STUDY DESIGN: Descriptive, cross-sectional. OBJECTIVES: We compared lower extremity anatomical characteristics in males and females between different maturation groups. BACKGROUND: Sex differences have been observed in lower extremity anatomical characteristics. While the reasons contributing to these sex differences in adults are unknown, there is evidence that anatomy and posture change considerably during growth and development. METHODS AND MEASURES: One hundred seventy-three young athletes (age range, 9–18 years) were assessed for stage of maturation and placed into 1 of 3 groups, according to Tanners stages 1 and 2 (MatGrp₁), 3 and 4 ( MatGrp₂), and 5 (MatGrp₃). Participants were measured for pelvic angle, hip anteversion, quadriceps angle, tibiofemoral angle, femur length, tibial length, genu recurvatum, tibial torsion, navicular drop, general joint laxity, and anterior knee laxity. Data were compared by sex and maturation group. RESULTS: When comparing maturation groups, limb length, pelvic angle, and tibial torsion increased with maturation, and anterior knee laxity, genu recurvatum, tibiofemoral angle, and foot pronation decreased with maturation. Females had greater general joint laxity, hip anteversion, and tibiofemoral angles, and shorter femur and tibial lengths than males, regardless of maturation group. Maturational changes in knee laxity and quadriceps angles were sex dependent. CONCLUSIONS: We observed a general change in posture with maturation that began with greater knee valgus, knee recurvatum, and foot pronation in MatGrp₁, then moved toward a relative straightening and external rotation of the knee, and supination of the foot in later maturation groups. While the majority of the measures changed similarly in males and females across maturation groups, decreases in quadriceps angles and anterior knee laxity were greater in males compared to females, and females were observed to have a more inwardly rotated hip and valgus knee posture, compared to males, particularly in later maturation groups. LEVEL OF EVIDENCE: Diagnosis, level 4.

J Orthop Sports Phys Ther. 2008;38(3):137-149, published online 16 October 2007. doi:10.2519/jospt.2008.2645

KEY WORDS:  alignment, development, growth, joint laxity, posture

STUDY DESIGN: Descriptive, cohort design. OBJECTIVES: To comprehensively examine sex differences in clinical measures of static lower extremity alignment (LEA). BACKGROUND: Sex differences in LEA have been included among a myriad of risk factors as a potential cause for the increased prevalence of knee injury in females.  While clinical observations suggest sex differences in LEA exist, little empirical data are available to support these sex differences or the normal values that should be expected in a healthy population. METHODS AND MEASURES: The right and left static LEA of 100 healthy college-age participants (50 males [mean ± SD age, 23.3 ± 3.6 years; height, 177.8 ± 8.0 cm; body mass, 80.4 ± 11.6 kg] and 50 females [mean ± SD age, 21.8 ± 2.5 years; height, 164.3 ± 6.9 cm body mass, 67.4 ± 15.2 kg]) were measured. Each alignment characteristic was analyzed via separate repeated-measures analyses of variance, with 1 between-subject factor (sex) and 1 within-subject factor (side). RESULTS: There were no significant sex-by-side interactions and no differences by side. Females had greater mean anterior pelvic tilt, hip anteversion, quadriceps angles, tibiofemoral angles, and genu recurvatum than males (P<.0001). No sex differences were observed in tibial torsion (P = .131), navicular drop (P = .130), or rearfoot angle (P = .590). CONCLUSION: Sex differences in LEA indicate that females, on average, have greater anterior pelvic tilt, thigh internal rotation, knee valgus, and genu recurvatum. These sex differences were not accompanied by differences in the lower leg, ankle, and foot. Understanding these collective sex differences in LEA may help us to better examine the influence of LEA on dynamic knee function and clarify their role as a potential injury risk factor.

J Orthop Sports Phys Ther. 2007;37(7):389-398, published online 16 April 2007. doi:10.2519/jospt.2007.2487

KEY WORDS: malalignment, posture, risk factor assessment