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Results of histological grading on 100 cases of hip prosthesis failure.

One hundred cases of hip prosthesis failure were classified on the basis of the different types of tissue reaction occurring around alloplastic material. The results revealed infectious phlogosis in 32% of the cases, phlogosis due to wear in 42%, phlogosis due to allergy in 1% and mixed phlogosis in 25%. The distribution of the type and degree of intensity of the phlogosis, in relation to the duration of the implant, is also highlighted. This new grading technique yields reproducible results.

Biocompatible Materials

Isolated mitral valve replacement. With Carpentier-Edwards bioprosthesis :independent risk factors for long-term survival and prosthesis failure.

From 1976 through 1986, 188 patients (female/male ratio: 2/1, age 20-77 years, mean 58 years) with isolated mitral valve disease underwent valve replacement using the Carpentier-Edwards porcine bioprothesis (CEPB). Nine hospital deaths (4.8%) were excluded from further analysis. Follow-up was 0.2-11.3 years (mean 5.2 years); preoperatively, 74% had atrial flutter/fibrillation, and 75% were in NYHA-classes III-IV. All patients were put on life-long coumadin treatment. Preoperative predictability of long-term survival and prosthesis-related complications was examined using Cox regression analysis. Five preoperative variables were found to have independent predictive value as regards long-term survival: myxomatous degeneration of the valve (p = 0.002), chronic regurgitation (p = 0.003), age (p = 0.004), NYHA-class III-IV (p = 0.05), and atrial flutter/fibrillation (p = 0.05). A prognostic index calculated form the final Cox model identified six risk groups (I-VI) having cumulative 10-year survivals +/- SE of: I (n = 9) 100%, II (n = 10) 90 +/- 9%, III (n = 30) 73 +/- 10%, IV (n = 70) 51 +/- 9%, V (n = 43) 17 +/- 10%, and VI (n = 17, 7-year survival) 16 +/- 13% (p less than 0.0001). The incidence of late valve-related complications (%/patient-years) were: hemorrhage, 1.2; thromboembolism, 0.5; Endocarditis, 1.0; paravalvular leak, 0.2; and primary tissue failure, 1.5. Previous closed comissurotomy adversely influenced the occurrence of hemorrhage, while calcified mitral annulus were predictive of endocarditis. Younger age (less than or equal to 45 years) had a strong predictive influence of primary tissue failure.(ABSTRACT TRUNCATED AT 250 WORDS)

Bioprosthesis

The pathology of the joint tissues and its clinical relevance in prosthesis failure.

Thirty-four hip and knee total arthroplasty failures due to infection, loosening, intractable pain and dislocation were examined for synovial and capsular tissue debris. Simiquantitative assessments were made for metal polyethylene, acrylic and cellular debris and inflammation. The most important finding was that in the amounts normally shed into joints, debris particles do not appear to stimulate a polymorphonuclear response. The magnitude of this response correlates best with clinical and/or bacteriological evidence of infection. The quantity of acrylic particles could be correlated with clinical evidence of loosening. Since the correlation between infection and polymorphonuclear leukocytes, debris particles, and the reasons for failure is high, frozen section may aid the surgeon in determining the methods and timing of revision operations.

Acrylates

Incidence of metal sensitivity in patients with total joint replacements.

Sensitivity to chromium, cobalt, nickel, molybdenum, vanadium, and titanium was studied by patch tests in 50 patients who had received total joint replacements. Nineteen (38%) were sensitive to one or more of the metals. In 23 patients non-traumatic failure of the prosthesis had occurred, and 15 of these patients were sensitive to metal. Out of 27 patients with no evidence of prosthesis loosening, four were sensitive to nickel and cobalt or nickel only. Dermatological reactions occurred in 13 patients after surgery; in only eight, however, was there evidence of metal sensitivity. These findings indicate that metal-on-metal total joint replacements may sensitise the patient to metals contained in the prosthesis. Although there is a high incidence of prosthesis failure among metal-sensitive patients it remains uncertain whether the loosening causes the sensitisation or vice versa.

Chromium

Reoperation for prosthetic heart valve replacement.

From 1974 to 1984, 847 heart valve replacement operations were performed with 1005 prosthetic valves. Thirty-nine (4.6%) were reoperations with 43 prosthetic valve replacements (PVR), on 38 patients. Thirty-three patients had received their initial valve replacement in our hospital and 5 elsewhere. Twenty additional cardiac procedures were required, concomitantly with the prosthesis replacement. Twenty-three patients underwent replacement of a mechanical prosthesis (61%) an average of 4.3 years after initial implantation and 15 patients a bioprosthesis (39%) after 2.8 years. Indications for PVR were endocarditis in 15 patients (39%), prosthesis failure in 13 (34%), periprosthetic leak in 7 (18%), thrombosis in 2 (5%), and a left ventricle subannular aneurysm in 1 (3%). Preoperatively 4 patients were in NYHA functional class II (11%), 15 in class III (39%) and 19 in class IV (50%). Six patients died early postoperatively (15.8%) Various risk factors were analyzed. The early mortality rate was 22% for mechanical prosthesis replacement and 7% for bioprosthesis; 11% for aortic position, 13% for mitral position and 50% to 100% for double valve replacement; 23% for non-elective and 6% for elective operations; 10% for patients with only an initial valve replacement and 43% with additional previous valve operations; 18% for active endocarditis, 15% for prosthesis failure, 14% for periprosthetic leak, 0% for thrombosis and 100% for subannular aneurysm; 0% for patients in class II, 7% in class III and 26% in class IV; 6% in patients with an aortic cross-clamp time less than 2 hours and 24% with more; 27% prior to 1981 and 9% during the last 4 years; and finally 50% in patients over the age of 60.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent

Dissociation of the tibial component in total knee replacements.

Dissociation of the polyethylene component from its metal backing in total knee arthroplasty is a recognized problem regarding the patella. Two cases of dissociation of the metal-backed tibial component from its polyethylene articulating surface presented symptoms of prosthesis failure: persistent pain, swelling, sensations of instability, and gait difficulty. Investigations ruled out prosthesis malalignment, loosening, and sepsis. Precise diagnosis of dissociation of the tibial component was made by diagnostic arthroscopy.

Adult

The radiographic resolution of beads from porous coated joint prostheses.

While there have been reports of the 750 microns chrome-cobalt beads disassociating from the PCA type prosthesis, failure of the 200 microns bead has not been documented despite reports of failed prosthesis, which use the smaller bead. As a result of the negative reports, the hypothesis was posed as to the limit of resolution in the image of the standard clinical radiographical film. To test the hypothesis, chrome-cobalt beads, ranging in size from 200 to 700 microns, in differing configurations were placed adjacent to a femoral prosthesis that had been implanted into a cadaveric specimen. Using standard clinical radiographic technique, differing exposures were made of the configurations. The results demonstrated that beads or a conglomerate of beads smaller than 300 microns could not be resolved and were therefore invisible and unrecordable. The clinical significance is to question whether all porous-coated prostheses shed metal alloy particles, some of which are radiographically undetectable due to the limitations of their resolvable size.

Arthrography

Lymphocytes in pseudomembranes of late prosthetic joint failure.

The pseudomembrane formed in association with late aseptic prosthesis failure contains a mixed giant cell and histiocytic infiltrate with variable numbers of lymphocytes. Immunolabelling with a panel of antibodies on paraffin sections was undertaken to define the nature of the lymphoid infiltrate in 19 cases. In all cases, the predominant lymphoid cell was a memory (CD45RO+, CD45RA-) T-cell. B-cells were rare. Tissue from patients with rheumatoid arthritis (RA) contained greater numbers of T-cells when compared with patients with osteoarthritis (OA), suggesting that the intensity of the lymphoid infiltrates reflects the underlying joint disease rather than necessarily being part of a hypersensitivity response to wear debris.

Aged

[Metal or plastic endoprostheses in malignant obstructive jaundice. A randomized and prospective comparison].

In a prospective randomized trial 58 patients (24 men, 34 women, mean age 67 +/- 13 [42-89] years) with inoperable malignant jaundice were treated with synthetic (S; n = 29) or expanding metal endoprostheses (M; n = 29). After endoscopic retrograde cholangiopancreatography patients were divided into a group with hilar (K: n = 7; M: n = 6) or distal involvement (K: n = 22, M: n = 23). In two cases with hilar involvement (28%) a synthetic endoprosthesis could not be implanted, while early prosthesis occlusion (after 2 days) was observed in one case. But in this group it was possible to implant all metal stents. In the group with distal involvement both synthetic and metal endoprostheses were successfully implanted. In the M group the proportion of patients with prosthesis failure (13.6%) was significantly higher than in the S subgroup (40.9%). The cholangitis incidence was 9% in the M group, significantly less (P less than 0.05) than in the K group (40.9%). Duration of hospital stay to treat prosthesis-related complications was significantly less in the M group (average 2.9 days) than the K group (12.9 days). It would be a great advance in palliative tumour treatment if it were possible significantly to reduce, by means of metal stents, the incidence of late cholangitis and the duration of hospital stay necessary to treat late complications. But improvement in the technique of implanting metal stents would be essential before their general use in distal lesions can be recommended.

Adult

Durability of glutaraldehyde-fixed pericardial valve prostheses: clinical and animal experimental studies.

Bovine pericardium has been widely employed as a xenograft tissue for the manufacture of bioprosthetic valve substitutes. Early three-leaflet valve models showed poor tissue preservation and shortcomings in valve design, which accounted for tissue wear and prosthesis failure due to cuspal tear. Reducing the number of cusps in the unicusp pericardial valve has proved unsuccessful due to stretching of the single pericardial leaflet with consequent valvular incompetence. The new generation of pericardial xenografts present basic changes in valve design and optimal tissue preservation after industrial processing, with no evidence of leaflet tear at medium term follow up. However, clinical experience is limited and, similarly to porcine xenografts, dystrophic calcification still appears to be a major problem.

Adult

Use of penile prostheses to maintain external condom catheter drainage in spinal cord injury patients.

This is a retrospective analysis of 79 spinal cord injury patients who have had penile implants from one to 14 years. The primary indication for implants was the loss of condom catheter with a small retractile penis. Mean period after injury to when the implants were placed was 8.24 years (range 1-21 years). Mean total length of time the implants have been followed was 7.08 years (1-14 years). Sixty patients responded to our detailed questionnaire and they have been subjected to further analysis: prior to the implant 46 patients (77%) frequently lost their condoms. Fourteen of the patients (23%) had indwelling catheters, and 3 (5%) had a suprapubic cystostomy since they could not retain an external condom for urinary drainage because of retraction of a small penis. Post implant, 81% of patients had no accidents involving condom loss, while 19% still lost condoms. All indwelling catheters could be removed except for one patient who continued with a suprapubic catheter following transurethral sphincterotomy (TURS) and a penile implant. Sixty-eight percent used the implant for sex and felt their wives were satisfied. Patient satisfaction survey showed a markedly increased self esteem, increased mobility without fear of condom loss, and an improved sex life. Overall, the long term prosthesis failure rate was 8%. The specific infection complication rate was less than 2%. The Flexirod semirigid, hinged prosthesis proved ideal in meeting the requirements for these patients.

Adult

Morphologic findings and causes of failure in 24 explanted Ionescu-Shiley low-profile pericardial heart valves.

From 1981 to 1987 just over 608 Ionescu-Shiley low-profile bovine pericardial bioprostheses were implanted at the Toronto Hospital. Twenty-four prostheses (11 aortic and 13 mitral) were surgically explanted from 1988 to 1990 from 20 adults (10 men and 10 women). Prosthesis failure was caused by primary tissue failure in 17 valves or by other mechanisms in seven valves. Variable degrees of tissue failure were also seen in four of the seven valves from the latter group. Primary tissue failure was characterized by fluid insudation between collagen bundles, para stent post tears (alignment stitch related, 20 valves), cusp perforation with prolapse, and calcification. The earliest cusp tears occurred at 28 months. Calcification (10 of 24 cases) was minimal in seven of 10 valves (occurring primarily at the margins of the torn cusp), moderate in two, and severe in one. Tissue overgrowth (pannus) was seen in all but three prostheses. Like its predecessor, the Ionescu-Shiley standard pericardial valve, this prosthesis failed at 2 to 5 years largely due to design-related (alignment stitch) causes and tissue degeneration. Calcification was less prominent, while tissue overgrowth (pannus) was more marked.

Adult

Lipid accumulation in prosthetic vascular grafts. Experimental study.

The present study demonstrates that the endoprosthetic tissue, developed at the contact of Dacron and Gore-Tex vascular prostheses replacing the infrarenal aortae of healthy dogs, presents a particular lipidic pattern as compared with the adjacent intimal arterial layer. The modified lipidic pattern is characterized by a significant increase in the total amounts of cholesterol, phospholipids, and triglycerides, despite a normal lipidic plasma profile. Histochemical studies showed that lipid droplets are accumulated in the cytoplasm of deeply situated cells and in the extracellular matrix. These findings support the idea that lipids may be trapped within the pseudo-intima of synthetic vascular grafts, even in the absence of a major plasma lipid disorder, and contribute to the prosthesis failure.

Animals

Mechanical failure of OmniPhase penile prosthesis.

We report a case of mechanical failure due to cable breakage in both cylinders of an OmniPhase penile prosthesis. The failure occurred six weeks after implantation and was manifested by inability to activate the device. X-ray films showed cable fracture at the point of insertion into the activator mechanism bilaterally. This failure appears to be an isolated episode, and the prosthesis has been successfully replaced with a similar device.

Erectile Dysfunction

Endoprosthetic replacement for stage IIB osteosarcoma.

Over an eight-year period, 100 patients with IIB osteosarcoma have been managed. Eighty-one were treated with limb-salvage procedures, 78 of which involved reconstruction utilizing endoprostheses. Only 19 patients received amputation as the primary treatment for local control. Since 1984, all patients received preoperative and post-operative adjuvant chemotherapy. Those patients who received chemotherapy had a statistically significant improvement in five-year survival over those who did not (57% and 32%, respectively, p = 0.014). The functional results were good overall, with excellent results seen in distal femoral reconstruction. Twenty-eight of the 78 patients treated with endoprosthetic reconstruction experienced 30 complications (36%). Mechanical failure was the most common complication (10%) but was generally correctable. The local recurrence rate was 5% and the infection rate was 3%. Local complications were manageable. A statistical analysis revealed that the relative risk of patient death was 2.5 times higher than prosthesis failure for the 78 patients with endoprosthetic reconstruction. The intermediate-term results, with a median follow-up period of 43 months, remains encouraging.

Adolescent

Thrombotic disc impediment in a Medtronic-Hall aortic valve prosthesis diagnosed by Doppler echocardiography followed by successful reoperation.

A case with impeded disc movement caused by thrombus formation in a Medtronic-Hall aortic valve prosthesis is reported. A correct diagnosis, including both mechanism and severity of the prosthesis failure, was established by Doppler echocardiography. The patient was promptly referred for surgery without invasive or other supplementary investigations.

Aortic Valve