Infected Joint Replacement Research Articles

Cost-effectiveness, cost-utility, and cost-benefit studies in rheumatology: a review of the literature, 2001-2002.

Economic analyses of prevention and treatment interventions in rheumatology are potentially powerful tools for evaluating many complex decisions facing clinical and public policy makers. Cost-effectiveness, cost-utility, and cost-benefit analyses allow for the assessment of the trade-offs between expended resources and expected health benefits. This review describes 12 cost-effectiveness analyses done in the past year. Each relates to a different intervention for a variety of rheumatologic conditions including osteoporosis, rheumatoid arthritis, the use of cyclooxygenase-II inhibitors, infected total joint replacements, back pain, and Lyme disease. While cost-effectiveness analyses of the use of the new biologic agents in rheumatoid arthritis have been presented at national meetings, these have yet to be published. Proper use of cost-effectiveness analysis could provide valuable evidence about treatment decisions for clinical and public policy makers in rheumatology.

Surgical techniques for revision of infected joint replacements

Infected joint arthroplasties are a challenging problem to the orthopaedic surgeon. The treating surgeon should be aware of the problems that can be encountered. Proper pre-operative planning, precise surgical techniques, and treatment protocols are key to the management of this dreaded complication. The aim is to eradicate the infection and reimplant a stable, aligned and well functioning revision hip or knee system. The bone stock should be preserved or restored, and the patients should return to their previous level of function. We describe our approach in treating this complex problem.

Predictors of wound infection in hip and knee joint replacement: results from a 20 year surveillance program

Background. Deep wound infection (DWI) in total knee (TKA) and total hip (THA) arthroplasty has been shown to highly correlate with superficial surgical site infection (SSSI). Although several studies have reported hospital factors that predispose to SSSI, patient factors have not been clearly elucidated. Methods. All patients undergoing TKA ( n=1181) and THA ( n=1124) surgery during the period 1977–1995 at our institution were observed at the end of a 30-day post-operative period. Thirty-three patients that developed SSSI during this period constituted the study group. The control group was composed of 64 matched subjects that did not develop SSSI. A chart review was applied to abstract DWI cases during the first 18 post-operative months for the study group and for an average of 6.7 years for the control group (range 5–18.2 years). Potential risk factors for SSSI were used as predictors of SSSI in a logistic regression analysis. Results. During the 18-month observation period 19 out of the 33 study subjects (58%) developed DWI. No DWI was registered in the control group (the difference was significant, p<0.0001). Of the nine pre-operative, five intra-operative, and five post-operative factors examined, only hematoma formation (odds ratio=11.8; p=0.001) and days of post-operative drainage (odds ratio=1.32; p=0.01) were significant predictors of SSSI. The cases consumed more health care resources at all stages of the medical process. Conclusions. Our results (1) confirm the strong correlation between the probability of developing DWI and SSSI; (2) indicate that hematoma formation and persistent post-operative drainage increase the risk of SSSI. We hypothesize that post-operative monitoring of patients for hematoma and persistent drainage enables earlier intervention that may lower the risk of developing SSSI and subsequent DWI.

18. FDG vs labelled leukocyte-marrow imaging for diagnosing the infected joint replacement

18. FDG vs labelled leukocyte-marrow imaging for diagnosing the infected joint replacement

Vacuum-assisted closure in the treatment of a 9-year-old child with severe and multiple dog bite injuries of the thorax

The vacuum-assisted closure (VAC; KCI International, San Antonio, TX) device is a negative pressure dressing, which we have used in the treatment of wounds with devitalized or infected tissues. Although introduced in plastic and reconstructive surgery, its use has extended to orthopedic and cardiothoracic surgical practice in the treatment of infected joint replacement and sternal wound infections, respectively. Although the VAC is becoming more widely used in surgical practice, only a small number of case reports exist in addition to the original case series by Argenta and Morykwas in 1997. Previously, the device was described in treating single wounds in adult patients. We report a case where it was successfully used to treat multiple dog bite injuries in a 9-year-old child.

Infected joint replacements in HIV-positive patients with haemophilia

Joint replacement in HIV-positive patients remains uncommon, with most experience gained in patients with haemophilia. We analysed retrospectively the outcome of 102 replacement arthroplasties in 73 HIV-positive patients from eight specialist haemophilia centres. Of these, 91 were primary procedures. The mean age of the patients at surgery was 39 years, and the median follow-up was for five years. The overall rate of deep sepsis was 18.7% for primary procedures and 36.3% for revisions. This is a much higher rate of infection than that seen in normal populations. A total of 44% of infections resolved fully after medical and/or surgical treatment. The benefits of arthroplasty in haemophilic patients are well established but the rates of complications are high. As this large study has demonstrated, high rates of infection occur, but survivorship analysis strongly suggests that most patients already diagnosed with HIV infection at the time of surgery should derive many years of symptomatic relief after a successful joint replacement. Careful counselling and education of both patients and healthcare workers before operation are therefore essential.

Infected joint replacements in HIV-positive patients with haemophilia

Joint replacement in HIV-positive patients remains uncommon, with most experience gained in patients with haemophilia. We analysed retrospectively the outcome of 102 replacement arthroplasties in 73 HIV-positive patients from eight specialist haemophilia centres. Of these, 91 were primary procedures. The mean age of the patients at surgery was 39 years, and the median follow-up was for five years. The overall rate of deep sepsis was 18.7% for primary procedures and 36.3% for revisions. This is a much higher rate of infection than that seen in normal populations. A total of 44% of infections resolved fully after medical and/or surgical treatment. The benefits of arthroplasty in haemophilic patients are well established but the rates of complications are high. As this large study has demonstrated, high rates of infection occur, but survivorship analysis strongly suggests that most patients already diagnosed with HIV infection at the time of surgery should derive many years of symptomatic relief after a successful joint replacement. Careful counselling and education of both patients and healthcare workers before operation are therefore essential.

Role of nuclear medicine in diagnosis of the infected joint replacement.

Some complications of joint replacement surgery are easily diagnosed; however, differentiating infection from aseptic loosening is difficult because these entities are remarkably similar at clinical and histopathologic examination. Clinical signs and symptoms, laboratory tests, radiography, and joint aspiration are insensitive, nonspecific, or both. Cross-sectional imaging modalities are hampered by artifacts produced by the prosthetic devices themselves. Radionuclide imaging is not affected by the presence of metallic hardware and is therefore useful for evaluating the painful prosthesis. Bone scintigraphy is useful as a screening test, despite an accuracy of only 50%-70%, because normal results essentially exclude a prosthetic complication. The addition of gallium-67, a nonspecific inflammation-imaging agent, improves the accuracy of bone scintigraphy to 70%-80%. The accuracy of combined leukocyte-marrow imaging, 90%, is the highest among available radionuclide studies. Its success is due to the fact that leukocyte imaging is most sensitive for detection of neutrophil-mediated inflammation (ie, infection). The success of leukocyte-marrow imaging is tempered by the limitations of in vitro labeling. In vivo labeling has been investigated, and a murine monoclonal antigranulocyte antibody appears promising. Some investigations have focused on fluorodeoxyglucose imaging. Although this method is sensitive, specificity is a concern.

Two-Stage Exchange Hip Arthroplasty for Deep Infection

Although the risk of infection after total hip arthroplasty has decreased over the last three decades with the use of prophylactic antibiotics, laminar airflow operating rooms and whole-body exhaust suites, deep infection after total hip arthroplasty remains a serious complication. Significant morbidity to the patient and the cost to the health care system remain. During this period of time, diagnostic techniques also have improved including the use of polymerase chain reaction amplification. Treatment options now include: suppressive antibiotics, irrigation and debridement with retention of components, one-stage reimplantation, two-stage reimplantation, and salvage procedures. Based on the medical literature, the successful eradication of a total joint replacement infection with a two-stage reimplantation protocol is over 90% while the success rate with a one-stage protocol is approximately 80%. These success rates may decline however as the prevalence of antibiotic resistant organisms increases. Current controversies regarding two-stage reimplantation protocols include: duration of intravenous antibiotic therapy, timing of the reimplantation, the use of allograft bone in the reconstruction, the choice of fixation (cement versus cementless), and the use of antibiotic-loaded cement spacers.

5. Utility of F-18 FDG Imaging for Diagnosing the Infected Joint Replacement

Purpose: F-18 FDG (FDG) is reportedly useful for detecting infection. Because the procedure is simple, with results being readily available, this prospective study was undertaken to evaluate the utility of FDG imaging for diagnosing infected joint replacements.Methods: 26 pts, 18 females and 4 males between 37 and 87 years old, with 31 joint replacements were studied. 21 pts had single joint replacement (10 hip, 11 knee); 5 pts had bilateral replacements (1 hip, 4 knee). Imaging was performed on a Hybrid PET system, with measured attenuation correction, one hour after administration of 150 MBq FDG. Increased peri-prosthetic uptake compared to adjacent, presumably normal, activity was interpreted as positive for infection.Results: 11 of 31 prostheses were infected. Sensitivity, specificity, and accuracy of FDG were 100%, 55%, and 71% respectively. The PPV was 55% and the NPV was 100%. Excluding the 5 asymptomatic prostheses in pts with bilateral joint replacements, the sensitivity, specificity, and accuracy were 100%, 47%, and 69% respectively. The PPV was 58% and the NPV was 100%. 4 pts with infected prostheses underwent a total of 6 follow-up studies after treatment. In 1 pt with persistent infection, all 3 follow-up studies were true positive. In the other 3 pts in whom infection had been eradicated, follow-up FDG studies were false positive.Conclusion: FDG imaging is sensitive but not specific; consequently, its role in pts with suspected prosthetic infection is limited to that of a screening test. These data also suggest that this technique is not useful for monitoring response to treatment.

(iii) The infected joint replacement: Prevention, diagnosis and treatment

(iii) The infected joint replacement: Prevention, diagnosis and treatment

Treatment of Infected Total Joint Replacement

Treatment of Infected Total Joint Replacement

Radionuclide imaging after skeletal interventional procedures

Although nuclear medicine is often used as an adjunct to planning skeletal therapeutic interventions, its role in the assessment of these various interventional procedures, after the fact, is equally important. Skeletal therapeutic interventions studied with radionuclide imaging include bone grafts, the postoperative spine, and joint replacements. Vascularized bone grafts allow the successful reconstruction of large bone gaps. Early detection of vascular compromise permits prompt reevaluation of the vascular anastomosis so that potentially reversible causes of ischemia can be corrected. Radionuclide bone scintigraphy is a simple noninvasive method to evaluate the anastomotic patency of these grafts. Scintigraphically, vascular patency is characterized by normal or diffusely increased tracer uptake throughout the graft, whereas failure of the graft presents as photopenia. Bone scintigraphy, especially single photon emission computed tomography (SPECT), is of considerable value in the work-up of patients with persistent back pain after spinal surgery. Postoperatively, spinal fusion is characterized by diffusely increased uptake of radiotracer in the fused area. In contrast, focally increased uptake has been shown to be related to bony nonunion or pseudoarthroses. In patients who have undergone laminectomy, SPECT bone scintigraphy can localize the level of maximum instability and vertebral stress. The radionuclide evaluation of joint replacement complications, especially of hip and knee prostheses, has been extensively studied for nearly 2 decades. Bone scintigraphy is probably most useful when the images are normal. Although periprosthetic sites of increased uptake may be indicative of postoperative problems such as loosening or infection, they may also merely reflect postoperative changes. Dual tracer studies, focusing primarily on the diagnosis of the infected joint replacement, have consequently become the norm. Bone-gallium scintigraphy was the earliest dual tracer modality used, with an accuracy of 60% to 80%. The current radionuclide study of choice for diagnosing the infected prosthesis is labeled leukocyte-marrow imaging. Both leukocytes and colloid tracers accumulate in marrow, whereas only leukocytes accumulate in infection. This technique facilitates the discrimination of labeled leukocyte uptake in aberrant, but not abnormal, marrow from uptake in infection. The reported accuracy of this technique consistently exceeds 90%.

Management of infected total joint replacement

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Local immune inflammatory response to infected total hip and knee replacements.

We studied the tissue response for periprosthetic pseudosynovial tissue in seven patients with a purulent endoprosthetic infection and six patients with common prosthesis loosening, using specific monoclonal antibodies in avidin-biotin-peroxidase complex staining. In infected cases, proline 4-hydroxylase positive fibroblasts dominated the stroma of the vascularized periprosthetic connective tissue, whereas diffuse local infiltrations of mononuclear cells characterized the cellular histological overview. Local cellular response consisted of CD11b and MHC locus II antigen-positive immunoreactive monocytes/macrophages and of T lymphocytes, mostly of the CD4 subset. Only a few CD25-positive cells could be detected. The local cellular response in six patients with prosthesis loosening of nonbacterial origin was mild, showing a sparse perivascular infiltration of CD11b- and Ia-positive monocytes/macrophages and CD4/CD8-positive T lymphocytes in a proportion of 2:1. Only occasional CD15- or lactoferrin-positive neutrophils and CD25-positive lymphocytes could be detected. Our results from chronically infected joint replacements suggest that neutrophils, being virtually absent in the tissue compartment, do not contribute to pathological events in the "pseudojoint" cavity, whereas local tissue response consists of a mononuclear inflammatory cell reaction of a macrophage-dependent foreign-body type.

COST-EFFECTIVENESS ANALYSIS OF PHARMACEUTICALS: ITS INFORMATIONAL CONTENT AND AN EXAMPLE

The importance of cost-effectiveness analysis within the health care sector will increase. This is due to changes in the health care sector where there is an emphasis on improving the efficiency. The changes will influence the incentive structure and, subsequently, the demand for reliable managerial information. Cost-effectiveness analysis of pharmaceuticals is a good example of the state-of-the-art of cost-effectiveness applied to health care. A study on the cost-effectiveness of prophylaxis against infection in total joint replacement is presented as an example of an economic evaluation of pharmaceuticals.

Infection in Total Joint Replacement

Although a small number of infections in total joint replacements are blood borne from distant sources, most infections appear to have been derived at operation. Strenuous attempts to reduce this risk by cleaning the air in the wound environment, coupled with prophylactic antibiotics, have reduced infection rates by an order of magnitude in a decade. During that time the potential for exchange arthroplasty in established infection has been shown, and the results are encouraging. Rigorous infection control is the key to containing this difficult and expensive problem.

The infected prosthetic total temporomandibular joint replacement: Report of two cases

Two cases of infected total temporomandibular joint replacements are reported. The WBC count, erythrocyte sedimentation rate, and temperature were within normal limits, but erythema, edema, and pain provided the initial clue to the infection. Ultrasonography ultimately revealed a fluid collection and allowed aspiration of the fluid-filled cavity, providing a diagnosis and directing antibiotic therapy.

Postoperative Infection of Total Joint Replacement and its Risk Factors The Effect of Bone Cement and Wear Debris upon Leucocyte Function

Postoperative Infection of Total Joint Replacement and its Risk Factors The Effect of Bone Cement and Wear Debris upon Leucocyte Function

How far does prophylaxis against infection in total joint replacement offset its cost?

Selection of a cost effective method of prophylaxis against infection for patients undergoing total joint replacement was shown to depend on the number of arthroplasties performed each year at individual hospitals. When 100 arthroplasties were performed each year the prophylactic use of systemic antibiotics minimised the total costs of the department--that is, the combined costs of prophylaxis and reoperation for deep sepsis. Some departments also used local antibiotic prophylaxis in the form of polymethylmethacrylate cement impregnated with gentamicin or a combination of systemic and local prophylaxis at almost as low a total cost and with comparable effect. Selection of a method of prophylaxis should not be determined solely on the basis of reducing costs. When a value was assigned to the effects of loss of health an economic optimum was established that allowed selection of a more costly method of prophylaxis together with further reductions in the incidence of infection and the need for reoperation.