Koster et al [30] showed that the presence of a bone contusion on MRI after acute knee trauma is highly predictive of the development of focal osteoarthritis 1 year after trauma. MRI facilitates diagnosis of the anterolateral ligament injuries that have frequent association with ACL injuries and anterolateral knee instability, of which a minority are associated with Segond fractures [31]. In a study by Kosy et al [32], MRI detected a larger number of anterolateral ligament injuries in association with the ACL injuries within 6 weeks of the acute knee trauma compared with scans performed later, which suggests that some injuries may resolve or become less visible with increased chronicity. MRI is proven helpful in detection and characterization of posterolateral corner injuries, which can be associated with the ACL ruptures and, if missed, may lead to considerable morbidity. In a study by Temponi et al [33], concomitant posterolateral corner injuries and the ACL ruptures were present in 19.7% of patients on MRI studies. Precise location and classification of the ACL tears on the MRI study may help in preoperative planning, in particular with a growing interest in this ligament preservation technique [34]. MRI can change management from surgical to conservative in up to 48% of patients presenting with a locked knee, which is usually an indication for arthroscopic procedure [35,36]. Bone Scan with SPECT or SPECT/CT Knee Tc-99m bone scan would not be the next best imaging study to evaluate for radiographically occult fractures and/or internal derangement. Tc-99m-methylene diophosphate bone SPECT/CT scan has been suggested as an alternative to MRI in evaluating suspected bone contusions and meniscal and ACL tears in the setting of acute knee trauma. A SPECT study by Even-Sapir et al [37] with arthroscopic and MRI correlation showed promising results in diagnosis of the ACL and meniscal tears and the associated bone contusions in patients with acute knee trauma.
Acute Trauma to the Knee. Koster et al [30] showed that the presence of a bone contusion on MRI after acute knee trauma is highly predictive of the development of focal osteoarthritis 1 year after trauma. MRI facilitates diagnosis of the anterolateral ligament injuries that have frequent association with ACL injuries and anterolateral knee instability, of which a minority are associated with Segond fractures [31]. In a study by Kosy et al [32], MRI detected a larger number of anterolateral ligament injuries in association with the ACL injuries within 6 weeks of the acute knee trauma compared with scans performed later, which suggests that some injuries may resolve or become less visible with increased chronicity. MRI is proven helpful in detection and characterization of posterolateral corner injuries, which can be associated with the ACL ruptures and, if missed, may lead to considerable morbidity. In a study by Temponi et al [33], concomitant posterolateral corner injuries and the ACL ruptures were present in 19.7% of patients on MRI studies. Precise location and classification of the ACL tears on the MRI study may help in preoperative planning, in particular with a growing interest in this ligament preservation technique [34]. MRI can change management from surgical to conservative in up to 48% of patients presenting with a locked knee, which is usually an indication for arthroscopic procedure [35,36]. Bone Scan with SPECT or SPECT/CT Knee Tc-99m bone scan would not be the next best imaging study to evaluate for radiographically occult fractures and/or internal derangement. Tc-99m-methylene diophosphate bone SPECT/CT scan has been suggested as an alternative to MRI in evaluating suspected bone contusions and meniscal and ACL tears in the setting of acute knee trauma. A SPECT study by Even-Sapir et al [37] with arthroscopic and MRI correlation showed promising results in diagnosis of the ACL and meniscal tears and the associated bone contusions in patients with acute knee trauma.