Prospective comparison of magnetic resonance imaging and computed tomography in diagnosing occult scaphoid fractures

Background Suspected scaphoid fracture (SF) after a fall on an outstretched hand is a common presentation in the emergency department. Magnetic resonance imaging (MRI) or computed tomography (CT) has been suggested to assist in the diagnosis or exclusion of SF. Purpose To compare MRI and CT at diagnosing occult SFs. Material and Methods We routinely perform CT scans in patients with clinically suspected occult SF, after 7–10 days of injury following two negative radiographs. All eligible patients with a clinically suspected SF, but negative radiographs and a negative CT, underwent an MRI scan to assess further for evidence of occult fracture. Results A total of 100 patients were included in our study. MRI showed fractures in 16% of the time (in 15 patients) when plain radiographs and CT did not. Of these fractures, 8% were SFs. In addition to fractures, 10% had bone bruising. A total of 25% of patients with fractures and bone bruising were referred to the hand surgery team for further follow-up. Conclusion The study demonstrated that MRI would identify a radiographically occult SF more often than CT. This supports NICE guidelines which recommend MRI as the best early diagnostic tool for occult SFs.

Incidence of Displaced Posterolateral Tibial Plateau and Lateral Femoral Condyle Impaction Fractures in the Setting of Primary Anterior Cruciate Ligament Tear

Background: Bone bruising of the posterolateral tibial plateau and the lateral femoral condyle sulcus terminalis has a well-established association with anterior cruciate ligament (ACL) tears. Impaction fractures of the femur and tibia may occur in these locations; however, there is a paucity of literature describing these fractures. Purpose: The primary objective was to quantify the incidence, size, and location of impaction fractures of the posterolateral tibial plateau and lateral femoral condyle in patients with primary ACL tears. The secondary objective was to investigate the association between impaction fractures and concomitant meniscal and ligamentous injuries. Study Design: Case series; Level of evidence 4. Methods: Patients with available magnetic resonance imaging (MRI) scans who were treated for primary ACL tear by a single surgeon were identified. MRI scans were reviewed with denotation of posterolateral tibial and femoral condylar contusions and displaced impaction fractures. Measurements of the lateral tibial plateau were taken in all patients with displaced lateral tibial plateau fractures and in a subset of control patients without tibial plateau fracture present to characterize the size and location of the bony lesion. Associations of impaction fractures with concomitant meniscal or ligamentous injuries were evaluated through use of chi-square testing. Results: There were 825 knees identified with available MRI scans. Lateral tibial plateau bone bruising was present in 634 knees (76.8%), and lateral femoral condyle bone bruising was present in 407 knees (49.3%). Posterolateral tibial plateau impaction fractures were present in 407 knees (49.3%), and lateral femoral condylar impaction fractures were present in 214 knees (25.9%). Patients with posterolateral tibial plateau impaction fractures were older than patients without these fractures (42.6 vs 32.7 years; P < .001), whereas patients with lateral femoral condylar impaction fractures were younger (23.8 vs 32.7 years; P < .001). There were 71 knees (8.6%) with a posterolateral tibial plateau impaction fracture with greater than 10% loss of lateral tibial plateau depth, and this group had an increased incidence of lateral meniscus posterior root tears (22.1% vs 12.0%; P = .02). Conclusion: Posterolateral tibial plateau impaction fractures occurred with a high incidence (49.3%) in patients with primary ACL tears and demonstrated an increased association with lateral meniscus posterior horn root tears as their size increased. Lateral femoral condylar impaction fractures occurred in 25.9% of patients with primary ACL tears and entailed an increased incidence of lateral meniscal tears and medial meniscal ramp lesions.

Reliability assessment of a mechanism-based approach to post-injury knee magnetic resonance imaging interpretation by general radiologists

Background: A mechanism-based approach to post-injury knee magnetic resonance imaging (MRI) interpretation, following acute complex knee injury, is cited by several authors to provide increased reporting accuracy and efficiency, by allowing accurate prediction of injury to at-risk structures. This remains to our knowledge untested in a developing world setting and is of interest to us as South African general radiologists. Objective: To assess the reliability of a mechanism-based approach to complex post-trauma knee MRI interpretation when implemented by general radiologists in a South African setting, and compare our results with the findings of North American authors who compiled and assessed the same classification. To measure the agreement between the observers. Methods: A quantitative, observational, investigative, retrospective study was performed using a sample of 50 post-trauma knee MRI studies conducted at Grey’s Hospital, Pietermaritzburg. Two investigators independently applied the consolidated mechanism-based approach compiled by Hayes et al. as a research tool to interpret the knee MRI studies, blinded to each other’s findings. Results: Injury mechanism was assigned in 32% of cases by the principle investigator and in 20% of cases by the supervisor, with fair agreement between the observers (k = 0.39). The investigators agreed that 62% of cases were not classifiable by mechanism, 26% because of highly complex injury and 26% because of non-specific findings. Conclusion: Our findings indicate that the Hayes et al. classification is a non-ideal tool when used by general radiologists in our setting, as the pure injury mechanisms described in the classification were rare in our study group. Patient epidemiology and investigator experience are highlighted as potential limiting factors in this study. Despite this, we advocate that the concept of a mechanism-based approach for the interpretation of acute post-trauma knee MRI holds value for general radiologists, particularly in patients imaged before resolution of bone bruising (within 12–16 weeks of injury), and those injured in sporting and similar athletic activities.

Magnetic Resonance Imaging-Based Diagnosis of Occult Osseous Injuries in Traumatic Knees

Background : Occult osseous knee injuries, such as bone bruises, can produce persistent pain and functional loss. Although bone bruises cannot be identified through direct examination or traditional radiographs, magnetic resonance imaging (MRI) has emerged as an effective diagnostic method. Nevertheless, the natural history of these injuries remains to be fully defined. Therefore, we used MRI to detect and follow bone bruise injuries secondary to knee trauma. Methods : We retrospectively reviewed knee MRIs from patients with bone bruising caused by trauma. Occult injuries were initially identified by MRI and subsequently rescanned for follow-up at 3 and 9 months. All patients underwent physical examinations, direct radiological imaging, and MRI. Results : Although direct radiographs showed no abnormalities, we used MRI to identify a total of 22 patients (age range: 19–42 years; mean: 28 years) with bone bruising. After 3 months, injuries remained detectable in 68.2% of the subjects, whereas 18.2% displayed bone bruising after 9 months. The majority of Type I lesions resolved spontaneously, whereas 80% of Type II injuries remained following 3 months, and 30% persisted at 9 months. Ligament and meniscal lesions were observed in 63.6% of patients with bone bruising and appeared to hinder recovery. Conclusion : Bone bruises generally resolved within 3 to 9 months in subjects with no soft tissue lesions and minor trauma. However, ligament and meniscal lesions were observed in the majority of patients, and these individuals required longer treatment and recuperation. Overall, these findings can contribute to improving the management of occult osseous knee injuries.