Giant cell tumor of the proximal tibia: MR and CT appearance

The magnetic resonance (MR) appearance of four cases of giant cell tumor (GCT) of the proximal tibia are described and the MR grading of these tumors is compared with CT and conventional radiography. Magnetic resonance showed the lesions to be well defined with respect to adjacent marrow and cortical bone. Homogeneous intermediate signal intensity or low signal within the tumors was seen on T1-weighted images. T2-weighted images showed mixed signal intensity with small "bright patches" of increased signal intensity in all four cases. No fluid levels were identified. Magnetic resonance was superior to CT and plain radiography in radiologic grading of the tumors. Computed tomography was superior in determining if cortical invasion was present. Intraarticular tumor extension was more accurately detected by MR and arthrotomography than CT. An MR manifestation of GCT of the proximal tibia is described which may be a common appearance of this tumor by this modality. Magnetic resonance is the procedure of choice in the radiologic grading of GCT.     

Therapeutic arthrography and bursography

Arthrography and bursography as therapeutic venues have found their place in the musculoskeletal procedure armamentarium. Therapeutic arthrography not only rules in and rules out the origin of pain but can provide 6 to 9 months of pain relief in diseased joints. Therapeutic arthrography allows injections of anesthetic, corticosteroid, or alternatively hyaluronic acid to be delivered accurately to the source of pain. Corticosteroids have a long history of use in osteoarthritis. Alternative therapy with hyaluronic acid is anew procedure. This article reviews the technique of arthrography in different joints and bursae and discusses the pros and cons of the use of corticosteroids versus viscosupplementation in therapeutic arthrography.     

The prone position for CT of the lumbar spine

In scanning the L5-S1 disk space, the known technical difficulty is limitation of the gantry angle. A prone scanning technique used to examine the lumbar spine may help to overcome or lessen this problem. A prospective CT scanning of the L5-S1 level was performed in both the prone and supine positions on 25 patients who had low back pain and who had not undergone previous laminectomy or fusion. The angle between the S1 vertebral end plate and maximum tilted gantry line (15 degrees on the G.E. 8800) was measured in the supine position and compared with the same angle in the prone position. In 20 of 25 cases (80%), significant improvement in alignment was noted in the prone position. The prone scanning technique is also more desirable if CT is performed with metrizamide. Finally, printed images from the prone technique allow easier image-patient orientation for viewing in the operating room.     

Prospective study of sequential technetium-99m phosphate and gallium imaging in painful hip prostheses (comparison of diagnostic modalities)

Twenty-two painful hip prostheses were studied prospectively with plain radiography, aspiration and arthrography, Tc-99m phosphate bone imaging, and gallium imaging to evaluate loosening, infection, or both and to compare the accuracy of these modalities. Fifteen prostheses were revised yielding 14 loose femoral and eight loose acetabular components. Five proved to have infected prostheses. Arthrograms, plain radiographs, and bone scans are highly sensitive in detecting loosening of the femoral component. This study confirmed a previous retrospective study in demonstrating that accuracy of diagnosis of an abnormal acetabular component using all four modalities is less than that for the femoral component. In infected prostheses, phosphate bone imaging showed high sensitivity of a pattern that accurately diagnosed all the infected cases, whereas gallium imaging missed one case.     

Efficacy of limited CT for nonvisualized lower cervical spine in patients with blunt trauma

Records of 100 patients with blunt injury and nonvisualization of C7 and T1 on cross-table lateral and swimmer's views were reviewed to evaluate the usefulness of limited computed tomographic (CT) scans in “clearing”¹ the lower cervical vertebrae of injury. CT was deemed necessary and performed in all of these cases because the lower cervical spine could not be evaluated clinically or with plain radiographs. Ninety-seven of these 100 patients had normal findings on CT and only three patients showed cervical spine fractures. All three had isolated and stable fractures. Two of these patients had “clay-shoveler” fractures at C6 and C7, respectively, and one had a single laminar fracture at C7. All three patients were conservatively treated. This study emphasizes the value of clinical correlation in the evaluation of cervical spine trauma. When deemed necessary in symptomatic patients, CT is useful to exclude skeletal injury in the lower cervical spine thus avoiding delay in the patient's workup and unnecessary hospitalization, and expediting patient discharge. Lack of pain and neurological findings in nonintoxicated, conscious, and alert patients is generally not associated with significant soft tissue or skeletal injury.     

Closed skeletal needle biopsy: review of 120 cases

A review of 120 percutaneous bone biopsies performed on 110 patients in the Radiology Department of the Hospital for Special Surgery showed a 72% concurrence of biopsy findings with the patient's other clinical findings and subsequent course. Of the biopsies, 58% were correctly positive for malignancy or infection and 14% were correctly negative. The rest, 28% of the biopsies, were either incorrectly negative or had insufficient tissue for diagnosis and were therefore unsatisfactory. Only eight positive cultures from biopsy material were obtained in 21 cases with bone infections. In diagnosing metastasis, a higher success rate (84%) was noted in vertebral biopsies than other sites (66%). Poor success (44%) was noted, however, in biopsying primary bone neoplasm.     

Semimembranosus tendon avulsion fracture of the posteromedial tibial plateau associated with posterior cruciate ligament tear and capsular rupture

Semimembranosus tendon avulsion fractures are an uncommon occurrence and are often associated with anterior cruciate ligament (ACL) and medial meniscus tears. We present the imaging features of an unusual case of semimembranosus avulsion fracture of the posteromedial tibial plateau associated with posterior cruciate ligament (PCL) tear, medial meniscus tear, and capsular rupture in a 26-year-old man with a football injury.