Well-functioning Prostheses Research Articles

Surgical valve replacement in adults late after total cavo-pulmonary connection/Fontan procedure.

There is dearth of data on long-term outcomes of systemic semilunar (SS) or atrioventricular (AV) valve operation in adult patients with a Fontan circulation. We describe a single-centre experience of adults who underwent valve surgery late after a Fontan procedure. We retrospectively reviewed all patients with a Fontan circulation who had a reoperation for severe valve disease during adulthood in our centre. Demographic, anatomical, clinical and periprocedural data and long-term outcome were retrospectively retrieved from our dedicated electronic hospital database and examined. Out of 233 adults with a Fontan operation, 8 (7 males [88%]) had valve surgery during the study period. Indication for surgery was severe symptomatic valve regurgitation in all patients (of the SS valve in seven cases and of the left AV valve in 1). Mechanical prosthesis was implanted in all cases. At a median follow-up of 10 years (interquartile range 5-20), one patient died due to hepatitis C virus infection. All the remaining 7 patients experienced a significant improvement of the New York Heart Association class compared to the pre-operative state (P = 0.015); echocardiography showed stable systemic ventricle ejection fraction in absence of volume overload (50.1 ± 7.9% vs 51.6 ± 8.7%, P = 0.399) and well-functioning prostheses. No patient needed further operation nor heart transplantation. Surgical SS valve replacement late after a Fontan operation in highly selected adult patients with valvular regurgitation performed in a tertiary dedicated centre resulted to be safe in our population and conveyed clinical benefit. Close monitoring of all Fontan patients developing valvular dysfunction is warranted, whereas future prospective research may refine selection criteria, optimal timing and outcomes.

Subjective and objective evaluation of masticatory function in patients with bimaxillary implant-supported prostheses.

People perform poorly in masticatory function tests despite well-functioning prostheses. However, it is unclear whether there is an agreement between subjective and objective measures of mastication. To investigate the association between subjective and objective measures of masticatory function in patients with bimaxillary implant-supported prostheses. An experimental group (n= 25, age=70.6± 7.5 years, eight women) with bimaxillary implant-supported fixed prostheses and a control group (n= 25, age=69.0± 5.3, 13 women) with natural dentition were recruited. The participants in the experimental group were included if they had been using the prosthesis for at least a year and had no obvious complaints with their prostheses. The control group was people with natural dentition and without any prostheses or complaints related to the masticatory system. The masticatory function was evaluated objectively with food comminution and mixing ability tests, and subjectively with jaw function limitation scale (JLFS) and oral health impact profile (OHIP). The experimental group performed poorly in both objective tests (p < .001). However, there was no significant differences between the two groups in total JFLS (p= .114) and OHIP (p= .312) scores. Though, there were certain positive correlations between the food comminution test and JFLS subdomains in the control group, and a positive correlation between food comminution test and specific subdomains of OHIP in the experimental group indicating poor correlation between the subjective and objective measures. Although patients with implant prostheses show poor masticatory performance, there is no agreement in the objective and subjective measures of mastication.

Assessment of masticatory function in older individuals with bimaxillary implant-supported fixed prostheses or with a natural dentition: A case-control study

Statement of problemA clinical assessment of the masticatory performance of edentulous people treated with bimaxillary implant-supported fixed prostheses is lacking. PurposeThe purpose of this case-control study was to compare the masticatory performance of edentulous people treated with bimaxillary implant-supported fixed prostheses to that of those with a natural dentition by using a simplified comminution test with hard viscoelastic test food and a mixing ability test. Material and methodsThirty-six participants were recruited and divided into 2 equal groups (n=18) based on their dental status. The experimental group (7 women, mean ±standard deviation age=69.8 ±7.5 years) had bimaxillary implant-supported fixed prostheses, and the control group (9 women, mean ±standard deviation age=68.3 ±5.6 years) had a natural dentition. A hard viscoelastic food comminution test and a mixing ability test with 2-colored chewing gum were performed in both groups. The number and total area of the particles during the comminution test and the variance of hue during the mixing ability test were measured. The data were analyzed with the parametric (paired t test) and nonparametric (Mann-Whitney U) tests to assess differences between the groups (α=.05). ResultsThe experimental group exhibited significantly fewer pieces in the food comminution test than the control group (P=.001). The experimental group also showed significantly higher variance of hue values than the control group (P<.001). ConclusionsPatients treated with bimaxillary implant-supported prostheses had reduced masticatory performance in comparison to those with a natural dentition, despite having been provided with satisfactory and well-functioning prostheses.

Mandibula-rezekált páciens protetikai ellátása implantációs fogpótlással

A maxillofaciális régióban a különböző daganatos kórképek gyógyítása során végzett radikális, csonkoló műtétek; balesetek,roncsolásos sérülések helyreállítása komplikált rehabilitációs technikákat igényel. Az alsó állcsont és az annakrégiójába tartozó lágyrész-képletek esetében a defektusok megszüntetése igen nehéz feladat. Amennyiben a mandibulafolytonossága sebészi módszerekkel nem biztosítható, a protetikai ellátás során további akadályokkal szembesülünk. Haa rágószerv-rendszer integritása, funkcionális egysége megbomlik, nemcsak a kedvezőtlen klinikai anatómiai viszonyok(beszűkült, esetleg részlegesen megszűnt vestibularis áthajlás, heges bucca stb.) jelentenek kihívást, hanem az állkapocspatológiás mozgása is kialakul, a temporomandibuláris ízület működése az érintett oldalon gyakorlatilag megszűnik, azellenoldalon viszont túlterheltté válik. Ilyen esetekben komoly kihívás egy működőképes fogmű kivitelezése, ebben nagysegítséget nyújt az implantációs protetika, amelynek tárháza nélkül szinte lehetetlen feladat a korrekt ellátás.

Changes in serum chromium levels over 12 years after Metasul metal-on-metal total hip arthroplasty

We reported the longitudinal changes in serum chromium levels over a minimum of 7 years postoperatively in five men and 25 women with a mean age of 60.3 years after primary unilateral total hip arthroplasty with a Metasul metal-on-metal articulation. The serum chromium ion level showed little variation (0.6–1.2 μg/L) from 2 to 12 years postoperatively in 16/30 patients after unilateral primary Metasul metal-on-metal total hip arthroplasty. On the other hand, the serum chromium level stayed high or showed gradual elevation in 8/30 patients, even though they had well-fixed and well-functioning prostheses.

Quadruple Valve Replacement for Carcinoid Heart Disease.

IntroductionCarcinoid heart disease most frequently involves the tricuspid or, more rarely, the pulmonary valve and presents with right heart failure as 5-HT is metabolized by the lung. Left-sided valve involvement is quite rare. We describe our experience of 3 patients presenting with heart failure secondary to carcinoid heart disease affecting all four cardiac valves. There are only four previous isolated case reports in the literature.MethodsAll three patients underwent quadruple valve replacement during a single operation. Right ventricular outflow tract reconstruction with a pericardial patch was performed in all patients. For 24 hours prior to surgery, all patients received intravenous octreotide, which continued in intensive care for at least 24 hours.ResultsMean cross-clamp and bypass times were 175 (range 164-197 minutes) and 210 (range 195-229 minutes) minutes, respectively. Mean intensive treatment unit (ITU) and inpatient stays were 2.3 (range 2-3 days) and 12 (range 9-16 days) days, respectively. One patient was reopened for bleeding 4 hours postoperatively from a ventricular pacing wire site. None required a permanent pacemaker postoperatively. There were no other complications in any patient. The quality of life was excellent at 6-16 months clinic follow-up as they were in NYHA 1. Postoperative echocardiography showed no paravalvular leaks and well-functioning prostheses in all cases.ConclusionSurgery to replace all four valves is feasible with excellent medium-term survival and a very low rate of complications. Patients with carcinoid heart disease should always be considered for surgery irrespective of the extent of valvular involvement.

Ultrasound Screening for Adverse Local Tissue Reaction after Hip Arthroplasty

Early detection of adverse local tissue reaction (ALTR) to prosthetic hip wear debris is vital to improve the success of revision surgery. Magnetic resonance imaging with metal artefact reduction sequencing (MARS MRI) is considered the modality of choice to provide cross-sectional imaging of the soft tissues. The areas adjacent to the prosthesis are, however, not readily imaged using these protocols. Ultrasound has also been recommended as an imaging modality in the follow-up of hip replacement surgery. We decided to characterise the typical ultrasound findings in a group of patients undergoing routine biennial review of arthroplastic hips with particular reference to the hip capsule, femoral neck and iliopsoas bursa and tendon adjacent to the implant. Fifty-two patients with a mean (±SD) age of 60.4 (±12) y were prospectively recruited. Twelve patients had bilateral hip prostheses, giving 64 hips for analysis. Mean (±SD) age of the prosthesis in situ was 8.2 (±3.3) y. Data were grouped on the basis of the shape of the iliofemoral ligament. The median (range) maximal anteroposterior synovial thickness was 5 (2–8) mm in the normal concave iliofemoral ligament group and 7 (4–56) mm in the abnormal straight/convex iliofemoral ligament group (p = 0.001). The anteroposterior iliopsoas tendon measurement was 5 (3–8) mm in the normal group and 5 (4–8) mm in the abnormal group (p = 0.065). ALTR development in asymptomatic well-functioning prostheses may be recognised earlier using ultrasound rather than MARS MRI by carefully assessing the shape of the iliofemoral ligament. Ultrasound findings of an abnormal straight or convex ligament may be suggestive of early ALTR and warrant streaming of patients to a more frequent surveillance program.

Retrospective cohort study of the performance of the Pinnacle metal on metal (MoM) total hip replacement: a single-centre investigation in combination with the findings of a national retrieval centre

ObjectivesTo determine risk factors for revision in patients implanted with a commonly used metal on metal (MoM) hip replacement.DesignRetrospective cohort study in combination with a prospective national retrieval study (Northern...

Systemic toxicity related to metal hip prostheses

Introduction. One in eight of all total hip replacements requires revision within 10 years, 60% because of wear-related complications. The bearing surfaces may be made of cobalt/chromium, stainless steel, ceramic, or polyethylene. Friction between bearing surfaces and corrosion of non-moving parts can result in increased local and systemic metal concentrations. Objectives. To identify and systematically review published reports of systemic toxicity attributed to metal released from hip implants and to propose criteria for the assessment of these patients. Methods. Medline (from 1950) and Embase (from 1980) were searched to 28 February 2014 using the search terms (text/abstract) chrom* or cobalt* and [toxic* or intox* or poison* or adverse effect or complication] and [prosthes* or ‘joint replacement’ or hip or arthroplast*] and PubMed (all available years) was searched using the search term ((“Chromium/adverse effects”[Mesh] OR “Chromium/poisoning”[Mesh] OR “Chromium/toxicity”[Mesh]) OR (“Cobalt/adverse effects”[Mesh] OR “Cobalt/poisoning”[Mesh] OR “Cobalt/toxicity”[Mesh])) AND (“Arthroplasty, Replacement, Hip”[Mesh] OR “Hip Prosthesis”[Mesh]). These searches identified 281 unique references, of which 23 contained original case data. Three further reports were identified from the bibliographies of these papers. As some cases were reported repeatedly the 26 papers described only 18 individual cases. Systemic toxicity. Ten of these eighteen patients had undergone revision from a ceramic-containing bearing to one containing a metal component. The other eight had metal-on-metal prostheses. Systemic toxicity was first manifest months and often several years after placement of the metal-containing joint. The reported systemic features fell into three main categories: neuro-ocular toxicity (14 patients), cardiotoxicity (11 patients) and thyroid toxicity (9 patients). Neurotoxicity was manifest as peripheral neuropathy (8 cases), sensorineural hearing loss (7) and cognitive decline (5); ocular toxicity presented as visual impairment (6). All these neurological features, except cognitive decline, have been associated with cobalt poisoning previously. Type of prosthesis and blood metal concentrations. Where blood or serum metal concentrations were reported (n = 17 for cobalt and n = 14 for chromium), the median cobalt concentration was 398 (range, 13.6–6521) μg/L and the median chromium concentration was 48 μg/L (in whole blood) (range, 4.1–221 μg/L including serum and blood values). Those patients reported to have systemic features who had received a metal-on-metal prosthesis (n = 8) had a median peak blood cobalt concentration of 34.5 (range, 13.6–398.6) μg/L; those with a metal-containing revision of a failed ceramic prosthesis (n = 10) had a median blood cobalt concentration of 506 (range, 353–6521) μg/L. Management. The most common treatment was removal of the metal-containing prosthesis, undertaken in all but 2 patients. This was usually associated with a fall in circulating cobalt concentration and improvement in some or all features. Clinical and toxicological assessment of systemic features. We propose the following criteria for assessing the likelihood that clinical features are related to cobalt toxicity: clinical effects consistent with the known neurological, cardiac, or thyroidal effects of cobalt, and for which any other explanation is less likely; increased blood cobalt concentrations (substantially higher than those in patients with well-functioning prostheses) several months after hip replacement; a fall in the blood cobalt concentration, usually accompanied by signs of improvement in features. When judged by these criteria, the systemic features in 10 of the reported cases are likely to be related to cobalt exposure from a metal-containing hip prosthesis. Conclusions. Rarely, patients exposed to high circulating concentrations of cobalt from failed hip replacements develop neurological damage, hypothyroidism and/or cardiomyopathy, which may not resolve completely even after removal of the prosthesis. The greatest risk of systemic cobalt toxicity seems to result from accelerated wear of a cobalt-containing revision of a failed ceramic prosthesis, rather than from primary failure of a metal-on-metal prosthesis.

Brain structure and function in patients after metal-on-metal hip resurfacing.

Hip prostheses that use a metal-on-metal articulation expose the brain to elevated metal concentrations that, in acute excess due to prosthesis malfunction, is associated with neurologic damage, including visual and hearing loss and motor deficits. Here, we examined whether chronic exposure to lower elevated metal levels, typical of well-functioning prostheses, also affects brain structure and function. We compared brain volumes, metal deposition, and gray matter attenuation by MR imaging and clinical neurologic function in patients 8 years after receiving a metal-on-metal hip resurfacing versus a matched group of patients with the same duration exposure to a conventional hip prosthesis. Twenty-nine patients (25 men; mean, age 59±7 years) after metal-on-metal hip resurfacing and 29 patients (25 men; 59±8 years) after total hip arthroplasty were compared. Whole blood cobalt and chromium concentrations were 5-10 times higher in the metal-on-metal hip resurfacing group (P<.0001). Occipital cortex gray matter attenuation tended to be lower (P<.005 uncorrected, P>.05 corrected), and the optic chiasm area tended to be lower (mean difference, -2.7 mm2; P=.076) in the metal-on-metal hip resurfacing group. Subgroup analyses in 34 patients (17 per group), after exclusion of primary ocular pathology, showed the same trend in gray matter attenuation in the occipital cortex and basal ganglia and a smaller optic chiasm in the metal-on-metal hip resurfacing group (mean difference, -3.9 mm2; P=.048). No other structural or functional differences were found between the groups. Chronic exposure to metal-on-metal hip resurfacing is associated with subtle structural change in the visual pathways and the basal ganglia in asymptomatic patients.

The histology around the cemented Müller straight stem

The aim of this study was to obtain detailed long-term data on the cement-bone interface in patients with cemented stems, implanted using the constrained fixation technique. A total of eight stems were removed together with adjacent bone during post-mortem examinations of patients with well-functioning prostheses. Specimens were cut at four defined levels, contact radiographs were obtained for each level, and slices were prepared for histological analysis. Clinical data, clinical radiographs, contact radiographs and histological samples were examined for signs of loosening and remodelling. The mean radiological follow-up was 9.6 years and all stems were well-fixed, based on clinical and radiological criteria. Contact radiographs revealed an incomplete cement mantle but a complete filling of the medullary canal for all implants. Various amounts of polyethylene particles were evident at the cement-bone interface of seven stems, with no accompanying inflammatory reaction. Cortical atrophy and the formation of an 'inner cortex' were confirmed in six of eight stems by contact radiographs and histology, but were only visible on two clinical radiographs. Our results confirm that a complete cement mantle is not essential for the survival of Müller straight stems into the mid term, and support our hypothesis that no benefit to long-term survival can be expected from modern cementing techniques.

A femoral component with proximal HA coating. An analysis of survival and fixation at up to ten years.

We describe the survival at ten years of 100 femoral components of the Freeman hip prosthesis. It is proximally hydroxyapatite (HA)-coated and was fixed without cement. Radiological assessment identified radiolucent lines (RLLs) and lytic lesions and was used to measure migration. The criterion of failure was revision or impending revision for aseptic femoral loosening. No femoral components were revised or are awaiting revision for aseptic loosening, giving 100% survival at ten years (95% confidence interval, 95.7 to 100), although 59 were at risk at ten years. Two components were revised for fracture of a ceramic head with damage to the trunnion. Although well fixed in each, for survival analysis we evaluated the hip as if the patient had died. Twelve acetabular components were revised and at each operation the femoral component was found to be well fixed, was not disturbed and remained in the survival analysis. Three patients were lost to follow-up, and 12 died with well-functioning prostheses. Radiologically, all except one of the components appeared to be well fixed with no RLLs and no lytic lesions at the latest follow-up. The mean vertical migration was 0.4 mm at one year, 0.8 mm at two years and 1.4 mm at ten years. One component had migrated 7.6 mm at ten years (2.1 mm in year 1) and developed RLLs in Gruen zones I and II. The symptoms, however, were only minor and revision was not indicated. Our study has shown that proximal HA coating gives effective fixation for a femoral component.

Managing the infected knee: As good as it gets

The clinical presentation is a useful guide for selecting the treatment of an infected total knee arthroplasty. Prosthesis retention is indicated in patients with infections that occur within 30 days after arthroplasty and in patients with well-functioning prostheses who develop an acute late hematogenous infection. Débridement attempts should be open and not arthroscopic. When prosthesis removal is required, the preferred approach is a delayed reconstructive technique, the 2-staged reimplantation, rather than a direct-exchange procedure. The use of block spacers or mobile articulating devices to deliver high-dose local antibiotics is recommended between implant removal and delayed revision surgery. The use of antibiotic-loaded acrylic cement for cemented prostheses or antibiotic-soaked bone–graft with cementless prostheses is helpful in the overall cure rate of infection. Copyright 2002, Elsevier Science (USA). All rights reserved.

Concentration of metal elements in the blood and urine in the patients with cementless total knee arthroplasty.

Titanium (Ti), cobalt (Co) and chromium (Cr) element concentrations in the whole blood and urine specimen in 40 patients with cementless total knee arthroplasty were determined by the electrothermal atomic absorption spectrophotometry. Their ages ranged from 55 to 78 years (mean, 65 years). Twenty of them had loosening of prosthesis and underwent revision surgery, including 4 subjects with Ti-6Al-4V alloy prosthesis and 16 subjects with Co-Cr-Mo alloy prosthesis. The other 20 patients had well-functioning stable prosthesis, including 5 subjects with Ti-6Al-4V alloy prosthesis and 15 subjects with Co-Cr-Mo alloy prosthesis. The mean duration of prostheses implantation in patients with loosened or well-functioning prostheses were 6.5 and 4.0 years, respectively. The control group consisted of 20 age-matched normal subjects who did not undergo any metal implant surgery. Analysis of variance showed that the metal element concentrations in the whole blood, either Co, Cr or Ti, was statistically higher in the patients with loosened prosthesis than the other two groups. However, the metal element concentrations in the urine did not show any difference. The linear regression analysis showed a moderate positive relationship between the metal element concentrations, either Co or Cr elements, in whole blood and urine only in the patients with loosened prostheses. In conclusion, elevated concentration of metal elements may indicate a loosening of prosthesis while the clinical significance of the metal element concentration in the urine needs further investigation.

Human postmortem retrieval of total hip arthroplasty

Postmortem retrieval of well-functioning prostheses from total hip arthroplasty is essential in determining the quality and success of the implant, implant fixation, and operative technique. This report describes the retrieval procedure, including details on informed consent, retrieval procedure, and types and benefits of specimen analysis. Bone densitometry, roentgenography, and microscopy studies permit a level of assessment of operative and prosthetic performance not obtainable from clinical and in vivo roentgenographic evaluation alone. Findings from these techniques yielding data on stress shielding, bone mineral density, extent of bone—prosthesis apposition and osseointegration, and histologic activity are ultimately of considerable clinical significance. The implementation of retrieval programs, along with establishing early family and patient cooperation and proper planning practices, will continue to contribute invaluably to advances in orthopaedic science.

Results of Implant Retrieval From Postmortem Specimens in Patients With Well-Functioning, Long-Term Total Hip Replacement

The evaluation of postmortem specimens provides a unique opportunity to gain understanding of the interface between host and well-functioning prostheses unavailable from revision specimens that, by nature, are accompanied by the artifacts generated during their removal. The preliminary findings from the relatively limited number of specimens described in this collaborative study demonstrate the value of the effort and are presented to encourage surgeons to participate in this program and to make their patients aware of the value of the information they may provide.

The Microscopic Anatomy of the Bone-Cement Interface in Failed Total Hip Arthroplasties

Thirty specimens were removed from the bone-cement interface in 25 hips revised for aseptic loosening of total hip arthroplasty. Histologic examination of the membranous tissues revealed that histiocytosis, fibrosis, and necrosis were present in every specimen. Other prominent features included particles of acrylic cement, polyethylene debris, and fragments of necrotic bone. Mechanical failure was characterized by cement fractures, and microfracture of bone. The presence of cement debris and bone detritus in the membranes, and smooth appearance of the removed cement mantles substantiated the presence of mechanical failure. The process of loosening was characterized by the recruitment of histiocytes into the interface and the subsequent resorption of bone around the prosthesis. This may be a manifestation of the rate of cement wear and tear, particle size, and the immunologic predispositions of the host. These observations on interfaces of loosened prostheses are reexamined and reinterpreted in the light of radiologic observations on interface radiolucent zones and well-functioning prostheses.