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BACKGROUND: Corticosteroid injections in or around tendons for the treatment of athletic injuries are a common practice among orthopaedic surgeons and are apparently efficacious in the short term, although controversies persist related to local complications. PURPOSE: This study evaluated short-term (48 hours) biomechanical, biochemical, and histological alterations after a single injection of betamethasone into the normal tendons of rabbits. STUDY DESIGN: Controlled laboratory study. METHODS: A total of 72 New Zealand White rabbits were randomly divided into 2 groups: the test group-in which 36 animals underwent 1 intratendinous injection of betamethasone (1.4 mg / 0.2 mL) in the right calcaneal tendon; the control group-in which the right calcaneal tendon of 36 animals was injected with saline (placebo control group) and the left calcaneal tendon was left untreated for normal standards (normal control). Forty-eight hours later, animals were euthanized and tendons were harvested. Metalloproteinase (MMP1 and MMP2) and interleukin (IL1 and IL6) expression levels, biomechanical resistance (load × elongation parameters), and histomorphometry (hematoxylin and eosin and picrosirius red stains for collagen fibers, tenocytes, and inflammatory cells) were analyzed in the tendons. RESULTS: The test group had a significant reduction in MMP2 expression as compared with the control groups ( P = .027). Regarding the other parameters, there were no additional significant differences between the groups. CONCLUSION: A single injection of corticosteroid into normal calcaneal tendons did not trigger acute local morphological, structural, or biomechanical injuries at 48 hours, but it did promote a significant decrease in MMP2 levels. Additional studies are needed with increased duration of follow-up, various doses, and multiple injections and in tendinopathic models. CLINICAL RELEVANCE: Some previous studies demonstrated early structural changes in tendons after a single corticosteroid injection, which was not corroborated by the present study. Metalloproteinase decrease is usually associated with a reduction in collagen degradation, which would be protective for the healing process. More studies are necessary to confirm the possible beneficial effect of these results in the long term and for tendinopathies.

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BACKGROUND: Low-dose combined oral contraceptives (COCs) can interfere with bone mass acquisition during adolescence. This study aimed to evaluate bone mineral density (BMD) and bone mineral content (BMC) in female adolescents taking a standard low-dose COC (ethinylestradiol 20 µg/desogestrel 150 µg) over a 1-year period and to compare their data with those of healthy adolescents from the same age group not taking COCs. METHODS: This was a non-randomized parallel-control study with a 1-year follow-up. Sixty-seven adolescents aged from 12 to 19 years, divided into COC users (n = 41) taking 20 µg ethinylestradiol/150 µg desogestrel and COC non-user controls (n = 26), were evaluated by bone densitometry examinations at baseline and after 12 months. Comparisons between the groups at the study onset were performed using the Mann-Whitney test with the significance level fixed at 5% or p < 0.05. Comparisons between the groups at the study onset and after 12 months were based on variations in the median percentages for bone mass variables. RESULTS: The COC users presented with low bone mass acquisition in the lumbar spine, and had BMD and BMC median variations of 2.07% and +1.57%, respectively, between the measurements at baseline and 12 months. The control group had median variations of +12.16% and +16.84% for BMD and BMC, respectively, over the same period. The total body BMD and BMC showed similar evolutions during the study in both groups. Statistical significance (p < 0.05) was seen for the BMC percentage variation between COC users and non-users. CONCLUSIONS: Use of a low-dose COC (ethinylestradiol 20 µg/desogestrel 150 µg) was associated with lower bone mass acquisition in adolescents during the study period. TRIAL REGISTRATION: Registry Number, RBR-5h9b3c.

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OBJECTIVE: To study bone mineral density (BMD) in adolescent females according to five groups of chronological age (CA), bone age (BA), and breast development stage (B), and to correlate these parameters with plasma bone biomarkers (BB). METHODS: This was a cross-sectional study performed in 101 healthy adolescent females between 10 and 20 years old. The study variables were: weight, height, body mass index (BMI), CA, B, BA, calcium intake, BMD, and BB. Osteocalcin (OC), bone alkaline phosphatase (BAP), and C-terminal telopeptide (S-CTx) were evaluated for BB. BMD was measured using dual energy X-ray absorptiometry (DXA). RESULTS: BMD in lumbar spine, proximal femur, and total body increased with age, and the respective observed averages were: in CA1 (10 years old), 0.631, 0.692, 0.798 g/cm2; in CA2 (11 to 12 years old), 0.698, 0.763, 0.840 g/cm2; in CA3 (13 to 14 years old), 0.865, 0.889, 0.972 g/cm2; in CA4 (15 to 16 years old), 0.902, 0.922, 1.013 g/cm2; and in CA5 (17 to 19 years old), 0.944, 0.929, 1.35 g/cm2. These results showed significant differences between 13 and 14 years of age (CA3) or when girls reached the B3 stage (0.709, 0.832, 0.867 g/cm2). The highest median concentrations of BB were between 10 and 12 years of age when adolescents were in the B2-B3 (p < 0.001). Median BB concentrations decreased in advanced BA and B. CONCLUSIONS: BB concentrations were positively correlated with the peak height velocity and negatively correlated with BMD in the study sites. Increased BMD and BB concentrations were observed in B3. .

OBJETIVO: Avaliar a densidade mineral óssea (DMO) em adolescentes do sexo feminino de acordo com a idade cronológica (IC), idade óssea (IO) e desenvolvimento das mamas (M) e suas correlações com biomarcadores de remodelação óssea em plasma (BO). MÉTODOS: Este foi um estudo transversal prospectivo feito em 101 adolescentes saudáveis do sexo feminino com idade entre 10 e 20 anos. As variáveis estudadas foram: peso, altura, índice de massa corpórea (IMC), IC, IO, M, ingestão de cálcio, DMO e BO. A osteocalcina (OC), fosfatase alcalina óssea (BAP) e o telopeptídeo C terminal (S-CTx) foram os biomarcadores de remodelação óssea avaliados. A DMO foi obtida por absorciometria de raios-X de dupla energia (DXA). RESULTADOS: A DMO de coluna lombar, fêmur proximal e corpo total aumentou com a idade, e as respectivas médias observadas foram: IC1 = 0,631, 0.692, 0,798 g/cm2; IC2, 0,698, 0,763, 0,840 g/cm2; IC3, 0,865, 0,889, 0,972 g/cm2; IC4, 0,902, 0,922, 1,013 g/cm2; e IC5, 0,944, 0,929, 1,35 g/cm2. Observou-se diferença significativa entre 13 e 14 anos (IC3) ou quando as meninas estavam em M3 (0,709, 0,832, 0,867 g/cm2). Os valores dos BO apresentaram elevação entre 10 e 12 anos e quando as adolescentes estavam em M2-M3 (p < 0,001). Os valores das medianas dos BO diminuíram com o avançar da IO e M. CONCLUSÕES: Os BOs mostraram paralelismo com o pico de velocidade de crescimento e demonstraram correlação negativa com a DMO no sítios avaliados. O aumento da DMO e dos BOs foi observado em M3. .

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OBJECTIVE: To study bone mineral density (BMD) in adolescent females according to five groups of chronological age (CA), bone age (BA), and breast development stage (B), and to correlate these parameters with plasma bone biomarkers (BB). METHODS: This was a cross-sectional study performed in 101 healthy adolescent females between 10 and 20 years old. The study variables were: weight, height, body mass index (BMI), CA, B, BA, calcium intake, BMD, and BB. Osteocalcin (OC), bone alkaline phosphatase (BAP), and C-terminal telopeptide (S-CTx) were evaluated for BB. BMD was measured using dual energy X-ray absorptiometry (DXA). RESULTS: BMD in lumbar spine, proximal femur, and total body increased with age, and the respective observed averages were: in CA1 (10 years old), 0.631, 0.692, 0.798 g/cm(2); in CA2 (11 to 12 years old), 0.698, 0.763, 0.840 g/cm(2); in CA3 (13 to 14 years old), 0.865, 0.889, 0.972 g/cm(2); in CA4 (15 to 16 years old), 0.902, 0.922, 1.013 g/cm(2); and in CA5 (17 to 19 years old), 0.944, 0.929, 1.35 g/cm(2). These results showed significant differences between 13 and 14 years of age (CA3) or when girls reached the B3 stage (0.709, 0.832, 0.867 g/cm(2)). The highest median concentrations of BB were between 10 and 12 years of age when adolescents were in the B2-B3 (p<0.001). Median BB concentrations decreased in advanced BA and B. CONCLUSIONS: BB concentrations were positively correlated with the peak height velocity and negatively correlated with BMD in the study sites. Increased BMD and BB concentrations were observed in B3.

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Eighty-seven male volunteers were grouped according to bone age (BA): 10-12 years (n=25), 13-15 years (n=36), and 16-18 years (n=26), and the following were recorded for each: weight (kg), height (m), BMI (kg/m(2)), calcium intake from three 24-h food recalls (mg/day), puberty evaluation by Tanner stages, bone biomarker (BB) evaluation, serum osteocalcin (OC), bone alkaline phosphatase (BAP), carboxyterminal telopeptide (S-CTx), and bone mineral density (BMD) evaluations by dual-energy X-ray absorptiometry (g x cm(2)) in the lumbar spine, proximal femur, and the whole body. BBs showed similar behaviors, and very high median values were observed for individuals aged 13-15 years (BAP = 155.50 IU/L, OC = 41.63 ng/mL, S-CT x =2.09 ng/mL). Lower median BB values were observed with advancing BA between 16 and 18 years (BA P =79.80 IU/L, O C =27.80 ng/mL, S-CT x =1.65 ng/mL). Stepwise multiple regression analysis showed body weight associated with BA as independent variables with greater determination power for S-CTx (r(2) = 0.40) and OC (r(2)=0.21). For BAP, stepwise analysis showed body weight and whole-body BMD (r(2) = 0.34). All predictive models showed significance ( p < 0.01). A high turnover for both bone formation and resorption biomarkers, particularly from 13 to 15 years of BA, were observed along with very low values in the 16-18 age range. Weight and BA were significant in determining predictive equations of OC and of S-CTx, whereas for BAP, weight and BMD of full body were selected.

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