Protrusio acetabuli in Marfan's syndrome

Marfan's syndrome is an autosomal dominant disorder of connective tissue, commonly involving the cardiovascular, ocular, and skeletal systems. Revised criteria for the clinical diagnosis of Marfan's syndrome regard skeletal involvement as a major criterion if at least four of eight typical skeletal manifestations are present, one of which is protrusio acetabuli. Using Kulman's method to determine the presence of protrusio, we analysed the pelvic X-rays of 15 patients with Marfan's syndrome and 15 controls. Protrusio was present in 47% (7/15) of Marfan patients, compared with 7% (1/15) of controls (P = 0.035). Using the revised criteria, the presence of protrusio would have affected the final diagnosis of Marfan's syndrome in only one patient out of 15. Therefore, we recommend that a pelvic X-ray is reserved for those cases in which the presence of protrusio will alter the final diagnosis. With regard to the radiological assessment of protrusio, in our opinion this can be performed simply and reliably using the position of the acetabular line alone.     

Protrusio acetabuli. An update on the primary and secondary acetabular protrusion

Acetabular protrusion refers to intrapelvic displacement of the medial wall of the acetabulum and is defined as inward movement of the acetabular line so that the distance between this line and the laterally located ilioischial line is 3 mm or more in adult men and 6 mm or more in adult women. As discussed in this article, acetabular protrusion may be found in many bone disorders such as degenerative joint disease, Paget's disease, rheumatoid arthritis, ankylosing spondylitis, osteomalacia, Marfan's disease and as an effect of irradiation. Protrusio acetabuli appearing in absence of any recognizable cause is termed primary acetabular protrusion or Otto pelvis. Primary acetabular protrusion usually affects both hips in young to middle aged women with a history of diminished abduction, rotation and hip pain since puberty. Radiographically one notes a bilateral axial migration of the femoral head without joint space loss and with moderate degenerative changes.     

MRI of the spleen: normal appearance and findings in sickle-cell anemia

The MRI appearance and characteristics of the normal and diseased spleen were prospectively evaluated using spin-echo imaging with a superconducting magnet operating at 0.35 T. Sixty normal patients and 13 patients with sickle-cell anemia involving the spleen were studied. The normal spleen was isointense or slightly more intense than liver at a repetition time of 0.5 sec. At a longer repetition time (TR 2.0 sec), the normal spleen was usually more intense than liver, becoming markedly hyperintense compared to liver on relatively T2-weighted images (TR 2.0 sec, TE 56 msec). All patients with sickle-cell anemia showed abnormally diminished signal intensity of the spleen.     

Acute chondrolysis on primary protrusio acetabuli in children

Two cases of acute chondrolysis of the upper femoral epiphysis associated with protrusio acetabuli are reported in two girls respectively 13 and 12 Y.O. The disease was unilateral in one patient and bilateral in other. Acute chondrolysis is characterized by onset of pain, restricted movements of the hip and evolution to an hip ankylosis within a few months. As usual no evidence of inflammatory disease could be shown at biology or at pathology of synovial membrane or of femoral head. CT and MR studies proved to be contributive in the first case. It's the author's opinion that in these 2 cases, chondrolysis appears as a complication of preexistent Protrusio Acetabuli.     

Thoracic extramedullary hematopoiesis in sickle-cell disease

The radiographic manifestations of thoracic extramedullary hematopoiesis are unilateral or bilateral, smooth, sharply delineated, often lobulated paraspinal masses without erosion of the vertebral bodies or ribs, sometimes associated with subpleural, paracostal masses. These radiographic findings were encountered in eight adult patients with homozygous sickle-cell disease. In one patient, the masses encompassed essentially the entire thoracic paravertebral area bilaterally. In the other seven patients, the masses were unilateral and limited to the region of the eighth to the 12th thoracic vertebrae. Two of the eight patients had lateral subpleural masses that were not contiguous with the paraspinal masses and that were located medial to the lateral portions of the ribs. Follow-up in seven of the cases ranged from 2 to 15 years and demonstrated, after relatively rapid growth initially, either no change in size or slow growth. Each patient was asymptomatic with regard to the thoracic masses. Histologic verification was not available in any case because of the lack of clinical indication for invasive diagnostic or therapeutic procedures. The presence of well-defined unilateral or bilateral paraspinal masses and/or paracostal masses in patients with homozygous sickle-cell disease and without related symptoms should alert one to the possibility of the presence of extramedullary hematopoiesis. These masses tend to be slow-growing and should not be subjected to aggressive diagnostic and therapeutic measures.     

The metacarpal index in homozygous sickle-cell disease

The metacarpal index (MCI) was measured in 240 patients with homozygous sickle-cell (SS) disease and in 1082 normal persons constituting a comparison group. The MCI was greater in females than in males, but there appeared to be no significant difference between genotypes. Arachnodactyly may occur in some patients with SS disease, but there is no evidence of a genotype-related increase in metacarpal index.     

Evaluation of the measurement methods for protrusio acetabuli in normal children

The normal values of the radiological lines most frequently used as references in the diagnosis of adult protrusio acetabuli were prospectively determined in 150 children (300 hips) without femoral pathology and aged between 2 and 15 years, mean age 8 years. The teardrop shape was modified according to the child's age, the crossed type predominating (48.7%). The mean centre edge (CE) angle fluctuated, with a median value of 31.2°±6.2°, increasing with age and with slightly greater values in females; a large spread of CE angle values was observed within age groups. Acetabular ilioischial line values ranged from +7 to -5 mm, with a mean of +1.8±2 mm. This last method was the most suitable because it was not modified by changes in incidence of X-rays in radiological studies. With this method protrusio is diagnosed in children when the acetabular line is projected medially, provided that the ilioischial line is 1 or 3 mm or more for boys and girls, respectively. We conclude that the most trustworthy method available to evaluate PA in children should be line crossing.