Showing papers on "Prosthesis published in 1973"
TL;DR: The results of these tests, particularly the differences in frictional moment and in the production of particulate debris, suggest a preference for high density polyethylene as one component of a total joint replacement prosthesis.
Abstract: 1. Currently available total replacement hip and knee prostheses were tested in a machine enabling flexion-extension movements to be applied whilst the prostheses were surrounded with Ringer9s solution or other liquid and loaded within the physiological range. 2. Prostheses of which both components were made in cobalt-chromium-molybdenum alloy produced visible quantities of alloy particles, whose sizes ranged down to about 0·1 microns, and cobalt and molybdenum ions in solution. 3. No metallic or plastic particles were detected during tests on a hip prosthesis made of stainless steel and high density polyethylene. 4. The frictional moments in cobalt-chromium-molybdenum hip prostheses were higher than in stainless steel-polyethylene hip prostheses, by a factor of at least 2 to 1. 5. It is accepted that the conditions of these tests were probably more severe than in life, but the difference is held to be one of degree and not one of kind. 6. The particulate alloy debris, when injected in massive doses into the muscles of rats, gave an incidence of malignant tumours which was comparable to that already established for pure cobalt powder, whereas particles of several other metals, tested in the same way, gave no tumours. 7. It is argued that the particles which are known to be produced in at least some patients using cobalt-chromium-molybdenum total replacement joint prostheses constitute a risk of tumour formation which is certainly small, possibly negligible, but not accurately calculable at present. 8. The results of these tests, particularly the differences in frictional moment and in the production of particulate debris, suggest a preference for high density polyethylene as one component of a total joint replacement prosthesis.
137 citations
TL;DR: It is clear after a decade of cardiac valve replacement that the ideal valve prosthesis is not yet available, or if available, not adequately tested, and valve replacement at this time must be reserved for the patient severely disabled by cardiac valve disease.
124 citations
TL;DR: The author describes a method by which the angle of anteversion of the Charnley-Muller total hip prosthesis may readily be obtained by measurements taken from the radiograph.
Abstract: The author describes a method by which the angle of anteversion of the Charnley-Muller total hip prosthesis may readily be obtained by measurements taken from the radiograph.
84 citations
TL;DR: Clinical investigations of this prosthesis in several centers have been associated with as low an incidence of thromboembolic complications as that achieved with the Teflon-disc prosthesis, and this improved prosthesis now has been released for general use.
28 citations
TL;DR: The authors believe this Björk-Shiley prosthesis to be superior in its hemodynamic characteristics and wear durability, with few late complications.
Abstract: One hundred and eighty-nine patients who had valvular replacement with 213 Bjork-Shiley prosthetic heart valves are presented who are 6 months to 2½ years postoperative. Surgical mortality was 2.6% in mitral valve replacement and 8.8% in aortic valve replacement. The late mortality for the entire series was 2.9%. Four patients had episodes of embolization, all from mitral prostheses. Only two incidences of paraprosthetic leaks were noted in patients with mitral valves, and none in patients with valves in the aortic position. The authors believe this prosthesis to be superior in its hemodynamic characteristics and wear durability, with few late complications.
25 citations
TL;DR: Improved Dacron velour-covered Teflon-disc mitral valve prosthesis using Pyrolite carbon for both the disc and the cage legs now is available and appears to offer significant advantages.
22 citations
TL;DR: It is believed that the implant principle in the hand is successful, but improvements in design and material are needed.
Abstract: Our 4-year clinical experience with reconstruction of worn metacarpo-phalangeal and proximal interphalangeal joints with silicone-Dacron prostheses in 121 patients is presented.
Emphasis is on preoperative assessment and proper selection of patients.
Three hundred sixty-nine metacarpophalangeal joint prostheses and 27 proximal interphalangeal joint prostheses have been inserted. Most of the patients had rheumatoid arthritis; several had degenerative arthroses, and a few had traumatic arthrosis.
Particular attention is directed to minor modification of surgical techniques and emphasis is on postoperative management. Suggestions for implant redesigning and modification are made.
The silicone-Dacron arthroplasties have been successful in decreasing pain, improving stability, increasing hand function, and in providing an adequate range of motion.
Complications have included five infections, two recognized fractured prostheses, and two instances of early dislocation of a prosthesis. The patients have consistently been relieved of pain: on the basis of this short-term experience, we believe that the implant principle in the hand is successful, but improvements in design and material are needed.
16 citations
TL;DR: The results indicate that potentially significant amounts of bone-marrow fat reached the general circulation immediately following the insertion of the femoral prosthesis.
Abstract: Summary In four patients undergoing operation for total hip replacement according to Charnley's technique, blood was withdrawn from the pulmonary artery and analysed for the presence of fat particles. Blood samples were taken: during the minute immediately following the insertion of the prosthesis into the acetabulum, during the minute following the insertion of the prosthesis into the femur, and 6–8 minutes after the insertion of the femoral prosthesis. Fat particles were found in 1 out of 4 patients following the insertion of the acetabular prosthesis, in 3 out of 4 patients after the insertion of the femoral prosthesis, and in none of the patients at 6–8 minutes after the insertion of the femoral prosthesis. The results indicate that potentially significant amounts of bone-marrow fat reached the general circulation immediately following the insertion of the femoral prosthesis. The embolization of fat and other thromboplastic material from the bone-marrow may contribute to the circulatory and respiratory complications observed in some patients during this phase of the operation.
14 citations
TL;DR: The Kay-Shiley protheses employed were small, accounting in part for significant prosthetic stenosis observed in some patients, and the in vivo effective orifice areas of the Kay- Shiley mitral and tricuspid prostheses averaged 75 percent of the in vitro orifice Areas.
12 citations
01 Jan 1973
TL;DR: There has been little research or analysis of the interface between the prosthesis and the femur, largely because clinically this region rarely gives rise to problems.
Abstract: In current clinical practice hip arthroplasty devices are being fitted to patients of progressively younger age groups (Charnley, 1971). Considerable research has been undertaken into the friction and wear characteristics required of the bearing surfaces of joint replacements (Duff Barclay, 1967; Scales, 1969). Attention has been directed principally to the design of the acetabular component of the hip joint and problems of attachment of this to the pelvic structure. There has been little research or analysis of the interface between the prosthesis and the femur, largely because clinically this region rarely gives rise to problems. The form of the femoral component of the prosthesis is generally a curved intramedullary stem of approximately rectangular cross-section secured either with bone chips or methyl methacrylate cement, a typical average design of stem being shown in figure 1.
TL;DR: Seventeen patients with organic impotence were treated by implantation of a prosthetic device into the penis, and those benefiting most were sexually active prior to either major surgery or accidental trauma.
Abstract: Summary Seventeen patients with organic impotence were treated by implantation of a prosthetic device into the penis. Surgical results were excellent in fifteen, and the prosthesis was removed in two because of infection. One patient requested that the prosthesis be removed two years after implantation. Those benefiting most were sexually active prior to either major surgery or accidental trauma, and patients who have much to gain from this procedure are often under the primary care of a surgeon. Knowledge of the effectiveness of a penile prosthesis can greatly add to the total care and happiness of the impotent patient.
TL;DR: Prosthetic malfunction was suspected because of sudden deterioration of cardiac status after a previously stable postoperative course and the diagnosis was confirmed radiologically and by cardiac catheterization and the patient underwent successful replacement of the mitral prosthesis.
TL;DR: This study investigates ceramic-coated metal hip prostheses which have the theoretical advantage of tissue ingrowth and fabricated a silicone rubber prosthesis for the pygmy goat, which initially has given good clinical results.
Abstract: Significant hazards to the use of femoral head prostheses–infection, corrosion, fatigue failure, interface motion, latent failure–dictate new standards for new prosthesis models. This study investigates ceramic-coated metal hip prostheses which have the theoretical advantage of tissue ingrowth. In long-term analysis, ingrowth did not occur in this study in the pygmy goat. Sintered metal prosteses were inserted in two dogs with bilateral congenital hip dysplasia. Excellent clinical results were obtained with radiologic evidence of bone envelopment of the sintered metal. Based on previous applications of silicone rubber to weight bearing by the author, the advantages of a silicone rubber prosthesis or silicone rubber-covered prosthesis are tissue compatibility, new bone formation, peak stress dispersal, and simulation of normal articular cartilage. A silicone rubber prosthesis was fabricated for the pygmy goat. It was inserted and initially has given good clinical results.
Journal Article•
TL;DR: Forty-nine individual silicone rubber arthroplasties of finger joints and wrist bones, performed in 17 patients, were reviewed and the prosthesis has a density similar to soft-tissue density.
Abstract: Forty-nine individual silicone rubber arthroplasties of finger joints and wrist bones, performed in 17 patients, were reviewed. The implant material is biologically inert silicone rubber. Surgical indications for the use of joint prostheses include loss of joint space, synovial proliferation with joint destruction, loss of normal joint alignment, and uncontrolled pain. Radiographically, the prosthesis has a density similar to soft-tissue density. Except for the hinge part, which appears as a denser band, the radiographic density is uniform. The technique of insertion and possible complications of joint prostheses are also discussed.