Cytoplasmic particles in hepatocytes of patients with Australia antigen-positive liver disease.

An electron microscope study was made of liver biopsy material obtained during life or shortly after death from 11 patients. In three of them, where serum was positive for Australia antigen (two had serum hepatitis and one active chronic hepatitis) the hepatocytes contained characteristic particles within membrane-bound cytoplasmic vesicles. The appearance of these particles was very similar to that of the Australia antigen particles found in the serum. Two sizes of cytoplasmic particles were observed, with average diameters of about 26 and 46 nm. Particles of both sizes often had a membrane-like outer component and a moderately electron-dense inner component. They differed in both size and structure from the mainly intranuclear particles described by previous authors and which were not found in the present patients. The nature of the vesicles containing the particles was not apparent.

The role of incompetence of the anterior cruciate and lateral ligaments in anterolateral and anteromedial instability. A biomechanical study of cadaver knees.

UNLABELLED: The anterolateral and anteromedial stability of seventeen fresh frozen cadaver knees was studied in a test apparatus designed to simulate physiological conditions. Statistically significant increases in internal rotation occurred in seven knees when only the anterior cruciate ligament was sectioned, and these increases were enhanced by subsequent sectioning of the posterolateral complex and the lateral collateral ligament, singly or in combination. On the other hand, sectioning of the posterolateral complex and of the lateral collateral ligament, leaving the anterior cruciate intact, did not produce significant increases in internal rotation until the anterior cruciate ligament was sectioned in seven knees. When the entire anterolateral capsule was sectioned as far posterior as the lateral collateral ligament in three knees, no changes in internal or external rotation occurred. Only when the posterolateral complex was sectioned was there a significant increase in external rotation in any of the ligament-sectioning sequences. Thus, it appears that for pathological internal rotation of the tibia on the femur to occur, the anterior cruciate ligament must be incompetent. CLINICAL RELEVANCE: The test apparatus and the results are useful in assessing which ligament structures contribute to clinically noted rotational knee instabilities.

The radiographic resolution of beads from porous coated joint prostheses.

While there have been reports of the 750 microns chrome-cobalt beads disassociating from the PCA type prosthesis, failure of the 200 microns bead has not been documented despite reports of failed prosthesis, which use the smaller bead. As a result of the negative reports, the hypothesis was posed as to the limit of resolution in the image of the standard clinical radiographical film. To test the hypothesis, chrome-cobalt beads, ranging in size from 200 to 700 microns, in differing configurations were placed adjacent to a femoral prosthesis that had been implanted into a cadaveric specimen. Using standard clinical radiographic technique, differing exposures were made of the configurations. The results demonstrated that beads or a conglomerate of beads smaller than 300 microns could not be resolved and were therefore invisible and unrecordable. The clinical significance is to question whether all porous-coated prostheses shed metal alloy particles, some of which are radiographically undetectable due to the limitations of their resolvable size.

Acute hematogenous osteomyelitis: a model with trauma as an etiology.

The etiology of acute hematogenous osteomyelitis (AHO) remains unknown, and the disease has no laboratory model. We describe an AHO model in the rabbit which resembles the human disease. The model was developed on the premise that previous attempts had omitted an essential etiologic factor other than the bacteria. Six-week-old white New Zealand rabbits were divided into three different groups. Group I received an injury to the proximal tibial physeal plate, group II received a standardized bacteremia with Staphylococcus aureus, and group III received both the fracture and the bacteremia. The physeal plate injuries healed within 7 days. The animals with bacteremia only had occasional small foci of osteomyelitis identified histologically. The animals with fracture and bacteremia developed significant osteomyelitis in almost all cases.

Varus-valgus and rotational stability in rotationally unconstrained total knee arthroplasty.

This study was designed to test the ability of the ligaments to restore rotational stability to the knee after rotationally unconstrained anterior cruciate-sacrificing total knee arthroplasty (TKA). Rotational and varus-valgus stability both were returned to near-normal values, and the normal screw home pattern of coupled external rotation with extension was restored when the ligaments were correctly tensioned. When the ligaments were tensioned so that the knee was either too loose or too tight, both varus-valgus and rotational laxity were affected equally. Rotational constraint is not necessary in a TKA system to achieve normal rotational stability of the knee, as long as normal varus-valgus stability is restored.

Granulomatous reaction and cystic bony destruction associated with high wear rate in a total knee prosthesis.

This is a case report of a Cloutier total knee arthroplasty that was removed from an obese, large, 66-year-old man three years after implantation because of aseptic loosening. At surgery there was a thickened black synovium and black cystic areas in the exposed bone. The articulating surfaces of the tibial component, which is made from Poly Two (a carbon polyethylene composite), were grossly abraded, and the supporting metal tray was broken in two. The femoral component showed signs of abnormal wear at the places where it was articulating with the displaced tibial component. The tissues showed a granulomatous reaction with marrow fibrosis and cystic destruction of bone. It is postulated that aseptic loosening was accelerated by a granulomatous response to overload, abrasion, and local dissemination of particles.

Device and method for controlling cement thickness.

The ideal thickness of cement between the prosthesis and bone has not been accurately determined, but there is general agreement that the surgeon should be able to provide and accurately produce a certain thickness of cement between the prosthesis and the bone. Conventional cementing technique could allow the surgeon to ovepush the cup into direct contact with the bone producing a very thin cement coat or a void. We have developed a simple method of achieving a predictable thickness. We insert small spacers made of methylmethacrylate, which can be placed between the bone of the acetabulum and the acetabular component, preventing voids or thin areas in the cement coat. The device has been used in over 50 patients and has proven to be a simple and reliable method of allowing the surgeon to produce a predictable thickness of cement surrounding a joint replacement component. An additional benefit obtained from the use of these spacers is the ability to rigidly hold the acetabular component during polymerization of the acrylic without fear of overpushing. This allows better packing of the bone cement and prevents imperfections caused by the cup contacting the bone.

The histopathology of camptomelia (bent limbs). A dyschondrogenesis.

Camptomelia is well established syndrome in which the most prominent osseous feature is bowing of the long bones. Although several patients have died, usually due to respiratory insufficiency caused by defects of the cartilage of the tracheal rings and lower respiratory tract, histologic studies of the bone in camptomelia have led to conflicting conclusions about pathogenesis. A complete autopsy of a neonatal case, including serial sections of the long bones, revealed normal enchondral growth sequences of the epiphyseal plate. In the diaphysis, centering around the angle of the bend, the cylinderization process was markedly abnormal. Extensive new secondary trabeculae formed on the concave (posterior) surface of the bone during resorption on the convex (anterior) surface. A cone of dense new bone formed at the apex at the convex anterior angle of the bend. These findings supported previous suggestions that bone formation and remodeling processes were normal. With the variation of bone involvement in different patients, these features indicate that camptomelia is the result of an abnormality of cartilage anlage formation, probably owing to a transient exogenous teratogen. Camptomelia is the preferred term. Basically, the syndrome is a dyschondrogenesis.

1 -Antitrypsin deficiency and neonatal hepatitis.

Five out of 28 infants investigated in a regional survey of neonatal hepatitis were found to have genetically-determined deficiency of alpha(1)-antitrypsin (ZZ phenotype). The clinical course and pathological changes varied considerably. All five infants had an acute hepatitis-like illness, and although this subsided cirrhosis later developed in three cases. The remaining two infants had minimal abnormalities of the liver function tests at 12 and 18 months of age, and one had increased hepatic fibrosis. Australia antigen was found in the serum of three infants, and Australia antigen or antibody in one or both parents of these and of one further case whose serum was negative. It is suggested that the association of neonatal hepatitis with alpha(1)-antitrypsin deficiency may be commoner than previously realized and that Australia antigen acts as a trigger factor in these cases.

A comparative study of dextran-70, warfarin and low-dose heparin for the prophylaxis of thrombo-embolism following total hip replacement.

In a randomized, controlled clinical study, dextran-70, warfarin, or low-dose heparin were administered to patients undergoing total hip replacement on one surgical unit in an attempt to prevent deep venous thrombosis and pulmonary embolism. Calf vein thrombosis was detected by the 125I-fibrinogen uptake test. None of the methods prevented calf vein thrombosis (dextran-70, 51%; warfarin, 58-6%; heparin, 52-6%). Pulmonary embolism was completely prevented in patients treated with warfarin but occurred in 4% of patients treated with dextran-70 and 15-5% of those treated with low-dose heparin. The incidence of complications of therapy was small and comparable in each group. It is suggested that calf vein thrombosis is a frequent and in itself a non-serious complication of total hip replacement surgery and that emphasis might be placed more usefully on prevention of pulmonary embolism.