Infection following total knee arthroplasty: prevention and management

Diagnostic value of triple-phase bone scintigraphy for the diagnosis of infection around antibiotic-impregnated cement spacers

Introduction

Two-stage revision arthroplasty is today considered as the gold standard for control of chronic deep prosthetic infection. Although the revision arthroplasty should only be considered when infection is eliminated, the diagnosis of residual infection prior to the revision remains a challenging problem.

Materials and methods

We evaluated triple-phase bone scintigraphy as a useful diagnostic test for the detection of residual infection around the antibiotic-impregnated cement spacer in patients waiting for the second-stage revision hip or knee arthroplasty. Increased uptake of radioisotope in all three phases was considered positive for infection. The final diagnosis was based on histopathological results in addition to microbiologic examinations of surgical specimens.

Results

Histopathological examination showed positive in 17 and negative in 13 out of 30 examinations. Among 17 samples positive for histopathology, there were only 4 samples positive for bacterial culture. All samples negative for histopathology showed negative for bacterial culture. The positive and negative predictive values of triple-phase bone scintigraphy for the presence of infection were 80% and 90%, respectively. The diagnostic sensitivity was 94% and the specificity was 69%.

Conclusion

Triple-phase bone scintigraphy was useful in the diagnosis of infection around the articulating cement spacer. In particular, when triple-phase bone scintigraphy shows negative, the residual infection around the cement spacer is unlikely.

Nasal MRSA screening for surgical patients: predictive value for postoperative infections caused by MRSA

PURPOSE

Postoperative methicillin-resistant Staphylococcus aureus (MRSA) infections are occasionally fatal. We hypothesized that nasal MRSA screening might predict the risk of postoperative MRSA infections. The aim of the current study was to elucidate the relationship between the positivity of nasal MRSA screening and postoperative MRSA infections.

METHODS

Six hundred and fourteen surgical patients who were admitted to the intensive care unit and underwent nasal MRSA screening between April 2006 and March 2011 were divided into MRSA-positive and -negative groups. The incidence of postoperative MRSA infections in the MRSA-positive and MRSA-negative groups were compared, and various risk factors for MRSA infections were evaluated.

RESULTS

The incidence of postoperative MRSA infections, such as pneumonia and enteritis, in the MRSA-positive group was significantly higher than that in the MRSA-negative group (41.9 vs. 3.1 %). The significant independent risk factors for postoperative MRSA infections were a positive MRSA screening, an operation lasting more than 300 min and an emergency operation. A positive MRSA screening was the most statistically significant risk factor for postoperative MRSA pneumonia and enteritis, but was not a risk factor for MRSA surgical site infections.

CONCLUSION

Nasal MRSA screening can help to identify patients who have an increased risk of developing postoperative MRSA infections, and would enable physicians to take a prompt action if these complications occur.

Is there still a place for continuous closed irrigation in the management of periprosthetic total knee infection?

In recent decades, many technical improvements have been achieved in the use of prosthetic joints, and the risk of infection has been greatly reduced, to current rates of 0.4-2.0% following primary knee replacement. However, the increasing rate of joint replacements being performed means that the absolute number of such infections remains significant and poses substantial costs to healthcare systems worldwide. Accordingly, further strategies to treat and prevent total joint infections should be investigated.

Infections following knee replacements can compromise the function and durability of arthroplasty. When these infections occur during the immediate postoperative period, irrigation and debridement with component retention can be attempted to salvage the implant. This is an attractive, cheap, low-morbidity treatment for periprosthetic knee infection. However, the results published regarding this procedure are uneven; some studies report the eradication of prosthetic joint infection by debridement alone in 70-90% of cases but conversely, others have reported a high failure rate for this procedure, averaging 68% (61-82%). The difference could be attributed in part to the multiplicity of variables that may influence the success of the procedure. One such is that of treatment with a continuous irrigation system, which has the theoretical advantage of enabling the administration of antimicrobial agents, as well as the drainage of debris and blood clots.

The objective of this study is to elucidate the overall efficacy of irrigation and debridement with prosthesis retention in infected total knee arthroplasty and to determine whether the addition of a continuous irrigation system influences this efficacy.

The use of erythromycin and colistin-loaded cement in total knee arthroplasty does not reduce the incidence of infection: a prospective randomized study in 3000 knees

BACKGROUND

The use of antibiotic-loaded cement is believed to prevent infection in primary total knee arthroplasty, but there is a lack of randomized studies to support this concept. The aim of this study was to evaluate the use of an antibiotic-loaded cement to reduce the infection rate in primary total knee arthroplasty.

METHODS

This is a prospective randomized study with 2948 cemented total knee arthroplasties, in which bone cement without antibiotic was used in 1465 knees (the control group) and a bone cement loaded with erythromycin and colistin was used in 1483 knees (the study group). All patients received the same systemic prophylactic antibiotics. The patients were followed for a minimum of twelve months. The rate of infection was analyzed according to the criteria of the Centers for Disease Control and Prevention.

RESULTS

The rate of deep infection (1.4% in the control group and 1.35% in the study group; p = 0.96) and the rate of superficial infection (1.2% and 1.8%, respectively; p = 0.53) were similar in both groups. The factors related to a higher rate of deep infection in a multivariate analysis were male sex and an operating time of >125 minutes.

CONCLUSIONS

The use of erythromycin and colistin-loaded bone cement in total knee arthroplasty did not lead to a decrease in the rate of infection when systemic prophylactic antibiotics were used, a finding that suggests that the use of antibiotic-loaded bone cement would not be indicated in the general population. Further research is needed to assess whether its use is recommended for patients with a higher risk of infection.

Simultaneous bilateral total knee arthroplasty. A multicenter feasibility study

INTRODUCTION

The value and risk of simultaneous total knee arthroplasty (TKA) in patients with bilateral knee arthritis is a subject of debate.

HYPOTHESES

The risk of complications following simultaneous bilateral TKA will be increased compared to the rates published in the literature for unilateral TKA, and the clinical and functional outcomes will be poorer in this particular group.

MATERIALS AND METHODS

One hundred and twenty-three patients who underwent simultaneous bilateral TKA between 2005 and 2011 in five specialized, high volume centers were evaluated. The files were analyzed retrospectively after a mean 33 months of follow-up.

RESULTS

The mean hospital stay was 11 days. Mean blood loss was 4.1g/dL. A postoperative transfusion was performed in 68 patients (55%), with a mean 3.1 units of blood. The mean global IKS score increased from 90 to 150 points. Eighty patients would agree to undergo simultaneous bilateral TKA again (65%), and 70 would recommend this procedure to others (57%).

DISCUSSION

The hypothesis was not confirmed: the risk of complications was not increased compared to the generally accepted risk of a unilateral procedure. The risk of complications in this study was very similar to that published in the literature for the same therapeutic strategy. Therefore, there is no solid medical evidence to prevent recommending this strategy. The results of the participating centers suggest that this therapeutic approach should be continued in selected indications.

LEVEL OF EVIDENCE

IV, retrospective study.

In Vitro Biofabrication of Tissues and Organs

In vitro fabrication of tissues and the regeneration of internal organs are no longer regarded as science fiction but as potential remedies for individuals suffering from chronic degenerative diseases. Tissue engineering has generated much interest from researchers in many fields, including cell and molecular biology, biomedical engineering, transplant medicine, and organic chemistry. Attempts to build tissues or organs in vitro have utilized both scaffold and scaffold-free approaches. Despite considerable progress, fabrication of three-dimensional tissue constructs in vitro remains a challenge. In this chapter, we introduce and discus current concepts of tissue engineering with particular focus on future clinical application.

Perioperative complications following total joint replacement

Total joint arthroplasty is a safe and highly effective treatment for moderate to severe osteoarthritic symptoms and other causes of joint derangement in the elderly population. Significant improvements in pain, function, and quality of life are nearly universal, with a low rate of complications and adverse outcomes. Because of its success and cost-effectiveness, the rate of utilization of TJR is increasing, and all health care providers must be familiar with the potential complications and perioperative management of these patients. Elderly patients may be at a higher risk for postoperative medical complications; however, the majority of these complications are minor and many are avoidable with appropriate preoperative screening and careful postoperative management. As with all patients undergoing TJR, patients should be prophylactically treated for infection and thromboembolism and carefully followed for the development of these potential complications as well as fracture, hip dislocation, and neurovascular dysfunction. Postoperative delirium may be minimized and prophylactically treated in appropriate elderly patients to maximize recovery and promote safety.

Increased revision rates after total knee arthroplasty in patients who smoke

The purpose of this study was to compare the clinical outcomes of total knee arthroplasty in patients who reported a history of tobacco use with those who were nonsmokers. Between 2006 and 2009, there were 131 total knee arthroplasties performed in patients who were smokers and 490 in patients who did not smoke. At a mean follow-up of 47 months (range, 24-79 months), the patients who were smokers had a statistically decreased overall survivorship of 90% (13 revisions) compared with 99% (5 revisions) in the nonsmokers. Surgical complication rates were not significantly different between the 2 groups; however, there was a significant difference in medical complications. Total knee arthroplasty in smokers has a higher risk of negative clinical outcomes compared with nonsmokers.

Does dual antibiotic prophylaxis better prevent surgical site infections in total joint arthroplasty?

INTRODUCTION

It is unclear which antibiotic regimen provides the best prophylaxis against surgical site infection (SSI) in patients undergoing hip and knee surgery.

QUESTIONS/PURPOSES

Therefore, we determined whether dual antibiotic prophylaxis (1) reduced the rate of SSI compared to single antibiotic prophylaxis and (2) altered the microbiology of SSI.

METHODS

We retrospectively reviewed 1828 primary THAs and TKAs performed between September 1, 2008 and December 31, 2010. We divided patients into two groups: (1) those who received a dual prophylactic antibiotic regimen of cefazolin and vancomycin (unless allergy), or (2) received cefazolin (unless allergy) as the sole prophylactic antibiotic. There were 701 males and 1127 females with an average age of 56 years (range, 15–97 years). We limited followup to 1 year, presuming subsequent infections were not related to the initial surgery.

RESULTS

During this period, there were 22 SSIs (1.2%). The infection rates for dual antibiotic prophylaxis compared to a single antibiotic regimen were 1.1% and 1.4%, respectively. Of 1328 patients treated with dual antibiotic prophylaxis, only one (0.08%) SSI was culture positive for methicillin resistant Staphylococcus aureus (MRSA), while four of 500 patients (0.8%) receiving only cefazolin prophylaxis had culture positive MRSA infection at the time of reoperation.

CONCLUSION

The addition of vancomycin as a prophylactic antibiotic agent apparently did not reduce the rate of SSI compared to cefazolin alone. Use of vancomycin in addition to cefazolin appeared to reduce the incidence of MRSA infections; however, the number needed to treat to prevent a single MRSA infection was very high.

LEVEL OF EVIDENCE

Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Primary total knee arthroplasty infected with Serratia marcescens

We report an unusual case of a Serratia marcescens infection of total knee arthroplasty 4 weeks after the procedure following aspiration carried out on the ward (contrary to local protocol). This was successfully treated with thorough wound debridement, irrigation, change of the polyethylene liner and systemic antibiotics using intravenous meropenem for 3 weeks followed by oral ciprofloxacin for another 3 weeks. Our patient made an uneventful recovery and there was no reported recurrence of infection at 8 months of follow-up. We are unsure as to whether the infection was introduced at the time of the joint aspiration or was a complication of the initial procedure despite all the standard aseptic measures taken at the time of surgery.

Identification and treatment of infected total hip arthroplasty

Periprosthetic joint infection (PJI) in the hip following prosthetic joint placement is a devastating outcome of an otherwise often successful surgical treatment (total-hip arthroplasty). Management of PJI is dependent upon accurate diagnosis and successful treatment, both of which are challenging. Recently, great strides have been made in improving the diagnosis of PJI, which has no 'gold standard' diagnostic tool. Proper diagnosis is essential as untreated or undetected PJI can quickly lead to biofilm formation on the implant surface depending upon the infecting organism. Upon complete biofilm formation, successful treatment requires prosthetic resection with immediate or delayed reimplantation. Even with the most aggressive surgical treatment, PJI eradication currently has a success rate of approximately 80%. Unfortunately, technologies to improve the local delivery of antibiotics are not expected to be available in the near future.