Proximal bone block with distal screw trajectory improves mechanical stability during distalization tibial tubercle osteotomy.

PURPOSE: The purpose of this study was to quantify differences in mechanical stability of a wedge-shaped distalization tibial tubercle osteotomy (TTO) with a standard technique, versus a modified technique with use of a proximal bone block and distally angled screw trajectory. METHODS: Ten fresh-frozen cadaver lower extremity specimens (five matched pairs) were utilized. Within each specimen pair, one specimen was randomly assigned to undergo a standard distalization osteotomy fixed with two bicortical 4.5-mm screws oriented perpendicular to the long axis of the tibia, and the other to undergo a distalization osteotomy with modified fixation utilizing a proximal bone block and distally angled screw trajectory. Each specimen's patella and tibia were mounted on a servo-hydraulic load frame using custom fixtures (MTS Instron). The patellar tendon was dynamically loaded to 400 N at a rate of 200 N/second for 500 cycles. Following the cyclic loading, loading to failure was done at 25 mm/min. RESULTS: The modified distalization TTO technique demonstrated significantly higher average load to failure compared to the standard distalization TTO technique (1339 N vs. 844.1 N, p < 0.001). Average maximum tibial tubercle displacement during cyclic loading was significantly smaller in the modified TTO technique group compared to the standard TTO technique (1.1 mm vs. 4.7 mm, p < 0.001). CONCLUSION: This study demonstrates that distalization TTO utilizing a modified technique with a proximal bone block and distally aimed screws is biomechanically superior to standard distalization TTO without proximal bone block and screw trajectory perpendicular to the long axis of the tibia. This increased stability may aid in reducing the reported higher complication rates (including loss of fixation, delayed union and nonunion) following distalization TTO, although future clinical outcome studies are warranted.

Associations of Early Sport Specialization and High Training Volume With Injury Rates in National Collegiate Athletic Association Division I Athletes.

BACKGROUND: There are 60 million US youth who participate in organized athletics, with large increases in both sport participation and specialization during the past 2 decades. There is some evidence that increased sport specialization and training volumes may be associated with increased injuries in adolescent populations. This study examines these variables in a population of elite college athletes. HYPOTHESIS: Early sport specialization (ESS) and a high training volume are risk factors for injury and/or surgery in National Collegiate Athletic Association (NCAA) Division I athletes. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: All Division I athletes at a single institution were surveyed regarding demographics, scholarship status, reason for specialization, age at specialization, training volume, and injury history. Chi-square and Mann-Whitney U tests were performed to identify significant differences. RESULTS: Athletes who specialized in their eventual varsity sport before age 14 years were more likely to report a history of injuries (86.9% vs 71.4%), multiple injuries (64.6% vs 48.8%), multiple college injuries (17.2% vs 6.0%), a greater number of total injuries (2.0 vs 1.0), and require more time out for an injury (15.2 vs 6.5 weeks) than those who did not. They were also more likely to be recruited (92.9% vs 82.1%) and receive a scholarship (82.8% vs 67.9%). Athletes who trained for greater than 28 hours per week in their eventual varsity sport before high school were more likely to report multiple injuries (90.0% vs 56.3%), multiple college injuries (40.0% vs 12.5%), a surgical injury (60.0% vs 22.9%), multiple surgical injuries (30.0% vs 4.7%), a greater number of total injuries (2.5 vs 2.0), and more time out for an injury (36.5 vs 11.0 weeks) than those who did not (all P < .05). However, these athletes were not more likely to be recruited (90.0% vs 89.8%) or receive a scholarship (80.0% vs 74.5%). CONCLUSION: NCAA Division I athletes with ESS and/or a high training volume sustained more injuries and missed more time because of an injury, but those with ESS were more likely to be recruited and receive a college scholarship. This knowledge can help inform discussions and decision making among athletes, parents, coaches, trainers, and physicians.

Matrix-Induced Autologous Chondrocyte Implantation With Autologous Bone Grafting for Osteochondral Lesions of the Femoral Trochlea.

Matrix-induced autologous chondrocyte implantation is a 2-stage surgical procedure used to treat symptomatic, full-thickness chondral lesions of the knee. This third-generation autologous chondrocyte implantation (ACI) technique improves on the limitations of previous methods, including the risk of uneven chondrocyte distribution at the time of implantation and graft hypertrophy. Given the compliant properties of the scaffold, the graft can be easily shaped to treat irregular chondral defects and applied to articular surfaces with multiplanar geometry (e.g., patella, trochlea). Although ACI techniques are ideally suited to treat chondral surface defects, the ACI "sandwich" technique can be used to treat large osteochondral defects with significant bone loss (>8 mm). Historically, this procedure uses autologous bone graft to replace areas of osseous deficiency along with 2 type I/III collagen bilayer membranes to securely contain the cultured chondrocytes within the defect. We present an analogous technique for the treatment of osteochondral lesions of the femoral trochlea using a single matrix-induced ACI scaffold and autologous bone grafting for a segmental osseous defect.

Fresh Osteochondral Allograft Transplantation for Uncontained, Elongated Osteochondritis Dissecans Lesions of the Medial Femoral Condyle.

Osteochondritis dissecans (OCD) lesions of the knee are a significant source of pain and disability. Although the pathologic process for this condition remains poorly understood, histologic studies suggest vascular insufficiency of the subchondral bone may be the underlying cause for focal necrosis and subsequent compromise of the overlying articular cartilage. These lesions most commonly affect the medial femoral condyle and can be found along the margins of the intercondylar notch. Because of significant bone involvement, osteochondral allograft (OCA) transplantation has emerged as a dominant treatment option for OCD lesions because it can accurately restore the entire osteochondral unit. Given the characteristic location and large, irregular shapes of these lesions, surgical management can be challenging. These lesions are often uncontained along the periphery of the condyle, which can compromise OCA graft fixation and healing. We describe our preferred technique for the treatment of large, uncontained OCD lesions of the medial femoral condyle using a unicompartmental OCA augmented with screw fixation.

Does Gender of Administrator Matter? National Study Explores U.S. University Administrators' Attitudes About Retaining Women Professors in STEM.

Omnipresent calls for more women in university administration presume women will prioritize using resources and power to increase female representation, especially in STEM fields where women are most underrepresented. However, empirical evidence is lacking for systematic differences in female vs. male administratorsÂS attitudes. Do female administrators agree on which strategies are best, and do men see things differently? We explored United States college and university administratorsÂS opinions regarding strategies, policies, and structural changes in their organizations designed to increase women professorsÂS representation and retention in STEM fields. A comprehensive review of past research yielded a database of potentially-effective, recommended policies. A survey based on these policies was sent to provosts, deans, associate deans, and department chairs of STEM fields at 96 public and private research universities across the U.S. These administrators were asked to rate the quality and feasibility of each strategy; 474 provided data, of which 334 contained complete numerical data used in the analyses. Our data revealed that female (vs. male) administrators believed the 44 strategies were higher in quality overall-but not higher in feasibility-with 9 strategies perceived differently by women and men, after imposing conservative statistical controls. There was broad general agreement on the relative-quality rankings of the 44 strategies. Women (vs. men) gave higher quality ratings to increasing the value of teaching, service, and administrative experience in tenure/promotion decisions, increasing flexibility of federal-grant funding to accommodate mothers, conducting gender-equity research, and supporting shared tenure lines enabling work-life balance. Women (vs. men) believed it was more feasible for men to stop the tenure clock for 1 year for childrearing and for universities to support requests for shared tenure lines, but less feasible for women to chair search committees. Our national survey thus supported the belief that placing women into administration creates greater endorsement of strategies to attract and retain women in STEM, although the effectiveness of these strategies was outside the scope of this research. Topics of disagreement between women and men are potentially important focuses of future policy, because female administrators may have insights into how to retain women that male administrators do not share.

Gay, Mostly Gay, or Bisexual Leaning Gay? An Exploratory Study Distinguishing Gay Sexual Orientations Among Young Men.

This exploratory study assessed physiological, behavioral, and self-report measures of sexual and romantic indicators of sexual orientation identities among young men (mean age = 21.9 years) with predominant same-sex sexual and romantic interests: those who described themselves as bisexual leaning gay (n = 11), mostly gay (n = 17), and gay (n = 47). Although they were not significantly distinguishable based on physiological (pupil dilation) responses to nude stimuli, on behavioral and self-report measures a descending linear trend toward the less preferred sex (female) was significant regarding sexual attraction, fantasy, genital contact, infatuation, romantic relationship, sex appeal, and gazing time to the porn stimuli. Results supported a continuum of sexuality with distinct subgroups only for the self-report measure of sexual attraction. The other behavioral and self-report measures followed the same trend but did not significantly differ between the bisexual leaning gay and mostly gay groups, likely the result of small sample size. Results suggest that romantic indicators are as good as sexual measures in assessing sexual orientation and that a succession of logically following groups from bisexual leaning gay, mostly gay, to gay. Whether these three groups are discrete or overlapping needs further research.

Sexual arousal: the correspondence of eyes and genitals.

Men's, more than women's, sexual responses may include a coordination of several physiological indices in order to build their sexual arousal to relevant targets. Here, for the first time, genital arousal and pupil dilation to sexual stimuli were simultaneously assessed. These measures corresponded more strongly with each other, subjective sexual arousal, and self-reported sexual orientation in men than women. Bisexual arousal is more prevalent in women than men. We therefore predicted that if bisexual-identified men show bisexual arousal, the correspondence of their arousal indices would be more female-typical, thus weaker, than for other men. Homosexual women show more male-typical arousal than other women; hence, their correspondence of arousal indices should be stronger than for other women. Findings, albeit weak in effect, supported these predictions. Thus, if sex-specific patterns are reversed within one sex, they might affect more than one aspect of sexual arousal. Because pupillary responses reflected sexual orientation similar to genital responses, they offer a less invasive alternative for the measurement of sexual arousal.

Male bisexual arousal: a matter of curiosity?

Conflicting evidence exists regarding whether bisexual-identified men are sexually aroused to both men and women. We hypothesized that a distinct characteristic, level of curiosity about sexually diverse acts, distinguishes bisexual-identified men with and without bisexual arousal. Study 1 assessed men's (n=277) sexual arousal via pupil dilation to male and female sexual stimuli. Bisexual men were, on average, higher in their sexual curiosity than other men. Despite this general difference, only bisexual-identified men with elevated sexual curiosity showed bisexual arousal. Those lower in curiosity had responses resembling those of homosexual men. Study 2 assessed men's (n=72) sexual arousal via genital responses and replicated findings of Study 1. Study 3 provided information on the validity on our measure of sexual curiosity by relating it to general curiosity and sexual sensation seeking (n=83). Based on their sexual arousal and personality, at least two groups of men identify as bisexual.