Revista Brasileira de Ortopedia (Apr 2011)
Correlação entre a ultrassonometria óssea do calcâneo e a densitometria em mulheres pós-menopausadas com fraturas por fragilidade óssea Correlation between calcaneal bone ultrasound measurements and densitometry among postmenopausal women with fractures caused by bone fragility
Abstract
OBJETIVO: Avaliar a correlação entre a ultrassonometria (US) do calcâneo e a densitometria (DEXA) em mulheres pós-menopausadas que já apresentavam uma fratura por fragilidade. MÉTODOS: Realizada coorte retrospectiva em 35 mulheres com fraturas osteoporóticas (punho ou coluna), deambulando, acima dos 40 anos, pós-menopausadas, sem tratamento prévio para osteoporose. Dessas, 16 com menos de 60 anos e 19 acima. Foram comparadas a Broadband Ultrasound Attenuation (BUA) e a Speed of Sound (SOS) com os sítios de DEXA (L1-L4, fêmur total, colo de fêmur e punhos), sendo utilizados dois valores de BUA diferentes como ponto de corte para osteoporose: BUA OBJECTIVE: To assess the correlation between ultrasound (US) measurement on the calcaneus and bone densitometry (DEXA), among postmenopausal women who already presented fragility fractures. METHODS: 35 postmenopausal women over 40 years of age, with the ability to walk and presenting osteoporotic fractures of the wrist or spine, without previous treatment for osteoporosis, were analyzed in a retrospective cohort. Of these, 16 were under 60 and 19 were over 60. The broadband ultrasound attenuation (BUA) and speed of sound (SOS) were compared using DEXA (L1-L4, total femur, femoral neck and wrist). Two different values of BUA were used as cutoff points for osteoporosis: BUA < 60 dB/MHz and BUA < 64 dB/MHz (P < 0.05); and SOS < 1600 m/s. The confidence interval was 95%. The DEXA and US data were plotted on dispersion graphs and, through linear regression, it was possible to establish correlations. Following this, the sample was stratified according to age (up to 60 years and 60 years and over). Thus, the values were again compared and correlated. RESULTS: The best correlation obtained between DEXA and US was between the T-score of the wrist and BUA < 64 dB/ MHz, with 92% sensitivity and 95% specificity. Better sensitivity at all DEXA sites was obtained when US was performed on patients over 60 years of age. The SOS compatible with osteoporosis was < 1592.5 m/s (89% sensitivity and 85% specificity). CONCLUSION: US on the calcaneus can be used for screening the risk of osteoporosis fractures, using a cutoff of BUA < 64 dB/ MHz, especially among patients over 60 years of age.
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