Healthcare disparities in adolescent idiopathic scoliosis: the impact of socioeconomic factors on Cobb angle.

STUDY DESIGN: Retrospective chart review. OBJECTIVES: The aim of this study is to assess the role of insurance type, geographic socioeconomic status, and ethnicity in AIS disease severity in a state with mandated scoliosis screenings. Early detection of adolescent idiopathic scoliosis (AIS) is associated with reduced curve progression, surgical treatment, and long-term sequelae. Type of insurance, ethnicity, and socioeconomic status are important determinants in healthcare access. METHODS: Data were obtained for 561 AIS patients aged 10-18 years, living within a single county, and presenting to a single healthcare system for initial evaluation of AIS between 2010 and 2016 that met inclusion criteria. Demographic data including gender, age, self-reported ethnicity, insurance, and zip code were collected. Outcome measures included Cobb angle, curve severity, and referral delay. A single fellowship-trained pediatric orthopedic surgeon calculated presenting Cobb angle for each case. Zip code was used as a proxy for household income level. Independent sample t tests, analysis of variance and covariance, and χ2 analysis were used to determine the significant differences and correlations. RESULTS: Female patients (n = 326, CA = 22.4°) had significantly greater Cobb angle measurements compared with male patients (n = 117, CA = 18.1°). Patients with government-supported insurance had significantly higher Cobb angles (CA = 22.1°) than privately insured patients (CA = 19.2°) but were both classified within the "mild" range clinically, and are likely not clinically significant. There was no correlation between income level and Cobb angle. Referral delay and Cobb angle severity did not vary by age, income, or insurance. A χ2 analysis showed no association between Cobb angle and race. CONCLUSIONS: Cobb angle severity was not influenced by SES factors, including ethnicity and household income. LEVEL OF EVIDENCE: Level-II.

Connexin 43 hemichannels protect bone loss during estrogen deficiency.

Estrogen deficiency in postmenopausal women is a major cause of bone loss, resulting in osteopenia, osteoporosis, and a high risk for bone fracture. Connexin 43 (Cx43) hemichannels (HCs) in osteocytes play an important role in osteocyte viability, bone formation, and remodeling. We showed here that estrogen deficiency reduced Cx43 expression and HC function. To determine if functional HCs protect osteocytes and bone loss during estrogen deficiency, we adopted an ovariectomy model in wild-type (WT) and two transgenic Cx43 mice: R76W (dominant-negative mutant inhibiting only gap junction channels) and Cx43 Δ130-136 (dominant-negative mutant compromising both gap junction channels and HCs). The bone mineral density (BMD), bone structure, and histomorphometric changes of cortical and trabecular bones after ovariectomy were investigated. Our results showed that the Δ130-136 transgenic cohort had greatly decreased vertebral trabecular bone mass compared to WT and R76W mice, associated with a significant increase in the number of apoptotic osteocyte and empty lacunae. Moreover, osteoclast surfaces in trabecular and cortical bones were increased after ovariectomy in the R76W and WT mice, respectively, but not in ∆130-136 mice. These data demonstrate that impairment of Cx43 HCs in osteocytes accelerates vertebral trabecular bone loss and increase in osteocyte apoptosis, and further suggest that Cx43 HCs in osteocytes protect trabecular bone against catabolic effects due to estrogen deficiency.

Validity of the Hispanic version of the American Academy of Orthopaedic Surgeons Foot and Ankle Outcomes Questionnaire in patients with traumatic foot and ankle injuries.

BACKGROUND: Hispanics represent the largest minority group in the United States and are projected to represent 29% of the US population by 2060. Enrolling Hispanic patients in clinical outcome trials is critical to study a representative sample of the general population. Lack of translated and validated survey tools has been identified as a major barrier to enrolling Spanish speaking patients. The purpose of this validation study was to study the correlation between the Spanish translation of the American Academy of Orthopaedic Surgeons Foot and Ankle Outcomes questionnaire (AAOS-FAOQ) and the Spanish versions of the Foot Function Index (FFI) and the Foot Health Status Questionnaire (FHSQ) in Hispanics from Mexican lineage with traumatic foot and ankle injuries. METHODS: A cross-sectional validation study in 36 Hispanic patients from Mexican lineage with foot and ankle injuries was performed. The Hispanic version of the AAOS-FAOQ and the Spanish translations of the FAOQ, FHSQ, FFI, and the Short-Form 36 questionnaire (SF-36) were distributed among all patients. Subsequent statistical analysis correlating the Hispanic version of the AAOS-FAOQ to the FFI, FHSQ, and SF-36 was performed. Additional analysis on the Hispanic AAOS-FAOQ included test-retest reliability and internal consistency. RESULTS: The Hispanic AAOS-FAOQ Global Foot and Ankle subscale showed statistically significant (P < .05) correlations with 5 of 8 subscales of the FHSQ, the FFI, and the Physical Component Summary subscale of the SF-36. The AAOS-FAOQ Global Foot & Ankle Scale also demonstrated a test-retest reliability of 0.736 and a strong internal consistency. CONCLUSIONS: This study further validates AAOS-FAOQ in Mexican Hispanics by showing strong correlations with the validated Spanish versions of the FFI and FHSQ.

Is Diabetic Skeletal Fragility Associated with Microvascular Complications in Bone?

PURPOSE OF REVIEW: The objective of this literature review is to determine whether there are indications that microvascular complications occur in diabetic bone. Evidence definitively linking diabetic skeletal fragility with microvascular complications in bone remains elusive. RECENT FINDINGS: Circumstantial evidence, some recent and some lost to time, suggests that atherosclerotic vascular diseases such as peripheral arterial disease cause poor blood perfusion of bone and subsequent hypoxia and contribute to low bone density and high cortical porosity, patterns similar to some recently observed in diabetic subjects. Evidence also exists to suggest that potentially anti-angiogenic conditions, such as impaired vascular endothelial growth factor (VEGF) signaling, predominate in diabetic bone. Microvascular complications may contribute, in part, to diabetic skeletal fragility but data supporting this interpretation are primarily circumstantial at this time. This review highlights gaps in our knowledge and hopefully spurs further discussions and research on this topic.

Treatment with a soluble receptor for activin improves bone mass and structure in the axial and appendicular skeleton of female cynomolgus macaques (Macaca fascicularis).

A recent study suggests that activin inhibits bone matrix mineralization, whereas treatment of mice with a soluble form of the activin type IIA receptor markedly increases bone mass and strength. To further extend these observations, we determined the skeletal effects of inhibiting activin signaling through the ActRIIA receptor in a large animal model with a hormonal profile and bone metabolism similar to humans. Ten female cynomolgus monkeys (Macaca fascicularis) were divided into two weight-matched groups and treated biweekly, for 3 months, with either a subcutaneous injection 10 mg/kg of a soluble form of the ActRIIA receptor fused with the Fc portion of human IgG(1) (ACE-011) or vehicle (VEH). Bone mineral density (BMD), micro-architecture, compressive mechanical properties, and ash fraction were assessed at the end of the treatment period. BMD was significantly higher in ACE-011 treated individuals compared to VEH: +13% (p=0.003) in the 5th lumbar vertebral body and +15% (p=0.05) in the distal femur. In addition, trabecular volumetric bone density at the distal femur was 72% (p=0.0004) higher than the VEH-treated group. Monkeys treated with ACE-011 also had a significantly higher L5 vertebral body trabecular bone volume (p=0.002) and compressive mechanical properties. Ash fraction of L4 trabecular bone cores did not differ between groups. These results demonstrate that treatment with a soluble form of ActRIIA (ACE-011) enhances bone mass and bone strength in cynomolgus monkeys, and provide strong rationale for exploring the use of ACE-011 to prevent and/or treat skeletal fragility.

Assessing the accuracy of high-resolution X-ray computed tomography of primate trabecular bone by comparisons with histological sections.

Different lines of evidence suggest that trabecular bone architecture contains a functional signal related to an organism's locomotor behavior. An understanding of the interspecific and intraspecific variation in extant nonhuman primate trabecular structure is needed to evaluate its usefulness as a tool to reconstruct the locomotor habits of extinct primates. High-resolution X-ray computed tomography (HRXCT) is a new imaging approach with a resolution in the tens of microns that allows nondestructive access to the internal structure of bony elements. Previous studies indicate that such resolution is necessary to accurately quantify structural parameters of trabecular bone. The primary goal of this study was to test the accuracy of HRXCT by comparing stereological measurements from HRXCT images and histological thin sections of cancellous bone taken from the proximal femur and humerus of baboons. To this end, 11 bone samples were scanned on an HRXCT scanner and then thin-sectioned to reveal the scanned plane. HRXCT images were thresholded using a modified half-maximum height protocol. The stereological measurements included bone volume fraction (BV/TV), trabecular number (Tb.N), bone surface to volume ratio (BS/BV), trabecular thickness (Tb.Th), and trabecular spacing (Tb.Sp). The measurement errors on the HRXCT images were 10.90% for BV/TV, 6.06% for Tb.N, 14.19% for BS/BV, 14.33% for Tb.Th, and 7.09% for Tb.Sp, but none of these measurements were significantly different from the histological standards (alpha = 0.05). A second goal of this study was to examine the influence of thresholding, a necessary step in any morphometric study using computed tomography, on the accuracy of the quantitative morphometry. Threshold values derived from a modified half-maximum height protocol showed that parameters derived from the region of interest (area in which stereological measurements were later taken) produced better reconstructions of the actual bone structure than threshold values derived from more inclusive areas of bone. We conclude that HRXCT can accurately reconstruct the complex architecture of trabecular bone, and that thresholding is a nontrivial step in trabecular bone studies, with even slight changes in the protocol greatly affecting the morphometric data. HRXCT represents a valuable analytical tool that should be of interest to a great many researchers in physical anthropology because it allows nondestructive access to internal morphology, thereby preserving valuable and limited skeletal collections.