Radiographic measurements do not predict syndesmotic injury in ankle fractures: an MRI study.

UNLABELLED: Several radiographic measurements have been described and are used to determine ligamentous injury in ankle fractures, particularly of the deltoid and syndesmosis complex. Because the accuracy of these radiographic measurements has been questioned, we sought to evaluate their accuracy using magnetic resonance imaging as an indicator for injury. Seventy patients with closed ankle fractures were entered prospectively into the study, and all had standard plain radiographic evaluations before reduction (anteroposterior, lateral, and mortise) and magnetic resonance imaging. Four radiographic measurements were made on initial ankle injury films: tibiofibular clear space on the anteroposterior view, tibiofibular overlap on the anteroposterior and mortise views, and medial clear space on the mortise view. These radiographic measurements and their association with magnetic resonance imaging findings then were analyzed. A medial clear space measurement greater than 4 mm correlated with disruption of the deltoid and the tibiofibular ligaments. We found no association between the tibiofibular clear space and overlap measurements on radiographs with syndesmotic injury on magnetic resonance imaging scans. LEVEL OF EVIDENCE: Prognostic study, Level II-1 (retrospective study). See the Guidelines for Authors for a complete description of levels of evidence.

Malignant fibrous histiocytoma arising within a bone infarct in a patient with sickle cell trait.

Sarcoma associated with osteonecrosis or bone infarction is a rare but well-documented pathological event. In this report, a 69-year-old man with sickle cell trait presented with malignant fibrous histiocytoma (MFH) in his distal tibia. The resected tumor was found in association with a large medullary infarct that extended 10 cm proximal from the tumor site. Bone infarcts can be caused by a number of processes including corticosteroid overuse, alcoholism, dysbarism, and hemoglobinopathies such as sickle cell disease. Patients with sickle cell anemia often develop osteonecrosis, but osteonecrosis has also been reported in people with sickle cell trait, albeit much more rarely. Our patient is only the third reported case of infarct-related bone sarcoma in a patient with sickle cell trait. Bone infarction may be a rare though serious consequence of sickle cell trait.

Correlation of interosseous membrane tears to the level of the fibular fracture.

OBJECTIVES: To correlate interosseous membrane (IOM) tears of the ankle to the height of fibular fractures in operative ankle fractures. DESIGN: Prospective clinical trial. SETTING: University Level 1 trauma center. PATIENTS: All patients admitted with a closed operative ankle fracture were included. Of 93 patients originally evaluated, 73 patients had adequate MRI for evaluation. INTERVENTION: Open reduction and internal fixation of each ankle fracture was performed after preoperative MRI evaluation of the IOM. Transsyndesmotic screw fixation was performed when evidence of syndesmotic instability was shown by intraoperative stress testing. MAIN OUTCOME MEASUREMENTS: Radiographs were analyzed for fracture classification and prediction of ligamentous injuries about the ankle. MRI evaluated the IOM integrity, correlating it to the height of the fibular fracture. RESULTS: Of the 73 ankle fractures with adequate MRI evaluation, 30 had identifiable complete IOM tears on MRI. Ten of the 30 IOM tears did not correlate with the level of the fractured fibula. Seven cases had IOM tears proximal to the fibular fracture as detected by MRI. Five of these cases were Weber B type fractures, and two were Weber C type fracture patterns. Conversely, three cases of Weber C type fractures had IOM tears that remained distal to the level of the fibular fracture. CONCLUSIONS: The level of the fibular fracture does not correlate reliably with the integrity or extent of the interosseous membrane tears identified on MRI in operative ankle fractures. One cannot consistently estimate the integrity of the IOM and subsequent need for transsyndesmotic fixation based solely on the level of the fibular fracture. An intraoperative syndesmotic stress test is recommended to establish the presence or absence of syndesmotic instability.

Impact of MRI on treatment plan and fracture classification of tibial plateau fractures.

OBJECTIVE: To evaluate the interobserver agreement for both treatment plan and fracture classification of tibial plateau fractures using plain radiographs, computed tomography (CT) scan, and magnetic resonance imaging (MRI). DESIGN: Prospective study to assess the impact of an advanced radiographic study on the agreement of treatment plan and fracture classification of tibial plateau fractures among three orthopaedic surgeons. SETTING/PARTICIPANTS: Patients presenting with tibial plateau fractures to a level I trauma center were evaluated with plain knee radiographs (anteroposterior, lateral, two oblique views), CT scan, and MRI. Three experienced attending orthopaedic trauma surgeons were randomly presented three sets of studies for each injury: radiographs alone, radiographs with CT, and radiographs with MRI (including soft tissue injuries documented by an experienced MRI radiologist). The surgeons were asked to render fracture classification and treatment plan based upon the blind reading of each individual radiographic set. MAIN OUTCOME MEASURES: Agreement among the three surgeons was measured using kappa coefficients. RESULTS: For fracture classification, radiographs alone yielded a mean kappa coefficient of 0.68, which increased to 0.73 for radiographs with CT scan and 0.85 for radiographs with MRI. Fracture classification (Schatzker) was changed an average of 6% with the addition of the CT scan and 21% based on radiographs with MRI. For the fracture management plan, the mean interobserver kappa coefficient for radiographs alone was 0.72, which increased to 0.77 for radiographs with CT scan and 0.86 for radiographs with MRI. MRI changed treatment plan in 23% of the cases. CONCLUSION: Magnetic resonance imaging increases the interobserver agreement on fracture classification and operative management of tibial plateau fractures.