A new classification of glenoid bone loss to help plan the implantation of a glenoid component before revision arthroplasty of the shoulder.

AIMS: Glenoid bone loss can be a challenging problem when revising a shoulder arthroplasty. Precise pre-operative planning based on plain radiographs or CT scans is essential. We have investigated a new radiological classification system to describe the degree of medialisation of the bony glenoid and that will indicate the amount of bone potentially available for supporting a glenoid component. It depends on the relationship between the most medial part of the articular surface of the glenoid with the base of the coracoid process and the spinoglenoid notch: it classifies the degree of bone loss into three types. It also attempts to predict the type of glenoid reconstruction that may be possible (impaction bone grafting, structural grafting or simple non-augmented arthroplasty) and gives guidance about whether a pre-operative CT scan is indicated. PATIENTS AND METHODS: Inter-method reliability between plain radiographs and CT scans was assessed retrospectively by three independent observers using data from 39 randomly selected patients. Inter-observer reliability and test-retest reliability was tested on the same cohort using Cohen's kappa statistics. Correlation of the type of glenoid with the Constant score and its pain component was analysed using the Kruskal-Wallis method on data from 128 patients. Anatomical studies of the scapula were reviewed to explain the findings. RESULTS: Excellent inter-method reliability, inter-observer and test-retest reliability were seen. The system did not correlate with the Constant score, but correlated well with its pain component. TAKE HOME MESSAGE: Our system of classification is a helpful guide to the degree of glenoid bone loss when embarking on revision shoulder arthroplasty.

Tumour-to-tumour metastasis of laryngeal leiomyosarcoma to an axillary hibernoma.

Tumour-to-tumour metastasis is a rare, but well-recognised occurrence. This case report documents the metastasis of a primary laryngeal leiomyosarcoma to a hibernoma. We believe that this is the first recorded case of leiomyosarcoma metastasising to another neoplasm, and the first recorded case of a hibernoma acting as a recipient tumour for metastasis. This case study emphasises the importance of re-imaging a known benign mass in the presence of new symptoms in a patient with underlying malignancy, to ensure prompt diagnosis and management of potentially treatable metastasis. The imaging findings including whole body magnetic resonance imaging (MRI) staging, macroscopic and histological features are presented.

Comparison of dynamic ultrasound and stress radiology for assessment of inferior glenohumeral laxity in asymptomatic shoulders.

OBJECTIVE: To determine the level of agreement between dynamic ultrasound imaging and stress radiography used for the measurement of inferior glenohumeral laxity in asymptomatic shoulders, and to determine the repeatability of the dynamic ultrasound technique. MATERIALS AND METHODS: Using a custom-made stress device to apply an inferior displacement force of 90 N, we assessed 20 asymptomatic male subjects for inferior glenohumeral laxity, using stress radiography and dynamic ultrasound. Paired differences between the two methods were evaluated by the 95% limits of agreement method. At a separate session, 19 subjects had inferior glenohumeral laxity assessed by two observers, using dynamic ultrasound. Inter- and intra-observer repeatability was determined for the ultrasound technique. RESULTS: The mean [(+/-standard deviation (SD)] inferior translation was 4.7+/-4.1 mm by stress radiography and 4.4+/-2.3 mm by dynamic ultrasound. The 95% limits of agreement showed good agreement between the two methods. The paired difference between the two measurement methods varied with the magnitude of the measurement (P<0.001). Intra-observer repeatability of dynamic ultrasound was determined by the use of intra-class correlation coefficients and was 0.94 and 0.89 for the two investigators. Inter-observer repeatability was 0.85. The standard error of the measurement was 0.60 mm and 0.66 mm, for repeated measurements by the two investigators, and 0.85 mm between investigators. Repeatability coefficients demonstrated excellent consistency of measurement between sessions and good consistency between observers. CONCLUSION: Dynamic ultrasound is a valid and reproducible method for the assessment and quantification of inferior glenohumeral laxity.

Melorheostosis of the tenth and eleventh thoracic vertebrae crossing the facet joint: a rare cause of back pain.

Melorheostosis affecting the axial skeleton is a rare condition. We present a case affecting a single thoracic zygoapophyseal (facet) joint that proved to be a diagnostic challenge. CT, MRI and radionuclide imaging with surgical and histopathology findings are discussed.

Alendronate in the treatment of primary hyperparathyroid-related osteoporosis: a 2-year study.

We investigated the effect of alendronate on calcium, PTH, and bone mineral density in 27 female and 5 male patients with primary hyperparathyroidism. The treatment group [n = 14; T score < or = -2.5 SD at the femoral neck (FN) or T < or = -1.0 SD plus previous nonvertebral fracture] was given alendronate 10 mg/d for 24 months. The second group (n = 18; T score > -2.5 SD at the FN) was untreated. Biochemistry was repeated at 1.5, 3, 6, 12, 18, and 24 months, and dual-energy x-ray absorptiometry at 12 and 24 months. There were no significant between-group baseline differences in calcium, creatinine, or PTH. Alendronate-treated patients gained bone at all sites [lumbar spine (LS), 1 yr gain, +7.3 +/- 1.7%; P < 0.001; 2 yr, +7.3 +/- 3.1%; P = 0.04). Untreated patients gained bone at the LS over 2 yr (+4.0 +/- 1.8%; P = 0.03) but lost bone elsewhere. Calcium fell nonsignificantly in the alendronate group between baseline (2.84 +/- 0.12 mmol/liter) and 6 wk (2.76 +/- 0.09 mmol/liter), with a nonsignificant rise in PTH (baseline, 103.5 +/- 14.6 ng/liter; 6 wk, 116.7 +/- 15.6 ng/liter). By 3 months, values had reverted to baseline. In primary hyperparathyroidism, alendronate is well tolerated and significantly improves bone mineral density at the LS (with lesser gains at FN and radius), especially within the first year of treatment. Short-term changes in calcium and PTH resolve by 3 months.

From the archives of the AFIP. Musculoskeletal angiomatous lesions: radiologic-pathologic correlation.

Vascular lesions of bone and soft tissue are relatively common musculoskeletal neoplasms. Hemangioma is the most frequently encountered angiomatous lesion. Osseous hemangioma commonly involves the spine and calvaria and often has a characteristic radiographic appearance, with either coarsened trabeculae lying adjacent to the vascular channels or multifocal lytic areas creating a honeycomb pattern. Soft-tissue hemangioma is the most frequent soft-tissue neoplasm of infancy and childhood. Radiography and computed tomography (CT) may show phleboliths in cavernous soft-tissue hemangioma. The magnetic resonance (MR) imaging appearance, however, is often more distinctive, because fat overgrowth and serpentine vascular channels can be seen. Lymphangioma usually occurs in the neck and axillae of young children as a soft-tissue mass composed of large cavernous spaces and is well evaluated with CT, ultrasound, or MR imaging. Vascular lesions can also diffusely involve both bone and soft tissue in angiomatosis. A group of more aggressive vascular neoplasms, including hemangioendothelioma, hemangiopericytoma, and angiosarcoma, may have a nonspecific imaging appearance; however, the vascular pattern can be recognized in some cases, allowing radiologic diagnosis. Imaging is important throughout the evaluation of angiomatous lesions for detection, diagnosis, preoperative assessment, and treatment.

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.