Sex and Maturational Differences in Lower Extremity Posture

Abstract

In the adult population, sex differences in lower extremity alignment have been identified in the structures of the hips and knees. While the reasons contributing to these sex differences are not entirely known, they are thought to be developmental in nature, emerging post puberty. PURPOSE: To examine sex and maturational differences in static lower extremity posture (LEP) of the hips and knees. METHODS: Clinical measures of pelvic angle (PA), hip anteversion (HA), standing Q-angle (StQ), tibiofemoral angle (TFA) and genu recurvatum (GR) were measured on the right side of 173 adolescents (88M, 14.3±2.8yrs, 163.4±15.6 cm, 57.5±19kg; 85F, 14.3±3.1 yrs, 156±21 cm, 57.8±26.7 kg) as part of a larger risk factor screening project. Subjects were classified into 3 maturation groups (MG) based on validated sex appropriate, self-administered questionnaires that assessed Tanner's stages (1–5) of development. Subjects were assigned to MG1 if they were in Tanner's stages 1 and 2 (N=26M, 25F), MG2 if they were in stages 3 and 4 (N=34M, 29F), and MG3 if they were in stage 5 (N=28M, 3 1F). Separate 2X3 factorial ANOVAs examined sex differences in each alignment characteristic across MGs. Alpha level was set at P<.05. RESULTS: Changes across MGs (1 vs. 2 vs. 3) occurred with PA (9.5°±4.5° vs. 8.8°±4.0deg; vs. 10.8deg;±3.5°),HA(10.1deg;±5.5°vs. 14.0°±5.7° vs. 10.5°±5.5°), TFA(10.6°±2.4° vs. 9.8°±2.3° vs. 8.9°±2.5°), and GR (6.3°±2.0° vs. 6.9°±1.9° vs. 2.6°±3.6°). Females were consistently higher than males (M vs. F) for HA (10.7°±5.4° vs. 12.7°±6.1°) and TFA (9.1°±2.4°vs. 10.4deg; ±2.3°),but not for PA(9.6deg;±4.3°vs. 9.8°±3.8°, P=.895)or GR (5.5°±3.2° vs. 5.0°±3.3°, P=.437). Sex differences in StQ changed by MG: M vs. F values were similar for MG1 (13.9°±4.9° vs. 14.1°±4.7°), with lower values for M vs. F for MG2 (11.1°±4.1°vs. 17.0deg;±6.8°)and MG3(9.4deg;±5.6°vs. 15.5°±5.4°). CONCLUSIONS: Lower extremity alignment of the hips and knees change with maturation. While sex differences in StQ were dependent on maturational development, females had consistently higher values for HA and TFA throughout maturation. Understanding how these sex and maturational differences interact to influence dynamic function and injury risk may potentially aid clinicians as they evaluate, manage, and ultimately, work toward prevention of knee injuries in females.