Faculty Bibliography

Age-related bone loss in women may begin at any time following attainment of peak skeletal maturity bone mass. The rate of bone loss may accelerate near the time of menopause and continue for several years thereafter. Women with low baseline bone mass and women who are fast bone losers are potentially at risk for early spinal osteoporosis. In a prospective longitudinal study, spinal trabecular bone mineral content (BMC) of 83 healthy women, 47-53 years old, was measured with use of computed tomography (CT) at 0, 12, 24, and 36 months. Fifty-four of these same women had a fifth measurement at 48 months. In 51 women the rate of bone loss was less than or equal to 2% per year (average 1.96%; normal bone losers); in 32, it was more than 2% per year (average 5.61%; fast bone losers). CT studies can identify women with low spinal trabecular BMC and/or fast bone loss--women likely to be at increased risk for early spinal osteoporosis. This information may be useful in selection of candidates for vigorous preventive measures, including estrogen replacement

The trabecular bone mineral content (BMC) of the spine was measured by computed tomography in 185 women aged 47-84 years with vertebral fracture (n = 74), hip fracture (n = 83), and both vertebral and hip fracture (n = 28). Eighty-seven percent of vertebral-fracture patients, 38% of hip-fracture patients, and 82% of vertebral- and hip-fracture patients had spinal BMC values below the fifth percentile for healthy premenopausal women and values 64%, 9%, and 68% below the fifth percentile for age-matched control subjects. No significant loss of spinal trabecular bone was seen in patients with hip fracture. If it is assumed that the rate of trabecular bone loss is the same in the spine and femoral neck, then hip fracture (unlike osteoporotic vertebral fracture) is not associated with disproportionate loss of trabecular bone. Hip fracture occurs secondary to weakening of bone and increased incidence of falls. Bone weakening may be due to disproportionate loss of trabecular or cortical bone, proportionate loss of both, or other as yet undetermined qualitative changes in bone

The capsular mechanism of the shoulder joint consists of the joint capsule, which is strengthened by the glenohumeral ligaments and the rotator cuff, the glenoid labrum, and a variable number of synovial recesses. Although the fibrous capsule is a lax structure, the normal function of the capsular mechanism makes it an effective barrier against anterior dislocation, particularly in external rotation. There has been a tendency in the past to overestimate the role of the glenoid labrum in stability of the shoulder joint. In patients with instability, the significance of the capsular attachment or its anomalous insertions to the glenoid has not been adequately recognized. Labral tears may develop as secondary lesions due to repeated dislocations and subluxations rather than representing the primary lesion responsible for instability. Operative visualization of capsular defects or detachments is often difficult. Prior knowledge of these lesions can effectively help the choice of an appropriate surgical procedure and reduce operating time. The results of computed tomographic (CT) arthrography of the shoulder joint in 45 patients are reported and the normal and pathologic variations of the joint capsule and particularly the capsular insertions are described. Configuration of the joint recesses and the glenoid labrum are also evaluated. These CT findings were correlated and verified by surgery or arthroscopy in 26 cases

Computed tomography of 16 spinal chordomas revealed lytic lesions, or lytic and blastic lesions, of 2 or more adjacent vertebrae and a fairly well-delineated soft tissue mass in 16 patients. Intravenous contrast enhancement revealed multiple zones of hypodensity in 5 tumors pathologically proved to contain areas of cystic degeneration. Invasion of the epidural space was noted on computed tomography in 2 vertebral and 7 sacral lesions, and on myelography in 7 vertebral lesions. Computed tomography is ideal for delineation of the soft tissue component of these lesions, detection of sacral lesions at an early stage, planning of surgical excision or irradiation treatment, and detection of recurrence

Computed tomography revealed a radiolucent nidus with a surrounding zone of osteosclerosis in 17 patients with osteoid osteoma. Plain films did not reveal any abnormality in 5 patients. Conventional tomography was negative in 3 patients. Computed tomography is the modality of choice for detection of osteoid osteoma when the lesion is deep-seated or when it occurs in complex anatomic regions with curvilinear and overlapping surfaces, such as acetabulum, knee, and spine

Three patients with symptoms related to metastases from hepatocellular carcinoma are described. The diagnosis of the primary tumor was made at autopsy in two cases and by biopsy in one. The skeletal lesions had a lytic, expansile, and hypervascular appearance. This hypervascularity may lead to bleeding either spontaneously or following biopsy. Hepatocellular carcinoma should be included in the differential diagnosis of osteolytic, expansile, hypervascular metastases, especially when such lesions are encountered in patients with liver cirrhosis

Twenty-six patients with suspected or known septic joints who had been studied by computed tomography were retrospectively reviewed. Eighteen patients (20 joints) proved to have septic arthritis. Computed tomography was advantageous in patients with acute septic arthritis of deep-seated axial joints, such as the hip and sacroiliac, where it demonstrated particular soft tissue swelling as early as 36 hours after the onset of symptoms. In three patients, this finding on computed tomography was helpful in accurately localizing the disease process and facilitating a diagnostic closed needle aspiration biopsy procedure. Four patients had a primary osseous focus of infection in an adjacent epiphyseal region that was documented by computed tomography. Computed tomography was superior to conventional radiology in revealing early articular bone erosion in joints with curved and overlapping articular surfaces in five patients, and resulted in alteration of their treatment. Fat-fluid levels within the suprapatellar bursae were noted in one patient (two joints). Computed tomography is a valuable modality for evaluation of patients with suspected septic arthritis of axial joints, particularly in the acute stage. Furthermore, it is helpful for evaluation of possible periarticular abscess formation and can serve as a guide for a percutaneous drainage procedure. Computed tomography can also be used when articular bone erosion or medullary extension of osteomyelitis is suspected but not fully documented by conventional radiography