Association of polymorphism in leptin receptor gene with susceptibility of adolescent idiopathic scoliosis.

PURPOSE: Abnormal leptin bioavailability has play key roles in the etiology of adolescent idiopathic scoliosis (AIS). Both leptin and its receptor levels may be modulated by the presence of genetic polymorphisms. This study aimed to evaluate the role of polymorphisms in the leptin (LEP) and its main receptor (LEPR) genes in the AIS susceptibility in girls. METHODS: A retrospective case-control study was conducted with 189 AIS and 240 controls. LEP rs2167270 and LEPR rs2767485 polymorphisms were genotyped using a TaqMan validated assay. Associations were evaluated by odds ratios (OR) and 95% confidence intervals (CI). RESULTS: The AIS group showed a predominance of girls under 18 years old (n = 140, 74.1%), 148 (78.3%) had low or normal BMI, 111 (58.7%) had Cobb ≥ 45º and 130 (68.7%) were skeletally mature. Minor allele frequencies of rs2167270 and rs2767485 were 35.7% and 18.3%, for AIS and 35.6% and 25.4% for controls, respectively. LEPR rs2767485 T and TC + TT were associated with higher risk of AIS (OR = 1.53; 95% CI = 1.09-2.13 and OR = 1.84; 95% CI = 1.69-2.01, respectively), since CC genotype was only present in the control group. In addition, the LEP rs2167270 GA + AA was more frequent in low weight group (BMI ≤ 24.9) of girls with AIS. There was no significant association between LEP rs2167270 and AIS susceptibility, and LEPR rs2767485 and BMI. CONCLUSION: The LEPR rs2767485 was associated with the genetic susceptibility of AIS and LEP rs2167270 with low BMI. These data can contribute to the identification of genetic biomarkers to improve the diagnosis and treatment.

Biological parameters for quality evaluation of allografts from the Brazilian National Institute of Traumatology and Orthopedics tissue bank.

Bone allografts are clinically used in a variety of surgical procedures, and tissue banks are responsible for harvesting, processing, quality testing, storing, and delivering these materials for transplantation. In tissue banks, the bone is processed for the removal of all organic content, remaining only the tissue structure (scaffold). However, several studies have shown that even after using different processing methods, viable cells, functional proteins, and DNA may still persist in the tissue, which constitute the main causes of graft rejection. Therefore, the objective of this study was to establish techniques and biological parameters for quality validation of allografts. To this end, we propose the use of 3 combined methods such as microscopy, histology, and molecular biology techniques to evaluate the quality of allografts harvested and processed by the Brazilian National Institute of Traumatology and Orthopedics (INTO) tissue bank according to the donation criteria of the Brazilian National Health Surveillance Agency and the Brazilian National Transplant System. Bone fragments from different processing stages showed no viable cells on histology, an intact extracellular matrix on scanning electron microscopy, and gradual reduction in DNA amount. Different techniques were used to demonstrate the quality of allografts produced by the INTO tissue bank and to establish biological parameters for ensuring the safety and quality of these products. Future studies need to be undertaken to assess and validate the efficacy of the decellularization process in larger bone grafts with diverse architectural configurations.

Genetic Variations in Susceptibility to Traumatic Muscle Injuries and Muscle Pain among Brazilian High-Performance Athletes.

Traumatic muscle injuries (TMIs) and muscle pain (MP) negatively impact athletes' performance and quality of life. Both conditions have a complex pathophysiology involving the interplay between genetic and environmental factors. Yet, the existing data are scarce and controversial. To provide more insights, this study aimed to investigate the association of single-nucleotide polymorphisms (SNPs) previously linked to athletic status with TMI and MP after exercise among Brazilian high-performance athletes from different sports modalities (N = 345). The impact of important environmental determinants was also assessed. From the six evaluated SNPs (ACTN3 rs1815739, FAAH rs324420, PPARGC1A rs8192678, ADRB2 rs1042713, NOS3 rs1799983, and VDR rs731236), none was significantly associated with TMI. Regarding MP after exercise, ACTN3 rs1815739 (CC/CT vs. TT; adjusted odds ratio (aOR) = 1.90; 95% confidence interval (95%Cl), 1.01-3.57) and FAAH rs324420 (AA vs. AC/CC; aOR = 2.30; 95%Cl, 1.08-4.91) were independent predictors according to multivariate binomial analyses adjusted for age (≥23 vs. <23 years), sex (male vs. female), and tobacco consumption (yes vs. no). External validation is warranted to assess the predictive value of ACTN3 rs1815739 and FAAH rs324420. This could have implications for prophylactic interventions to improve athletes' quality of life.

Conventional versus locked plates for hip dislocation in cerebral palsy: a matched cohort analysis.

PURPOSE: Bone quality of non-ambulatory patients with cerebral palsy (CP) is a matter of concern for proximal femoral varus derotational osteotomies (VDRO). Locking plates (LCP) have been designed to compensate this biological downfall. Little data exist comparing the LCP with the conventional femoral blade plate. METHODS: We retrospectively studied 32 patients submitted to VDRO (40 hips), operated with blade plates or LCP. Groups were matched, and the minimal follow-up was 36 months. Clinical (age at surgery, sex, GMFCS class, CP patterns) and radiological characteristics (neck shaft angle [NSA], acetabular index [AI], Reimers migration index [MP] and time until bone healing), as well as postoperative complications and the cost of treatment, were evaluated. RESULTS: Preoperative clinical characteristics and radiographic measurements were comparable, except for a higher AI in the BP group (p < 0.01). Mean follow-up was longer in the LCP group (57.35 vs 34.6 months). Mean NSA, AI and MP had comparable correction with surgery (p < 0.01). At final follow-up, dislocation recurrence speed was higher in BP group although not statistically significant (0.56% vs 0.35%/month; p = 0.29). The complication rate was similar in both groups (p > 0.05). Finally, the cost of the treatment was 62% higher in the LCP group (p = 0.01). CONCLUSION: Our cohorts showed LCP or BP equivalence clinically and radiographically in mid-term follow-up, with the former increasing the cost of treatment by a mean of 62%. This may raise a question on the real necessity of locked implants for these operations. LEVEL OF EVIDENCE: Level III-Retrospective comparative study.

Association of FBN1 polymorphism with susceptibility of adolescent idiopathic scoliosis: a case-control study.

BACKGROUND: Fibrillin-1 (FBN1) is an extracellular matrix glycoprotein essential to the structural component of microfibrils and FBN1 gene polymorphisms can be associated with adolescent idiopathic scoliosis (AIS) susceptibility. This study aimed to evaluate the potential role of the FBN1 rs12916536 polymorphism in AIS development or severity and the variation in Cobb angle in relation to patient's characteristics. METHODS: DNA from 563 subjects (185 AIS patients and 378 controls) were genotyped using a validated TaqMan allelic discrimination assay. A multivariate logistic regression model evaluated the association between polymorphism and AIS, using the adjusted odds ratios (OR) with their respective 95% confidence intervals (95% CI). A linear regression analysis evaluated the variation in Cobb angle according to the patient's age and body mass index (BMI). RESULTS: Among the AIS group there was a predominance of females (12:1), low or normal BMI (90%), 58% had a Cobb angle greater than 45° and 74% were skeletally mature. Age was a risk factor (4-fold) for curve progression higher than BMI (P < 0.001). The allelic frequency of the rs12916536 G > A polymorphism was 40% in controls and 31% in AIS cases; and this difference was statistically significant (P = 0.004). FBN1 rs12916536 GA + AA genotypes were associated with a lower risk of AIS susceptibility (OR = 0.58 and 95% CI = 0.35-0.98), after adjustment for age, sex and BMI. However, no significant differences were detected in polymorphism distribution with the severity of the disease (Cobb < 45° or ≥ 45°). CONCLUSION: Age was a risk factor for progression of the scoliotic curve and FBN1 rs12916536 polymorphism a protective factor for AIS susceptibility.

Influence of type I collagen polymorphisms and risk of anterior cruciate ligament rupture in athletes: a case-control study.

BACKGROUND: Anterior cruciate ligament (ACL) rupture is a common and severe knee injury in sports and occurs mostly due to noncontact injuries. There is an increasing amount of evidence associating ACL rupture to single nucleotide polymorphisms (SNPs), and SNPs in the collagen type I genes can change its expression and tissue mechanical features. This study aimed to investigate the association between SNPs in COL1A1 and COL1A2 with sports-related ACL tears. METHODS: A total of 338 athletes from multiple sports modalities were analyzed: 146 were diagnosed with ACL rupture or underwent an ACL reconstruction surgery and 192 have no musculoskeletal injuries. SNPs were genotyped using validated TaqMan assays. The association of the polymorphisms with ACL rupture was evaluated by a multivariable logistic regression model, using odds ratios (OR) and 95% confidence intervals (CI). RESULTS: The age, sport modality, and training location were associated with an increased risk of a non-contact ACL tear. COL1A2 SNPs (rs42524 CC and rs2621215 GG) were associated with an increased risk of non-contact ACL injury (6 and 4-fold, respectively). However, no significant differences were detected in the distribution of COL1A1 rs1107946 and COL1A2 rs412777 SNPs between cases and controls. There was a protective association with ACL rupture (OR = 0.25; 95% CI = 0.07-0.96) between COL1A1 rs1107946 (GT or TT) and the wildtype genotypes of the three COL1A2 (rs412777, rs42524, rs2621215). COL1A2 rs42524 and rs2621215 SNPs were associated with non-contact ACL risk. CONCLUSION: The combined analysis of COL1A1-COL1A2 genotypes suggests a gene-gene interaction in ACL rupture susceptibility.

Musculoskeletal injuries in athletes from five modalities: a cross-sectional study.

BACKGROUND: Musculoskeletal injuries (MSK-I) are a serious problem in sports medicine. Modifiable and non-modifiable factors are associated with susceptibility to these injuries. Thus, the aim of this study was to describe the prevalence of and identify the factors associated with MSK-I, including tendinopathy and joint and muscle injuries, in athletes. METHODS: In this cross-sectional observational study, 627 athletes from rugby (n = 225), soccer (n = 172), combat sports (n = 86), handball (n = 82) and water polo (n = 62) were recruited at different sports training centres and competitions. Athlete profiles and the prevalence of MSK-I were assessed using a self-reported questionnaire. Only previous MSK-I with imaging confirmation and/or a positive physical exam by a specialized orthopaedist were considered. The association of the epidemiological, clinical and sports profiles of athletes with MSK-I was evaluated by a logistic regression model. RESULTS: The mean age was 25 ± 6 years, and 60% of the athletes were male. The epidemiological, clinical and sports profiles of the athletes were different for the five sport groups. The MSK-I prevalence among all athletes was 76%, with 55% of MSK-I occurring in a joint, 48% occurring in a muscle and 30% being tendinopathy, and 19% of athletes had three investigated injuries. The MSK-I prevalence and injury locations were significantly different among sport groups. There was a predominance of joint injury in combat sports athletes (77%), muscle injury in handball athletes (67%) and tendinopathy in water polo athletes (52%). Age (≥30 years) was positively associated with joint (OR = 5.2 and 95% CI = 2.6-10.7) and muscle (OR = 4.9 and 95% CI = 2.4-10.1) injuries and tendinopathy (OR = 4.1 and 95% CI = 1.9-9.3). CONCLUSION: There is a high prevalence of tendinopathy and joint and muscle injuries among rugby, soccer, combat sports, handball and water polo athletes. The analysis of associated factors (epidemiological, clinical and sports profiles) and the presence of MSK-I in athletes suggests an approximately 4-5-fold increased risk for athletes ≥30 years of age. The identification of modifiable and non-modifiable factors can contribute to implementing surveillance programmes for MSK-I prevention.

The obturator oblique and iliac oblique/outlet views predict most accurately the adequate position of an anterior column acetabular screw.

OBJECTIVE: Percutaneous fixation of the acetabulum is a treatment option for select acetabular fractures. Intra-operative fluoroscopy is required, and despite various described imaging strategies, it is debatable as to which combination of fluoroscopic views provides the most accurate and reliable assessment of screw position. MATERIALS AND METHODS: Using five synthetic pelvic models, an experimental setup was created in which the anterior acetabular columns were instrumented with screws in five distinct trajectories. Five fluoroscopic images were obtained of each model (Pelvic Inlet, Obturator Oblique, Iliac Oblique, Obturator Oblique/Outlet, and Iliac Oblique/Outlet). The images were presented to 32 pelvic and acetabular orthopaedic surgeons, who were asked to draw two conclusions regarding screw position: (1) whether the screw was intra-articular and (2) whether the screw was intraosseous in its distal course through the bony corridor. RESULTS: In the assessment of screw position relative to the hip joint, accuracy of surgeon's response ranged from 52% (iliac oblique/outlet) to 88% (obturator oblique), with surgeon confidence in the interpretation ranging from 60% (pelvic inlet) to 93% (obturator oblique) (P < 0.0001). In the assessment of intraosseous position of the screw, accuracy of surgeon's response ranged from 40% (obturator oblique/outlet) to 79% (iliac oblique/outlet), with surgeon confidence in the interpretation ranging from 66% (iliac oblique) to 88% (pelvic inlet) (P < 0.0001). CONCLUSIONS: The obturator oblique and obturator oblique/outlet views afforded the most accurate and reliable assessment of penetration into the hip joint, and intraosseous position of the screw was most accurately assessed with pelvic inlet and iliac oblique/outlet views. EVIDENCE: Clinical Question.

Fc receptor-like 3 (-169T>C) polymorphism increases the risk of tendinopathy in volleyball athletes: a case control study.

BACKGROUND: Tendinopathy pathogenesis is associated with inflammation. Regulatory T (Treg) cells contribute to early tissue repair through an anti-inflammatory action, with the forkhead box P3 (FOXP3) transcription factor being essential for Treg function, and the FC-receptor-like 3 (FCRL3) possibly negatively regulating Treg function. FCRL3 -169T>C and FOXP3 -2383C>T polymorphisms are located near elements that regulate respective genes expression, thus it was deemed relevant to evaluate these polymorphisms as risk factors for tendinopathy development in athletes. METHODS: This case-control study included 271 volleyball athletes (146 tendinopathy cases and 125 controls) recruited from the Brazilian Volleyball Federation. Genotyping analyses were performed using TaqMan assays, and the association of the polymorphisms with tendinopathy evaluated by multivariate logistic regression. RESULTS: Tendinopathy frequency was 63% patellar, 22% rotator cuff and 15% Achilles tendons respectively. Tendinopathy was more common in men (OR = 2.87; 95% CI = 1.67-4.93). Higher age (OR = 8.75; 95% CI = 4.33-17.69) and more years of volleyball practice (OR = 8.38; 95% CI = 3.56-19.73) were risk factors for tendinopathy. The FCRL3 -169T>C frequency was significantly different between cases and controls. After adjustment for potential confounding factors, the FCRL3 -169C polymorphism was associated with increased tendinopathy risk (OR = 1.44; 95% CI = 1.02-2.04), either considering athletes playing with tendon pain (OR = 1.98; 95% CI = 1.30-3.01) or unable to train due to pain (OR = 1.89; 95% CI = 1.01-3.53). The combined variant genotypes, FCRL3 -169TC or -169CC and FOXP3 -2383CT or -2383TT, were associated with an increased risk of tendinopathy among athletes with tendon pain (OR = 2.24; 95% CI: 1.14-4.40 and OR = 2.60; 95% CI: 1.11-6.10). The combined analysis of FCRL3 -169T>C and FOXP3 -2383C>T suggests a gene-gene interaction in the susceptibility to tendinopathy. CONCLUSIONS: FCRL3 -169C allele may increase the risk of developing tendinopathy, and together with knowledge of potential risk factors (age, gender and years playing) could be used to personalize elite athletes' training or treatment in combination with other approaches, with the aim of minimizing pathology development risk.

The effect of bone allografts combined with bone marrow stromal cells on the healing of segmental bone defects in a sheep model.

BACKGROUND: The repair of large bone defects is a major orthopedic challenge because autologous bone grafts are not available in large amounts and because harvesting is often associated with donor-site morbidity. Considering that bone marrow stromal cells (BMSC) are responsible for the maintenance of bone turnover throughout life, we investigated bone repair at a site of a critically sized segmental defect in sheep tibia treated with BMSCs loaded onto allografts. The defect was created in the mid-portion of the tibial diaphysis of eight adult sheep, and the sheep were treated with ex-vivo expanded autologous BMSCs isolated from marrow aspirates and loaded onto cortical allografts (n = 4). The treated sheep were compared with control sheep that had been treated with cell-free allografts (n = 4) obtained from donors of the same breed as the receptor sheep. RESULTS: The healing response was monitored by radiographs monthly and by computed tomography and histology at six, ten, fourteen, and eighteen weeks after surgery. For the cell-loaded allografts, union was established more rapidly at the interface between the host bone and the allograft, and the healing process was more conspicuous. Remodeling of the allograft was complete at 18 weeks in the cell-treated animals. Histologically, the marrow cavity was reestablished, with intertrabecular spaces being filled with adipose marrow and with evidence of focal hematopoiesis. CONCLUSIONS: Allografts cellularized with AOCs (allografts of osteoprogenitor cells) can generate great clinical outcomes to noncellularized allografts to consolidate, reshape, structurally and morphologically reconstruct bone and bone marrow in a relatively short period of time. These features make this strategy very attractive for clinical use in orthopedic bioengineering.

Patellar and quadriceps tendon rupture are associated with hip fracture in hemodialysis patients with severe hyperparathyroidism.

Spontaneous rupture of the patellar (PTR) and quadriceps (QTR) tendon is infrequent. Systemic diseases such as diabetes mellitus, CKD, and secondary hyperparathyroidism (SHPT) are risk factors. The present cohort study aimed to evaluate risk factors associated with tendon rupture in hemodialysis (HD) patients with SHPT, as well as outcomes including surgical complications, re-ruptures, and fracture. Baseline clinical, laboratorial data, and radiographs were analyzed. Patients were followed up from March 2012 to March 2020. One-hundred thirty-one patients (≥18 yr of age, on HD ≥ 6 mo, with SHPT) were included. Incidence rates of PTR and QTR were 2.3 and 1.7/10000 HD patients/yr, respectively. The mean age of patients with tendon rupture was 44.0 ± 11.2 yr. These patients exhibited higher serum levels of phosphorus (6.3 ± 1.5 mg/dL vs 5.6 ± 1.1 mg/dL; P = .005), PTH (2025.7 ± 667.6 pg/mL vs 1728.4 ± 684.8 pg/mL; P = .035), and C-reactive-protein (35.4 ± 32.9 mg/dL vs 17 ± 24.5 mg/dL; P = .002) compared to the group without tendon rupture. The mean follow-up was 56.7 ± 27.1 mo. No patient required a new surgical approach or experienced re-rupture. Of all patients, 31% experienced hip fracture: 50% in the group with rupture (29.5 ± 17.4 mo after the tendon rupture) vs 26% without tendon rupture (P = .015). After adjustment, the hazard ratio for hip fracture was 2.87 (95% CI, 1.27-6.49; P = .012). Patients with SHPT and high levels of phosphorus, PTH, and inflammatory markers were at greater risk for tendon rupture. Surgical complication rates were low. However, results suggest that tendon rupture of knee extensor mechanism in HD patient with SHPT should be regarded as a "red flag" for future hip fracture.

Potential and Limitations of Induced Pluripotent Stem Cells-Derived Mesenchymal Stem Cells in Musculoskeletal Disorders Treatment.

The burden of musculoskeletal disorders (MSK) is increasing worldwide. It affects millions of people worldwide, decreases their quality of life, and can cause mortality. The treatment of such conditions is challenging and often requires surgery. Thus, it is necessary to discuss new strategies. The therapeutic potential of mesenchymal stem cells (MSC) in several diseases has been investigated with relative success. However, this potential is hindered by their limited stemness and expansion ability in vitro and their high donor variability. MSC derived from induced pluripotent stem cells (iPSC) have emerged as an alternative treatment for MSK diseases. These cells present distinct features, such as a juvenile phenotype, in addition to higher stemness, proliferation, and differentiation potential than those of MSC. Here, we review the opportunities, challenges, and applications of iPSC as relevant clinical therapeutic cell sources for MSK disorders. We discuss iPSC sources from which to derive iMSC and the advantages and disadvantages of iMSC over MSC as a therapeutic approach. We further summarize the main preclinical and clinical studies exploring the therapeutic potential of iMSC in MSK disorders.

Open Fracture of the Femoral Neck in an Adult: Case Report and Surgical Solution.

Intracapsular proximal femoral fracture is a frequent injury in elderly patients, often associated with low-energy trauma and reduced bone mass. In young patient, it is uncommon, usually caused by high-energy trauma and accompanied by damage to the adjacent soft tissues. However, reports of open intracapsular proximal femoral fracture due to indirect trauma are rare in the orthopedic literature. In the present article, we describe a case of this injury in a 35-year-old man involved in a car accident. The proximal femur was exposed at the gluteal region due to a mechanism similar to dislocation of the posterior hip. We describe the initial treatment and subsequent management until achieving a definitive solution using total hip arthroplasty and muscle transfer to reconstruct the abductor mechanism of the hip. At 10 months of follow-up, the patient presented good functional outcome, with gradual recovery of the abductive strength and a Harris Hip Score of 91 points. In addition, a radiographic study showed that the cemented total prosthesis was well-positioned. This therapeutic strategy (total hip arthroplasty with muscle transfer to reconstruct the abductor musculature) was successful to treat an intracapsular proximal femoral fracture with bone exposure.

Characterization of the Masquelet Induced Membrane Technique in a Murine Segmental Bone Defect Model.

Objective To reproduce in an animal model the surgical technique of Masquelet used in the treatment of critical bone defects and to analyze the characteristics of the membrane formed around the bone cement. Methods A 10mm critical defect was created in the femoral shaft of 21 Sprague-Dawley rats. After resection of the central portion of the diaphysis, the defect was stabilized with a Kirschner wire introduced through the medullary canal and with the interposition of a bone cement spacer. After 2, 4, and 6 weeks of the surgical procedure, the animals were euthanized and evaluated on radiographs of the posterior limb regarding the size of the defect, alignment and stability of the osteosynthesis. The membranes formed around the spacer were subjected to histological analysis to assess thickness, connective tissue maturation and vascular density. Results Over time, the membranes initially made up of loose connective tissue were replaced by membranes represented by dense connective tissue, rich in thick collagen fibers. At six weeks, membrane thickness was greater (565 ± 208µm) than at four (186.9 ± 70.21µm, p = 0.0002) and two weeks (252.2 ± 55.1µm, p = 0.001). All membranes from the initial time showed foci of osteogenic differentiation that progressively reduced over time. Conclusion In addition to the structural and protective function of the membrane, its intrinsic biological characteristics can actively contribute to bone regeneration. The biological activity attributed by the presence of foci of osteogenesis confers to the membrane the potential of osteoinduction that favors the local conditions for the integration of the bone graft.

Monoaxial Mechanical Tests on Porcino Knee Ligaments.

The failure of ligament reconstruction has different risk factors, among which we can highlight the period before its incorporation, which is a mechanically vulnerable period. Loss of resistance over time is a characteristic of living tissues. Dissection with bone insertions of the cruciate ligaments of animal models is not described; however, it is essential for monoaxial assays to extract information from tests such as relaxation. The present work describes the dissection used for the generation of a test body for the performance of nondestructive tests to evaluate the mechanical behavior. We performed dissection of four porcino knee ligaments, proposing a dissection technique for the cruciate ligaments with bone inserts for comparison with collateral ligaments. The ligaments were submitted to relaxation tests and had strain gauges placed during the tests. The results showed viscoelastic behavior, validated by strain gauges and with a loss over time; with some ligaments presenting with losses of up to 20%, a factor to be considered in future studies. The present work dissected the four main ligaments of the knee demonstrating the posterior approach that allows maintaining their bone insertions and described the fixation for the monotonic uniaxial trials, besides being able to extract the viscoelastic behavior of the four ligaments of the knee, within the physiological limits of the knee.

Genetic Polymorphisms in COL1A2 gene and the Risk of Tendinopathy: Case-Control Study.

Objective To evaluate the influence of polymorphisms on genes encoding type I collagen and the genetic susceptibility of tendinopathy. Methodology Case-control study involving 242 Brazilian athletes from different sports modalities (55 cases of tendinopathy and 187 controls). The polymorphisms COL1A1 (rs1107946) and COL1A2 (rs412777, rs42524, and rs2621215) were analyzed by the TaqMan system. Odds ratio (OR) with their 95% confidence intervals (CIs) were calculated using a nonconditional logistic regression model. Results The mean age was 24.0 ± 5.6 years old and 65.3% were men. Of the 55 cases of tendinopathy, 25.4% had > 1 affected tendon, the most frequent being patellar (56.3%), rotator cuff (30.9%) and elbow or hand flexors (30.9%). Age and amount of time of sports practice were associated with a higher chance of presenting tendinopathy (5 and 8 times, respectively). The frequency of variant alleles in control and case patients, respectively, was: COL1A1 rs1107946 24.0 and 29.6%; COL1A2 rs412777 36.1 and 27.8%; rs42524 17.5 and 25.9%; and rs2621215 21.3 and 27.8%. After adjusting for confounding factors (age and years of sports practice), COL1A2 rs42524 and rs2621215 polymorphisms were associated with increased risk of tendinopathy (OR = 5.5; 95%CI = 1.2-24.6 and OR = 3.9; IC95% = 1.1-13.5, respectively). The haplotype COL1A2 CGT was associated with low risk for disease development (OR = 0.5; 95%CI = 0.3-0.9). Conclusion Age (≥ 25 years old), time of sports practice (≥ 6 years) and polymorphisms in the COL1A2 gene increased the risk of developing tendinopathy.

Continuous Vertical Inside-Out Versus Traditional Vertical Inside-Out Meniscal Repair: A Biomechanical Comparison.

Background: Biomechanical assessment of meniscal repairs is essential for evaluating different meniscal suturing methods and techniques. The continuous meniscal suture technique is a newer method of meniscal repair that may have biomechanical differences compared with traditional techniques. Purpose: To evaluate the displacement, stiffness after cyclical loading, and load to failure for a continuous vertical inside-out meniscal suture versus a traditional vertical inside-out meniscal suture in a porcine medial meniscus. Study Design: Controlled laboratory study. Methods: A total of 28 porcine knees were acquired and divided into 2 test groups of 14 medial meniscus each. A 2.0-cm longitudinal red-white zone cut was made in the body of the medial meniscus for each knee. The continuous suture (CS) group received 4 vertical stitches performed with a continuous vertical meniscal suture technique, and the inside-out suture (IO) group received a traditional vertical suture with 4 stitches. Two traction tapes were passed between the sutures and positioned in the biomechanical testing fixture device. Each specimen underwent load-to-failure testing at 5 mm/s, and displacement, system stiffness, and maximum load to failure were compared between the groups. Results: The displacement after the cyclic test was 0.53 ± 0.12 and 0.48 ± 0.07 mm for the CS and IO groups, respectively. There was no significant difference between the groups (P = .2792). The stiffness at the ultimate load testing was 36.3 ± 1.9 and 35.3 ± 2.4 N/mm for groups CS and IO, respectively, with no significant difference between the groups (P = .2557). In the load-to-failure test, the ultimate load was 218.2 ± 63.9 and 238.3 ± 71.3 N in the CS and IO groups, respectively, with no significant group differences (P = .3062). Conclusion: A continuous vertical meniscal suture created a configuration for treating longitudinal meniscal lesions that was beneficial and biomechanically similar to a traditional vertical suture technique. Clinical Relevance: The study findings indicate that use of the continuous vertical inside-out meniscal suture technique is a possible therapeutic option.

Factors associated with mortality, length of hospital stay and diagnosis of COVID-19: Data from a field hospital.

BACKGROUND: During the pandemic of COVID-19, phylogenetic changes have been observed in the characteristics of the virus, in the diagnosis and treatment of the disease. The clinical course and the severe form of the disease depends on several factors. This study characterized the beginning setting for patient care of COVID-19 in a referral center in one of the main capital cities of Brazil. In addition, were evaluated the factors associated with mortality, length of stay, and diagnostic outcome. METHODS: A cross-sectional study was conducted during May 2020 (n = 1100). The association of the variables with outcome was evaluated by a multivariable logistic regression model, using odds ratios (OR) and 95 % confidence intervals (CI). RESULTS: Overall, 76 % of patients were COVID-19 positive, and 70 % were diagnosed by RT-qPCR. The majority were male (56 %), and over 52 years old (74 %), 68 % had hypertension, 44 % had diabetes mellitus, and 32 % were obese. The mean length of stay was 10 ± 8 days, which was higher in the 34 % who died (≥14; OR=2; 95 %CI=1.4-4) and who had hypertension (OR=2; 95 %CI=1.3-3) (P < 0.001). The mean length of stay was also higher (P = 0.008) for those patients with pulmonary impairment ≥ 50 % (10.72 ± 8.24), than those with< 50 % (8.98 ± 6.81). Age (>62 and 65 years) was associated with longer hospitalization (OR=2; 95 %CI=1.4-3) and death (OR=6; 95 %CI=3-11). The time of sample collection for RT-qPCR was different between positive and negative tests (P = 0.001), with the time of 4-10 days showing a greater chance for virus detection (OR=2.9; 95 %CI=1.6-5). CONCLUSION: Death was associated with age and pulmonary impairment. The length of hospitalization was associated with age, hypertension, pulmonary impairment and death. The time of sample collection to perform RT-qPCR and the rapid test was associated with a positive result for COVID-19. These results highlight the ongoing challenge of diagnosing, treating, and mitigating the effects caused by the COVID-19 pandemic.

Polymorphisms in paired box 1 gene were associated with susceptibility of adolescent idiopathic scoliosis: A case-control study.

Background: Association of genetic polymorphisms in paired box 1 (PAX-1) gene can influence the development of adolescent idiopathic scoliosis (AIS). PAX-1 is mainly expressed in the region of the vertebral bodies and intervertebral discs, being important for the proper formation of spinal structures. Objectives: The objective of this study was to evaluate the association of polymorphisms in PAX-1 gene with the susceptibility of AIS. Settings and Design: This was an analytical observational case-control study. Materials and Methods: Samples of 59 AIS indicated for surgical treatment, and 119 controls, without spinal disease were genotyped for PAX-1 rs6137473 and rs169311 polymorphisms. Statistical Analysis: The association of the polymorphisms with AIS was evaluated by a multivariable logistic regression model, using odds ratios (OR) and 95% confidence intervals (CI). Results: According to Lenke's classification, 89.8% had Type I and 10.2% II curves. The mean value of the Cobb angle of the proximal thoracic curve was 30.8°, 58.7° thoracic, and 30.4° for the lumbar and on the bending films 14.6°, 40.7°, and 11°, respectively. Among the AIS group, there was a predominance of females (8.8:1). The PAX-1 rs169311 and rs6137473 polymorphisms were positively associated with developing the AIS (OR = 1.98; 95% CI = 1.2-3.3 and OR = 3.16; 95% CI = 1.4-7.3, respectively). The rs6137473 polymorphism was associated with the lumbar modifier B and C compared to A (OR = 2.52; 95% CI = 1.1-5.8). Conclusions: PAX-1 polymorphisms were associated with an increased risk of developing the AIS and with curve severity and can be used as a biomarker to map the risk of developing surgical-grade AIS, guiding the treatment of patients.

ANALYSIS OF THE MECHANICAL BEHAVIOR OF THE POSTERIOR CRUCIATE LIGAMENT IN A PORCINE MODEL.

Introduction: The knee has shown a significant increase in the frequency of injury due to sports practice. This increase and the improvement of surgical techniques of ligament reconstruction have led to a greater indication of this treatment to achieve a function close to normal. Objective: To conduct a preliminary analysis of the ligament behavior. Methods: The study consisted of the validation of an anatomical model of the pig, in which five models were subjected to mechanical tests. The data on the loads of the in situ model and the strains of the posterior cruciate ligament were collected. Results: The analysis of the tensile load showed, at first, a nonlinear increase in stresses. Subsequently, the pig's knee showed a relatively linear intermediate response until failure around 1,200 N. Strain × time showed a response of the posterior cruciate ligament, which also has a relatively linear response. Conclusion: We observed a linear behavior in the range of 1,000 to 5,000 microstrains in the strain of the posterior cruciate ligament. We suggest further studies to understand knee ligaments regarding their behavior in their function. Level of Evidence IV, Biomechanical Study.

Introdução: O joelho tem demonstrado um aumento significativo de frequência de lesão devido à prática esportiva. Esse aumento e a melhoria das técnicas cirúrgicas de reconstrução ligamentar têm levado a maior indicação desse tratamento com o objetivo de se atingir uma função próxima do normal. Objetivo: Realizar uma análise preliminar do comportamento ligamentar. Métodos: O estudo consistiu na validação de um modelo anatômico do porco, em que cinco modelos foram submetidos a ensaios mecânicos. Foram coletados os dados das cargas do modelo in situ e das deformações do ligamento cruzado posterior. Resultados: Na análise da carga trativa, foi observado que em um primeiro momento existe um aumento não linear das tensões. Em sequência, há uma resposta intermediária relativamente linear do joelho suíno até a falha em torno de 1.200 N. A deformação versus tempo mostrou uma resposta do ligamento cruzado posterior, que também possui uma resposta relativamente linear. Conclusão: Observou-se um comportamento linear na faixa de 1.000 até 5.000 microstrains na deformação do ligamento cruzado posterior. Sugerem-se novos estudos para a compreensão dos ligamentos do joelho quanto ao comportamento deles na sua função. Nível de Evidência IV, Estudo Mecânico.