures, minimize hip pain, rehabilitate hip injuries, and design osteogenic exercises for the hip. The purpose of this study was to compare femoral neck stress during stair ascent and descent and to identify the contribution of muscles and reaction forces to the stress environment in mature adult subjects (n = 17; age: 50-65 y). Motion analysis and inverse dynamics were combined with musculoskeletal modeling and optimization, then used as input to an elliptical femoral neck cross-sectional model to estimate femoral neck stress. Peak stress values at the 2 peaks of the bimodal stress curves (stress vs time plot) were compared between stair ascent and descent. Stair ascent had greater compressive stress than descent during the first peak at the anterior (ascent: -18.0 [7.9] MPa, descent: -12.9 [5.4] MPa, P < .001) and posterior (ascent: -34.4 [10.9] MPa, descent: -27.8 [10.1] MPa, P < .001) aspects of the femoral neck cross section. Stair descent had greater tensile stress during both peaks at the superior aspect (ascent: 1.3 [7.0] MPa, descent: 24.8 [9.7] MPa, peak 1: P < .001; ascent: 15.7 [6.1] MPa, descent: 18.0 [8.4] MPa, peak 2: P = .03) and greater compressive stress during the second peak at the inferior aspect (ascent: -43.8 [9.7] MPa, descent: -51.1 [14.3] MPa, P = .004). Understanding this information can provide a more comprehensive view of bone loading at the femoral neck for older population.

Heterogeneous Spatial and Strength Adaptation of the Proximal Femur to Physical Activity: A Within-Subject Controlled Cross-Sectional Study

“…We recently used a subject‐specific musculoskeletal model of the lower extremity and CT‐based FE model of the proximal femur to show weight‐bearing loading with the hip in flexion (eg, during stair ascent) engendered greatest strain within the superior femoral neck in postmenopausal women . An alternative research group suggested stair descent loaded the superior femoral neck more so than stair ascent, but the study applied forces to a generic elliptical femoral neck cross‐sectional model as opposed to a subject‐specific FE proximal femur model, raising concerns regarding model accuracy . Martelli and colleagues produced data suggesting maximal hip extension and knee flexion exercises maximally loaded the thinnest region of the superior femoral neck; however, data were limited to the study of a single individual and the application of musculoskeletal loads calculated from a young volunteer to an FE model of the proximal femur from an older individual.…”

“…(8) An alternative research group suggested stair descent loaded the superior femoral neck more so than stair ascent, but the study applied forces to a generic elliptical femoral neck cross-sectional model as opposed to a subject-specific FE proximal femur model, raising concerns regarding model accuracy. (51) Martelli and colleagues (52) produced data suggesting maximal hip extension and knee flexion exercises maximally loaded the thinnest region of the superior femoral neck; however, data were limited to the study of a single individual and the application of musculoskeletal loads calculated from a young volunteer to an FE model of the proximal femur from an older individual. There is a definite need for further studies to model proximal femur and particularly femoral neck loading to better define activities that may target and adapt the superior femoral neck.…”

Measuring femoral neck loads in healthy young and older adults during stair ascent and descent

“…Modelling procedures were developed and presented in a previous publication [25] with older adults ascending and descending stairs. This study focuses on differences that may exist between young adults and older adults.…”

“…These measurements provide a direct measure of the hip joint forces that are invaluable, but the invasive nature and limited subject pool reduces the practicality of this protocol in most laboratory and clinical settings which studies the healthy population. In this study, multiscale modelling techniques were used to estimate hip joint kinetics during stair ascent and descent (or uphill and downhill) [19][20][21][22] with an acceptable accuracy compared with the direct measurements [23], and potentially went further to estimate femoral neck stress or strains [24,25] for the healthy population in a non-invasive way. In addition, some specific modelling methods allow the sources of the bone stress to be identified (muscle vs. reaction and forces vs. moments) and analyzed, the counteract effect of different stress components could be analyzed and strategies to decrease the total stress on the femoral neck could be explored.…”

“…In addition, some specific modelling methods allow the sources of the bone stress to be identified (muscle vs. reaction and forces vs. moments) and analyzed, the counteract effect of different stress components could be analyzed and strategies to decrease the total stress on the femoral neck could be explored. In the previous research, the femoral neck stresses and stress source analysis were done for the older population [25] but the differences of stress and its source between older and young population were not conducted yet. The comparison between older and young population for the total femoral neck stresses and the components of the stresses could explain the reason of possible stress change on the femoral neck due to aging and the cause of higher risk of femoral neck injuries.…”