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PubMed1990

Prosthesis-related infection. Etiology, prophylaxis and diagnosis (a review).

The recent literature concerning prosthesis-related infection is reviewed with respect to etiology, prophylaxis and diagnosis. Most prosthesis-related infections are initiated during operation by contamination with bacteria-carrying particles from the air as a result of dispersion of skin scales from individuals in the operating room. A small number of infections are caused by hematogenous seeding of bacteria. Glycocalyx, a slime layer produced by bacteria, plays an important role in the pathogenesis of infections, especially in the presence of biomaterial. Clean-air systems in combination with perioperative systemic antibiotics reduce prosthesis-related infections from 3 or 4 per cent to a few per thousand. The use of antibiotic-loaded bone cement is advised in high risk patients although further evaluation is needed. Physical examination of the patient, laboratory tests such as the E.S.R. and C-reactive protein, serial radiograms, isotope scanning techniques and joint aspiration can all help diagnose prosthesis-related infection. However definitive diagnosis is possible only by culturing several samples of material obtained from the interface during revision operation. A perioperative frozen section of interface tissue showing acute (more than 5 leucocytes per field) or severe chronic (more than 50 lymphocytes) inflammation is highly suggestive of sepsis.

Anti-Bacterial Agents↗
PubMed1990

[Results of the use of the Austin Moore prosthesis for the treatment of femur neck fracture at Tygerberg Hospital. A retrospective study].

A retrospective study was done on 116 patients who received an Austin Moore prosthesis at Tygerberg Hospital between 1982 and 1983. The patients all had displaced intracapsular femoral neck fractures (Garden type III and IV). Although the Moore prosthesis must be fitted meticulously for good results, the operation can be performed effectively by the less experienced surgeon. This cementless monoprothesis is a good option for the elderly and/or poor-risk patient with a limited life expectancy. It has a low intraoperative mortality, a low percentage of re-operation and results in early and good mobilisation. In contrast to series on cemented prosthesis, we had a very low sepsis rate. In comparison to a total hip replacement, this is a much cheaper prosthesis and operation.

Aged↗
PubMed1990

[Prosthesis-endocarditis in the aortic position in a 22-year case load. Surgical versus conservative treatment].

During the period 1965-1986, a total of 852 patients underwent isolated aortic valve replacement. With 4,875 patients-years at risk, 24 patients developed prosthetic valve endocarditis (PE; 0.49% per patient-year). The five, ten and fifteen year cumulative freedoms from PE were 98.2%, 95.4% and 93.0%, respectively. PE was unrelated to pre- or intraoperative data. No patients submitted to operation for acute/subacute bacterial endocarditis of the native aortic valve developed PE. Out of the 12 episodes of PE within two years of the operation, seven (58%) were caused by Staphylococcus albus compared with two out of 12 (17%; p less than 0.05) subsequent episodes of PE. Seven of the nine infections with Staphylococcus albus were caused by a highly resistant nosocomial variant. Ten of the PE patients underwent replacement of the prosthesis while 14 were treated conservatively. The two therapeutic groups were comparable, although the surgically treated patients tended to be younger and to have more impaired cardiac status. All surgically treated patients and all patients treated conservatively and in whom post mortem verification was possible had paravalvular defects, annular abscesses and/or vegetations on the prosthesis. The thirty-day, one year and ten year cumulative survivals were 80%, 80% and 50%, respectively, after replacement of the prosthesis and 64%, 21% and 7%, respectively, after conservative treatment (p = 0.02). A Cox regression analysis identified conservative treatment, infection with Escherichia coli or Haemophilus influenzae and the need to intensify digitalis/diuretic treatment for congestive heart failure as independent risk factors. It is concluded that replacement of the prosthesis early in the course of the disease should be considered as the treatment of choice.

Adolescent↗
PubMed1990

[Complications after osteosynthesis using Partridge's method in femoral fracture near the prosthesis].

The object of the investigation is to illustrate the results and complications following Partridge's osteosynthesis of proximal fractures in the neighbourhood of the prosthesis. During a period of 40 months, eight consecutive patients (two men and six women) with proximal fractures of the femur in the neighbourhood of a hip prosthesis were subjected to osteosynthesis by Partridge's method. All of the fractures resulted from low energy trauma. The average age was 72 years (51-84) and the average duration of observation was 2.3 years. Weight-bearing was permitted after an average of 14.5 weeks and the radiographically assessed healing time was 16 weeks on an average. In all of the patients, cortical erosion developed under the Partridge bands 10-16 weeks postoperatively. In five patients, the initial erosions were of limited extent and were stationary during the period of observation. In three patients, the osteolysis was progressive and reoperation with introduction of a long-shafted femur prosthesis proved necessary. In addition, homologous boney transplants were necessary in two of these patients. Stability and healing of the fracture are obtained by osteosynthesis by Partridge's method but, on account of the osteolysis which is frequently pronounced and progressive, the patients should be followed-up meticulously in view of the possibility of removal of the Partridge material and possible replacement by a long-shafted femur prosthesis before the bone is completely eroded.

Aged↗
PubMedDate not supplied

[Choice of the size and shape of a mitral valve prosthesis].

The authors discuss the results of mitral valve replacement in 438 patients with intraoperative selection of the prosthesis and in 77 patients with preoperative selection by means of an original method based on two-dimensional echocardiography. The intraoperative selection proved to be insufficiently effective: in the postoperative periods 13.9 +/- 2.7% of patients had marked signs of lack of correspondence of the prostheses to the size and structure of the left ventricle, which was verified at autopsy or by the findings of intravital catheterization of the heart with ventriculograph. The method of preoperative selection of the prosthesis, which was suggested by the authors, is more effective. It allows implantation of an inadequate prosthesis to be absolutely avoided. The method showed implantation of a ball prosthesis to be contraindicated for 33.7 +/- 5.4% of patients with mitral and mitral-aortic valvular diseases.

Adult↗
PubMed1988

Inadvertent extramedullary placement of Austin Moore prosthesis. A case report.

Virtually complete extramedullary insertion of an Austin Moore prosthesis is a rare complication. The prosthesis is seldom left in such a position once the complication has been recognized. To the authors' knowledge, this is the first reported long-term follow-up study of such a case in which the result could be considered reasonably well-tolerated. The prosthesis was revised to a total hip arthroplasty 15 years following implantation. That the reason for excision was acetabular wear indicates that the prosthesis was load bearing. This case raises the question of whether the concept of extramedullary fixation of hip prostheses could be valid.

Adolescent↗
PubMed1987

[Technical development and radiological surveillance of the Schmitt minimadreporic uncemented total hip prosthesis. Evaluation of 275 arthroplasties with a follow-up of more than 6 years for the oldest cases].

The authors describe a porous-coated uncemented total hip prosthesis which has been used for more than six years: the Schmitt minimadreporic prosthesis. A homogenous series of 275 arthroplasties has been reviewed with a mean follow-up of three years and five months. The method of radiological assessment of the position of the femoral and acetabular components and their possible loosening is described in detail. Infection (0.72%) and aseptic loosening (1.8%) specific to this type of prosthesis was rare. For the series as a whole there were 92% of good, very good and excellent results and for 81 arthroplasties with a follow-up greater than four years the figure was 90%. The frequency of secondary displacement of the femoral component is emphasised, with 15 prostheses sinking downwards and 96 displacing into varus. Statistical analysis has shown the principal factors affecting the clinical result and has demonstrated the effect of resorption of the calcar in causing downward displacement of the femoral stem and insufficient filling of the medullary cavity on the development of varus angulation of the prosthesis.

Bacterial Infections↗
PubMed1986

The influence of tibial-patellofemoral location on function of the knee in patients with the posterior stabilized condylar knee prosthesis.

Function of the knee and patellofemoral symptoms were correlated with the position of the implant in 101 consecutive patients with 116 posterior stabilized condylar knee prostheses. All of the patients were followed for a minimum of two and a half years with sequential physical examinations, radiographs, and functional evaluation of the knee. In sixteen knees (14 per cent), clicking or catching of the patella in terminal extension or painless crepitation throughout the arc of flexion developed without lowering the functional knee-evaluation score. Pain or mechanical problems, or both, that lowered the functional knee-evaluation score occurred in another fourteen knees (12 per cent), within the first postoperative year. Of these fourteen, eight required revision solely for patellofemoral complaints. Critical analysis of the tibial-patellofemoral mechanical axis identified three surgical variables that were found to markedly affect the functional result of the prosthesis: the distance from the center line of the tibial prosthesis to the center line of the tibial plateau, a change in the position of the joint line of the prosthesis relative to the hip and ankle, and the patellar height, measured as the perpendicular distance from the inferior pole of the patellar implant to the joint line of the prosthesis. Functional knee scores, range of motion, patellofemoral pain or mechanical symptoms, the need for revision, and the necessity of manipulation could all be statistically significantly correlated with the three independent variables. In addition, a range of neutral alignment was developed.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

[Analysis of arterial microporous teflon prosthesis following surgical excision].

Twenty-one prosthetic explants were analysed after being surgically excised from 19 patients whose average age at implantation was 54.8 years. The arterial prosthesis was implanted 19 times for an advanced arteriopathy (stage III and stage IV) and twice for a stage II. The average time that the implants were in place was 14.8 months (with extremes of 19 days and 4 years). Surgical reintervention was caused by thrombosis (18 cases), infection (twice) and one case of degeneration of the prosthesis. The explanted prostheses displayed an irregular capsule, an uneven filling of the wall and a fibrous proliferation adhering to the internal surface. The role of the latter appeared essential to the prevention of the invasion of the prosthesis wall by fibrous tissues. The destruction of the structure of the microporous teflon is also prevented. Furthermore, this prosthesis seemed adversely affected when creased by flexion: the reduction in the caliber of the internal lumen caused thrombosis and a detachment of the external capsule. When such a material is implanted, everything must be done to prevent twisting or damaging the prostheses.

Aged↗
PubMed1985

Missing stapes and stapes-replacing prosthesis.

Our study of 205 ears with missing stapes, secondary to some type of chronic ear disease, showed that only 40% of such ears are suitable for ossiculoplasty. The remaining 60% are unsuitable because of a fixed footplate, severe atelectasis, hearing better than 25 dB (these patients do not need the operation), or poor discrimination. A new stapes replacement prosthesis (SRP), which we term Tabor, is described for use where indicated. The prosthesis has two parts: The lower part (or base) is made of a broad inorganic, biocompatible material (Teflon). This part fits and covers most of the footplate, ensuring maximal stability. The upper part of the prosthesis is made of autograft or homograft bone--usually a malleus head--the contact of which with the drum prevents extrusion. In twelve out of fourteen ears insertion of this prosthesis was successful; the average postoperative air conduction went from 56 dB to 29 dB, leaving an average air-bone gap of 16 dB. The bone conduction also improved, from an average of 20 dB to 13 dB.

Bone Conduction↗
PubMedDate not supplied

The total condylar knee prosthesis: the first 5 years.

The total condylar knee prosthesis evolved from previous experience with other prostheses at the Hospital for Special Surgery. This evolution includes patellar resurfacing. Subsequent modifications have led to the total condylar knee prosthesis II (a cruciate substituting prosthesis), and the total condylar knee prosthesis III (a TCP II with increased constraint). The surgical technique requires ligamentous balance with correction of preoperative deformity by a soft-tissue release. Subsequently a standard operation is performed. Four hundred and sixty-one knees were reviewed with a minimum of one year follow-up and a maximum of 5 years. Seventy-five per cent were osteoarthritic knees. Using the Hospital for Special Surgery Knee Rating Scale, the results were excellent in 312 knees (68%), good in 109 knees (23.5%), fair in 18 knees (4%) and poor in 22 knees (4.5%). Osteoarthritic knees (excellent or good 93.5%) did slightly better than rheumatoid knees (excellent or good 87%). Complications include 6 infections, 6 subluxations and 10 cases of component loosening. There were 15 reoperations (3%). The results approach total hip arthroplasty in quality and so far have not deteriorated with time.

Adult↗
PubMedDate not supplied

The "caviar" madreporic knee prosthesis.

The madreporic ("caviar") prosthesis is a hinged knee prosthesis that can be inserted without the use of cement. The surfaces of the intramedullary stems are constructed with contiguous spheres one mm in diameter. These spaces are filled by bone trabeculae and haversian bone, providing permanent biologic fixation. Experimental madreporic knee arthroplasties in dogs show that bone probes these surfaces and produces solid attachments. Histologically, the trabeculae remain separated from the metal by a fine layer of fibrous tissue. The method of insertion of the prosthesis is simple. Preparing the epiphyses before any bone resection avoids the possibility of rotational positioning errors. The form of the intramedullary stems offers good positioning in the frontal plane. The analysis of an initial series of 15 cases shows results that are far from outstanding. The 2 deaths, the 2 cases of sepsis, and the recuperation of only mediocre motion can be explained, at least in part, by the advanced age of the patients and the poor bone quality of the rheumatoid patients. Nevertheless, this type of prosthesis has 2 important advantages. It avoids the complications from the use of acrylic cement and allows for a revision operation for cases of failed surface replacement designs. Obviously further experimentation with noncemented designs will continue and definitive studies will be reported later.

Animals↗
PubMed1977

Herbert total knee prosthesis: combined laboratory and clinical assessment.

We tested the Herbert knee prosthesis, which was designed to restore intrinsic stability with limited degrees of freedom for rotation to severely damaged or deformed knees, in a knee simulator. These tests indicated a tendency for the prosthesis to fracture through the medial femoral housing after cycling for the equivalent of one to three years of normal use. In a clinical series of thirty-five knees treated with the prosthesis, there were five failures similar to those produced by laboratory testing. On the basis of this combined study, the Herbert prosthesis appears to have design characteristics that seriously limit its usefulness for long-term knee replacement. Testing in a knee simulator in this case appeared to be a valid predictor of clinical failure.

Biomechanical Phenomena↗
PubMed1984

[Mechanical fatigue of an arterial prosthesis].

This case study reports the analysis of a knitted polyester arterial prosthesis that was implanted in an 18-year old patient for five years following a bicycle accident which injured the left external iliac artery. In spite of the prosthesis, the patient continued to participate in competitive cycling. The graft became dilated and stretched by tension from the hypertrophic psoas muscle, and because the patient presented with pain and claudication, a second surgical operation was performed. The central region of the prosthesis was badly kinked. A segment was resected and analyzed in terms of pathological, textile and chemical properties. The analysis showed a poorly healed graft that had suffered from mechanical and chemical degradation. The findings point to the wisdom of implanting woven rather than knitted grafts in young patients and also suggest that in this particular case, where mechanical deterioration was accompanied by chemical degradation, it would have been preferable to remove the whole prosthesis.

Adolescent↗
PubMed1983

A passive system using rifampin to create an infection-resistant vascular prosthesis.

Vascular prosthesis infection is a devastating complication of vascular operations. The development of a simple process for imparting infection resistance to vascular prosthesis material would be invaluable. Rifampin was added to the blood that was used to preclot 8 mm Dacron vascular prostheses that were used to replace the infrarenal aorta in 10 mongrel dogs. Rings of the grafts were resected after blood had flowed through them for 0 minute, 15 minutes, 60 minutes, and 24 hours. The resected graft rings were placed on culture plates that had been inoculated heavily with Staphylococcus aureus. The rate of antibiotic dialysis from the graft was determined by comparison of the inhibition rings that were produced by the graft rings at each subsequent interval. At 60 minutes, inhibition was 94% of that at time 0. Inhibition at 24 hours was 91%, which demonstrated no significant decrease from 60 minutes. Other antibiotics were screened by this technique, but none of them demonstrated inhibition at 24 hours. In a pilot study in which two dogs were given parenteral rifampin before and after operation and grafts were preclotted with blood that contained rifampin, it was suggested that there was a slight increase in inhibition at 24 hours (93%). The data indicated that rifampin that is added to the blood that is used to preclot a porous Dacron prosthesis is so slowly dialyzed from the graft that inhibition remains at 24 hours. This passive system imparts potential resistance to the prosthesis.

Animals↗
PubMed1981

[The use of the B.A.S.K. total prosthesis for the reconstruction of the proximal femur after tumour excision (author's transl)].

The authors have used an original model of total hip prosthesis (B.A.S.K. Prosthesis) which allows for repair of bone losses up to 13 cm. The length of the femoral device is adjustable and it articulates with a mobile cup. It has been used in 15 cases, 13 of which were bone metastases. Three died after operation. The others were able to walk and leave hospital. No dislocation or infection occurred. One prosthesis fractured after one year. The authors believe that this type of prosthesis is worth-while in cases with a limited expectation of survival.

Adult↗
PubMed1984

The posterior cruciate condylar total knee prosthesis. A five-year follow-up study.

Remarkable results were demonstrated for the nonlinked, semiconstrained total condylar knee prosthesis in the first long-term follow-up study. The posterior cruciate condylar prosthesis, a variation of the basic design, leaves the posterior cruciate ligament intact. Ninety-four consecutive knees were observed for a minimum postoperative follow-up period of five years. Apart from this design modification and a slightly different program of postoperative care, the methods and techniques used were identical to those used with the total condylar knee prosthesis. By the same method of assessment (The Hospital for Special Surgery Knee Rating Scale), 54 of the ninety-four knees (57.4%) were rated excellent; 37 (39.4%), good; two (2.1%), fair; and one (1.0%), poor. The average preoperative score was 48 points, and the average postoperative score was 81 points (85-100 points = excellent). The posterior cruciate condylar total knee prosthesis represents an excellent prosthetic design for a wide variety of knee deformities and maintains the posterior cruciate ligament for supplementary posterior support.

Adult↗
PubMed1981

[Long-term course of patients with Smeloff-Cutter aortic valve prosthesis].

The long-term results (5 to 12 years) of 77 patients with Smeloff-Cutter aortic valve prostheses are reported. These patients were comparable in age, preoperative clinical condition and type of aortic valve replacement. The postoperative follow-up period of this series was however significantly longer. The 5 year survival rate was of 87%. The causes of death included thromboembolism, infectious endocarditis and cardiac failure. Mortality was higher in the first 5 postoperative years : 2,4% patient-years compared to 1,5% patient-years in the following years. Thromboembolism and neurological complications were particularly rare, representing a risk of 1,04% patient-years but these complications were lethal in half the cases in which they occurred. No haemolytic complications were observed. Infective endocarditis always occurred in patients with a history of infection, the complication usually being late (after 3 years). The life expectancy of patients seen after 5 years is at least 5 additional years in 80% of cases. The haemodynamic profile of the prosthesis did not degrade with time. After 5 years, 58,6% of patients in functional Class IV at operation were in Class I or II afterwards. 84,4% of patients operated in functional Class III were in Class I or II, and 93% operated in functional Class II were in Class I or III. A control of 3 prostheses carried out by the Cutter laboratory after 10 and 11 years' function shows practically no deterioration of the prosthesis. The low incidence of thromboembolism, the absence of haemolysis and long-term deterioration of the prosthesis are particularly valuable characteristics of this prosthesis in the aortic position.

Adult↗