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At least 163 records · Page 9Linked to original sources
PubMed2004

Effect of augmented cup fixation on stability, wear, and osteolysis: a 5-year follow-up of total hip arthroplasty with RSA.

To evaluate different modes of cementless fixation of hemispherical cups, we operated on 87 hips in 81 patients using 4 different means of cup fixation. The hips were randomly assigned to fixation with press-fit technique only (PF), or with augmentation with screws (S), pegs (P), or hydroxyapatite (HA) coating. The patients were evaluated with radiostereometric analysis (RSA) for cup migration and wear, conventional radiography for osteolysis, and Harris Hip Score for clinical outcome over 5 years. The fixation of the cups did not differ between the groups, but HA showed a tendency to decrease proximal migration. HA-coated cups displayed the best interface with hardly any signs of radiolucent lines, indicating a superior sealing effect of the HA coating. Cups with screws or pegs had more radiolucent lines and osteolytic lesions than the other groups. Radiolucent lines were correlated to higher proximal migration, young age, and female gender (r2=.2). The wear rate of the ethylene oxide-sterilized polyethylene liner was high (0.2 mm/y) but did not differ between the groups. Two cups with a perioperative fracture of the acetabular rim showed large initial migration but stabilized thereafter.

Aged↗
PubMed2004

Effect of ion implantation on the tribology of metal-on-metal hip prostheses.

Nitrogen ion implantation (which considerably hardens the surface of the bearing) may represent one possible method of reducing the wear of metal-on-metal (MOM) hip bearings. Currently there are no ion-implanted MOM bearings used clinically. Therefore a physiological hip simulator test was undertaken using standard test conditions, and the results compared to previous studies using the same methods. N2-ion implantation of high carbon cast Co-Cr-Mo-on-Co-Cr-Mo hip prostheses increased wear by 2-fold during the aggressive running-in phase compared to untreated bearing surfaces, plus showing no wear reductions during steady-state conditions. Although 2 specimens were considered in the current study, it would appear that ion implantation has no clinical benefit for MOM.

Arthroplasty, Replacement, Hip↗
PubMed2005

Successful reimplantation of a phrenic nerve stimulator after traumatic exteriorisation.

A quadriplegic patient experienced post-traumatic exteriorisation of the subcutaneous receiver of a phrenic pacemaker. In the absence of infection and stimulation dysfunction in the patient, the device was reimplanted with full success at 1 year. This strategy can, exceptionally, be considered if removal and subsequent implantation is impossible or refused.

Diaphragm↗
PubMedDate not supplied

Five- to thirteen-year follow-up of the GSB III total elbow arthroplasty.

Between 1988 and 1995, the senior author performed total elbow arthroplasty in 28 elbows (23 patients) with the GSB III prosthesis. At the most recent follow-up, 7 patients had died (9 elbows) and 1 had the implant removed because of a deep infection. The remaining 18 elbows (15 patients) were available for clinical and radiographic review at a mean period of 7.6 years (range, 5.5-11.9 years). All 15 patients were satisfied with the results of their elbow replacement, with a mean Mayo elbow performance score of 91 (range, 75-100). The mean flexion/extension and supination/pronation arcs improved by 33 degrees and 67 degrees, respectively. Radiographic follow-up demonstrated progressive loosening in only 1 patient and no progressive loosening in those with an adequate cement technique. Mild or moderate lysis of the distal humeral or proximal ulnar components was noted in 10 elbows, and severe lysis of the distal humerus was seen in 1. Of the patients, 6 (21%) had mild complications: triceps avulsions in 3, superficial wound infections in 2, and an undisplaced fracture of the distal humeral medial condyle in 1. In 4 patients (14%) complications developed requiring reoperation, including exchange of the polyethylene bushing because of wear, debridement of synovitis, resection arthroplasty for deep infection, and exploration of an ulnar nerve palsy. In 2 additional patients (7%), persistent ulnar nerve paresthesias developed postoperatively. Of the 28 elbow replacements performed with the GSB III prosthesis, only 1 required revision because of loosening at a mean follow-up of 7.6 years. The results of this series of GSB III elbow replacements in patients with rheumatoid arthritis demonstrate reasonable survivorship of this prosthesis.

Arthritis, Rheumatoid↗
PubMed2005

Exercise hemodynamics of bovine versus porcine bioprostheses: a prospective randomized comparison of the mosaic and perimount aortic valves.

OBJECTIVE: This prospective randomized study compares a porcine with a bovine bioprosthesis in the aortic position with regard to hemodynamic performance during exercise. METHODS: Between August of 2000 and December of 2002, 136 patients underwent aortic valve replacement with the porcine Medtronic Mosaic (n = 66) or the bovine Carpentier-Edwards Perimount (n = 70) bioprosthesis. Transthoracic echocardiography was performed to assess hemodynamic and dimensional data preoperatively and 10 months postoperatively; the latter follow-up included stress echocardiography with treadmill exercise. RESULTS: At rest and during exercise (25 and 50 W), there was a significant difference in mean pressure gradient between the bovine and the porcine valves with labeled sizes 21 and 23, with superiority of the Perimount prosthesis. There was no difference in effective orifice area and incidence of patient-prosthesis mismatch among all sizes. The left ventricular mass index decreased significantly within 10 months postoperatively in the size 23 bovine group and the size 25 porcine group. CONCLUSIONS: Our data show a significant superiority of pressure gradients for the bovine bioprosthesis, especially with small valve sizes, when compared with the porcine device, which is more distinctive during exercise.

Aged↗
PubMed2006

The use of prostheses in skeletally immature patients.

Prosthetic reconstruction in the skeletally immature patient is challenging because of the necessity to cope with expected disruption of limb growth after resection of one or more major growth plates and the high demands placed on implants by young patients. Although prosthetic reconstruction in children is fraught with many problems, it is usually possible to obtain a good functional limb at skeletal maturity. Extendable prostheses are readily acceptable to patients and their parents. The availability of noninvasive extendable prostheses is expected to lead to fewer complications, fewer surgical interventions, and even improved function. This article reviews the indication, evolution, and clinical and functional results of extendable endoprostheses, drawing from experience in the last 30 years of using such prostheses in children.

Adolescent↗
PubMed2004

Changes in keratoconic corneas after intracorneal ring segment explantation and reimplantation.

PURPOSE: To evaluate the outcome and potential reversibility of the changes induced in keratoconic eyes after intracorneal ring segment explantation. DESIGN: Retrospective, interventional case series. PARTICIPANTS: Five eyes of 4 patients who underwent uneventful implantation of one or two intracorneal ring segment segments for the correction of clear corneal keratoconus and who required explantation of one segment due to complications. MAIN OUTCOME MEASURES: Visual acuity, refraction, keratometric readings, and corneal topography. The follow-up was up to 1 year from the primary implantation procedure in all cases. RESULTS: Explantation was performed easily in all cases without intraoperative or postoperative complications. The segments were extracted due to migration and local melting. The visual, refractive, and topographic map findings regressed to approximate the original clinical situation before segment implantation. CONCLUSIONS: Intracorneal ring segments are safely and easily explanted from keratoconic eyes. Most of the visual, refractive, and topographic findings return to near the preimplantation levels.

Adult↗
PubMed2001

Experience with the 19-mm Carpentier-Edwards pericardial bioprosthesis in the elderly.

BACKGROUND: Valve replacement in small aortic root remains a surgical challenge. The objective of this study was to compare results of the 19-mm bioprosthesis with those of larger prostheses in the elderly. METHODS: The 443 patients, 70 years of age and older, who underwent aortic valve replacement with Carpentier-Edwards pericardial bioprostheses were reviewed. RESULTS: There were 93 patients with a mean age of 76+/-4 years with implantation of 19-mm prostheses and 350 patients with a mean age of 75+/-4 years with larger bioprostheses. Associated aortoplasty was performed in 10 patients (11%) with 19-mm bioprostheses and in 8 patients (2%) with larger bioprostheses (p = 0.001). There were 11 deaths (12%) within 30 days of surgery in patients with 19-mm prostheses and 22 deaths (6%) among those with larger prostheses (p = 0.1). The 7-year survival rate averaged 61%+/-7% in patients with 19-mm prostheses and 67%+/-4% in those with larger prostheses (p = 0.8). The 7-year freedom rates from all valve-related events averaged 96%+/-2% and 93%+/-2%, respectively (p = 0.6). CONCLUSIONS: Aortic valve replacement with the 19-mm Carpentier-Edwards pericardial bioprosthesis offers excellent midterm results in the elderly.

Actuarial Analysis↗
PubMed2001

Hemodynamic comparison of second- and third-generation stented bioprostheses in aortic valve replacement.

BACKGROUND: The hemodynamic performance of aortic replacement prostheses is of extreme importance. There is renewed interest in hemodynamics because of the influence of prosthesis-patient mismatch on left ventricular mass regression and the potential influence on survival. METHODS: The hemodynamic performance of the second-generation Carpentier-Edwards supraannular porcine and pericardial (Perimount) bioprostheses and the third-generation Medtronic Mosaic porcine bioprosthesis were compared for mean gradient and effective orifice area index. The effective orifice area index of at least 0.85 cm2/M2 was considered as lack of prosthesis-patient mismatch. The study group included included 53 patients with Carpentier-Edwards supraannular porcine, 48 with pericardial, and 98 with Medtronic Mosaic porcine bioprostheses. RESULTS: The mean gradients were not different between the prostheses by prosthesis size. The Medtronic Mosaic was not provided in size 19. The mean gradients for the prostheses, except in the very large sizes, were all double-digit values. The effective orifice area index was not different between the prostheses but there was a trend toward prosthesis-patient mismatch in smaller size prostheses. CONCLUSIONS: There was no apparent hemodynamic advantage between porcine and pericardial bioprostheses in the aortic position.

Aortic Valve↗
PubMed2001

Early experience with a quadrileaflet stentless mitral valve.

BACKGROUND: Presently no ideal prosthesis for mitral valve replacement exists. The quadrileaflet mitral valve (SJM-Quattro-MV; St. Jude Medical, Inc, St. Paul, MN) is a chordally supported stentless bioprosthesis. Due to its specific geometry it seems to be particularly suited for mitral valve replacement. METHODS: From March 1999 to October 2000, 12 patients (ages 71+/-2 years) received the SJM-Quattro-MV. Six patients suffered from valvular stenosis and 6 patients from incompetence. Preoperatively, all patients were in New York Heart Association functional class III, with left ventricular ejection fraction amounts of 54%+/-17%. RESULTS: Eleven patients received a medium size SJM-Quattro-MV and one patient received a large size SJM-Quattro-MV. Cross-clamp time was 99.8+/-4.9 minutes. Additional procedures were coronary artery bypass grafting (n = 3) and left atrial microwave ablation (n = 2). Postoperative mortality (n = 1) was procedure related. At follow-up of 11.6+/-5.4 months, all patients were well, the transvalvular pressure gradient was 5.0+/-1.4 mm Hg, and the effective orifice area 2.7+/-0.2 cm2. CONCLUSIONS: Our preliminary experiences with the SJM-Quattro-MV presented good clinical results and promoted an optimistic way of thinking about the further development of these valve prostheses.

Aged↗
PubMed1997

Effects of implant anchorage on midface prostheses.

STATEMENT OF PROBLEM: Acquired midface defects may produce functional and psychologic impairments that adversely effects a patient's quality of life. Conventional prostheses may lack adequate retention and stability, diminishing the patient's confidence that the prosthesis will remain in place during routine activities. PURPOSE: The experience with and patient response to endosseous implants in prosthetic restoration of midface defects is presented in this study. MATERIAL AND METHODS: Five patients in age from 36 to 88 years were treated with 19 titanium endosseous root-form implants to provide retention and stability for prostheses. Patients responded to a questionnaire rating overall use, effectiveness, and satisfaction of their prosthesis, before and after the use of implants. RESULTS: All 19 implants were judged to be osseointegrated at abutment connection. Of the 17 implants used prosthetically, 14 (82%) remained osseointegrated and 3 (18%) failed. Analysis of the questionnaire tends to indicate an improvement of the quality of life for the patients with an implant-retained prosthesis.

Activities of Daily Living↗
PubMed2000

Retrograde perfusion sphincterometry with a flexible cystoscope: method of troubleshooting the AMS 800.

We developed the technique of retrograde perfusion sphincterometry to troubleshoot the AMS 800 device. We implanted artificial urinary sphincters in men who were incontinent after prostatectomy and performed intraoperative retrograde perfusion sphincterometry. Retrograde perfusion sphincterometry using a flexible cystoscope is simple and allows early recognition of intraoperative urethral injury and mechanical malfunction.

Aged↗
PubMed2003

UHMWPE oxidation increases granulocytes activation: a role in tissue response after prosthesis implant.

Ultra-high molecular weight polyethylene (UHMWPE), a biopolymer widely used in orthopaedic implants, is oxidized during gamma-ray sterilization; such surface oxidation is considered as major responsible for inflammation and prosthesis failure. As granulocytes are involved in first contact inflammation, we have measured their oxidative burst by flow cytometry using dihydrorhodamine 123 (DRH) to evaluate their activation following contact with normal and oxidized UHMWPE. Peripheral blood cells (obtained by lysed blood) were loaded with DRH, seeded onto polystyrene, normal and heat-oxidized UHMWPE disks for 30min and then collected for analysis. Granulocytes were individuated using FSC and SSC signals and their cell associated green fluorescence was analyzed. Both normal and oxidized UHMWPE stimulated granulocytes activation as showed by the mean fluorescence emitted (109.3+/-3.8 and 150.1+/-9.2, respectively) compared to control samples (81.6+/-0.3). Moreover oxidized UHMWPE activated a significantly higher percentage of granulocytes (73.35+/-5.2%) compared to not-oxidized UHMWPE (21.5+/-3.8%). UHMWPE surface oxidation responsible for increased granulocyte activation seems to play a role in tissue response to implants.

Adult↗
PubMed2004

The induction of MMP-9 release from granulocytes by vitamin E in UHMWPE.

Ultra-high molecular weight polyethylene (UHMWPE) is a biopolymer widely used in orthopaedic implants and its oxidation is considered as major responsible for inflammation and the prosthesis failure. We have studied the effect on the activation of resting human granulocytes of the addition of Vitamin E (Vit.E, alpha-tocopherol), a natural biological antioxidant and antiinflammatory agent, to UHMWPE. We have measured changes in granulocytes morphology and respiratory burst by flow cytometry using Dihydrorhodamine 123 and matrix metalloproteinase 9 (MMP-9, gelatinase B) release and activity in the growth medium using substrate zymography following contact (60 min at 37 degrees C) with cell grade polystyrene (PS), normal UHMWPE (PE) and Vit.E added UHMWPE (PE Vit.E). FTIR analyses showed that the surfaces of PE and PE-Vit.E were not significantly different. PS, PE and PE Vit.E did not alter granulocytes morphology and respiratory burst as showed by the mean fluorescence emitted (PS=12.0+/-0.1, PE=13.0+/-0.4, PE Vit.E=14.5+/-0.1). PE Vit.E was able to increase MMP-9 release compared to PS and normal PE (215+/-16% of the control, p<0.001). The PE Vit.E-induced MMP-9 release was abolished by okadaic acid (0.5 nM), suggesting a direct role of Vit.E in the phenomenon.

Adult↗