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At least 1,423 records · Page 79Linked to original sources
PubMed1999

Polyethylene wear and calcar osteolysis.

We have examined retrospectively the correlation between linear wear of the polyethylene socket and calcar height loss (osteolysis) in 266 patients with 410 total hip arthroplasties who were followed up for a minimum of 10 years. A positive correlation existed between wear and osteolysis. The correlation was stronger in patients with osteoarthrosis. Simultaneous bilateral hip arthroplasty showed no difference in the relationship between polyethylene wear and calcar height loss when comparing the right and left hip. There was poor correlation between calcar height loss and wear in patients with rheumatoid arthritis. Our findings support the theory that femoral osteolysis in the total hip arthroplasty is related to the amount of liberated particles generated by the wear of components. The poor correlation found in cases with rheumatoid arthritis could be related to suppression of the immune response in these patients.

Adult↗
PubMed2001

Comparative wear and wear debris under three different counterface conditions of crosslinked and non-crosslinked ultra high molecular weight polyethylene.

The wear debris generated from ultra high molecular weight polyethylene (UHMWPE) have been recognised as one of the major causes of failure in total hip replacements (THR). It is essential to reduce the wear debris generated from UHMWPE acetabular cups in order to minimise this problem. Debris in the submicron size range is believed to have greater osteolytic potential. It is now known that crosslinked UHMWPE acetabular cups have reduced volumetric wear rates but little is known about the influence of crosslinking on the size and morphology of the wear debris. In this study, the wear of grade GUR 1020 crosslinked (vacuum gamma irradiated), GUR 1120 crosslinked (acetylene enhanced irradiated) and non cross linked (ethylene oxide sterilised) GUR 1020 UHMWPE was compared in multidirectional pin-on-plate wear tests under three different counterface conditions (smooth, isotropically rough and scratched counterfaces). Multidirectional motion was chosen because this motion was closer to the relative motion in the natural hip. From this study, better wear resistance of crosslinked UHMWPE compared with non-crosslinked UHMWPE was demonstrated for the smooth counterface conditions. However, in the rough and scratched counterface conditions, the vacuum gamma irradiated crosslinked material produced significantly higher wear rates than the non-crosslinked material. The analysis of the wear debris showed that the majority of the volume of the acetylene enhanced crosslinked UHMWPE wear debris was in the most biologically active size range (0.1 to 0.5 microm). In contrast, the non-crosslinked material and the vacuum gamma irradiated crosslinked material had a greater proportion of the volume of the debris in the larger size ranges which are less biologically active. This has important implications for its osteolytic potential.

Acetylene↗
PubMed2006

[Wear and periprosthetic osteolysis of modular, hemispheric acetabular cups].

Osteolysis associated with polyethylene wear has become one of the most prevalent complications associated with uncemented modular, hemispherical cups. Sixty-five consecutive total hip arthroplasties (ABG i, Howmedica, Stryker) were followed 6-12 years. Cumulative survivorship for the cup was 55.7% after 10 years. There were 20 cups revisions because of polyethylene wear and periprosthetic osteolysis (14 cups) or cup loosening (6 cups). Stability was assessed intraoperatively, 14 cups were revised, whereas 6 new polyethylene cups were cemented into stable metal-back of acetabular component. The average annual wear of revised cups was 0.32 mm. The annual wear of not revised cups was 0.12 mm. The differences were statistically significant (p = 0.002). The mean area of osteolysis was 472 mm2 (SD 257 mm2). There was no significant correlation between wear and area of osteolysis. There was significant correlation R = 0.54, p = 0.014) between time to revision and area of osteolysis. There were no significant differences of wear of polyethylene inlay or area of osteolysis between stable and unstable acetabular cups.

Acetabulum↗
PubMedDate not supplied

Results of treatment of 20 patients with implant-retained auricular prostheses.

A prospective study of 20 patients receiving rehabilitation for a missing external ear revealed the failure of three flanged implants in a total of 60 placed for the support of a prosthesis and 10 for retention of a bone-anchored hearing aid. Factors limiting an optimal outcome were health of the cutaneous cuff around the abutments, bonding of the silicone ear to the acrylic-resin substructure, and the ability to minimize disfigurement of a congenitally deformed face.

Acrylic Resins↗
PubMed1994

[The evaluation of the mechanism of mitral bioprosthesis malfunction by transesophageal echocardiography].

OBJECTIVES: The aim of this study was to assess the usefulness of transesophageal echocardiography for detection of the mechanism of dysfunction in bioprosthetic valves in the mitral position. METHODS: Transthoracic and transesophageal echocardiograms were performed in 40 patients (mean age 61 +/- 12 years) with a dysfunctional bioprosthetic mitral valve. Echocardiographic results were compared to surgical findings in all except 1 patient. RESULTS: All 9 patients with stenotic degenerated bioprosthesis were diagnosed by transthoracic and transesophageal echocardiography. Mechanism of dysfunction in the remaining patients were as follows: cusp tear or rupture in 18, dehiscence in 4 and endocarditis in 6. Transthoracic and transesophageal echocardiography visualized respectively: 8 (44%) and 15 (83%; p < 0.05) with cusp tears or ruptures; 3 (75%) and 3 (75%) with dehiscence; 3 (50%) and 6 (100%; p < 0.1) with endocarditis. One patient with pannus formation and 1 of 2 bioprosthetic thrombosis were not correctly identified by either echocardiographic technique. CONCLUSIONS: Transesophageal echocardiography is suited for the assessment of mechanism of mitral regurgitation and for the diagnosis of vegetations in most of patients with bioprosthetic mitral valves. Transesophageal echocardiography adds little information to the transthoracic study in the evaluation of patients with stenotic bioprosthetic mitral valves, particularly in calcified degeneration.

Adult↗
PubMed2004

Allograft-prosthesis composite for revision of catastrophic failure of total elbow arthroplasty.

BACKGROUND: Revision of a failed total elbow arthroplasty is a challenging procedure, often associated with bone deficiency. The purpose of this investigation was to review our experience with a composite allograft-implant reconstruction for patients with a failed total elbow arthroplasty. METHODS: Thirteen patients (thirteen elbows) in whom a total elbow arthroplasty had failed, primarily as a result of loosening of the humeral or ulnar component, were operated on with use of an allograft-prosthesis composite; the composite was placed on the humeral side in four of these patients and on the ulnar side in nine. The delay between the last total elbow arthroplasty and the allograft-prosthesis-composite procedure averaged eight years. RESULTS: At an average of forty-two months after the revision, the Mayo Elbow Performance Score was excellent for four elbows, good for three, fair for one, and poor for five. Nine of the thirteen patients had no or only slight pain in the elbow. The mean arc of flexion was 97 degrees, with an average of 28 degrees (range, 0 degrees to 60 degrees ) of extension to 125 degrees (range, 100 degrees to 140 degrees ) of flexion. There were seven complications affecting seven elbows, and five of the seven required a revision procedure. Deep infection developed in four elbows, and the allograft-prosthesis composite had to be removed from three. Two nonunions occurred at the allograft-humeral junction. CONCLUSIONS: An allograft-prosthesis composite can be a valuable option in selected patients with a failed total elbow arthroplasty with massive bone loss. The union and implant survival rates are high. Deep infection remains the main complication. Hence, we recommend the pursuit of other revision options, such as strut graft reconstruction, whenever possible before resorting to the use of an allograft-prosthesis composite in the surgical treatment of a failed total elbow arthroplasty with massive bone loss.

Adult↗
PubMed2005

Survivorship of the Charnley Elite Plus cemented femoral stem.

We report the results of the Charnley Elite Plus femoral stem in multiple surgeons' hands at a minimum of 3 years after implantation. Over a 4-year period, 244 patients underwent 268 primary hip arthroplasty procedures using this particular stem. Patients underwent postal and radiographic review at a mean of 4.5 (3.0--6.8) years following their arthroplasty. There were five revision procedures for aseptic loosening (5/268; 1.9%). Radiological assessment revealed gross radiological failure in a further 12 femoral stems (12/208; 5.8%). In the best case scenario, using revision for aseptic loosening as the endpoint, the survivorship for this period was 98.1%. If radiographic failures are incorporated into this endpoint, survivorship is 93.1%. This failure rate at an early stage raises concerns as to the long-term survivorship of this prosthesis.

Adult↗
PubMed1987

Asynchronous primary valve failure in patients with porcine bioprosthetic aortic and mitral valves.

Seventy-three patients with aortic and mitral porcine bioprosthetic valves (PBV) have been followed for up to 14 1/2 years. In that time, 11 patients have undergone replacement of one or more PBVs for primary tissue failure. Three patients underwent repeat aortic and mitral valve replacement for synchronous PBV failure. Two patients underwent aortic valve replacement alone and six had only the mitral PBV replaced. The one survivor of the repeat aortic valve replacement has a normally functioning mitral PBV, which has now been in place for 48 months. The six patients who had their mitral PBVs replaced have normally functioning aortic PBVs that have now been in place for periods from 96 to 176 months. Our experience shows that with asynchronous PBV failure only the dysfunctioning valve needs to be replaced. Prophylactic PBV replacement is not warranted if the prosthesis demonstrates normal hemodynamics on cardiac catheterization and normal structure on the echocardiogram, regardless of the length of time it has been implanted.

Actuarial Analysis↗
PubMed1994

Early and late outcome after reoperation for prosthetic valve dysfunction: analysis of 549 patients during a 26-year period.

Factors influencing operative mortality and late survival of 549 patients undergoing a first reoperation for prosthetic valve failure during the interval from 1966 to 1992 were analyzed; 347 patients had reoperation on a mitral prosthesis, 173 on an aortic prosthesis and 29 on both aortic and mitral prostheses. Univariate analysis showed that hospital mortality was higher in patients in functional class IV compared with those in class II-III (35% vs. 8%, p < 0.001), in those who required emergency reoperation (57% vs. 11%, p < 0.001), in those reoperated for endocarditis (59%) or valve thrombosis (43%) compared with those reoperated for structural valve deterioration (9%, p < 0.001), and in those with a failing mechanical prosthesis compared to patients with a bioprosthesis (21% vs. 10%, p < 0.05). Furthermore, operative mortality decreased from 41% in the period from 1966 to 1977, to 12% from 1977 to 1983 and to 8% from 1984 to 1992 (p < 0.001). Hospital survivors were followed from 0.1 to 22 years (mean follow-up 11 +/- 5 years) with an overall actuarial survival at 15 years of 24 +/- 5%. At 15 years actuarial survival is 24 +/- 5% for patients in preoperative functional class II-III and 20 +/- 6% for those in functional class IV (p < 0.05). It is concluded that in prosthetic valve recipients both early and late outcome is greatly influenced by preoperative clinical status. Increasing surgical experience, better myocardial protection and patient management have contributed to reducing the operative risk. More accurate patient follow up and possibly earlier reoperation might also improve the long term outcome.

Adolescent↗