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Biomedical subjects

M Soudry

Publications and source records attributed to M Soudry.

35 records · Page 2Linked to original sources
PubMed1986

Nuclear magnetic resonance proton imaging of bone pathology.

Thirty-two patients with diversified pathology were examined with a supraconductive NMR imager using spin echo with different TR and TE to obtain T1 and T2 weighted images. They included 20 tumors (12 primary, eight metastasis), six osteomyelitis, three fractures, two osteonecrosis, and one diffuse metabolic (Gaucher) disease. In all cases except for the stress fractures, the bone pathology was clearly visualized in spite of the normal lack of signal from the compact cortical bone. Nuclear magnetic resonance (NMR) imaging proved to be at least as sensitive as radionuclide scintigraphy but much more accurate than all other imaging procedures including computed tomography (CT) and angiography to assess the extension of the lesions, especially in tumors extended to soft tissue. This is due both to easy acquisition of sagittal and coronal sections and to different patterns of pathologic modifications of T1 and T2 which are beginning to be defined. It is hoped that more experience in clinical use of these patterns will help to discriminate between tumor extension and soft-tissue edema. We conclude that while radionuclide scintigraphy will probably remain the most sensitive and easy to perform screening test for bone pathology, NMR imaging, among noninvasive diagnostic procedures, appears to be at least as specific as CT. In addition, where the extension of the lesions is concerned, NMR imaging is much more informative than CT. In pathology of the spine, the easy visualization of the spinal cord should decrease the need for myelography.

Adolescent↗
PubMed1986

Radiographic and scintigraphic evaluation of total knee arthroplasty.

Various radiographic and scintigraphic methods are used to supplement clinical findings in the evaluation of total knee arthroplasty and its complications. Serial roentgenograms offer reliable information for diagnosing mechanical loosening. Wide and extensive radiolucency at the cement-bone interface and shift in position and alignment of prosthetic components can be seen in almost all cases by the time revision is necessary. Radiographic abnormalities are usually not present in acute infection, but are often present in chronic infection. Bone scanning has a high sensitivity for diagnosis of infection or loosening, but is nonspecific because increased uptake is often present around asymptomatic total knee arthroplasties with normal radiographs. Differential bone and Gallium scanning and scanning with Indium 111-labeled leukocytes have a greater specificity for diagnosis of infection than does bone or Gallium scanning alone. Routine radiographic and scintigraphic studies have shown a high incidence of deep vein thrombosis in the calf after total knee arthroplasty. Clinically significant pulmonary embolization is infrequent.

Gallium Radioisotopes↗
PubMed1986

Total knee arthroplasty without patellar resurfacing.

Twenty-seven knees treated between 1974 and 1980 had a total condylar type knee arthroplasty without patellar resurfacing; the average follow-up period was 5.2 years. Compared with a previously reported group of 100 consecutive total condylar arthroplasties, the overall results in this series were very similar. However, there was a significant difference in stair-climbing ability, and one-third of the patients could not use the operated knee for this activity. In most knees the patella could be resurfaced. A working hypothesis assumes that the patellar button can be omitted in patients with relatively normal patellar cartilage, or relatively young, active, or obese patients who are considered a high risk for patellar bone fractures.

Adult↗
PubMed1986

Total knee arthroplasty in Charcot and Charcot-like joints.

Nine total knee arthroplasties were performed in seven patients with the diagnosis of neuropathic arthropathy. The patients were divided into two groups, classical Charcot and Charcot-like. The histopathological findings in all of the knees, however, were essentially the same. These included hyperplastic synovium with bone and/or cartilage detritus, severe disorganization of the articular cartilage with invasion by a fibrous pannus, and hemosiderin deposits in synovial macrophages. Chronic inflammatory synovitis was noted in all cases. The results of total knee arthroplasty an average of three years after surgery (range, two to 4.25 years) were excellent in eight knees in six patients and good in one knee. Neuropathic knees can be treated by total joint arthroplasty if severe bone loss is corrected by either bone grafting or a custom-augmented prosthesis and if ligamentous balancing is adequately secured.

Aged↗
PubMed1985

Successive bilateral total knee replacement.

We studied the results of 304 posterior stabilized condylar knee arthroplasties, performed over a two and a half-year period, to compare unilateral, bilateral one-stage, and bilateral staged arthroplasty. The minimum length of clinical follow-up was two years. Using The Hospital for Special Surgery rating system, we found the clinical results to be identical for all three groups. The medical complications were similar in each group except that there was a higher incidence of thromboembolism and pulmonary embolism, as seen venographically, in the patients with staged procedures. We concluded that one-stage bilateral knee arthroplasty is preferable in a patient who requires replacement for severely arthritic knees.

Adult↗
PubMed1985

Patellar dislocation following total knee replacement.

The reported incidence of patellar problems after total knee replacement has ranged from 5 to 30 per cent. Patellar dislocation is infrequent but can cause disabling symptoms. Between January 1974 and May 1982, eleven patients (twelve knees) with symptomatic lateral dislocation of the patella after total knee replacement were treated at The Hospital for Special Surgery by realignment of the extensor mechanism. All of the patients were women. Their average age was sixty-two years and average weight, eighty-seven kilograms. The diagnosis was osteoarthritis in seven knees and rheumatoid arthritis in five. Most of the patients had had preoperative valgus deformity (average, 18 degrees). The cause of dislocation was trauma in three knees, incorrect tracking of the patella after replacement in six, and malrotation of the tibial component in three. Four different prosthetic designs had been used. The design of the implant did not appear to be a factor causing dislocation in this group. The patellar dislocation was treated by proximal realignment of the quadriceps in ten knees, lateral retinacular release alone in one, and revision of the tibial and femoral components combined with proximal realignment in one. After an average follow-up of thirty-four months (range, twenty-four to fifty-seven months), the results according to The Hospital for Special Surgery knee-rating scale were excellent in ten knees and good in two, and there had been no redislocations.

Arthritis, Rheumatoid↗
PubMed1984

Neuropraxis secondary to hemorrhage in a traumatic dislocation of the shoulder.

A case of traumatic shoulder dislocation associated with a tear of the subscapular artery is presented. The main clinical feature was a dramatic neurologic loss of the brachial plexus, reversed by exploration, evacuation of hematoma, and ligation of the bleeding vessel. Early surgical decompression to achieve neurologic recovery is emphasized.

Aged↗
PubMed1984

Failure of total condylar knee replacement. Correlation of radiographic, clinical, and surgical findings.

The authors reviewed 55 failed total condylar knee replacements, correlating the radiographic and surgical findings at removal or revision. Failure was due to infection in 20 cases, mechanical loosening in 18, instability without loosening in 10, malalignment without loosening in 4, a supracondylar fracture in 2, and unknown causes in 1. In infection with loosening or chronic infection, radiographs usually showed a wide, extensive radiolucent region at the cement-bone interface around one or more components without shifting, while in acute infection without loosening the radiographs were normal. In mechanical loosening, in addition to a similar lucent region, the prosthesis became tilted in 16 out of 18 cases. Most loosening involved tilting of the tibial component into the varus position with subsidence into the medial tibial plateau, collapse of the cancellous bone, and plastic deformation. Radiographs can be helpful in determining the reason for failure of a total knee replacement, which is important in planning surgery.

Adult↗
PubMed1984

Control of cement penetration in total knee arthroplasty.

A radiographic study of 45 knees immediately and at least two years after operation showed that the average depth of cement penetration was 1.5-3.0 mm at different locations around the interface and that there was a strong inverse relation between the development of radiolucency and initial cement penetration. In laboratory studies of penetration in the upper tibia, penetration was approximately proportional to bone pore diameter and to the square root of the applied pressure and inversely proportional to the time after initial mixing. There was a low correlation of the tensile strength of the cement-bone bond with the depth of penetration, probably due to the variability of the trabecular bone strength. Failure occurred by direct cement pullout or by partial or total fracture through the bone. In light of all factors, the suggested ideal depth of cement penetration is 3-4 mm. This penetration can be achieved by using the left-lift method about four minutes after initial cement mixing, but with some selective prepenetration around the periphery of the tibia.

Biomechanical Phenomena↗
PubMed1984

[Forces at the implant-bone interface of condylar knee prosthesis--with special reference to the retention of the posterior cruciate ligament].

Breakdown of the implant-bone interface is the most important factor limiting the effective life of total joint replacement. A particular example is the tibial component of the knee prosthesis which interfaces with trabecular bone. It is postulated that one of the major reasons for interface breakdown is excessive shear, compressive and moment stresses at the implant-bone interface. These stresses can be greatly influenced by the design of the prostheses, namely surface contour of the tibial component and the retention of the posterior cruciate ligament. Forces across the tibial component-bone interface was measured for prostheses both retaining and sacrificing the posterior cruciate ligament and for partially conforming and non-conforming, flat geometries. The results are as follows: Shear force, normal force and moment force across the interface were significantly greater for the prostheses sacrificing the posterior cruciate ligament than for those retaining it. Moment force was markedly greater for the tibial component with anterior curvature than for flat tibial component. It was suggested from this experiment that the knee prosthesis should retain the posterior cruciate ligament and the surface of the tibial component should probably be flatter for reducing the forces at the implant-bone interface.

Biomechanical Phenomena↗
PubMedDate not supplied

Total knee arthroplasty.

The standard prosthesis for most arthritic conditions is a tricompartmental type. Patellar resurfacing should be done in most cases. The question of cruciate preservation or substitution is unresolved, and both types give equivalent clinical results. No advantage has been shown for left or right components. Correction of deformity occurs by soft-tissue release and ligament balancing, rather than by bone resection. Most primary replacements can be performed in this manner, but alignment is critical to the function and survival of a functioning arthroplasty. Most failures can be attributed to incorrect ligament balance or incorrect alignment. Cement fixation of the components has proved effective, and there is no immediate need for alternative methods such as bone ingrowth; new methods will have to prove themselves against the standard already established for cemented prostheses. Patellar complications such as fatigue fracture of the patellar bone now constitute the majority of problems following total knee arthroplasty.

Adult↗