Another study by Siegel et al [38] suggested that the degree of radiotracer uptake in the knee, as determined by SPECT, positively correlates with the severity of pathology seen at arthroscopy. However, a more recent SPECT study with arthroscopic correlation by Wertman et al [39] showed a lower sensitivity, specificity, and accuracy than MRI in evaluating meniscal injuries. US Knee US is not used as the next best imaging study to evaluate for radiographically occult fractures and/or internal derangement. US is an excellent and easily performed imaging study in detection of knee joint effusions. However, because of its technical limitations, US may only evaluate the outer bone surface and has a limited role in detection of the occult knee fractures. Therefore, this imaging modality is not routinely used for the evaluation of suspected occult knee fractures but may detect a lipohemarthrosis, which is typically associated with intra-articular fractures. A comparison of US studies with radiography and CT examinations by Bonnefoy et al [40] serving as the reference standard and using a knee lipohemarthrosis as a criterion, yielded a sensitivity of and specificity of 94% for US detection of acute intra-articular fractures. A recent study by Klos et al [41] showed a higher prevalence of Segond avulsions fractures on US studies than previously reported in literature on the MRI or radiography. The lateral femoral condyle impaction injury was the best variable in predicting the presence of a Segond fracture [41]. Acute Trauma to the Knee US study by Dai et al including 551 patients from 7 prospective studies revealed pooled sensitivity of 88% and specificity of 90% in diagnosis of meniscal injuries [46]. Variant 4: Skeletally immature child. Fall or acute twisting trauma to the knee. No fracture seen on radiographs. Suspect occult fracture or internal derangement. Next study.
Acute Trauma to the Knee. Another study by Siegel et al [38] suggested that the degree of radiotracer uptake in the knee, as determined by SPECT, positively correlates with the severity of pathology seen at arthroscopy. However, a more recent SPECT study with arthroscopic correlation by Wertman et al [39] showed a lower sensitivity, specificity, and accuracy than MRI in evaluating meniscal injuries. US Knee US is not used as the next best imaging study to evaluate for radiographically occult fractures and/or internal derangement. US is an excellent and easily performed imaging study in detection of knee joint effusions. However, because of its technical limitations, US may only evaluate the outer bone surface and has a limited role in detection of the occult knee fractures. Therefore, this imaging modality is not routinely used for the evaluation of suspected occult knee fractures but may detect a lipohemarthrosis, which is typically associated with intra-articular fractures. A comparison of US studies with radiography and CT examinations by Bonnefoy et al [40] serving as the reference standard and using a knee lipohemarthrosis as a criterion, yielded a sensitivity of and specificity of 94% for US detection of acute intra-articular fractures. A recent study by Klos et al [41] showed a higher prevalence of Segond avulsions fractures on US studies than previously reported in literature on the MRI or radiography. The lateral femoral condyle impaction injury was the best variable in predicting the presence of a Segond fracture [41]. Acute Trauma to the Knee US study by Dai et al including 551 patients from 7 prospective studies revealed pooled sensitivity of 88% and specificity of 90% in diagnosis of meniscal injuries [46]. Variant 4: Skeletally immature child. Fall or acute twisting trauma to the knee. No fracture seen on radiographs. Suspect occult fracture or internal derangement. Next study.