Results of 2-stage reimplantation for infected total knee arthroplasty

Local antibiotic delivery via intra-articular catheter infusion for the treatment of periprosthetic joint infection: a systematic review

INTRODUCTION

There is an increasing interest in the use of intra-articular (IA) antibiotic infusion as a stand-alone or adjuvant therapy to standard revision surgery for periprosthetic joint infection (PJI). The objective of this systematic review is to evaluate the evidence with respect to this up-and-coming treatment modality.

METHODS

A systematic review of studies published until April 2023 was conducted using PubMed, Embase, MEDLINE and Cochrane databases. Quality assessment was performed with the National Institute of Health quality assessment tool. Inclusion criteria were adult patients (≥ 18 years) with a mean follow-up of ≥ 11 months and a score ≥ 6 on the National Institute of Health quality assessment tool. Primary outcome was eradication of infection.

RESULTS

15 articles, encompassing 631 PJIs in 626 patients, were included in the final analysis, all level IV case series. The majority was treated with single-stage revision with adjuvant IA antibiotic infusion (79.1%). The remaining PJIs were treated with stand-alone IA antibiotic infusion (12.2%), DAIR (debridement, antibiotics and implant retention) with adjuvant IA antibiotic infusion (5.7%) or two-stage revision with adjuvant IA antibiotic infusion (3.0%). Mean duration of IA antibiotic infusion was 19 days (range 3-50). An overall failure rate of approximately 11% was found. In total 117 complications occurred, 71 were non-catheter-related and 46 were catheter-related. The most common catheter-related complications were premature loss of the catheter (18/46) and elevated blood urea nitrogen (BUN) and creatinine levels (12/46).

CONCLUSIONS

Due to the lack of comparative studies the (added) benefit of IA antibiotic infusion in the treatment of PJI remains uncertain. Based on the current evidence, we would advise against using it as a stand-alone treatment. A prospective randomized controlled trial using a well-described infusion protocol is needed to see if the potential benefits justify the increased costs and potential complications of this treatment modality.

What Is the Most Effective Treatment for Periprosthetic Joint Infection After Total Joint Arthroplasty in Patients with Rheumatoid Arthritis?: A Systematic Review

BACKGROUND

Rheumatoid arthritis (RA) is a risk factor for periprosthetic joint infection (PJI) after total joint arthroplasty (TJA). The purpose of this study was to perform a systematic review comparing the failure rates of debridement, antibiotics, and implant retention (DAIR), one-stage exchange arthroplasty/revision (OSR), and 2-stage exchange arthroplasty/revision (TSR) for RA patients with PJI and identify risk factors in the RA population associated with increased treatment failure rate.

METHODS

PubMed, Ovid MEDLINE, and Ovid Embase databases were screened with the terms "rheumatoid arthritis," "total joint arthroplasty," "prosthetic joint infection," and "treatment for PJI" on August 29, 2021. Four hundred ninety-one studies were screened, of which 86 were evaluated. The primary outcome evaluated was failure of surgical treatment for PJI.

RESULTS

Ten retrospective cohort studies were included after full-text screening, yielding 401 patients with RA. Additional demographic and PJI management data were obtained for 149 patients. Patients with RA who underwent TSR demonstrated a lower failure rate (26.8%) than both DAIR (60.1%) and OSR (39.2%) (χ2 = 37.463, p < 0.00001). Patients with RA who underwent DAIR had a 2.27 (95% CI, 1.66-3.10) times higher risk of experiencing treatment failure than those who underwent TSR. Among risk factors, there was a significant difference in the C-reactive protein of patients who did vs. did not experience treatment failure (p = 0.02).

CONCLUSION

TSR has a higher rate of success in the management of PJI patients with RA compared with DAIR and OSR. The complete removal of the infected prosthesis and delayed reimplantation may lower the treatment failure rate.

LEVEL OF EVIDENCE

Level III. See Instructions for Authors for a complete description of levels of evidence.

Tibial Tubercle Osteotomy in Revision Total Knee Arthroplasty for Periprosthetic Infection: Indications and Outcomes

BACKGROUND

Adequate exposure is essential in revision total knee arthroplasty (RTKA). Tibial tubercle osteotomy (TTO) enhances exposure, but its use is controversial in the setting of periprosthetic infection. The purposes of this study were to determine (1) the rates of complications and revisions due to TTO during RTKA in the setting of a periprosthetic infection, (2) the rate of septic failure, and (3) functional outcomes at a minimum 2-year follow-up.

METHODS

A single-center retrospective study from 2010 to 2020 was performed. The cases of a total of 68 patients who received a TTO during RTKA in the setting of periprosthetic infection with a minimum follow-up of 2 years (mean, 53.3 months; range, 24 to 117 months) were analyzed. Complications and revisions due to TTO were reported. The functional outcomes were assessed using the Knee Society Score (KSS) and range of motion.

RESULTS

Seven knees (10.3%) had complications secondary to the TTO (3 had fracture-displacement of the TTO; 2, nonunion; 1, delayed union; and 1, wound dehiscence). The mean time to union (and standard deviation) was 3.8 ± 3.2 months (range, 1.5 to 24 months). Two knees (2.9%) underwent a TTO-related revision (1 had wound debridement, and 1 had tibial tubercle osteosynthesis). Eighteen knees (26.5%) had recurrence of infection requiring revision: 17 were managed with debridement, antibiotics, and implant retention (DAIR), and 1 had 2-stage RTKA. Flexion improved after surgery (from a mean of 70° to a mean of 86°; p = 0.009), as did the KSS knee (46.6 to 79; p < 0.001) and function (35.3 to 71.5; p < 0.001) subscores. Overall, 42.6% of infected knees managed with RTKA with the TTO procedure were considered successful without any complication at the last follow-up. Only 2 knees (2.9%) required revision related to the TTO.

CONCLUSIONS

TTO in RTKA involving periprosthetic infection is an effective surgical exposure aid and has excellent rates of union (97.1%) despite the presence of infection. However, the risk of failure because of persistent or recurrent infection remains high in the first 2 years following RTKA for infection.

LEVEL OF EVIDENCE

Therapeutic Level IV . See Instructions for Authors for a complete description of levels of evidence.

Change in organism between first- and second-stage revision for periprosthetic joint infection of knee arthroplasty independently associated with increased risk of failure

Aims

Achievement of accurate microbiological diagnosis prior to revision is key to reducing the high rates of persistent infection after revision knee surgery. The effect of change in the microorganism between the first- and second-stage revision of total knee arthroplasty for periprosthetic joint infection (PJI) on the success of management is not clear.

Methods

A two-centre retrospective cohort study was conducted to review the outcome of patients who have undergone two-stage revision for treatment of knee arthroplasty PJI, focusing specifically on isolated micro-organisms at both the first- and second-stage procedure. Patient demographics, medical, and orthopaedic history data, including postoperative outcomes and subsequent treatment, were obtained from the electronic records and medical notes.

Results

The study cohort consisted of 84 patients, of whom 59.5% (n = 50) had successful eradication of their infection at a mean follow-up of 4.7 years. For the 34 patients who had recurrence of infection, 58.8% (n = 20) had a change in isolated organism, compared to 18% (n = 9) in the infection eradication group (p < 0.001). When adjusting for confound, there was no association when the growth on the second stage was the same as the first (odd ratio (OR) 2.50, 95% confidence interval (CI) 0.49 to 12.50; p = 0.269); however, when a different organism was identified at the second stage, this was independently associated with failure of treatment (OR 8.40, 95% CI 2.91 to 24.39; p < 0.001). There were no other significant differences between the two cohorts with regard to patient demographics or type of organisms isolated.

Conclusion

Change in the identified microorganism between first- and second-stage revision for PJI was associated with failure of management. Identification of this change in the microorganism prior to commencement of the second stage may help target antibiotic management and could improve the success of surgery in these patients.

Functional Outcome of Above-Knee Amputation After Infected Total Knee Arthroplasty

Background

Periprosthetic joint infection is a serious complication of total knee arthroplasty (TKA). Management usually involves irrigation and debridement, polyethylene liner exchange, one-stage revision, two-stage revision, knee arthrodesis, or ultimately above-knee amputation (AKA). We present our experience with 21 patients who underwent AKA as a sequela of unresolved infected TKA, highlighting their etiology and functional outcomes.

Methods

A retrospective chart review was performed for all cases of infected TKA treated with AKA at 1 institute from January 2007 to December 2020, with a minimum follow-up of 1 year. Patient demographics, Charlson comorbidity index, culture results, ambulation status, prosthesis fitting, and functional outcomes were collected. Short Form-36 and activities of daily living questionnaires were used for functional outcome assessment.

Results

Twenty-one patients were identified, 7 of whom were male (33.3%). Mean ± standard deviation follow-up was 5.7 ± 3.1 years (range, 1-11 years). Mean ± standard deviation age was 57.9 ± 10.7 years (range, 38-87 years), and the mean body mass index was 33.5 ± 6.4 kg/m2 (range, 25.4-46 kg/m2). Gram-positive organisms were identified in 15 cases (66.7%). Prosthesis fitting was successful in 17 patients (81%). Post-AKA ambulation was achieved in 12 patients (57.1%). The ambulating group showed higher Short Form-36 and activities of daily living scores when compared with patients who did not ambulate (60.2 vs 43.3, P = .041, and 67.2 vs 52.7, P = .029, respectively).

Conclusions

AKA should be considered solely as the final recourse for infected TKA. Despite the low-to-moderate patient-reported postoperative outcomes, prosthesis fitting and maintaining ambulation can improve postoperative functional outcomes.

Description of reinfection of joint prosthesis after 2-stage replacement (infection of the 2nd stage prosthesis): A multicenter study

INTRODUCTION

Two-stage exchange is the gold standard in the surgical management of prosthetic joint infection (PJI). However, perioperative reinfections (RePJI) can occur to newly inserted prosthesis, which highlights the importance of an adequate antibiotic prophylaxis, although there is scarce evidence in this field. Our objective was to evaluate the characteristics of RePJI, its prognosis and the antibiotic prophylaxis that is commonly used in second-stage surgery.

METHODS

Multicentric retrospective observational study in Spanish hospitals including patients with RePJI between 2009 and 2018.

RESULTS

We included 92 patients with RePJI from 12 hospitals. The most frequent isolated microorganism was Staphylococcus epidermidis in 35 cases (38.5%); 61.1% of staphylococci were methiciliin-resistant. In 12 cases (13%), the same microoganism causing the primary PJI was isolated in RePJI. When comparing with the microbiology of primary PJI, there were more cases caused by Gram-negative bacteria (the most frequent was Pseudomonas spp.) and less by Gram-positive bacteria. Failure occured in 69 cases (75%). There were 43 different courses of antibiotic prophylaxis after the second-stage surgery; the most frequent was a unique preoperative cefazolin dose, but most patients received prophylaxis before and after the second-stage surgery (61 cases).

CONCLUSIONS

The most frequent microorganisms in RePJI are coagulase-negative staphylococci, although Gram-negative bacteria, especially Pseudomonas spp. are also common. There is a significant heterogeneity in antibiotic prophylaxis for a second-stage surgery. ReIPJI treatment has a high failure rate.

Management of acute periprosthetic knee infection: a comparison of arthroscopic and open debridement

INTRODUCTION

In acute periprosthetic knee infections, debridement and implant retention (DAIR) is the preferred treatment prior to one- and two-stage revisions. The aim of this study is to compare the outcomes of arthroscopic and open debridement of infected primary total knee arthroplasties (TKA).

MATERIAL AND METHODS

We analyzed clinical, laboratory, and antibiotic treatment data, collected in patients with periprosthetic knee infection treated with DAIR at a Swiss Level 1 orthopedic and trauma center over a 10-year period between January 2005 and May 2015. Inclusion criteria were primary total knee arthroplasty and early postoperative or acute hematogenous periprosthetic joint infection (PJI). The primary endpoint was the need for further revision surgery due to persistent infection. The secondary endpoint was the prosthesis salvage in further infection surgeries.

RESULTS

Forty-two patients with 44 acute or hematogenous periprosthetic knee infections were included. We recorded 20 recurrent infections (45%) in our study population: 10 (77%) out of 13 in the arthroscopic DAIR group and 10 (32%) out of 31 in the open DAIR group. Two-stage revision, meaning complete removal of the TKA, insertion of a spacer and replantation at a second stage, had to be performed in three patients treated initially arthroscopically (23%) and in six patients treated initially with an open surgical procedure (21%).

CONCLUSIONS

Open debridement for acute periprosthetic knee infection shows clear benefits in terms of infection eradication and prosthesis salvage compared to arthroscopic DAIR.

Treatment patterns and failure rates associated with prosthetic joint infection in unicompartmental knee arthroplasty: A systematic review

Background

Prosthetic joint infection (PJI) following unicompartmental knee arthroplasty (UKA) is a rare but challenging complication. A paucity of literature exists regarding the management of PJI in UKA. This systematic review aims to assess current treatment patterns in UKA PJI and analyze the failure rates associated with treatment.

Methods

PubMed, Scopus, and EMBASE were systematically searched for studies that presented cases of PJI following UKA. Data regarding study design, country of publication, index procedure type, diagnosis of PJI, number and incidence of PJI, timing of PJI (acute versus chronic), treatment, and outcomes were recorded. Failure rates in acute and chronic PJI as well as total failure rates were analyzed.

Results

Sixteen articles were identified that met inclusion criteria. These included 97 PJI cases (37 acute, 58 chronic, 2 unknown timing); incidence across all studies of 0.80%. The most common treatment for all PJI cases was debridement, antibiotics, and implant retention (DAIR) (40.2%), followed by two-stage conversion to total knee arthroplasty (TKA) (33.0%), one-stage conversion to TKA (23.7%), and one-stage exchange UKA (3.1%). There were no significant differences in failure rates across procedures for acute, chronic or overall PJI management (p > 0.05 for all).

Conclusion

This systematic review found relatively few studies reporting on PJI after UKA compared to the available TKA evidence. Further research is warranted to better elucidate the most appropriate treatment of PJI after UKA in both the acute and chronic setting along with risk factors for failure.

Against the Norm: Do Not Rely on Serum C-Reactive Protein and White Blood Cell Count Only When Assessing Eradication of Periprosthetic Joint Infection

Introduction: Periprosthetic joint infections (PJI) following primary arthroplasty continue to be a serious complication, despite advances in diagnostics and treatment. Two-stage revision arthroplasty has been commonly used as the gold standard for the treatment of PJI. However, much discussion persists regarding the interim of the two-stage procedure and the optimal timing of reimplantation. Serology markers have been proposed as defining parameters for a successful reimplantation. The objective of this matched-pair analysis was to assess the role of serum C-reactive protein (CRP) and white blood cell count (WBC) in determining infection eradication and proper timing of reimplantation. We investigated the delta (∆) change in CRP and WBC values prior to both stages of two-stage revision arthroplasty as a useful marker of infection eradication. Methods: We analyzed 39 patients and 39 controls, matched by propensity score matching (BMI, age, ASA-classification), with a minimum follow-up of 24 months and treated with a two-stage revision THA or TKA in our institution. Data of serum CRP and WBC values were gathered at two selected time points: prior to the explantation of the implant (preexplantation) and following the completion of antibiotic treatment regimen, both systemic and with a drug-eluting cement spacer (prereimplantation). Patient records were reviewed electronically for preexisting comorbidities, overall health status, synovial fluid cultures, inflammatory serologies, revision surgeries, and recurrent or persistent infection based on the modified Musculoskeletal Infection Society criteria. Patient demographics, ∆CRP, ∆WBC, and time interval to reimplantation were statistically analyzed using receiver operator curves (ROC), Pearson’s correlation coefficient, Levene’s test, and Student’s t-test. Results: Infection-free patients exhibited higher mean CRP and WBC than did patients who were reinfected at both time points. When comparing preexplantation with prereimplantation values, the median ∆CRP was 9.48 mg/L (interquartile range (IQR) 2.3−36.6 mg/L) for patients who did not develop a reinfection versus 2.74 mg/L (IQR 1.4−14.2 mg/L) for patients who developed reinfection (p = 0.069). The median ∆WBC was 1.5 × 109/L (IQR 0.6−4.0 × 109/L) for patients who remained infection-free versus 1.2 × 109/L (IQR 0.8−2.2 109/L) for patients who developed reinfection (p = 0.072). Analysis of areas under the curve (AUC) using ROC demonstrated poor prediction of persistent infection by ∆CRP (AUC = 0.654) and ∆WBC (AUC = 0.573). Although a highly significant correlation was found between the interim interval and infection persistence (r = 0.655, p < 0.01), analysis using ROC failed to result in a specific threshold time to reimplantation above which patients are at significantly higher risk for reinfection (AUC = 0.507). Conclusion: No association could be determined between the delta change in serum CRP and WBC before and after two-stage revision arthroplasty for PJI and reinfection risk. Even though inflammatory serologies demonstrate a downtrending pattern prior to reimplantation, the role of CRP and WBC in determining the optimal timing of reimplantation seems to be dispensable. Planning a second-stage reimplantation requires assessing multiple variables rather than relying on specific numeric changes in these inflammatory marker values.

Long Term Results of Two-Stage Revision for Chronic Periprosthetic Knee Infection: A Multicenter Study

BACKGROUND

Long-term reinfection and mortality rates and clinical outcomes with sufficient subject numbers remain limited for patients undergoing two-stage exchange arthroplasty for chronic periprosthetic knee infections. The purpose of this study was to determine the long-term reinfection, complication, and mortality following reimplantation for two-stage exchange following knee arthroplasty.

METHODS

Retrospective review of 178 patients who underwent two-stage exchange knee arthroplasty for chronic PJI at three large tertiary referral institutions with an average of 6.63-year follow-up from reimplantation from 1990 to 2015. Rates of reinfection, mortality, and all-cause revision were calculated along with the cumulative incidence of reinfection with death as a competing factor. Risk factors for reinfection were determined using Cox multivariate regression analysis.

RESULTS

Overall rate of infection eradication was 85.41%, with a mortality rate of 30.33%. Patients with minimum 5-year follow-up (n = 118, average 8.32 years) had an infection eradication rate of 88.98%, with a mortality rate of 33.05%.

CONCLUSION

This is a large series with long-term follow-up evaluating outcomes of two-stage exchange knee arthroplasty resulting in adequate infection eradication and high mortality. Results were maintained at longer follow-up. This technique should be considered in patients with chronic PJI; however, realistic expectations regarding long-term outcomes must be discussed with patients.

Long Term Results of Two-Stage Revision for Chronic Periprosthetic Hip Infection: A Multicenter Study

BACKGROUND

Two-stage exchange arthroplasty remains the gold standard in the United States for treatment of chronic periprosthetic joint infection (PJI). Long-term reinfection rates and clinical outcomes with sufficient subject numbers remain limited. The purpose was to evaluate the long-term outcomes following two-stage exchange following hip arthroplasty.

METHODS

Retrospective review of 221 patients who underwent two-stage exchange hip arthroplasty for chronic PJI at three large tertiary referral institutions from 1990-2015. Outcomes including reinfection, mortality, and all-cause revision were calculated. Cumulative incidence of reinfection with death as competing factor was also calculated. Risk factors for reinfection were determined using Cox multivariate regression analysis.

RESULTS

Rate of infection eradication and all-cause revision was 88.24% and 22.6%, respectively. Overall mortality rate was 40.72%. Patients with minimum five-year follow-up (n = 129) had a success rate of 91.47% with mortality rate of 41.1%. Major risk factors for reinfection included polymicrobial infection (HR = 2.36, 95% CI: 1.08-5.14) and antibiotic resistant organism (HR = 2.36, 95% CI: 1.10-5.04).

CONCLUSION

This is the largest series with greater than 5-year follow-up evaluating outcomes of two-stage exchange hip arthroplasty. This technique resulted in a relatively high infection eradication, however, the mortality rate is alarmingly high. Antibiotic resistant organisms appear to be highest risk factor for failure.

Predictors of failure of two-stage revision in periprosthetic knee infection: a retrospective cohort study with a minimum two-year follow-up

PURPOSE

Despite the standardization of two-stage knee revision protocols, a high percentage of failures still occurs. Identifying the predictors of failure is necessary to determine appropriate management and counsel for patients with a periprosthetic knee infection. This study aimed to identify risk factors predicting the failure, to describe implant survival, and to report the mid-term clinical outcomes of patients undergoing two-stage revision for periprosthetic knee infection.

METHODS

Data of patients who underwent two-stage knee revision from 2012 to 2016 were analyzed, and 108 patients were included. The mean age was 66.6 ± 9.2 years. The mean follow-up was 52.9 ± 15.6 months. Logistic regression was conducted to identify predictors of treatment failure. Kaplan-Meier curves were generated to assess implant survival. Preoperative functional outcomes were compared to those registered at the final follow-up.

RESULTS

Difficult-to-treat infections (OR = 4.2, 95% CI 1.2-14.5, p = 0.025), the number of previous surgeries (OR = 1.8, 95% CI 1.2-2.6, p = 0.005), and the level of tibial bone defect (OR = 2.3, 95% CI 1.1-4.7, p = 0.027) significantly predicted the failure of two-stage knee revision. Survivorship of implants was significantly lower for patients presenting these risk factors (p < 0.05). Mean Knee Society Score improved from 49.0 ± 12.0 to 80.2 ± 13.6 (p < 0.001). Mean Oxford Knee Score improved from 22.2 ± 4.9 to 36.1 ± 6.0 points (p < 0.001).

CONCLUSION

Difficult-to-treat pathogens, the number of previous surgeries, and the level of tibial bone defect were independent risk factors of two-stage knee revision failure. Overall, the two-stage protocol provided a good survival rate and functional outcome.

Periprosthetic Joint Infection (PJI)—Results of One-Stage Revision with Antibiotic-Impregnated Cancellous Allograft Bone—A Retrospective Cohort Study

Controversy exists regarding the optimal treatment of periprosthetic joint infection (PJI), considering control of infection, functional results as well as quality of life. Difficulties in treatment derive from the formation of biofilms within a few days after infection. Biofilms are tolerant to systemically applied antibiotics, requiring extreme concentrations for a prolonged period. Minimum biofilm eradicating concentrations (MBEC) are only feasible by the local application of antibiotics. One established approach is the use of allograft bone as a carrier, granting a sustained release of antibiotics in very high concentrations after appropriate impregnation. The purpose of this study was to determine the rate of reinfection after a one-stage revision of infected hip or knee prostheses, using antibiotic-impregnated allograft bone as the carrier and avoiding cement. Between 1 January 2004 and 31 January 2018, 87 patients with PJI, according to MSIS, underwent a one-stage revision with antibiotic-impregnated cancellous allograft bone. An amount of 17 patients had insufficient follow-ups. There were 70 remaining patients (34 male, 36 female) with a mean follow-up of 5.6 years (range 2–15.6) and with a mean age of 68.2 years (range 31.5–86.9). An amount of 38 hips and 11 knees were implanted without any cement; and 21 knees were implanted with moderate cementing at the articular surface with stems always being uncemented. Within 2 years after surgery, 6 out of 70 patients (8.6%, CI 2–15.1) showed reinfection and after more than 2 years, an additional 6 patients showed late-onset infection. Within 2 years after surgery, 11 out of 70 patients (15.7%, CI 7.2–24.2) had an implant failure for any reason (including infection) and after more than 2 years, an additional 7 patients had an implant failure. Using Kaplan-Meier analysis for all 87 patients, the estimated survival for reinfection was 93.9% (CI 88.8–99.1) at 1 year, 89.9% (CI 83.2–96.6) at 2 years and 81.5% (CI 72.1–90.9) at 5 years. The estimated survival for implant failure for any reason was 90.4% (CI 84.1–96.7) at 1 year, 80.9% (CI 72.2–89.7) at 2 years and 71.1% (CI 60.3–81.8) at 5 years. One-stage revision with antibiotic-impregnated cancellous allograft bone grants comparable results regarding infection control as with multiple stages, while shortening rehabilitation, improving quality of life for the patients and reducing costs for the health care system.

The Joint-Specific BACH classification: A predictor of outcome in prosthetic joint infection

BACKGROUND

There is currently no commonly accepted method of stratifying complexity of prosthetic joint infection (PJI). This study assesses a new classification, the Joint-Specific, Bone involvement, Anti-microbial options, Coverage of the soft tissues, Host status (JS-BACH) classification, for predicting clinical and patient reported outcomes in PJI.

METHODS

Patients who received surgery for PJI at two centres in the UK between 2010 and 2015 were classified using JS-BACH as 'uncomplicated', 'complex' or 'limited treatment options'. Patient reported outcomes were recorded at 365-days following the index operation and included the EuroQol EQ-5D-3L index score and the EQ-visual analogue score (VAS). Clinical outcome data were obtained from the most recent follow-up appointment.

FINDINGS

220 patients met the inclusion criteria. At 365-days following the index operation, patients with 'uncomplicated' PJI reported similar EQ-index scores (0.730, SD:0.326) and EQ-VAS (79.4, SD:20.9) compared to the age-matched population. Scores for 'uncomplicated' PJI were significantly higher than patients classified as having 'complex' (EQ-index:0.515 SD:0.323, p = 0.012; EQ-VAS:68.4 SD:19.4, p = 0.042) and 'limited treatment options' PJI (EQ-index:0.333 SD:0.383, p < 0.001; EQ-VAS:60.2, SD:23.1, p = 0.005). The median time to final follow-up was 4.7 years (inter-quartile range 2.7-6.7 years) where there were 74 cases (33.6%) of confirmed recurrence. Using death as a competing risk, the Cox proportional-hazards ratio of recurrence for 'complex' versus 'uncomplicated' PJI was 23.7 (95% CI:3.23-174.0, p = 0.002) and having 'limited options' verses 'uncomplicated' PJI was 57.7 (95% CI:7.66-433.9, p < 0.001).

INTERPRETATION

The JS-BACH classification can help predict likelihood of recurrence and quality of life following surgery for PJI. This will aid clinicians in sharing prognostic information with patients and help guide referral for specialist management of PJI.

Long-term outcome of two-stage revision surgery after hip and knee prosthetic joint infections: an observational study

Introduction: Two-stage revision surgery is the most frequently performed procedure in patients with a chronic periprosthetic joint infection (PJI). The infection eradication rates in the current literature differ between 54 % and 100 %, which could be attributed to different treatment strategies. The aim of this study was to retrospectively evaluate the infection eradication rate in patients with chronic PJI treated with two-stage revision surgery of the hip or knee in primary and re-revision cases. Methods: All patients treated with a two-stage revision for chronic PJI between 2005 and 2011 were analysed. Patient and infection characteristics were retrieved. Primary outcome was successful infection eradication at last follow-up. Successful eradication is specified as no need for subsequent revision surgery or suppressive antibiotic treatment. Results: Forty-seven patients were treated with a two-stage revision. Infection eradication was achieved in 36 out of 47 cases. Thirty-eight patients had positive cultures: 35 monomicrobial infections and 3 polymicrobial infections. Nine cases of culture-negative infections were identified. Accompanying eradication rates were 26 out of 35 cases, 2 out of 3 cases, and 8 out of 9 cases respectively. Mean follow-up was 128 (27–186) months. For hip and knee revisions the eradication rates were 22 out of 31 cases and 14 out of 16 cases respectively. After primary arthroplasty the infection was eradicated in 29 out of 38 cases and after re-revision in 7 out of 9 cases. Conclusion: In this study, the infection eradication rate for two-stage revision surgery after PJI of the hip and knee in primary and re-revision cases was 77 %. No statistically significant patient, infection and micro-organism characteristics were found which influence the infection eradication rates at long-term follow-up of 128 (27–186) months.

Risk of reinfection after two- or multiple-stage knee revision surgery using superficial vancomycin coating and conventional spacers

This study investigates the effect of superficial vancomycin coating (SVC) in two- or more-stage exchange procedures of prosthetic knee joint infections. We hypothesized that spacer treatment with SVC result in lower reinfection rates than conventional spacers after prosthetic reimplantation. Our secondary aim was to determine the demographic and treatment factors associated with reinfection rates. This retrospective cohort study compromised 96 cases with prosthetic knee infections. Twenty-four cases were treated with a temporary SVC spacer and 72 cases with conventional spacers. Prosthetic reinfection occurred after a median observation period of 1.7 ± 4.0 years in 24 cases (25%). The prevalence of having a reinfection was not significantly different between the two treatment groups (13% [3 cases] in the SVC group vs. 29% [21 cases] in the conventional spacer group [p = .104]). In seven cases (7.3%), two in the SVC group (8.3%) and five (6.9%) in the conventional spacer group (p ≥ .999), histological, respectively microbiological evaluations from the intraoperative specimens revealed persistent infection at the second stage. Nevertheless, in all seven cases no significant higher risk of periprosthetic reinfection was observed during follow-up (p = .750). Our secondary investigation of cofactors revealed that spacers additionally stabilized by nails were significantly associated with a 3.9-fold higher hazard ratio of sustaining a reinfection of revision prosthesis (p = .005).

The Double DAIR: A 2-Stage Debridement with Prosthesis-Retention Protocol for Acute Periprosthetic Joint Infections

Background

Debridement and implant retention (DAIR) has variable success as a treatment for acute periprosthetic joint infection (PJI), with generally poor outcomes reported in the literature¹. Because of the unacceptably high failure rate of DAIR, we implemented a 2-stage debridement protocol that includes the use of high-dose antibiotic beads between stages for the treatment of acute PJI. In 2 previous studies, with an average follow-up of 3.5 years in each study, we reported overall infection-control rates of 87% and 90%^2,3.

Description

Following exposure of the joint, cultures are obtained, and all modular components are removed, scrubbed, and soaked in an antiseptic solution. A thorough irrigation and debridement with complete synovectomy is performed, followed by temporary reinsertion of the original modular parts. High-dose antibiotic cement beads are inserted into the joint, and the joint is closed. Approximately 5 to 6 days later, a second debridement is performed, the beads are removed, and the new modular, sterile components are implanted. The patient is placed on a course of intravenous and, later, oral antibiotics, in addition to a standard postoperative rehabilitation protocol.

Alternatives

Long-term suppressive antibiotic therapy.One-stage DAIR.One-stage exchange arthroplasty.Two-stage exchange arthroplasty.Resection arthroplasty.Amputation.

Rationale

The treatment of acute PJI has historically consisted of a single irrigation and debridement, with exchange of modular parts and retention of the components, followed by intravenous antibiotic therapy. Despite having lower rates of patient morbidity compared with a 2-stage exchange arthroplasty, this more traditional procedure also has a higher rate of failure, with reported rates as high as 60% to 84%^4-12. The utility of component retention continues to be a topic of debate¹³. Alternatives to component retention include both 1- and 2-stage exchange procedures. Although these modalities offer potentially higher rates of infection control, they are associated with substantial patient morbidity, particularly in patients with well-fixed implants^14-16. Furthermore, exchange procedures may result in substantial iatrogenic bone loss, which can be problematic in revision total joint arthroplasty procedures, in which bone stock may already be limited. The double-DAIR protocol offers infection-control rates that are comparable with those of component-exchange procedures, but with the lower patient morbidity associated with component-retention procedures. Furthermore, the double-DAIR procedure provides the added benefit of retaining important bone stock.

Expected Outcomes

The success rate for the double-DAIR procedure has been reproducible, with infection-control rates of 87% and 90% reported in 2 studies from a single cohort at our institution^2,3. These rates represent a substantial improvement compared with a single irrigation and debridement¹, and are on par with those reported for 2-stage exchange arthroplasty procedures^17-21. The infection-control rates of the double-DAIR procedure did not significantly vary depending on whether infection occurred following a total knee or total hip arthroplasty. However, not surprisingly, patients who underwent debridement following a revision procedure had a lower rate of success (77.1% successful infection control) compared with patients debrided following a primary procedure (93.8% successful infection control). We could not demonstrate an association with organism and success or failure of treatment.Although not significant, there was a trend toward an association between the time from symptom onset to initial treatment and infection control (p = 0.07)². Patients with successful infection control underwent the initial debridement an average of 6.2 days after symptom onset, compared with 10.7 days in patients in whom treatment had failed. Several other studies have demonstrated that successful infection control is associated with earlier initial irrigation and debridement^22-27. We strongly support that, in the setting of confirmed acute PJI, prompt initiation of treatment optimizes the chances for successful infection control.

Important Tips

Thorough debridement is key to successful infection control of infection.Antibiotic-loaded bone cement has repeatedly been demonstrated to be safe, and we recommend its use^28-31.Extended oral antibiotics following debridement with component retention can increase infection-free survivorship³².

Long-term result of a second or third two-stage revision total knee arthroplasty for infected total knee arthroplasty

Background

Persistent or recurrent infection after two-stage revision total knee arthroplasty (TKA) for the treatment of an infected TKA is a dreaded complication. The purpose of the current study was to determine the ability of a second or third two-stage revision TKA to control infection, evaluate the long-term survivorship of the TKA prosthesis, and measure the functional outcome after a second or third two-stage revision TKA for reinfection.

Methods

We evaluated 63 patients (65 knees) with failed two-stage TKA treated with a second or a third two-stage revision TKA. There were 25 men and 38 women (mean age, 67 ± 10.2 years). The mean follow-up from the time of a second two-stage TKA revision was 15.1 years (range, 10 to 19 years) and the mean follow-up from the time of a third two-stage TKA revision was 7 years (range, 5 to 10 years).

Results

Overall, infection was successfully controlled in 49 (78%) of 65 knees after a second two-stage revision TKA was performed. In the remaining 16 knees, recurrent infection was successfully controlled in 12 knees (75%) after a third two-stage revision TKA. Survivorship, free of implant removal for recurrent infection, was 94% at 15.1 years (95% CI, 91 to 100%). Survival free of revision TKA for mechanical failure was 95% (95% CI, 92 to 100%).

Conclusions

The results of the current study suggest that a second or a third two-stage revision TKA is a reasonable option for controlling infection, relieving pain, and achieving a satisfactory level of function for patients with infected TKAs.

Periprosthetic knee infection reconstruction with a hinged prosthesis: Implant survival and risk factors for treatment failure

BACKGROUND

Severe bone and soft tissue defects are common after failed two-stage exchange arthroplasty for periprosthetic joint infection (PJI). There is a paucity of evidence on the outcomes of using a hinged prosthesis for knee PJI reconstruction during second-stage re-implantation, especially regarding implant survivorship, reinfection risk factors, and functionality after successful reconstruction.

METHODS

A total of 58 knee PJI patients with Anderson Orthopaedic Research Institute (AORI) type II/III defect and soft tissue insufficiency underwent reconstruction with hinged prosthesis. Enrolled patients adhered to a two-stage exchange arthroplasty protocol and were evaluated for a mean follow up of 65.1 months. Kaplan-Meier analysis was conducted for implant survivorship and infection-free survival. Multivariate analysis was used to determine independent risk factors for recurrent infections. Knee Society Score (KSS) was used to evaluate functional outcomes.

RESULTS

The survivorship of hinged prosthesis was 86.2% at 2 years and 70.2% at 5 years. Infection-free analysis revealed an estimation of 68.9% at 2 years and 60.6% at 5 years. Of the 58 patients, 13 (22.4%) developed recurrent PJI, three (5.2%) aseptic loosening, and one (1.7%) periprosthetic fracture. Multivariate analysis revealed that obesity (hazard ratio (HR), 3.11), high-virulent pathogen (HR, 3.44), and polymicrobial infection (HR, 3.59) were independent risk factors for reinfection. Patients showed a mean improvement of 32.8 ± 7.7 in Knee Society Clinical Score (KSCS) and 30.8 ± 11.0 in Knee Society Function Score (KSFS) after successful reconstruction (P<0.001).

CONCLUSIONS

Using hinged knee prosthesis for PJI reconstruction provided an overall implant survival of 70.2% and an infection-free survival of 60.6% at mid-term follow up. Obesity, virulent pathogens, and polymicrobial infections were independent risk factors for infection recurrence.

Fabrication and characterization of high molecular keratin based nanofibrous membranes for wound healing

Keratin is widely used in the biomaterial application, but the keratin prepared by the physical or chemical approach has relatively low molecular weight and mechanical properties. Here we report the preparation of high molecular keratin (HMK) with molecular weight of 120 kDa via multi-enzyme cascade pathway and its application in wound healing. Briefly, we prepared the soluble keratin from wool by keratinase and improved the molecular weight of keratin by transglutaminase (TGase). The HMK was coelectrospun with poly(3-hydroxybutyric acid-co-3-hydroxyvaleric acid) (PHBV) and the prepared nanofibrous mats demonstrated improved mechanical properties. Ag nanoparticles (AgNPs) were synthesized on the nanofibers via in situ bioreduction, using the above-mentioned keratinase as the reducing agent. It is demonstrated that the PHBV/HMK/AgNPs nanofibrous mats possess favorable antibacterial properties and good biocompatibility. Moreover, in vivo wound healing assessment, the PHBV/HMK/AgNPs membrane displayed better wound healing ability than the control group. These results indicate that PHBV/HMK/AgNPs mats exhibit significant potential in tissue engineering.

A Randomized Trial of Static and Articulating Spacers for the Treatment of Infection Following Total Knee Arthroplasty

BACKGROUND

There is no consensus whether the interim antibiotic spacer utilized in the 2-stage exchange arthroplasty should immobilize the joint or allow for motion. The purpose of this multicenter, randomized clinical trial was to compare static and articulating spacers as part of the 2-stage exchange arthroplasty for the treatment of chronic periprosthetic joint infection complicating total knee arthroplasty as defined with use of Musculoskeletal Infection Society criteria.

METHODS

Sixty-eight patients undergoing 2-stage exchange arthroplasty were randomized to either a static (32 patients) or an articulating (36 patients) spacer. An a priori power analysis determined that 28 patients per group would be necessary to detect a 13° difference in range of motion between groups. Six patients were excluded after randomization, 6 died, and 7 were lost to follow-up before 2 years.

RESULTS

Patients in the static group had a hospital length of stay that was 1 day greater than the articulating group after stage 1 (6.1 compared with 5.1 days; 95% confidence interval [CI], 5.3 to 6.9 days and 4.6 to 5.6 days, respectively; p = 0.032); no other differences were noted perioperatively. At a mean of 3.5 years (range, 2.0 to 6.4 years), 49 patients were available for evaluation. The mean motion arc was 113.0° (95% CI, 108.4° to 117.6°) in the articulating spacer group, compared with 100.2° (95% CI, 94.2° to 106.1°) in the static spacer group (p = 0.001). The mean Knee Society Score was higher in the articulating spacer cohort (79.4 compared with 69.8 points; 95% CI, 72.4 to 86.3 and 63.6 to 76.1, respectively; p = 0.043). Although not significantly different with the sample size studied, static spacers were associated with a greater need for an extensile exposure at the time of reimplantation (16.7% compared with 4.0%; 95% CI, 0.6% to 38.9% and 0.5% to 26.3%, respectively; p = 0.189) and a higher rate of reoperation (25.0% compared with 8.0%; 95% CI, 9.8% to 46.7% and 1.0% to 26.0%, respectively; p = 0.138).

CONCLUSIONS

Articulating spacers provided significantly greater range of motion and higher Knee Society scores at a mean of 3.5 years. Static spacers were associated with a longer hospital stay following removal of the infected implant. When the soft-tissue envelope allows and if there is adequate osseous support, an articulating spacer is associated with improved outcomes.

LEVEL OF EVIDENCE

Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Definitive Resection Arthroplasty of the Knee: A Surprisingly Viable Treatment to Manage Intractable Infection in Selected Patients

BACKGROUND

Resection arthroplasty of the hip is considered a viable option after multiple failed attempts to eradicate a prosthetic joint infection (PJI). However, much less information about resection arthroplasty of the knee is available. The goals of this study were to determine the success of infection eradication with a resection arthroplasty of the knee and subsequent functional outcomes in this group.

METHODS

We retrospectively identified 25 knees (23 patients) treated with resection arthroplasty of the knee for PJI performed at a single institution between 1974 and 2016. The mean age at resection arthroplasty was 65 years. The mean body mass index was 37 kg/m², and the mean Charleston Comorbidity Index was 5. Patients had a mean of 5 operations on the knee (mean of 3 operations for infection) before the resection arthroplasty. Failure to eradicate the infection was defined as any reoperation for infection. Clinical outcomes were assessed via ambulatory status, use of gait aids, and ongoing pain. The mean follow-up was 4 years.

RESULTS

At most recent follow-up, 84% (21 of 25) of knees were free of infection. Three patients had recurrent infection within the first year, and 1 patient had a late infection at 4 years postoperatively. However, only 1 patient required a subsequent amputation. Forty-five percent were community ambulators, 35% were household ambulators, and 20% were only able to transfer. All patients required knee bracing and assistive devices. Fifteen percent of patients were using long-term narcotics.

CONCLUSION

This large series demonstrates the results of selected use of resection arthroplasty as a treatment for recalcitrant periprosthetic knee infections that have failed multiple attempts to eradicate an ongoing PJI. The resection definitively solved the infection in 84% of patients. Functional results were variable but surprisingly good in some. All patients required bracing and assistive devices.

Is short-course systemic antibiotic therapy using an antibiotic-loaded cement spacer safe after resection for infected total knee arthroplasty? A comparative study

BACKGROUD/PURPOSE

Most patients who undergo two-stage exchange arthroplasty surgery for total knee arthroplasty prosthetic joint infection (TKA-PJI) receive a six-week course of systemic antibiotic treatment after the first stage procedure. However, the optimal duration of therapy has not been conclusively determined.

METHODS

We included 64 patients with periprosthetic knee infection who had undergone two-stage exchange arthroplasty. Between March 2003 and December 2009, 21 patients were given a short-course (less than 1 week) antibiotic treatment, and 43 were given a standard-course (4-6 weeks) treatment during the interim period. We compared length of hospital stay, duration of intravenous and overall systemic antibiotic treatments, and rate of recurrent periprosthetic knee infection between groups.

RESULTS

Short-course antibiotic treatment was associated with a shorter hospital stay and a shorter duration of intravenous and systemic antibiotic treatment. Implant survival regarding re-resection arthroplasty and chronic oral antibiotic suppression as primary endpoints was not significant different statistically between two groups (p = 0.317). The 1-year implant survival rates were 91.7% in the short-course group and 89.8% in the standard-course group. The 5-year implant survival rates were 85.2% and 74.0%, respectively.

CONCLUSION

After the first stage of resection arthroplasty for a two-stage exchange arthroplasty, a short course of antibiotic treatment had similar implant survival rates in comparison to the standard 6-week course. With radical debridement combined with an antibiotic-loaded cement spacer along with serial monitoring of the patient, a short course antibiotic treatment may be adequate in patients with TKA-PJI.

The effect of patient institutional transfer during the interstage period of two-stage treatment for prosthetic knee infection

Aims

The aim of this study was to assess the effects of transferring patients to a specialized arthroplasty centre between the first and second stages (interstage) of prosthetic joint infection (PJI) of the knee.

Patients and Methods

A search of our institutional database was performed to identify patients having undergone two-stage revision total knee arthroplasty (TKA) for PJI. Two cohorts were created: continuous care (CC) and transferred care (TC). Baseline characteristics and outcomes were collected and compared between cohorts.

Results

A total of 137 patients were identified: 105 in the CC cohort (56 men, 49 women; mean age 67.9) and 32 in the TC cohort (17 men, 15 women; mean age 67.8 years). PJI organism virulence was greater in the CC cohort (36.2% vs 15.6%; p = 0.030). TC patients had a higher rate of persisting or recurrent infection (53.6% vs 13.4%; p < 0.001), soft-tissue complications (31.3 vs 14.3%; p = 0.030), and reduced requirement for porous metal augments (78.1% vs 94.3%; p = 0.006). Repeat first stage debridement after transfer led to greater need for plastic surgical procedures (58.3% vs 0.0%; p < 0.001).

Conclusion

Patient transfer during the interstage of treatment for infected TKA leads to poorer outcomes compared with patients receiving all their treatment at a specialized arthroplasty centre. Cite this article: Bone Joint J 2019;101-B:1087–1092.

DAIR (Debridement, Antibiotics and Implant Retention) less effective in hematogenous total knee arthroplasty infections

Background

Debridement and irrigation with prosthetic retention followed by antibiotic therapy (DAIR) is one of the treatments of choice in acute infections after a total knee arthroplasty. However, the success rate varies widely in the literature, depending on several factors such as comorbidities of the patient, duration of infection, and microorganisms involved. The goal of this study was to assess the outcomes of this therapeutic option and to identify possible predictors of the result.

Methods

We retrospectively reviewed cases of acute postoperative (≤ 3 months from index procedure) and acute hematogenous periprosthetic knee infections treated with DAIR at our hospital between 2004 and 2016. Overall, 26 knees were included, with a mean age of 73.4 years. Several variables related to patient characteristics, infection type, and surgery were examined to evaluate their influence on outcome, and functional and radiographic outcome were assessed. The mean follow-up was 41 months. A descriptive analysis was carried out on the collected data, and a univariate analysis was performed with the objective of searching for influential factors in the resolution of the infection using the chi-square nonparametric test in the case of the categorical variables and the Wilcoxon test for the continuous ones. Moreover, univariate cox regression analysis was performed.

Results

The overall success rate was 77% at the last follow-up, recording a significantly greater cure in acute infections (93% acute vs 58% acute hematogenous, p = 0.03). The infections in which the Staphylococcus aureus was isolated had a significantly lower cure rate, with only 33% of success, compared to 82% of the non-aureus microorganisms (p <  0.05).

Conclusions

The present study shows a considerable cure rate in the treatment of acute knee infections through DAIR, although patient comorbidities, type of infection, and causative microorganism should be considered for decision-making.

Two-Stage Debridement With Prosthesis Retention for Acute Periprosthetic Joint Infections

BACKGROUND

Historically, infection control rates with debridement and component retention have been poor in the management of acute prosthetic joint infections. We previously described a 2-stage debridement with prosthesis retention protocol for acute periprosthetic joint infection and reported a 90% success rate in a sample of 20 patients.

METHODS

A retrospective review of 83 patients who underwent a 2-stage debridement with implant retention with a minimum 1-year follow-up was performed. Patient data were primarily analyzed to determine infection control rates. Infections were considered controlled when patients had not undergone a reoperation for infection, and demonstrated lack of any clinical signs or symptoms of infection (a well healed wound, diminishing swelling and warmth, absence of erythema, improvement in baseline pain symptoms) A secondary goal of this study was to examine the effects of symptom duration on infection control rate.

RESULTS

Average patient follow-up was 41.8 months (range 12-171) for all patients. The overall protocol success rate was 86.7% (72/83): 82.9% in hips and 89.6% in knees. Additionally, protocol success was observed in 45 of 48 primary joints (93.8%) and 27 of 35 (77.1%) revision joints (P = .046). Average time from onset of symptoms to surgery was 6.2 days for successfully treated patients (range 0-27 days) compared to 10.7 days for those who failed treatment (range 1-28 days, P = .070).

CONCLUSION

This 2-stage retention protocol resulted in a higher likelihood of infection control compared to prior reports of single stage debridement and modular part exchange.

The efficacy of a drug holiday test on two-stage revision for infected total knee arthroplasty

BACKGROUND

We compared the clinical efficacy of normal C-reactive protein (CRP) expression (<1.0 mg/dL), with a 2-week drug holiday test (DHT) and no drug holiday test (DHT) as a reimplantation criterion, based on subsequent infections after a two-stage revision of a total knee arthroplasty of a periprosthetic joint infection (PJI).

METHODS

In a 10-year review of 58 patients (mean age: 73.3-years-old; mean follow-up: 46.2 months), there were 31 patients in the DHT group and 27 patients in the DHT group. Primary outcome was recurrent infection rate. Secondary outcomes included length of hospital stay in the revision stage and CRP resurge one day before revision.

RESULTS

We reported that the CRP resurge rate in the DHT group (0%) was significantly (p = 0.029) lower than that in the DHT group (16.1%) one day before the revision. The DHT group also had a significantly shorter mean length of stay (LOS) in the hospital (9.6 vs 12.7 days, p = 0.015) and a nonsignificantly lower subsequent infection rate (14.8% vs 29%, p = 0.195).

CONCLUSION

We found that disciplined use of DHT as a reimplantation criterion reduced CRP resurges before reimplantation and yielded a shorter LOS afterward. DHT positively affected the subsequent mid-term infection rate after PJI treatment.

Are Sonication Cultures of Antibiotic Cement Spacers Useful During Second-stage Reimplantation Surgery for Prosthetic Joint Infection?

BACKGROUND

Organisms may persist on polymethylmethacrylate (PMMA) spacer surfaces, and subclinical infection is postulated to be a source of infection recurrence. Several small patient series have shown a high proportion of positive sonication cultures on PMMA spacers at the second stage of a two-stage revision. However, the association between a positive sonication culture and the risk for recurrence of infection after two-stage exchange is not fully elucidated.

QUESTIONS/PURPOSES

Are cultures derived from sonication of antibiotic spacers associated with infection control or recurrence after two-stage revision for prosthetic joint infection (PJI)?

METHODS

Between September 2013 and April 2016, we treated 67 patients with PJI with two-stage revisions. At the second stage, all cement spacers were explanted and sonicated. A total of`10 (15%) patients were lost to followup or failed to reach 1-year followup during the study period, and another 16 (24%) were excluded for prespecified reasons, leaving 41 patients for analysis in this study. Of the 41 patients included in this study, there were 25 TKAs, 15 THAs, and one distal femoral replacement. All patients met the Musculoskeletal Infection Society criteria for PJI at Stage 1 of the two-stage revision. The most common infecting organisms prompting two-stage revision were methicillin-sensitive Staphylococcus aureus and coagulase-negative staphylococci. PMMA spacers were most frequently loaded with gentamicin or gentamicin/vancomycin. Standard 6-week intravenous antibiotic courses were used for index infections and postreimplantation suppression was used for 3 months in all patients as determined by cultures and sensitivities. Patients were assessed for recurrence of infection at postoperative clinic visits completed at standard intervals. The average length of followup was 1.9 years with a range of 1 to 3.3 years.

RESULTS

Sonication cultures that reached a threshold of 5 colony-forming units for positive culture had poor screening utility for subclinical persistent infection (sensitivity: 0%; confidence interval [CI], 0%-60%), but reasonable use for ruling in successful two-stage revision (specificity: 95%; 95% CI, 82%-99%). Positive sonication culture results in the two of 41 (4.9%) explanted spacers yielded coagulase-negative staphylococci, different from primary prosthesis cultures in both patients (Corynebacterium and Proteus mirabilis), and did not alter antibiotic choice. Neither of the patients has developed a reinfection at followup of 1.2 and 1.9 years. Of the 39 two-stage revisions with negative spacer sonication cultures, four developed reinfections.

CONCLUSIONS

Positive sonication fluid culture of PMMA spacers during reimplantation surgery was not associated with persistent or recurrent infection at minimum followup of 1 year. We do not recommend routine sonication of explanted PMMA spacers in the absence of clinical evidence suggesting persistent infection. Multicenter, prospective studies with long-term followup are needed to determine if sonication of PMMA spacers can predict persistent or recurrent infection.

LEVEL OF EVIDENCE

Level III, diagnostic study.

What Markers Best Guide the Timing of Reimplantation in Two-stage Exchange Arthroplasty for PJI? A Systematic Review and Meta-analysis

BACKGROUND

There is no consensus on the appropriate marker to use when deciding to perform reimplantation after two-stage exchange arthroplasty for periprosthetic joint infection (PJI).

QUESTIONS/PURPOSES

What tests provide acceptable diagnostic value to guide appropriate timing of reimplantation in two-stage exchange arthroplasty for PJI?

METHODS

A search of online databases (MEDLINE, EMBASE, OVID, and Cochrane database) was performed containing articles that provided sensitivity and specificity values for accuracy for predicting reimplantation of the hip and/or knee. Twelve articles were included for final analysis, which included data from 1047 patients. Data that described the diagnostic accuracy of markers for reimplantation were evaluated and categorized into four main entities according to diagnostic method (serologic, synovial, tissue, and diagnostic imaging). Twelve parameters were examined, including serum erythrocyte sedimentation (ESR) rate, serum C-reactive protein (CRP), serum white blood cell (WBC) count, synovial fluid Gram stain, synovial fluid culture, synovial fluid sonication culture, synovial fluid WBC, synovial fluid polymorphonucleocyte percentage (PMN%), tissue Gram stain, tissue culture, positron emission tomography scan, and leukocyte scan. Each of the included articles was independently analyzed for risk of bias and applicability by using QUADAS-2. Statistical heterogeneity was calculated by using the Cochran Q test, and an α of 0.10 was considered significant for heterogeneity.

RESULTS

Tissue culture (sensitivity 0.82 [0.72-0.90], specificity 0.91 [0.89-0.95], diagnostic odds ratio (DOR) 46.87 [95% confidence interval {CI}, 22.03-99.69], synovial fluid PMN% (sensitivity 0.77 [0.46-0.95], specificity 0.74 [0.67-0.81], DOR 11.27 [95% CI, 2.89-43.61]), and synovial fluid culture (sensitivity 0.64 [0.52-0.74], specificity 0.96 [0.93-0.98], DOR 27.07 [95% CI, 2.55-288.00]) showed relatively high diagnostic performance. Other parameters had poorer diagnostic accuracy: ESR (sensitivity 0.56 [0.40-0.72], specificity 0.60 [0.53-0.66], DOR 2.41 [95% CI, 0.60-9.72), CRP (sensitivity 0.53 [0.39-0.67], specificity 0.72 [0.66-0.78], DOR 2.25 [95% CI, 0.09-4.63), and synovial fluid WBC count (sensitivity 0.37 [0.19-0.58], specificity 0.49 [0.41-0.57], DOR 0.94 [95% CI, 0.06-14.74). However, interpretation is limited, because only two to three studies were available for each pooled analysis. Both risks of bias and applicability concerns were low in the four domains assessed in QUADAS-2.

CONCLUSIONS

This meta-analysis suggests that no single marker was superior to all the others, and none (when used alone) is likely sufficient to confirm control of infection after the first stage of a two-stage protocol for PJI. Therefore, the current approach using multiple tools rather than a single marker is essential. Additionally, further studies must be conducted so that pooled analysis can be performed using multiple studies to determine ideal markers for reimplantation.

LEVEL OF EVIDENCE

Level III, diagnostic study.

High Rate of Positive Cultures in Patients Referred With Antibiotic Spacers as Part of 2-Stage Exchange

BACKGROUND

Two-stage exchange for periprosthetic joint infection (PJI) in total knee arthroplasty (TKA) remains the gold standard treatment in North America. Occasionally, patients with knee PJI are referred for definitive management after resection and antibiotic spacer placement. Currently, little literature exists to suggest how these patients should be managed. The purpose of this study is to report the clinical outcomes of these patients.

METHODS

We retrospectively identified 54 patients (54 knees) from 2000 to 2012 treated for PJI with initial TKA resection and spacer placement performed somewhere other than the definitive treatment center. The mean age at reimplantation was 64 years, with 59% being male. Redebridement and antibiotic spacer exchange was performed for all patients. Mean follow-up was 6.5 years.

RESULTS

Of the 54 knees, 22 (41%) grew an organism from a culture taken at the time of redebridement and spacer exchange. The most common organism identified at redebridement was Staphylococcus aureus (41%). Obtaining positive cultures at redebridement was not associated with presenting erythrocyte sedimentation rate (P = .46), C-reactive protein (P = .57), or the presence of retained cement (P = .13). Forty-nine of 54 (91%) knees were ultimately reimplanted. Two-year survivorship free of infection in reimplanted knees was 98%.

CONCLUSION

Patients referred with an antibiotic knee spacer for PJI have a high rate of positive cultures at the time of redebridement. Neither the presenting serology nor the identification of retained cement was associated with obtaining positive cultures at the time of redebridement. Nevertheless, this unique cohort of patients has favorable outcomes when redebrided with spacer exchange prior to reimplantation.

Multidrug-Resistant Organisms in the Setting of Periprosthetic Joint Infection-Diagnosis, Prevention, and Treatment

BACKGROUND

Periprosthetic joint infection (PJI) is a rare yet challenging problem in total hip and knee arthroplasties. The management of PJI remains difficult primarily due to the evolution of resistance by the infecting organisms.

METHODS

This review profiles acquired mechanisms of bacterial resistance and summarizes established and emerging techniques in PJI diagnosis, prevention, and treatment.

RESULTS

New techniques in PJI diagnosis and prevention continue to be explored. Antibiotics combined with 1 or 2-stage revision are associated with the higher success rates and remain the mainstay of treatment.

CONCLUSION

With higher prevalence of antibiotic-resistant organisms, novel antibiotic implant and wound care materials, improved methods for organism identification, and well-defined organism-specific treatment algorithms are needed to optimize outcomes of PJI.

Management of Prosthetic Joint Infection

Although uncommon, prosthetic joint infection is a devastating complication. This challenging condition requires a coordinated management approach to achieve good patient outcomes. This review details the general principles to consider when managing patients with prosthetic joint infection. The different medical/surgical treatment strategies and how to appropriately select a strategy are discussed. The data to support each strategy are presented, along with discussion of antimicrobial strategies in specific situations.

Repeat Two-Stage Exchange Arthroplasty for Periprosthetic Knee Infection Is Dependent on Host Grade

BACKGROUND

Two-stage exchange arthroplasty after a previous, failed 2-stage exchange procedure is fraught with difficulties, and there are no clear guidelines for treatment or prognosis given the heterogeneous group of patients in whom this procedure has been performed. The Musculoskeletal Infection Society (MSIS) staging system was developed in an attempt to stratify patients according to infection type, host status, and local soft-tissue status. The purpose of this study was to report the results of 2-stage exchange arthroplasty following a previous, failed 2-stage exchange protocol for periprosthetic knee infection as well as to identify risk factors for failure.

METHODS

We retrospectively identified 45 patients who had undergone 2 or more 2-stage exchange arthroplasties for periprosthetic knee infection from 2000 to 2013. Patients were stratified according to the MSIS system, and risk factors for failure were analyzed. The minimum follow-up was 2 years (mean, 6 years; range, 24 to 132 months).

RESULTS

At the time of follow-up, twenty-two (49%) of the patients had undergone another revision due to infection and 28 (62%) had undergone another revision for any reason. The infection recurred in 6 (75%) of 8 substantially immunocompromised hosts (MSIS type C) and in 3 (30%) of 10 uncompromised hosts (type A) following the second 2-stage exchange arthroplasty (p = 0.06). The infection recurred in 4 (80%) of 5 patients with compromise of the extremity (MSIS type 3) and 3 (33%) of 9 patients with an uncompromised extremity (type 1) (p = 0.27). Both extremely compromised hosts with an extremely compromised extremity (type C3) had recurrence of the infection whereas 3 (30%) of the 10 uncompromised patients with no or less compromise of the extremity (type A1 or A2) did. Five patients in the failure group underwent a third 2-stage exchange arthroplasty following reinfection, and 3 of them were infection-free at the time of the latest follow-up.

CONCLUSIONS

Uncompromised hosts (MSIS type A) with an acceptable wound (MSIS type 1 or 2) had a 70% rate of success (7 of 10) after a repeat 2-stage exchange arthroplasty, whereas type-B2 hosts had a 50% success rate (10 of 20). The repeat 2-stage exchange procedure failed in both type-C3 hosts; thus, alternative salvage procedures should be considered for such patients.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Aggressive Early Debridement in Treatment of Acute Periprosthetic Joint Infections After Hip and Knee Replacements

BACKGROUND

Periprosthetic Joint Infection Remains a Dreaded Complication After Hip and Knee Replacement Surgery. Treatment Options for Acute Postoperative and Acute Hematogenous Infections Include Arthroscopic or Open Debridement With Retention or Exchange of the Prostheses. This Review Article Aims to Summarize the Evidence for Management of Acute Postoperative And Acute Hematogenous Infections.

METHODS

A Systematic Literature Search Was Performed Using a Computer-based Search Engine Covering Medline (OvidSP), PubMed Database (U.S. National Library of Medicine, National Institutes of Health), Embase, Web of Science, Cochrane and Google Scholar for Relevant Articles.

RESULTS

Common Themes Around Treatment of Acute Postoperative and Acute Hematogenous Infections Discussed in this Review Include the Timing of Intervention, Description of the Optimal Procedure and How we Perform it at our Institution, the Role of Arthroscopic Debridement, Most Commonly Isolated Micro-organisms and Prognostic Factors for Infection Control.

CONCLUSION

Success in Treating Acute Postoperative and Acute Hematogenous Infections Depends on Early Diagnosis and Aggressive Surgical Debridement Combined With Effective Antibiotic Therapy.

Two-stage Revision for Periprosthetic Hip and Knee Joint Infections

Background:

Periprosthetic joint infection (PJI) continues to be one of the leading causes of failure following hip and knee surgery. The diagnostic workflow of PJI includes detailed clinical examination, serum markers, imaging and aspiration/biopsy of the affected joint. The goals of treatment are eradication of the infection, alleviation of pain, and restoration of joint function. Surgical management of PJI consists of debridement, antibiotics and implant retention (DAIR) and single or two-stage revision procedures. Two-stage revision remains the gold standard for treatment of PJIs. We aim to discuss the two stage procedure in this article and report the outcomes.

Methods:

The first stage of the two stages consists of removal of all components and associated cement with aggressive debridement and placement of an antibiotic-loaded cement spacer. Patients are then treated with variable periods of parenteral antibiotics, followed by an antibiotic free period to help ensure the infection has been eradicated. If the clinical evaluation and serum inflammatory markers suggest infection control, then the second stage can be undertaken and this involves removal of the cement spacer, repeat debridement, and placement of a new prosthesis.

Results:

Common themes around the two-stage revision procedure include timing of the second stage, antibiotics used in the interim period, length of the interim period before consideration of reimplantation and close liaising with microbiologists.

Conclusion:

Successful eradication of infection and good functional outcome using the two stage procedure is dependent on a multidisciplinary approach and having a standard reproducible startegy.

Infection recurrence factors in one- and two-stage total knee prosthesis exchanges

PURPOSE

Revision of infected total knee replacements (TKR) is usually delayed for a period in which the joint space is filled with an antibiotic-loaded acrylic spacer. In contrast, one-stage re-implantation supposes immediate re-implantation. Formal comparisons between the two methods are scarce. A retrospective multi-centre study was conducted to investigate the effects of surgery type (one-stage vs. two-stage) on cure rates. It was hypothesised that this parameter would not influence the results.

METHOD

All infected TKR, treated consecutively between 2005 and 2010 by senior surgeons working in six referral hospitals, were included retrospectively. Two hundred and eighty-five patients, undergoing one-stage or two-stage TKR, with more than 2-year follow-up (clinical and radiological) were eligible for data collection and analysis. Of them, 108 underwent one-stage and 177 received two-stage TKR. Failure was defined as infection recurrence or persistence of the same or unknown pathogens. Factors linked with infection recurrence were analysed by uni- and multi-variate logistic regression with random intercept.

RESULTS

Factors associated with infection recurrence were fistulae (odds ratio (OR) 3.4 [1.2-10.2], p = 0.03), infection by gram-negative bacteria (OR 3.3 [1.0-10.6], p = 0.05), and two-stage surgery with static spacers (OR 4.4 [1.1-17.9], p = 0.04). Gender and type of surgery interacted (p = 0.05). In men (133 patients), type of surgery showed no significant linkage with infection recurrence. In women (152 patients), two-stage surgery with static spacers was associated independently with infection recurrence (OR 5.9 [1.5-23.6], p = 0.01). Among patients without infection recurrence, International Knee Society scores were similar between those undergoing one-stage or two-stage exchanges.

CONCLUSION

Two-stage procedures offered less benefit to female patients. It suggests that one-stage procedures are preferable, because they offer greater comfort without increasing the risk of recurrence. Routine one-stage procedures may be a reasonable option in the treatment of infected TKR.

LEVEL OF EVIDENCE

III.

Smooth Pins Reinforcing Static Cement Spacers for Infected Total Knee Arthroplasty Are Not Safe

Prosthetic joint infection is one of the most dreaded complications following elective lower extremity primary total joint arthroplasty, resulting in substantial pain, disability, and health care costs. Both static and articulating antibiotic-impregnated spacers have been used in the management of 2-stage revision for infected total knee arthroplasty, which remains the gold standard for treatment of these infections. Articulating spacers may provide theoretical benefits with regard to improved range of motion after reimplantation secondary to less scar formations and soft tissue contractures. However, static spacers may be necessary to overcome instability associated with substantial bone defects, incompetent extensor mechanisms, and collateral ligament insufficiencies. In these scenarios, static spacers are often reinforced with intramedullary rods or Steinmann pins to provide additional knee stability, improve construct strength, maintain extension, and avoid flexion contractures. This case report describes an extremely rare case of migration of smooth pins through the posterior tibia into the calf following static spacer use in a 48-year-old man. Various mechanical and systemic complications have been reported in up to 50% of patients with the use of polymethyl methacrylate spacer devices, such as acute renal failure, allergic reactions from antibiotic use, stiffness, bone loss, fractures, and dislocations. However, to the best of the authors' knowledge, this complication of hardware migration has not been reported previously in the literature. The authors believe that orthopedic surgeons should consider the use of threaded pin dowels or intramedullary rods to avoid this potential untoward complication. [Orthopedics. 2016; 39(3):e553-e557.].

Influence of the cause of the revision on the outcome after revision knee arthroplasty with condylar constrained implant

INTRODUCTION

Revision total knee arthroplasty (TKA) is a common procedure with varying results depending on the cause. Our objective was to compare the clinical and radiological outcomes in patients undergoing aseptic revision versus revision due to prosthetic infection.

MATERIAL AND METHODS

The study included 41 patients who underwent TKA revision with the same varus-valgus constrained implant. In all cases a clinical evaluation was performed including pain, range of motion (ROM), Knee Society Score (KSS), complications, as well as radiological study. A comparative analysis was performed on the pre- and postoperative results between septic and aseptic groups. The mean follow-up was 6 years.

RESULTS

ROM had a mean increase of 17 degrees (p<.01). KSS and functional KSS improved significantly postoperatively. In the radiological study, joint interline and limb alignment were restored in all cases. Radiolucencies were found in 36.5% of cases; however they were unrelated to the appearance of loosening of the implant. There were complications in 29.2% of cases, mostly related to the surgical wound. Mobility, KSS, KSS functional and satisfaction at follow-up were better in the septic group. Implant survival was 95% at follow-up.

CONCLUSION

Revision arthroplasty with constrained varus-valgus implant is safe, and has successful mid-term results despite the cause of the replacement procedure.

Functional outcomes of acutely infected knee arthroplasty: a comparison of different surgical treatment options

BACKGROUND

An infected total knee arthroplasty (TKA) can be treated with irrigation and débridement with polyethylene exchange (IDPE) or a 2-staged revision (2SR). Although research has examined infection eradication rates of both treatments, patient outcomes have not been reported. We examined patient-reported outcomes following treatment compared with matched, noninfected controls.

METHODS

We retrospectively identified patients with infected TKAs who had undergone the index procedure between May 1991 and November 2011. Patient-reported outcomes included the 12-item Short Form Health Survey, Western Ontario and McMaster Universities Arthritis Index, and Knee Society Scores as well as range of motion. Patients with noninfected primary TKAs matched by age and age-adjusted Charlson Comorbidity Index score were used as controls. Intention-to-treat groups of 2SR and IDPE were used, with the IDPE group subdivided into successful and unsuccessful groups.

RESULTS

We included 145 patients with infected TKAs with mean follow-up of 64.2 months and 145 controls with a mean follow-up of 35.4 months in our analysis. Outcomes of the controls and the successful IDPE groups were equivalent. The 2SR cohort had lower scores in all categories than controls. There was a 39% success rate in eradicating infection with IDPE. Patients in whom IDPE failed had lower scores in all categories than controls. There was no difference between the failed IDPE group and the 2SR group.

CONCLUSION

Controversy regarding treatment options for acutely infected TKA has been focused on infection eradication. However, functional outcomes following treatment need to be taken into consideration. Patients whose infections were successfully treated with IDPE had equivalent outcomes to controls.

Irrigation and Debridement Before a 2-Stage Revision Total Knee Arthroplasty Does Not Increase Risk of Failure

BACKGROUND

Studies have suggested that the success of 2-stage revision total knee arthroplasty (rTKA) may be compromised by a prior failed irrigation and debridement (I&D). The purpose of this study was to use 2 large state inpatient databases to compare the 2-stage rTKA failure rates for those patients with and without a prior I&D.

METHODS

This retrospective, longitudinal study used inpatient discharge data from the State Inpatient Database of 2 states (California and New York) from 2005 to 2011. A combination of International Classification of Diseases, Ninth Revision, diagnosis and procedure codes was used to identify rTKA patients and compare failure rates for rTKA patients with and without prior I&D. The primary outcome was failure of the staged revision, which was defined as subsequent surgery due to infection within 4 years of the 2-stage rTKA.

RESULTS

Of the 750 patients who underwent 2-stage rTKA, 57 had undergone a prior I&D. In all, 126 patients failed rTKA. After 4 years, the estimated failure rate was 8.7% (95% confidence interval [CI], 1.9%-16.9%) in the group with prior I&D and 17.5% (95% CI, 14.7%-20.4%) in the group without prior I&D. After adjusting for sex, race, insurance, median household income, and comorbidities, the hazard ratio for the group with a failed I&D was 0.49 (P = .122; 95% CI, 0.20-1.20), which indicated a lower risk of failure compared to the group without prior I&D.

CONCLUSION

These findings indicate that the failure rate of 2-stage rTKA is not increased by prior failed I&D.

Intra-articular infusion

Bactericidal levels of antibiotics are difficult to achieve in infected total joint arthroplasty when intravenous antibiotics or antibiotic-loaded cement spacers are used, but intra-articular (IA) delivery of antibiotics has been effective in several studies. This paper describes a protocol for IA delivery of antibiotics in infected knee arthroplasty, and summarises the results of a pharmacokinetic study and two clinical follow-up studies of especially difficult groups: methicillin-resistant Staphylococcus aureus and failed two-stage revision. In the pharmacokinetic study, the mean synovial vancomycin peak level was 9242 (3956 to 32 150; sd 7608 μg/mL) among the 11 patients studied. Serum trough level ranged from 4.2 to 25.2 μg/mL (mean, 12.3 μg/mL; average of 9.6% of the joint trough value), which exceeded minimal inhibitory concentration. The success rate exceeded 95% in the two clinical groups. IA delivery of antibiotics is shown to be safe and effective, and is now the first option for treatment of infected total joint arthroplasty in our institution.

Cite this article: Bone Joint J 2016;98-B(1 Suppl A):31–6.

Temporary arthrodesis using fixator rods in two-stage revision of septic knee prothesis with severe bone and tissue defects

PURPOSE

The present study describes a new temporary arthrodesis procedure, which aims for septic knee prosthesis replacement, in particular for larger bone and soft tissue defects. Our technique offers high stability and full weight-bearing capacity of the knee joint.

METHODS

The study included 16 patients with major bone defects (AORI type IIb or greater) after receiving a radical debridement and a septic two-stage revision total knee arthroplasty. After removing the infected prosthesis and debridement, two AO fixator rods were positioned into the intramedullary space of the femur and tibia. Subsequently, both rods were joined tube-to-tube and adjusted in the center of the knee joint. Finally, the whole cavity of the knee joint was filled with PMMA. The number of previous surgeries, bacterial spectrum, risk factors for further infection and reinfection rates was recorded. Immediately after the temporary arthrodesis, radiographs of the knee with the enclosed spacers were taken in order to compare to previous radiographs and avoiding to miss possible spacer loosening.

RESULTS

Nine of sixteen patients underwent more than two revision surgeries before receiving our new arthrodesis technique. No cases of spacer loosening were observed in all 16 patients; further, there were no peri-implant fractures, and four persistent infections were noted.

CONCLUSIONS

Temporary arthrodesis using AO fixator rods offers a high stability without loosening. Its potential to replace conventional augmentation techniques should be taken into account, particularly in the case of larger bone and tissue defects. In clinical practice, the cemented spacer using AO fixator rods could be an alternative technique for temporary knee arthrodesis after septic debridement.

LEVEL OF EVIDENCE

Retrospective case series, Level IV.

Single-Stage Hip and Knee Exchange for Periprosthetic Joint Infection

Periprosthetic joint infections following hip and knee arthroplasty are challenging complications for Orthopaedic surgeons to manage. The single-stage exchange procedure is becoming increasingly popular with promising results. At our Institute we have demonstrated favourable or similar outcomes compared to the 'gold-standard' two-stage exchange, and other published single-stage results. The aim of this study is to describe the patient selection criteria and perioperative steps in a single-stage exchange for hip and knee arthroplasty undertaken at our Institute. The outlined protocol can be performed using standard debridement, attention to detail and well-recognised reconstructive techniques.

Comparison of infection control rates and clinical outcomes in culture-positive and culture-negative infected total-knee arthroplasty

BACKGROUND

To compare the outcomes of the culture positive and the culture negative infected TKA.

METHODS

We determined the infection control rate in the 242 patients (140 patients with culture-positive and 102 patients with culture-negative diagnoses) with infected TKAs.

RESULTS

The overall infection control rate was 90% in the culture positive group and 95% in the culture negative group.

INTERPRETATION

The infection control rates and clinical outcomes of infected TKAs was not different between culture-positive and culture-negative groups.