Beverly J. Levine

Relationships Between Lower Extremity Alignment and the Quadriceps Angle

Objective:To determine the extent to which select lower extremity alignment characteristics of the pelvis, hip, knee, and foot are related to the Q angle. Design:Descriptive cohort study design. Setting:Applied Neuromechanics Research Laboratory. Participants:Two hundred eighteen participants (102 males, 116 females). Assessment of Risk Factors:Eight clinical measures of static alignment of the left lower extremity were measured by a single examiner to determine the impact of lower extremity alignment on the magnitude of Q angle. Main Outcome Measures:Q angle, pelvic angle, hip anteversion, tibiofemoral angle, genu recurvatum, tibial torsion, navicular drop, and femur and tibia length. Results:Once all alignment variables were accounted for, greater tibiofemoral angle and femoral anteversion were significant predictors of greater Q angle in both males and females. Pelvic angle, genu recurvatum, tibial torsion, navicular drop, and femur to tibia length ratio were not significant independent predictors of Q angle in males or females. Conclusions:Greater femoral anteversion and tibiofemoral angle result in greater Q angle, with changes in tibiofemoral angle having a substantially greater impact on the magnitude of the Q angle compared with femoral anteversion. As such, the Q angle seems to largely represent a frontal plane alignment measure. As many knee injuries seem to result from a combination of both frontal and transverse plane motions and forces, this may in part explain why Q angle has been found to be a poor independent predictor of lower extremity injury risk.

A Comparison of Cyclic Variations in Anterior Knee Laxity, Genu Recurvatum and General Joint Laxity across the Menstrual Cycle

Changes in anterior knee laxity (AKL), genu recurvatum (GR) and general joint laxity (GJL) were quantified across days of the early follicular and early luteal phases of the menstrual cycle in 66 females, and the similarity in their pattern of cyclic variations examined. Laxity was measured on each of the first 6 days of menses (M1–M6) and the first 8 days following ovulation (L1–L8) over two cycles. The largest mean differences were observed between L5 and L8 for AKL (0.32 mm), and between L5 and M1 for GR (0.56°) and GJL (0.26) (p < 0.013). At the individual level, mean absolute cyclic changes in AKL (1.8 ± 0.7 mm, 1.6 ± 0.7 mm), GR (2.8 ± 1.0°, 2.4 ± 1.0°), and GJL (1.1 ± 1.1, 0.7 ± 1.0) were more apparent, with minimum, maximum and delta values being quite consistent from month to month (ICC2,3 = 0.51–0.98). Although the average daily pattern of change in laxity was quite similar between variables (Spearman correlation range 0.61 and 0.90), correlations between laxity measures at the individual level were much lower (range −0.07 to 0.43). Substantial, similar, and reproducible cyclic changes in AKL, GR, and GJL were observed across the menstrual cycle, with the magnitude and pattern of cyclic changes varying considerably among females.

The Relationship Between Lower Extremity Alignment Characteristics and Anterior Knee Joint Laxity

Background: Lower extremity alignment may influence the load distribution at the knee, potentially predisposing the anterior cruciate ligament to greater stress. We examined whether lower extremity alignment predicted the magnitude of anterior knee laxity in men and women. Hypothesis: Greater anterior pelvic angle, hip anteversion, tibiofemoral angle, genu recurvatum, and navicular drop will predict greater anterior knee laxity. Study Design: Descriptive laboratory study. Methods: Women (n = 122) and men (n = 97) were measured for anterior knee laxity and 7 lower extremity alignment variables on their dominant stance leg. Linear regression determined the extent to which the alignment variables predicted anterior knee laxity for each sex. Results: Lower anterior pelvic tilt and tibiofemoral angle, and greater genu recurvatum and navicular drop were related to greater anterior knee laxity in women, explaining 28.1% of the variance (P < .001). Lower anterior pelvic tilt and greater hip anteversion, genu recurvatum and navicular drop were predictors of greater anterior knee laxity in men, explaining 26.5% of the variance (P < .001). Conclusion: Lower anterior pelvic tilt, greater knee hyperextension, and foot pronation predicted greater anterior knee laxity in both men and women, with genu recurvatum and navicular drop having the greatest impact on anterior knee laxity. Greater hip anteversion was also a strong predictor in men, while a lower tibiofemoral angle was a significant predictor in women. Clinical Relevance: The associations between lower extremity alignment and anterior knee laxity suggest that alignment of the hip, knee, and ankle may be linked to or contribute to abnormal loading patterns at the knee, potentially stressing the capsuloligamentous structures and promoting greater joint laxity.

Reproductive and Hormonal Risk Factors for Ductal Carcinoma In situ of the Breast

One-fifth of all newly diagnosed breast cancer cases are ductal carcinoma in situ (DCIS), but little is known about DCIS risk factors. Recent studies suggest that some subtypes of DCIS (high grade or comedo) share histopathologic and epidemiologic characteristics with invasive disease, whereas others (medium or low grade or non-comedo) show different patterns. To investigate whether reproductive and hormonal risk factors differ among comedo and non-comedo types of DCIS and invasive breast cancer (IBC), we used a population-based case-control study of 1,808 invasive and 446 DCIS breast cancer cases and their age and race frequency-matched controls (1,564 invasive and 458 DCIS). Three or more full-term pregnancies showed a strong inverse association with comedo-type DCIS [odds ratio (OR), 0.53; 95% confidence interval (95% CI), 0.30-0.95] and a weaker inverse association for non-comedo DCIS (OR, 0.73; 95% CI, 0.42-1.27). Several risk factors (age at first full-term pregnancy, breast-feeding, and age at menopause) showed similar associations for comedo-type DCIS and IBC but different associations for non-comedo DCIS. Ten or more years of oral contraceptive showed a positive association with comedo-type DCIS (OR, 1.31; 95% CI, 0.70-2.47) and IBC (OR, 2.33; 95% CI, 1.06-5.09) but an inverse association for non-comedo DCIS (OR, 0.51; 95% CI, 0.25-1.04). Our results support the theory that comedo-type DCIS may share hormonal and reproductive risk factors with IBC, whereas the etiology of non-comedo DCIS deserves further investigation. (Cancer Epidemiol Biomarkers Prev 2009;18(5):1507–14)

Knee Joint Laxity and Its Cyclic Variation Influence Tibiofemoral Motion during Weight Acceptance

PURPOSE to better understand how sex differences in anterior knee laxity (AKL) affect knee joint biomechanics, we examined the consequence of greater absolute baseline (males and females) and cyclic increases in AKL during the menstrual cycle (females) on anterior tibial translation (ATT) as the knee transitioned from non-weight-bearing to weight-bearing conditions, while also controlling for genu recurvatum (GR). METHODS males and females (71 females and 48 males, aged 18-30 yr) were measured for AKL and GR and underwent measurement of ATT. Women were tested on the days of their cycle when AKL was at its minimum (T1) and maximum (T2); males were matched in time to a female with similar AKL. Linear regressions examined relationships between absolute baseline (AKLT1, GRT1) and cyclic changes (Δ = T2 - T1; AKLΔ, GRΔ) (females only) in knee laxity with ATT as measured at T1 and T2 and Δ (T2 - T1) (females only). RESULTS AKL and GR increased in females, but not in males, from T1 to T2. Greater AKLT1 and GRT1 predicted greater ATTT1 and ATTT2 in males (R = 21.0, P < 0.007). The combination of greater AKLT1, AKLΔ, and less GRΔ predicted greater ATTT1 and ATTT2 in females (R = 12.5-13.1, P < 0.05), with AKLΔ being a stronger predictor (coefficient, P value) of ATTT2 (0.864, P = 0.027) compared with ATTT1 (0.333, P = 0.370). AKLΔ was the sole predictor of ATTΔ (R = 0.104 and 0.740, P = 0.042). CONCLUSIONS greater absolute baseline and cyclic increases in AKL were consistently associated with greater ATT produced by transition of the knee from non-weight-bearing to weight-bearing. Because the anterior cruciate ligament is the primary restraint to ATT, these findings provide insight into the possible mechanisms by which greater AKL may be associated with at-risk knee biomechanics during the weight acceptance phase of dynamic tasks.

Accuracy of calendar-based methods for assigning menstrual cycle phase in women.

Background: Sex steroid hormone fluctuations during the menstrual cycle are considered a risk factor for noncontact anterior cruciate ligament injuries. Objective: To determine whether self-reported menstrual history data can be used to accurately categorize menstrual cycle events using calendar-based counting methods. Study Design: Descriptive laboratory study. Methods: Seventy-three women completed a menstrual history questionnaire and submitted to blood sampling for the first 6 days of menses and 8 to 10 days after a positive ovulation test over 2 consecutive months. Frequency counts determined whether appropriate criterion hormone (progesterone) levels were achieved at predefined calendar days. Results: For the criterion of progesterone >2 ng/mL, 18% and 59% of women attained it when counting forward 10 to 14 days after the onset of menses and counting back 12 to 14 days from the end of the cycle, respectively. Most women (76%) attained the criterion for ovulation 1 to 3 days after a positive urinary ovulation test. Regardless of the counting method employed, the criterion of progesterone >4.5 ng/mL for identifying midluteal phase was attained in 67% of cases. Serial blood sampling for 3 to 5 days after the positive urinary ovulation test captured 68% to 81% of the hormone values indicative of ovulation and 58% to 75% indicative of the luteal phase. Conclusion: These data suggest that self-reported menstrual history and calendar-based counting methods should not be used alone if accurate identification of ovulation is essential. A urinary ovulation test and serial blood samples for verification of progesterone postovulation enhance the proper identification of menstrual cycle events. Clinical Relevance: Given the cost of serial blood sampling on numerous days, the use of urinary ovulation kits and strategically selected serial blood sampling could significantly reduce participant burden and provide cost-effective measures for clinical studies related to anterior cruciate ligament injury epidemiology.

Some sex hormone profiles are consistent over time in normal menstruating women: implications for sports injury epidemiology

Purpose It is unclear whether sex hormone profiles obtained in two consecutive months are consistent within women. Month-to-month consistency in daily, nadir, peak and mean hormone concentrations during the early follicular and luteal phases in recreationally active, young eumenorrheic women was prospectively examined. Methods 60 healthy, non-smoking women who reported normal and consistent menstrual cycles lasting 26–32 days for the past 6 months were followed prospectively to obtain serum samples for the first 6 days of menses and for 8 days after a positive ovulation test over two consecutive months. Month-to-month consistency of daily concentrations of oestradiol (pg/ml), progesterone (ng/ml), testosterone (ng/dl), sex hormone-binding globulin (nmol/l) and free androgen index were determined using linear mixed models. Month-to-month consistency in nadir, peak and mean concentrations were then assessed using intraclass correlation coefficients and SEM to more precisely examine intraindividual consistency. Results Linear mixed models revealed stable hormone concentrations across cycles and cycles by day. Reliability estimates for nadir, peak, mean menses and mean postovulatory concentrations range from 0.56 to 0.86 for oestradiol, 0.44 to 0.91 for progesterone, 0.60 to 0.86 for testosterone, 0.88 to 0.97 for sex hormone-binding globulin and 0.78 to 0.91 for free androgen index. Conclusions Hormone profiles were reproducible over two consecutive months. To reduce month-to-month intraindividual variations and improve measurement consistency, it is recommended that multiple samples be taken over consecutive days as opposed to a single sample.