Advanced imaging of melorheostosis with emphasis on MRI.

OBJECTIVE: To describe the CT and MR imaging appearance of both osseous and extraosseous manifestations of melorheostosis. DESIGN AND PATIENTS: We retrospectively reviewed the CT (n=7) and/or MR imaging findings (n=12) of 17 patients with characteristic radiographic findings of melorheostosis (undulating cortical hyperostosis with marked uptake on radionuclide bone scintigraphy). RESULTS: CT and MR imaging revealed cortical hyperostosis as high attenuation and low signal intensity on all MR pulse sequences, respectively. Encroachment on the marrow space was seen in all cases resulting from endosteal involvement. Thirteen patients demonstrated 14 soft tissue masses with infiltrative margins in 80% of cases and seven showed extensive mineralization on CT or MR imaging (low intensity on all pulse sequences). Seven soft tissue masses were predominantly nonmineralized with intermediate signal intensity on T1-weighted and intermediate to high signal on T2-weighted MR images corresponding to vascularized fibrous tissue with variable collagen content pathologically. Enhancement after intravenous gadolinium was seen in all patients imaged with soft tissue masses (n=2). Two patients demonstrated muscle atrophy resulting from nerve involvement. CONCLUSIONS: The osseous abnormalities in melorheostosis are identical on advanced imaging and radiographs. Mineralized or nonmineralized soft tissue masses should be recognized as another manifestation of this disease as opposed to a more ominous finding, making biopsy unwarrranted.

Wrist and hand injuries.

Wrist and hand injuries are common occurrences. These are often caused by a fall on the outstretched hand, but other mechanisms, from sports-related injuries to high-speed motor vehicle collisions, can lead to injuries that may be subtle on initial imaging or may produce characteristic radiographic findings. In all cases, careful attention to certain anatomic details along with a sound understanding of different injury patterns should allow an accurate diagnosis to be made. The following this article illustrates these concepts, emphasizing features that should be familiar to both radiologists and orthopedic surgeons.

Small cell osteosarcoma of the ulna: a case report and review of the literature.

We report a case of small cell osteosarcoma arising in the distal ulna. The radiologic and pathologic features of this histologic variant of osteosarcoma that allow differentiation from other lytic lesions with small round cells are discussed.

Hemodialysis-related amyloidosis of the sternoclavicular joint.

Amyloid deposition is an important cause of morbidity in long-term hemodialysis patients, but it has rarely been reported in the sternoclavicular joint, where the clinical picture may be consistent with an infection. The imaging features of one case are discussed. Biopsy with specific staining for the beta-2 microglobulin component of amyloid should be considered in the work up of a lesion of this joint in this clinical setting.

Severity of radiographic findings in hip osteoarthritis associated with total hip arthroplasty.

OBJECTIVE: The decision to perform total hip arthroplasty (THA) in patients with osteoarthritis (OA) of the hip is based largely on patients' reports of pain and disability and not on radiographic findings of OA. We determine the severity of radiographic OA and its association with disability in patients undergoing THA. METHODS: Individual radiographic features (osteophytes, joint space narrowing, sclerosis, cysts, deformity) and global severity of hip OA were assessed in 95 consecutive elderly patients with hip OA undergoing THA who were enrolled in a Patient Outcome Research Team (PORT) project. RESULTS: Eighty-seven patients (91.5%) had either severe or moderate OA in the hip to be replaced; 17% of these had a previous contralateral THA. Only 8 patients (8.4%) had mild or no signs of OA in the hip to be replaced and 4 (50%) of these patients had their opposite hip replaced previously. CONCLUSION: These data indicate that radiographic features of moderate to severe hip OA are associated with clinical findings and the necessity to perform THA in the majority of patients. Patients who have had a prior hip replacement, however, may be more likely to have a contralateral replacement done earlier (p = 0.03), before radiographic signs are evident.

Gas bubbles in the hip joint on CT: an indication of recent dislocation.

OBJECTIVE: The purpose of this study was to determine if gas bubbles in the hip joint seen on CT scans after trauma are reliable indicators of recent (< 48 hr) hip dislocation. We believe that the gas seen in the hip joint represents intracapsular nitrogen bubbles that result from the vacuum created by forcible distraction associated with traumatic dislocation. MATERIALS AND METHODS: CT scans of 79 consecutive patients with pelvic injury were reviewed retrospectively. We noted the number and position of intracapsular gas bubbles, presence of joint effusion, soft-tissue injury, and associated fractures or dislocations. Intracapsular gas bubbles were defined as round areas of low attenuation, in an intracapsular position, that on visual inspection were equivalent to air. Seventy-three of 79 patients were imaged within 48 hr of injury. Most patients had been involved in a motor vehicle collision or were pedestrians struck by a motor vehicle. Fifteen patients had hip dislocation, including one patient with bilateral dislocation. Fifty-five patients had pelvic fractures without hip dislocation, and nine patients had soft-tissue injury without fracture or dislocation. Fourteen of 16 dislocations had been reduced at the time of scanning. RESULTS: Gas bubbles were seen in the hip joint on CT scans in 13 (81%) of the 16 dislocated hips, including 12 (92%) of 13 dislocations in patients scanned within 4 hr of admission. Bubbles were present in 11 (79%) of 14 hip joints that had dislocations reduced at the time of scanning and in both hip joints that remained dislocated. Most bubbles were located anterior to the femoral neck; however, bubbles were also seen posteriorly. Bubble size (1-3 mm) and number (1-7) varied. Only two (3%) of 64 patients without dislocation had intracapsular gas bubbles; one had been shot and the other had extensive soft-tissue emphysema. CONCLUSION: In the absence of penetrating trauma, intracapsular gas bubbles on CT are reliable indicators of recent hip dislocation and may be the only objective finding of this injury.

Case report 792. Eosinophilic granuloma of bone.

Eosinophilic granuloma is commonly thought of as a disease of children which can occur in either the axial or the appendicular skeleton. Only approximately 10% of cases occur in patients over the age of 40 years, and only approximately 12% of lesions occur in the pelvis, with no previously illustrated cases of this combination of age and location. These facts along with the nonspecific radiographic appearance made biopsy necessary for the correct diagnosis in the patient described.

Double injuries of the forearm: a common occurrence.

To evaluate the frequency of different types of forearm fractures and, in particular, determine the frequency of double injury to the forearm, the authors prospectively examined 119 consecutive forearm fractures and found double injuries to the forearm in all but five cases. In 79 of the 119 patients (66%), ligamentous injury was seen in addition to the obvious fracture. Nine patients with apparent isolated fractures on initial radiographs underwent examination by means of radionuclide bone scanning, which revealed a second injury in eight of them. Four patients with apparent single fractures did not undergo bone scanning because of their critical conditions. In four patients, a single fracture was initially diagnosed, but after reduction and casting, dislocation of the radioulnar joint was seen. These findings indicate that injury to the forearm almost invariably occurs at two or more sites and involves either both bones or bone and ligament. Because the distal radioulnar joint was affected in 71 patients (60%), scrutiny of the wrist is imperative whenever injuries to the bones of the forearm are discovered.