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At least 883 records · Page 49Linked to original sources
PubMed1979

A new cardiac prosthesis: the St. Jude Medical cardiac valve: in vivo results.

The St. Jude Medical cardiac valve prosthesis is a low profile, lightweight, bi-leaflet, central-flow device constructed entirely of pyrolytic carbon. In vivo testing was performed in 24 cows in which the tricuspid valve (n = 14) or mitral valve (n = 10) was replaced by a St. Jude Medical prosthesis with a 26 mm tissue annulus diameter. Eight animals died in the operative period. The 16 surviving animals were sacrificed at 4, 8, 12, or 18 weeks. There were no valve-related deaths nor mechanical valve failures. Anticoagulation was not used in the postoperative period during which time monthly laboratory parameters were obtained including hemoglobin, hematocrit, white cell count, red cell count and indices, lactic acid dehydrogenase, serum haptoglobin, and, additionally at sacrifice, platelet and red cell morphology. Values indicated this prosthesis did not cause hemolysis. At sacrifice the pulmonary arterial tree and peripheral organs showed no evidence of thromboemboli. There was smooth endocardial ingrowth on all valve sewing rings. One valve had thrombus formation on the valve sewing ring. Nine animals were anesthetized prior to sacrifice and underwent open cardiac catheterization. Ventriculography (n = 6) showed minimal transvalvar reflux, and atriograms (n = 6) demonstrated central flow. Transvalvar gradients were 0 to 22 mm Hg (n = 9). One valve of an 18-week tricuspid implant was examined for wear; valve life was calculated to be greater than 2500 years. These data in conjunction with in vitro test results justify clinical trial of the St. Jude Medical prosthesis.

Animals↗
PubMed1982

Cementless isoelastic RM total hip prosthesis.

Some surgeons are beginning to doubt the reliability of bone cement in joint replacements. In 1967 Robert Mathys conceived the idea of an isoelastic prosthesis made of plastic, which would anchor into the bone without cement. He developed the idea by extensive tests in animals and, in 1973, the first human RM cementless hip prosthesis was inserted by E Morscher. In this paper the concept of the cementless isoelastic prosthesis is developed by Robery Mathys, and Professor Bombelli records his experience with the prosthesis between 1977 and 1981.

Aged↗
PubMed2003

Endovascular repair of external iliac artery occlusion after hip prosthesis migration.

PURPOSE: To report emergent endovascular intervention to restore lower extremity arterial patency after migration of a hip prosthesis caused thrombosis of the external iliac artery (EIA). CASE REPORT: Nine months following left hip revision arthroplasty, a 66-year-old woman presented to the Emergency Department with the complaints of an acutely painful left lower extremity for over 6 hours. Imaging showed the metallic acetabular portion of the hip prosthesis in the iliac fossa, with severe external compression of the EIA. After thrombolysis to remove clot from the EIA, an 8x60-mm self-expanding Smart stent was deployed in the left EIA from a contralateral access. The procedure was successful, and the patient was discharged. An infected wound from a compartment fasciotomy delayed revision of the hip prosthesis. Nine weeks after stenting, the patient returned with a cold, pulseless left limb; a femorofemoral bypass was constructed to restore perfusion. CONCLUSIONS: While stent placement restored flow for 9 weeks after the initial ischemic event, the recurrent thrombosis could have been prevented by earlier revision of the migrated prosthesis.

Aged↗
PubMed1995

Total knee arthroplasty with the kinematic condylar prosthesis. A ten-year follow-up study.

Of 168 consecutive knees (118 patients) that had been treated with an arthroplasty with use of a kinematic total condylar prosthesis that allowed retention of the posterior cruciate ligament, 119 knees (eighty-four patients) were available for review at a mean of 10.0 +/- 0.7 years after the operation. The Hospital for Special Surgery knee score improved significantly, from a mean of 55 +/- 12 points preoperatively to a mean of 81 +/- 9 points at ten years (p < 0.0001). Radiolucent lines about the patellar component, present in thirty-five of eighty-three knees at the latest follow-up examination, were related to malpositioning of the tibial and femoral components. Six revisions were performed, and four of them were for a loose patellar component. The rate of deep infection was 1 per cent (one knee). Complications occurred in twenty-six knees (22 per cent). With revision as the end point, the rate of survival of the prostheses was estimated to be 96 per cent at ten years. The knee scores, the rate of survival of the implants, and the range of motion of the knees in the current study were similar to those reported previously for patients who had insertion of a total condylar prosthesis with sacrifice of the posterior cruciate ligament and for those who had substitution of the posterior cruciate ligament with a posterior stabilized prosthesis. A prosthesis that has a metal-backed tibial component and that allows preservation of the posterior cruciate ligament provides durable results, but loosening of the patellar component remains a major problem.

Adult↗
PubMed2005

Revision arthroplasty with use of a total femur prosthesis.

BACKGROUND: Surgeons performing revision arthroplasties of the hip and knee are confronted with a growing number of patients with extensive loss of bone stock. Implantation of a total femur prosthesis is a possible method of treatment of such patients. The purpose of this study was to assess the functional outcomes and the complications associated with total femur replacements used in revision arthroplasty. METHODS: We evaluated the results associated with 100 total femur prostheses that had been implanted during revision arthroplasty in 100 consecutive patients without infection. The mean duration of follow-up was five years. The prosthesis was implanted because of a complication of a total hip replacement in seventy-seven patients, because of a complication of a total knee replacement in four, and because of a complication affecting the diaphysis of the femur in nineteen. Thirty-nine patients had sustained a periprosthetic fracture, usually in combination with loosening of the prosthesis, before the revision. The radiographs made at the time of the latest follow-up were evaluated for signs of loosening and material failure. The preoperative and postoperative function of the hip and knee was assessed according to the Enneking score. Five patients were lost to follow-up. RESULTS: Sixty-five patients (68%) had no complications. Deep infection was found in twelve patients (13%); dislocation, in six (6%); material failure, in three (3%); patellar problems, in two (2%); and peroneal nerve palsy, in one (1%). The mean preoperative Enneking score for hip function was 1.25 points, and it improved to 3.29 points postoperatively. The mean Enneking score for knee function was 2.09 points preoperatively and 3.29 points postoperatively. CONCLUSIONS: We believe that the total femur prosthesis is a useful implant for patients with extensive bone loss at revision arthroplasty. While the infection rate was high, the overall functional results for both the hip and the knee were rated as better than good with the Enneking classification.

Adult↗
PubMed2004

The influence of prosthesis designs and loading conditions on the stress distribution of tooth-implant supported prostheses.

The aim of this study was to observe the influence of prosthesis design and loading condition on the stress distributions of tooth-implant supported prostheses. Six 2D finite element models, two reference models, and four experimental models were computed to simulate different prosthesis designs. Six different loading conditions were applied to investigate the stress distributions of tooth and implant, respectively. The stresses of reference models were considered as 100%; the stresses of experimental models at the same locations were compared with those of reference models. The stresses around implants were higher than those around teeth. When vertical loading was applied only on the implant, the stresses to both the implant and teeth were at their lowest. The highest stress to the tooth was in the model TTPF and the lowest in the model TPFF. The highest stress to the implant was in the model TPPF and the lowest in the model TPFF. These data indicated that the loading on the tooth-implant supported prosthesis was mainly supported by the implant. Minimizing the loading on the tooth decreased the stress to both the tooth and the implant. Adding fixtures as abutment was more effective in decreasing the stress than adding tooth as abutment in tooth-implant supported prosthesis.

Alveolar Process↗
PubMed1990

K-edge digital subtraction arthrography of the painful hip prosthesis: a feasibility study.

K-edge energy subtraction radiography is a method for detecting the presence of iodinated contrast material by subtracting two digital radiographs produced by X-ray beams with energies above and below the iodine K edge. We performed a feasibility study on the application of K-edge energy digital subtraction arthrography (KEDSA) to painful hip prostheses. During arthrography, loosening of the prosthesis is implied if contrast material is seen dissecting around the prosthesis, an often difficult detection task because of adjacent prosthesis metal or cement. In conventional arthrography a preliminary mask image is thus used from which films obtained after injection of iodinated contrast material are subtracted. Movement by the patient during this process may preclude subsequent subtraction. With KEDSA, since multiple image pairs may be obtained after the injection of contrast material, the problem of patient motion is virtually eliminated. A conventional X-ray tube operating between 55 and 65 kVp was alternately filtered by iodine and cerium filters to produce the KEDSA images. The apparatus was capable of producing a subtracted image within 3 sec. The technique was applied to phantoms and to six patients immediately after hip arthrography that had been positive for prosthesis loosening. Although of lower spatial resolution, the KEDSA images were, in all cases, positive for loosening in a pattern consistent with the conventional arthrographic images. KEDSA was shown to be successful in detecting extraarticular contrast material. During a single study, subtraction in various imaging planes as well as postexercise subtraction imaging can be accomplished-techniques not heretofore possible in routine subtraction arthrography.

Aged↗
PubMed2004

The use of targeted muscle reinnervation for improved myoelectric prosthesis control in a bilateral shoulder disarticulation amputee.

A novel method for the control of a myoelectric upper limb prosthesis was achieved in a patient with bilateral amputations at the shoulder disarticulation level. Four independently controlled nerve-muscle units were created by surgically anastomosing residual brachial plexus nerves to dissected and divided aspects of the pectoralis major and minor muscles. The musculocutaneous nerve was anastomosed to the upper pectoralis major; the median nerve was transferred to the middle pectoralis major region; the radial nerve was anastomosed to the lower pectoralis major region; and the ulnar nerve was transferred to the pectoralis minor muscle which was moved out to the lateral chest wall. After five months, three nerve-muscle units were successful (the musculocutaneous, median and radial nerves) in that a contraction could be seen, felt and a surface electromyogram (EMG) could be recorded. Sensory reinnervation also occurred on the chest in an area where the subcutaneous fat was removed. The patient was fitted with a new myoelectric prosthesis using the targeted muscle reinnervation. The patient could simultaneously control two degrees-of-freedom with the experimental prosthesis, the elbow and either the terminal device or wrist. Objective testing showed a doubling of blocks moved with a box and blocks test and a 26% increase in speed with a clothes pin moving test. Subjectively the patient clearly preferred the new prosthesis. He reported that it was easier and faster to use, and felt more natural.

Anastomosis, Surgical↗
PubMedDate not supplied

Longitudinal forces acting at side-to-end and end-to-side anastomoses when a knitted polyester arterial prosthesis is implanted in the dog.

In a previous study, which investigated the tensions at the proximal and distal end-to-end anastomoses of a vascular prosthesis, no significant differences were found in the longitudinal forces between the two anastomotic sites after different periods of implantation. The present follow-up study was devised to study the longitudinal forces at a proximal side-to-end and a distal end-to-side anastomosis using a warp knitted polyester prosthesis implanted as a canine thorocoabdominal bypass. The external surface of the prosthesis contained a specially printed "tension indicator" design, which enabled changes in length to be assessed photographically at the two anastomoses at the time of implantation and at sacrifice. The longitudinal force at each site was then calculated using a relationship obtained experimentally between the total longitudinal force and the changes in length of the virgin graft in vitro. The in vitro measurements on the prosthesis were performed using a computer-controlled laser calibration system. Although the results showed a tendency toward a gradual loss in longitudinal force at both anastomoses over 7 months in situ, statistical analysis showed no significant difference in the longitudinal force at the two anastomotic sites after any period of implantation. Histopathological and textile analysis also showed that the characteristics of the prostheses were similar at both anastomotic sites. This does not mean, however, that the intramural stress concentrations experienced by the two sites were the same. While comparing the level of the longitudinal forces measured in this study with those observed in the previous thoracic aorta study using end-to-end anastomoses, no significant differences were observed due to the different types of anastomoses. It would appear that the longitudinal force is not one of the main etiological factors that cause the formation and localization of anastomotic failure.

Anastomosis, Surgical↗
PubMed1977

The Monk hip arthroplasty. Preliminary report on the uncemented standard Monk prosthesis.

The Monk hip prosthesis is a one-piece block prosthesis consisting of a metal femoral component with the head enclosed in a polyethylene cup. The standard type is fixed without cement. Most of the hip movements take place between the metal and the polyethylene cup. 104 Monk arthroplasties were performed. 95 hips in 84 patients have been available for regular examination and follow-up. The follow-up period was from 12 to 30 months, an average of 19 months. Out of the 95 cases, 72 were classified as excellent, 10 as good and 13 as unchanged. The results obtained during the first year were comparable to those obtained with the Ring prosthesis, but during the following 1 1/2 years eight revisions had to be performed. The main reason for the deterioration was loosening of the femoral component, probably because in the standard type it is too short and the neck has too great a varus inclination, resulting in a rather strong tilting force. Because no cement has been used the revisions have been quite easy to perform. Another reason for failure has been wear of the polyethylene cup, in one case with a massive foreign body reaction. In spite of a short follow-up period this report illustrates the failures due to the design of the prosthesis, and therefore an improved construction is now in use.

Adult↗
PubMed1981

The Attenborough total knee prosthesis. Results of 25 operations evaluated according to two different assessment systems.

The Attenborough stabilized gliding total knee prosthesis was used in cases of severely damaged, highly unstable or deformed knees. Twenty-five operated cases were followed for 1 1/2 years (range 12-28 months). The results were assessed according to two different knee evaluation systems: The Lotke & Ecker knee evaluation index and the knee function assessment chart (BOA chart) suggested by the British Orthopaedic Association. The overall results were excellent or good in 84 per cent (21/25) of the cases according to both systems, but when considering the improvement in individual clinical features the BOA chart results were more optimistic. Neither of the systems takes into consideration that the results are influenced by possible disorders in other joints. If only the function of the knees was being judged the results of the operations with the Attenborough prosthesis were excellent or good in 96 per cent (24/25) in this series. In general the results to be as good as those obtained in less disabled knees treated with compartmental prostheses. As more extensive surgery and bone resection is needed for insertion of the Attenborough prosthesis compared with compartmental prostheses, its use should be restricted to severely damaged knees which would otherwise be treated with a hinged prosthesis or an arthrodesis.

Adult↗
PubMed1989

Total knee arthroplasty using the kinematic rotating hinge prosthesis.

Patients receiving a Kinematic Rotating Hinge total knee prosthesis with a 25-month minimum follow up were reviewed. A total of 46 patients and 54 knees were included in the study. A detailed clinical assessment was available on 38 knees. Twenty of these knees had primary arthroplasties performed with the Kinematic Rotating Hinge prosthesis and 18 knees had revision arthroplasty. Ninety-five percent of primary knees and 83% of revision knees caused no or mild pain postoperatively. Using the Brigham and Women's Hospital and Harvard Medical School knee rating system, 80% of primary knees and 61% of revision knees were rated as good to excellent. Using the criteria defined in this article, 90% of primary knees and 83% of revision knees were labeled as having a satisfactory result. Forty-five percent of primary components and 52% of revision components demonstrated lucent lines on radiographic review. Seven percent of primary knees and 20% of revision knees showed evidence of aseptic lucency progression in one or more zones. No radiographic evidence of aseptic loosening was noted in this review. Documented sepsis occurred in one primary knee and two revision knees. Patellar instability occurred in 21% of primary knees and 36% of revision knees, representing the major complication. The Kinematic Rotating Hinge prosthesis is intended for use in arthroplasty cases where there is functional absence of collateral ligament stability. This review suggests that a high percentage of satisfactory clinical results can be achieved with this prosthesis with long-term radiographic stability.

Activities of Daily Living↗
PubMed1995

Early performance appraisal of the Omniflow II Vascular Prosthesis as an indicator of long-term function.

The search for the ideal vascular prosthesis for below the knee replacement or coronary surgery continues. Long-term explant analysis of a biosynthetic composite vessel, the Omniflow Vascular Prosthesis I, has previously shown sound structural durability. An important determinant in defining durability has been the evaluation of the degree of persistence of the original biological components and the augmentation by new tissue. The development of a panel of specific monoclonal antibodies to collagens, that allow detection of new host collagen among the original collagens of the prosthesis has been a key factor. In the present study, these antibodies have been used to investigate the degree and rate of new collagen tissue infiltration in an improved version of the Omniflow prosthesis. The data show that new collagen types III and VI can be detected as early as 3 months in the adventitial tissue, and that complete tissue augmentation throughout the entire vessel wall is apparent by 6 months after implant. The novel explant analyses serve as a good predictive indication to the in vivo performance of the device and would be useful in rapid monitoring of further modifications to this vessel or to other collagen-based prostheses.

Animals↗
PubMed1976

A new total knee prosthesis: the "total-condylar".

We have described the instrumentation and surgical technique of a new total knee prosthesis, the Total-Condylar, designed at the Hospital for Special Surgery (New York) and which we are the first to use in Italy. This prosthesis has evolved from the "sliding" prosthesis and seems to us to constitute a real step forward. The femoro-patellar compartment is completely substituted. The cruciate ligaments are removed, which markedly increases the possibility of correcting even severe deformities. The fixation of the tibial component is improved by the adoption of a short stem. The prosthesis has a certain intrinsic stability on weightbearing. The surgical technique is characterised by bone sections perpendicular to each other by the use of aligning instruments which simplify the operation. Our experience is just beginning (five cases) but our results so far are very encouraging and correspond to those reported in a very much larger series in the United States.

Aged↗
PubMed2000

Efficacy, safety and patient satisfaction outcomes of the AMS 700CX inflatable penile prosthesis: results of a long-term multicenter study. AMS 700CX Study Group.

PURPOSE: We performed a long-term multicenter study of the AMS 700CX 3-piece inflatable penile prosthesis, focusing on longevity, morbidity and patient satisfaction in men implanted up to 134 months with a median followup of 47.7 months. MATERIALS AND METHODS: We performed a large scale retrospective multicenter study in 2 phases. Phase 1 was a medical record review of 372 men who underwent implantation with the AMS 700CX penile prosthesis from 1987 to 1996 by 7 frequent penile prosthesis implanters. Phase 2 included a structured telephone interview of 207 patients by a neutral observer. RESULTS: For the 372 men in phase 1 mean device mechanical reliability plus or minus standard deviation was 92.1% + or - 3.3% after 3 and 86.2% + or - 4.6% after 5 years. Patient age was 21 to 79 years (mean 57.6 + or - 11.0) at implantation. The etiology of erectile dysfunction was vascular in 27.7% of the cases, Peyronie's disease in 16.9%, diabetes mellitus in 12.9% and radical surgery in 11.6%. Of the men 55.6% received previous treatment for erectile dysfunction. Postoperative infection and device malfunction developed in 3.2% and 17.5% of the cases, respectively. Of the 207 men interviewed in phase 2, 86% still had an AMS 700CX penile prosthesis implanted, including 87.1% with erection suitable for coitus. Currently 79% of those with a device use it at least twice monthly and 88.2% would recommend an implant to a relative or friend. CONCLUSIONS: The AMS 700CX penile implant produced suitable erection and excellent patient satisfaction at long-term followup in the majority of men. Implant reliability is excellent and postoperative morbidity is low.

Adult↗
PubMed2001

Revision of shoulder replacement with a reversed shoulder prosthesis (Delta III): report of five cases.

The authors report on their experience in revision total shoulder arthroplasty using the Delta III shoulder prosthesis, a reversed constrained prosthesis which is known to give good functional results in the rotator cuff-deficient shoulder. It was implanted in patients with a failed total or hemishoulder prosthesis. The Constant-Murley score was used to assess the functional outcome. The preliminary results achieved in four patients (one bilaterally) are discussed and compared with the results of other treatments. After two years follow-up, the Constant-Murley score has improved from 14/100 preoperatively to 62/100 postoperatively. Although these initially good functional results may be temporary and loosening may occur over the longer term, the authors recommend the Delta III shoulder prosthesis as an alternative solution for revision shoulder arthroplasty.

Adult↗
PubMed2001

[Luxation of hip prosthesis].

BACKGROUND: Our aim was to elucidate the dislocation rate after total hip arthroplasty at Haugesund County Hospital, Norway. MATERIAL AND METHODS: Information was obtained from the Norwegian Arthroplasty Register and from hospital patient files. All 1,076 patients (781 female) operated at the hospital 1987-2000 were included. The ITH prosthesis was used in 545 patients and the Charnley prosthesis with a smaller head in 531 patients. RESULTS: 21 patients (2.0%) experienced dislocation after total hip arthroplasty, 17 during activities of daily living and three after a fall. 17 dislocations happened within six months postoperatively. The dislocation risk was smaller for women than for men (1.3% vs 3.7%, p = 0.01). Patients with a Charnley prosthesis had a greater risk for recurrent luxations than those with a ITH prosthesis (1.7% vs 0.2%, p = 0.01). INTERPRETATION: The rate of dislocation after total hip arthroplasty in this study is similar to that of other reports in the literature.

Adult↗
PubMedDate not supplied

Integration of laser surface digitizing with CAD/CAM techniques for developing facial prostheses. Part 1: Design and fabrication of prosthesis replicas.

PURPOSE: This article presents a novel manufacturing approach that integrates laser surface digitizing/scanning and computer-aided design (CAD) and manufacturing (CAM) to achieve automated fabrication of spatially and anatomically accurate extraoral facial prostheses. MATERIALS AND METHODS: Topologic data of the patient's face, including the site of deformity and the anatomy of a healthy "donor" organ, were acquired using laser surface digitizing. Two different CAD data manipulation techniques were developed to alleviate problems encountered in laser-digitized data sets. To reduce patient involvement, fitting of the prosthesis was conducted using a computer model of the patient's face. Once finalized, rapid prototyping techniques were employed to fabricate a master pattern to cast the final prosthesis. RESULTS: Three case studies involving different facial prostheses were conducted to evaluate the integrated manufacturing system. The results demonstrated the many advantages of the system for facial prosthesis production. CONCLUSION: With the new manufacturing approach, reduced patient discomfort, minimal dependence on the artistic skills of the prosthetist, and short turnaround times for prosthesis production can be expected.

Computer Simulation↗