Periprosthetic Joint Infection Is the Main Cause of Failure for Modern Knee Arthroplasty: An Analysis of 11,134 Knees

Diagnostic accuracy of synovial fluid D-lactate for periprosthetic joint infection: a systematic review and meta-analysis

BACKGROUND

Periprosthetic joint infection is a grievous complication after arthroplasty that greatly affects the quality of life of patients. Rapid establishment of infection diagnosis is essential, but great challenges still exist.

METHODS

We conducted research in the PubMed, Embase, and Cochrane databases to evaluate the diagnostic accuracy of D-lactate for PJI. Data extraction and quality assessment were completed independently by two reviewers. The pooled sensitivity, specificity, likelihood ratios, diagnostic odds ratio (DOR), summarized receiver operating characteristic curve (sROC), and area under the sROC curve (AUC) were constructed using the bivariate meta-analysis framework.

RESULTS

Five eligible studies were included in the quantitative analysis. The pooled sensitivity and specificity of D-lactate for the diagnosis of PJI were 0.82 (95% CI 0.70-0.89) and 0.76 (95% CI 0.69-0.82), respectively. The value of the pooled diagnostic odds ratio (DOR) of D-lactate for PJI was 14.18 (95% CI 6.17-32.58), and the area under the curve (AUC) was 0.84 (95% CI 0.80-0.87).

CONCLUSIONS

According to the results of our meta-analysis, D-lactate is a valuable synovial fluid marker for recognizing PJI, with high sensitivity and specificity.

Synchronous Periprosthetic Joint Infections: High Mortality, Reinfection, and Reoperation

BACKGROUND

Synchronous periprosthetic joint infections (PJIs) are a catastrophic complication with potentially high mortality. We aimed to report mortality, risk of reinfection, revision, reoperation, and implant survivorship after synchronous PJIs.

METHODS

We identified 34 patients treated for PJI in more than one joint within a single 90-day period from 1990 to 2018. PJIs involved bilateral knee arthroplasty (27), bilateral hip arthroplasty (4), 1 knee arthroplasty and 1 elbow arthroplasty (1), 1 knee arthroplasty and 1 shoulder arthroplasty (1), and bilateral hip and knee arthroplasty (1). Irrigation and debridement with component retention was performed in 23 patients, implant resection in 10 patients, and a combination of irrigation and debridement with component retention and implant resection in 1 patient. A competing risk model was used to analyze implant survivorship, and Kaplan-Meier survival was used for patient mortality. Mean follow-up was 6 years.

RESULTS

Mortality was high at 18% at 30 days and 27% at 1 year. The 1-year cumulative incidence of any reinfection was 13% and 27% at 5 years. The 1-year cumulative incidence of any revision or implant removal was 6% and 20% at 5 years. The 1-year cumulative incidence of unplanned reoperation was 25% and 35% at 5 years. Rheumatoid arthritis was associated with increased risk of mortality (HR 7, P < .01), as was liver disease (HR 4, P = .02).

CONCLUSION

In the largest series to date, patients with synchronous PJIs had a high 30-day mortality rate of 18%, and one-fourth underwent unplanned reoperation within the first year.

Bacterial DNA screening to characterize surgical site infection risk in orthopaedic patients

Purpose

To provide an initial characterization of relevant bacterial DNA profiles for patients undergoing closed-fracture fixation or total joint arthroplasties.

Patients and methods

Swabs were collected and analyzed using Polymerase Chain Reaction from adult patients undergoing closed-fracture fixation or total shoulder, knee, or hip arthroplasties.

Results

Bacterial DNA profiles varied across the different orthopaedic patient populations, and produced uncharacteristic profile shifts with direct relevance to each clinical infection.

Conclusion

Findings provide a foundational dataset regarding bacterial colonization of relevant anatomic sites that can act as sources of surgical site infections for patients.

Clinical outcomes of two-stage revision total knee arthroplasty in infected cases with antibiotic-loaded cement spacers produced using a handmade silicone mold

Purpose

This study assessed the clinical outcomes of periprosthetic joint infection patients who underwent two-stage revision total knee arthroplasty with antibiotic-loaded cement spacers fabricated using a handmade silicone mold.

Materials and methods

This study included seven patients (average age 77 years, average follow-up time 54 months) who underwent surgery at our hospital between 2009 and 2013. Clinical outcomes including knee scores, function scores, knee range of motion, and walking ability at the final observation, period from the primary total knee arthroplasty to implant removal, period from implant removal to revision total knee arthroplasty, and follow-up period after revision total knee arthroplasty were investigated.

Results

At the final follow-up, the average knee range of motion was 99°, with no significant differences at each stage; average knee and function scores were 84 and 77, respectively. With cement spacers, five patients were able to walk with a t-cane. No recurrence of infection was observed.

Conclusions

The clinical outcomes of the current case series demonstrated good knee function with preserved walking ability, without any recurrence of periprosthetic joint infection. This study suggests that using a handmade silicone mold could be an effective option for periprosthetic joint infection after a total knee arthroplasty.

sCD28, sCD80, sCTLA-4, and sBTLA Are Promising Markers in Diagnostic and Therapeutic Approaches for Aseptic Loosening and Periprosthetic Joint Infection

Aseptic prosthetic loosening and periprosthetic joint infections (PJI) are among the most frequent complications after total knee/hip joint arthroplasty (TJA). Current research efforts focus on understanding the involvement of the immune system in these frequent complications. Different immune cell types have already been implicated in aseptic prosthetic loosening and PJI. The aim of this study was to systematically analyze aspirates from knee and hip joints, evaluating the qualitative and quantitative composition of soluble immunoregulatory markers, with a focus on co-inhibitory and co-stimulatory markers. It has been shown that these molecules play important roles in immune regulation in cancer and chronic infectious diseases, but they have not been investigated in the context of joint replacement. For this purpose, aspirates from control joints (i.e., native joints without implanted prostheses), joints with TJA (no signs of infection or aseptic loosening), joints with aseptic implant failure (AIF; i.e., aseptic loosening), and joints with PJI were collected. Fourteen soluble immunoregulatory markers were assessed using bead-based multiplex assays. In this study, it could be shown that the concentrations of the analyzed immunoregulatory molecules vary between control, TJA, AIF, and PJI joints. Comparing TJA patients to CO patients, sCD80 was significantly elevated. The marker sBTLA was significantly elevated in AIF joints compared to TJA joints. In addition, a significant difference for eight markers could be shown when comparing the AIF and CO groups (sCD27, sCTLA-4, sCD137, sCD80, sCD28, sTIM-3, sPD-1, sBTLA). A significant difference was also reached for nine soluble markers when the PJI and CO groups were compared (sLAG-3, sCTLA-4, sCD27, sCD80, sCD28, sTIM-3, sPD-1, IDO, sBTLA). In summary, the analyzed immunoregulatory markers could be useful for diagnostic purposes as well as to develop new therapeutic approaches for AIF and PJI.

Benchmarking total knee replacement constructs using noninferiority analysis: the New Zealand joint registry study

BACKGROUND

The aim of this study was to compare the relative performance of total knee replacement constructs and discern if there is variability in performance in currently commonly used prostheses in the New Zealand Joint Registry (NZJR) using a noninferiority analysis.

METHODS

All patients who underwent a primary total knee replacement (TKR) registered in the NZJR between 1st January 1999 to June 2020 were identified. Using a noninferiority analysis, the performance of total knee replacement prostheses were compared with the best performing contemporary construct. Construct all-cause revision rate was estimated using the 1-Kaplan Meier survival function method to estimate net failure. The difference in all-cause revision rates between the contemporary benchmark and all other constructs was tested.

RESULTS

In total 110 183 TKR were recorded and 25 constructs (102 717 procedures) had > 500 procedures at risk at 3 years post-primary of which 5 were inferior by at least 20 % relative risk of which, one was inferior by at least 100 % relative risk. 14 constructs were identified with > 500 procedures at risk at 10 years with 5 inferior by at least 20 %, of which 2 were inferior by > 100 % relative risk.

CONCLUSIONS

We discerned that there is great variability in construct performance and at all time points, greater than 25 % of constructs are inferior to the best performing construct by at least 20 %. These results can help inform patients, clinicians and health care funders when considering TKR surgery.

Cost of septic and aseptic revision total knee arthroplasty: a systematic review

BACKGROUND

The increasing incidence of primary total knee arthroplasty (TKA) has led to an increase in both the incidence and the cost burden of revision TKA procedures. This study aimed to review the literature on the cost of revision TKA for septic and aseptic causes and to identify the major cost components contributing to the cost burden.

METHODS

We searched MEDLINE (OvidSp), Embase, Web of Science, Cochrane Library, EconLit, and Google Scholar to identify relevant studies. Selection, data extraction and assessment of the risk of bias and cost transparency within the studies were conducted by two independent reviewers, after which the cost data were analysed narratively for 1- or 2-stage septic revision without re-revision; 2-stage septic revision with re-revision; and aseptic revision with and without re-revision, respectively. The major cost components identified in the respective studies were also reported.

RESULTS

The direct medical cost from the healthcare provider perspective for high-income countries for 2-stage septic revision with re-revision ranged from US$66,629 to US$81,938, which can be about 2.5 times the cost of 1- or 2-stage septic revision without re-revision, (range: US$24,027 - US$38,109), which can be about double the cost of aseptic revision without re-revision (range: US$13,910 - US$29,213). The major cost components were the perioperative cost (33%), prosthesis cost (28%), and hospital ward stay cost (22%).

CONCLUSIONS

Septic TKA revision with re-revision for periprosthetic joint infection (PJI) increases the cost burden of revision TKA by 4 times when compared to aseptic single-stage revision and by 2.5 times when compared to septic TKA revision that does not undergo re-revision. Cost reductions can be achieved by reducing the number of primary TKA that develop PJI, avoidance of re-revisions for PJI, and reduction in the length of stay after revision.

TRIAL REGISTRATION

PROSPERO; CRD42020171988 .

The combination of medical devices and medicinal products revisited from the new European legal framework

Medical devices and medicinal products have many similarities in their nature, scope or specific medical purposes, and despite the differences in their principal means of action, they are often used in combination. Indeed, many medicinal products depend on medical devices for their administration, and it is increasingly common for medical devices to contain medicinal substances to support their action. Therefore, the combination of medicinal products and medical devices provides additional benefits for patients. However, their higher technical complexity requires a strengthening of their authorisation and certification requirements. In this regard, more comprehensive requirements and classification rules are introduced by a new European regulation on medical devices that fully applies from May 26^th 2021. On account of their therapeutic significance, this review aims at gaining insight into the borderline between medical devices and medicinal products in this new 2021 regulatory framework. For the first time, any item containing a medical device and a medicinal product will have both parts evaluated. Through exemplification of both marketed and investigational devices incorporating medicinal substances and drug-device combinations, the new European requirements and their implications are thoroughly illustrated herein.

Facilitating the Approval Process of Anti-Infective Technologies and Advancing Them to the Market: Insights from an FDA Workshop on Orthopaedic Device-Related Infections

Orthopaedic device-related infection is one of the most devastating complications in orthopaedic and trauma surgery. With increasing life expectancies as well as the lifelong risk of bacterial seeding on an implant, the prevention and treatment of device-related infection remains an important area for research and development. To facilitate information exchange and enhance collaboration among various stakeholders in the orthopaedic community, the U.S. Food and Drug Administration (FDA) Center for Devices and Radiological Health (CDRH) organized an inaugural workshop on orthopaedic device-related infections, exploring the regulatory challenges that are faced when proceeding from the bench level to marketing and clinical implementation of new infection-control devices and products. This article summarizes the perspectives of scientists, clinicians, and industry partners on the current regulatory approval process for orthopaedic anti-infective technologies as well as the proposed strategies to overcome these regulatory challenges.

Infection and periprosthetic fracture are the leading causes of failure after aseptic revision total knee arthroplasty

AIM

The purpose of this study was to clarify the medium to long term survival of aseptic revision total knee arthroplasty (RTKAs) and identify the common modes of failure following RTKAs.

MATERIALS AND METHODS

A multi-center, retrospective study included all aseptic RTKAs performed at three tertiary referral hospitals between 2003 and 2016. Patients were excluded if the revision was for prosthetic joint infection (PJI) or they had previously undergone revision surgery. Minor revisions not involving the tibial or femoral components were also excluded. Demographics, surgical data and post-operative outcomes were recorded and analyzed. Survival analysis was performed and the reasons for revision failure identified.

RESULTS

Of 235 aseptic RTKAs identified, 14.8% underwent re-revision at mean follow-up of 8.3 years. Survivorship of RTKA was 93% at 2 years and 83% at 8 years. Average age at revision was 72.9 years (range 53-91.5). The most common reasons for failure following RTKA were periprosthetic joint infection (PJI) (40%), periprosthetic fracture (25.7%) and aseptic loosening (14.3%). Of those whose RTKA failed, the average survival was 3.33 years (8 days-11.4 years). No demographic or surgical factors were found to influence RTKA survival on univariate or multivariate analysis.

CONCLUSION

PJI and periprosthetic fracture are the leading causes of re-revision surgery following aseptic revision TKA. Efforts to improve outcomes of aseptic revision TKA should focus on these areas, particularly prevention of PJI.

Periprosthetic joint infection after primary TKA in the medicare population: How frequently are patients revised at a different hospital?

BACKGROUND

Periprosthetic infection (PJI) after total knee arthroplasty (TKA) places a significant burden on hospitals. We sought to describe the proportion of patients undergoing revision for PJI at a different hospital within one year of primary TKA and whether patient characteristics or hospital volume were associated with this change.

METHODS

Medicare data from 2005 to 2014 was retrospectively reviewed using PearlDiver. All patients over 64 years undergoing revision for PJI within one year of primary TKA were stratified by the revision occurring within 90 days. Hospitals were grouped by annual TKA volume as Low (<50), Medium (51-100), High (101-200), and Very High (>200). Associations of patient characteristics and hospital volume with revision at a different hospital were assessed using Chi-squared tests and Somers' D.

RESULTS

Of 8,337 patients undergoing revision within 90 days of TKA, 1,370 (16%) were revised at a different hospital. Changing hospitals was associated with having primary TKA at a lower volume hospital (24% for low, 15% medium, 12% high, and 12% very high; P < 0.001). Of 7,608 patients undergoing revision between 91 and 365 days, 1,110 (15%) were revised at a different hospital. Changing hospitals was associated with having primary TKA at a lower volume hospital (26% for low, 14% medium, 10% high, and 9% very high; P < 0.001). Changing hospitals was not associated with sex or age.

CONCLUSION

Patients frequently undergo revision for PJI at a different hospital, even within 90 days of TKA. Further research is needed to understand these implications of this care pathway shift.

Postoperative Infection Risk in Total Joint Arthroplasty After Perioperative IV Corticosteroid Administration: A Systematic Review and Meta-Analysis of Comparative Studies

BACKGROUND

Perioperative corticosteroid administration is associated with reduced postoperative nausea, pain, and enhanced recovery after surgery. However, potential complications including wound and periprosthetic joint infections remain a concern for surgeons after total joint arthroplasty (TJA).

METHODS

A systematic review of the search databases PubMed, Google Scholar, and EMBASE was made in January 2021 to identify comparative studies evaluating infection risk after perioperative corticosteroid administration in TJA. PRISMA guidelines were used for this review. Meta-analysis was used to assess infection risk in accordance with joint and corticosteroid dosing regimen used.

RESULTS

201 studies were returned after initial search strategy, with 29 included for review after application of inclusion and exclusion criteria. Studies were categorized as using low- or high-dose corticosteroid with single or repeat dosing regimens. Single low-dose corticosteroid administration was not associated with an increased risk of infection (P = .4; CI = 0.00-0.00). Single high-dose corticosteroid was not associated with an increased infection risk (P = .3; CI = 0.00-0.01) nor did repeat low-dose regimens result in increased risk of infection (P = .8; CI = -0.02-0.02). Studies assessing repeat high-dosing regimens reported no increased infection, with small numbers of participants included. No significant risk difference in infection risk was noted in hip (P = .59; CI = -0.03-0.02) or knee (P = .2; CI = 0.00-0.01) arthroplasty. Heterogeneity in patient profiles included in studies to date was noted.

CONCLUSION

Use of perioperative corticosteroid in TJA does not appear to be associated with increased risk of postoperative infection in patients with limited comorbidities. Further research is warranted to evaluate postoperative complications after TJA in these at-risk patient populations.

Recent trends in revision knee arthroplasty in Germany

We aimed to answer the following questions: (1) How did numbers of revision knee arthroplasty procedures develop in Germany over the last decade compared to primary TKA? (2) How high was the percentage of septic interventions in knee prosthesis revisions? (3) Which treatment strategy was chosen for surgical treatment of knee PJI? Revision arthroplasty rates as a function of age, gender, infection and type of prosthesis were quantified based on Operation and Procedure Classification System codes using revision knee arthroplasty data from 2008 to 2018, provided by the Federal Statistical Office of Germany (Destatis). In 2018, a total number 23,812 revision knee arthroplasties were performed in Germany, yielding an overall increase of 20.76% between 2008 and 2018. In comparison, primary TKA procedures increased by 23.8% from 152,551 performed procedures in 2008 to 188,866 procedures in 2018. Hence, 12.6% of knee arthroplasties required a revision in 2018. Septic interventions increased by 51.7% for all revisions. A trend towards higher numbers in younger patients was observed. Compared to 2008, 17.41% less DAIR procedures were performed, whereby single-stage and two- or multi-stage change increased by 38.76% and 42.76% in 2018, respectively. The increasing number of revision knee arthroplasty in Germany, especially in younger patients and due to infection, underlines the need for future efforts to improve treatment strategies to delay primary arthroplasty and avoid periprosthetic joint infection.

One-Stage Implant-Retaining Revision for Simultaneous Bilateral Infected Total Knee Arthroplasty: A Report of a Rare Case

There is little information on the management of simultaneous infected total knee arthroplasties in the same patient. Although general principles of management for periprosthetic joint infection apply, there might be certain aspects worth to be considered. We present a case of a 78-year-old patient, who was referred in preseptic conditions 10 years following bilateral TKA. The onset of symptoms was less than one week, proposing an acute hematogenous infection. Analysis of joint fluid revealed that both of his TKAs were infected with Streptococcus sanguinis. Diagnostic algorithms, surgical principles, and the course of the patients following bilateral revision are being described. The reasons for an implant-retaining procedure with irrigation and debridement including the exchange of the polyethylene liners are being discussed as well as possible principles of management of bilateral periprosthetic joint infections.

Clinical Outcomes in Isolated Tibial Revision With Cruciate Retaining Total Knee Arthroplasty

BACKGROUND

Tibial component loosening is one of the most common modes of failure in contemporary total knee arthroplasty (TKA). Limited literature is available on the outcomes of isolated tibial revision with retention of the cruciate retaining (CR) femoral component. The purpose of this study was to determine the results of isolated tibial revisions in CR TKA.

METHODS

We identified 135 patients who underwent an isolated tibial revision after a primary CR TKA from our institutional registry between January 2007 and January 2017. The mean time between the primary and revision was 2.9 years (range 0.1-15.4). Revision with a press-fit stem was performed in 79 patients and 56 patients were revised with a fully cemented stem. Patients were evaluated at a minimum of two years using Knee Society Score, Knee Injury and Osteoarthritis Score for Joint Replacement, and radiography. Implant survivorship was determined using Kaplan-Meier survival analysis.

RESULTS

At a mean follow-up of 5.1 years, there were six (4.4%) repeat revisions: three for periprosthetic infection (2.2%), two for instability (1.5%), and one for a fractured tibial stem (0.7%). The mean Knee Society Score and Knee Injury and Osteoarthritis Score for Joint Replacement increased from 51.6 and 56.1 preoperatively to 90.1 and 89.7 after surgery (P < .001). Survivorship free of repeat revision for any cause was 93.3% at 5 years, and aseptic revision survivorship was 95.8% at 5 years. No implants were radiographically loose.

CONCLUSION

In patients with isolated tibial loosening and a well-fixed and well-positioned CR femoral component, isolated tibial revision provides excellent early to midterm implant survivorship and clinical outcomes with a low risk of instability and recurrent tibial loosening.

Globulin, the albumin-to-globulin ratio, and fibrinogen perform well in the diagnosis of Periprosthetic joint infection

Background

Although periprosthetic joint infection (PJI) is a severe complication of total joint arthroplasty (TJA), the diagnosis of PJI remains challenging. Albumin (ALB), globulin (GLB), the albumin-to-globulin ratio (AGR), and fibrinogen could be indicators of the body’s inflammatory state. This study aimed to compare the diagnostic accuracy of these biomarkers with that of other inflammatory biomarkers in PJI patients.

Methods

We conducted a retrospective cohort study that included a consecutive series of patients undergoing debridement antibiotic irrigation and implant retention (DAIR), one-stage or the first stage of a two-stage revision total knee arthroplasty (TKA) or total hip arthroplasty (THA) for acute (n = 31) or chronic (n = 51) PJI, or revision TKA or THA for aseptic failures (n = 139) between January 2017 and December 2019 in our hospital. The 2013 criteria of the Musculoskeletal Infection Society (2013 MSIS) were used as the reference standard for the diagnosis of PJI. The preoperative ALB, GLB, AGR, fibrinogen, D-dimer, platelet count, fibrin degradation product (FDP), platelet-to-lymphocyte (PLR), platelet count to mean platelet volume ratio (PVR), neutrophil-to-lymphocyte ratio (NLR), erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels were assessed. The receiver operating characteristic curve (ROC), sensitivity, and specificity were utilized to compare different biomarkers.

Results

Compared with the aseptic patients, the GLB, D-dimer, fibrinogen, FDP, platelet count, PVR, PLR, NLR, ESR, and CRP levels of PJI patients were significantly higher (P < 0.01); however, the ALB and AGR levels were significantly lower (P < 0.01). The area under the curve (AUC), sensitivity and specificity were 0.774, 67.50, 77.54% for ALB; 0.820, 57.50, 89.86% for GLB; 0.845, 66.25, 93.48% for AGR; 0.832, 78.48, 78.95% for fibrinogen; 0.877, 81.48, 85.07% for ESR; 0.909, 83.95, 88.89% for CRP; 0.683, 55.22, 75.83% for D-dimer; 0.664, 38.81, 88.33% for FDP; 0.678, 52.44, 79.86% for platelet count; 0.707, 48.78, 86.33% for PVR; 0.700, 51.22, 80.58% for PLR; and 0.678, 52.44, 81.30% for NLR, respectively. In the clinic, GLB, AGR and fibrinogen could be used for diagnosis of patients suspected of having PJI.

Conclusion

Our study demonstrated that GLB, AGR, and fibrinogen were promising biomarkers in the diagnosis of PJI.

What Is the Likelihood of Union After Coronal Limb Realignment Using Revision Osteosynthesis and Concurrent TKA in Patients with Advanced Arthritis and Loss of Fixation After Distal Metaphyseal Femur Fractures?

BACKGROUND

Metaphyseal fracture healing in the distal femur requires a stable biomechanical environment. The presence of arthritis-induced coronal-plane knee deformities can cause deviation of the mechanical axis, which results in asymmetric loading and increased bending forces in fractures of the distal femur metaphysis. This predisposes patients to nonunions or loss of fixation. Concurrent TKA during revision osteosynthesis might facilitate fracture healing, owing to its ability to correct coronal alignment, thereby restoring normal loading patterns at the fracture site, but to our knowledge, this has not been studied.

QUESTIONS/PURPOSES

(1) Does TKA with concurrent revision internal fixation achieve fracture union in patients with coronal-plane deformity from knee arthritis and nonunion or loss of fixation in distal metaphyseal femoral fractures? (2) What is the survivorship and what are the short-term functional outcomes after these reconstructions? (3) What complications occur after these reconstructions?

METHODS

Between 2015 and 2018, one surgeon treated 16 patients with a distal metaphyseal femur fracture nonunion and/or loss of fixation using concurrent TKA plus revision internal fixation. Autologous iliac crest bone grafting was performed in five patients with evident gaps at the fracture site. The indications for the procedure included patients older than 55 years of age presenting with a nonunion and/or loss of fixation of a distal metaphyseal femur fracture in the setting of painful Ahlbäck Grade III to V knee arthritis with an associated coronal-plane deformity. All patients meeting these indications were treated with this approach during the study period. Fracture union assessed by radiological bridging of at least three cortices, TKA survival free from revision due to any reason, coronal-plane correction using tibiofemoral angle, and patient mobility status assessed presurgery and at follow-up using the Parker mobility score (scored 0-9 points, with 9 indicating best mobility) were assessed by two surgeons who were not involved in the care of the study patients. Immediate and delayed complications were recorded. Patients were followed for a minimum of 24 months. The median (range) follow-up was 38 months (27 to 52 months).

RESULTS

All fractures united after concurrent TKA plus revision internal fixation. In all, 14 of 16 fractures healed before 5 months, while the remaining two fractures united by 6 months. Survivorship analysis revealed a TKA component survival of 94% (95% CI 63% to 99%) at 52 months. The median (range) preoperative Parker mobility score of 5 points (3 to 8) improved to 7 points (2 to 9) at 12 months postoperatively and was maintained at last follow-up (p = 0.001). Four patients experienced complications; these were (1) prolonged surgical wound drainage resulting in debridement and polyethylene liner exchange, (2) deep knee infection needing a staged revision, (3) popliteal vein thrombosis, and (4) prolonged graft site pain.

CONCLUSION

Concurrent TKA plus revision internal fixation is effective for achieving union in patients with distal metaphyseal femur nonunion and loss of fixation in the setting of coronal-plane deformity induced by knee arthritis. Short-term TKA survival and improvement in patient mobility are excellent, although 4 of 16 patients in this report experienced complications, as one might expect with a procedure of this magnitude. Based on our results, correction of arthritis-induced coronal-plane knee malalignment can be considered part of the surgical strategy when treating such distal metaphyseal femur nonunions. Better preoperative evaluation of the deformity and control-based comparative studies can further validate the utility of this technique.

LEVEL OF EVIDENCE

Level II, therapeutic study.

Drug Reaction with Eosinophilia and Systemic Syndrome in Revision Arthroplasty for a Prosthetic Knee Infection: A Case Report

CASE

A 51-year-old woman underwent stage I of a 2-stage revision for a prosthetic knee infection with a vancomycin-impregnated articulating cement spacer followed by IV vancomycin and ceftriaxone. Four weeks later, she developed fevers, a diffuse cutaneous eruption, lymphadenopathy, transaminitis, and acute renal tubular necrosis before being diagnosed with drug reaction with eosinophilia and systemic syndrome (DRESS).

CONCLUSION

DRESS is a rare, potentially life-threatening adverse drug reaction with cutaneous manifestations and multiorgan involvement. Although rare, its incidence in orthopaedic patients is likely to increase with the aging population. It must be recognized early to minimize end-stage organ dysfunction and mortality.

Poor performance of open incisional biopsy for the microbiological diagnosis of periprosthetic knee joint infection

The accurate preoperative diagnosis of periprosthetic joint infection (PJI) of total knee arthroplasty (TKA) can be difficult despite the use of a combination of serum and synovial markers. In such inconclusive cases, incisional open biopsy might be considered. This study investigates the usefulness of biopsies in patients with inconclusive diagnostic findings. We retrospectively identified 63 patients who underwent incisional biopsy for chronic PJI in the operation theatre following TKA revision between 2010 and 2018 after inconclusive preoperative diagnostics for PJI. In all cases, 5 independent biopsies were taken. Results from open biopsy for PJI were analyzed for diagnostic accuracy using the intraoperative results from following revision surgery as gold standard. 27 patients (43%) had a positive culture taken during biopsy. 15 cases (24%) met the diagnostic criteria for a chronic PJI. Most common organisms were Coagulase-negative staphylococci (67%) and Cutibacterium acnes (30%). Compared to the findings during revision surgery, biopsies showed a sensitivity of 47% and a specificity of 77% for PJI. Open incisional biopsy following inconclusive serum- and synovial diagnostics for low grade PJI may be considered for identification of microorganisms. Due to its low sensitivity and moderate specificity found in the present cohort, microbiological analysis should be combined with additional diagnostic markers and histological investigation.Level of Evidence. Retrospective cohort study (Level III).

Aseptic Tibial Implant Loosening After Total Knee Arthroplasty: Preventable?

Aseptic loosening is a considerable complication that affects the longevity of total knee arthroplasty (TKA) implants. Surgeon technique may help minimize aseptic loosening after TKA. Meticulous cementation of the prosthesis and the bone surface during various stages of cement polymerization will maximize cement adherence to the prosthesis and the bone, respectively. Pressurization of the cement in the canal and at the cut surface to achieve at least 2 mm of cement depth penetration has been reported to increase TKA implant longevity.

Variation and trends in reasons for knee replacement revision: a multi-registry study of revision burden

Background and purpose - Studies describing time-related change in reasons for knee replacement revision have been limited to single regions or institutions, commonly analyze only 1st revisions, and may not reflect true caseloads or findings from other areas. We used revision procedure data from 3 arthroplasty registries to determine trends and differences in knee replacement revision diagnoses.Patients and methods - We obtained aggregated data for 78,151 revision knee replacement procedures recorded by the Swedish Knee Arthroplasty Register (SKAR), the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR), and the Kaiser Permanente Joint Replacement Registry (KPJRR) for the period 2003-2017. Equivalent diagnosis groups were created. We calculated the annual proportions of the most common reasons for revision.Results - Infection, loosening, and instability were among the 5 most common reasons for revision but magnitude and ranking varied between registries. Over time there were increases in proportions of revisions for infection and decreases in revisions for wear. There were inconsistent proportions and trends for the other reasons for revision. The incidence of revision for infection showed a uniform increase.Interpretation - Despite some differences in terminology, comparison of registry-recorded revision diagnoses is possible, but defining a single reason for revision is not always clear-cut. There were common increases in revision for infection and decreases in revision for wear, but variable changes in other categories. This may reflect regional practice differences and therefore generalizability of studies regarding reasons for revision is unwise.

Orthopedic surgery approach with uncemented metallic prosthesis in knee osteoarthritis increases the quality of life of young patients

Osteoarthritis is mainly located in the knee area. It is an important concern related to the population health, determined by the influence on the quality of life of patients. Total knee arthroplasty (TKA) with uncemented fixation is among the most encountered procedures performed in patients of a younger age. The present study investigated the response of patients (quality of life, mobility and pain management) with titanium/hydroxyapatite-coated implants with polyethylene inserts. A total of 57 patients with knee arthroplasty were studied with an average age of 54.1±4.9 years and 57.8% were females. The present study focused on the following aspects: The components of such a prosthesis and the way they contribute to a physiological fixation/recovery; how the implant surgery is performed; the clinical and demographic characteristics of the patients; postoperative pain assessment in different types of movement; the management of the movement capacity 1 year after the surgery; and complications that may occur. One year after the surgery, these patients reported pain release, considerably favorable results in every-day activities, and good mobility (capable of using the car, rising from the bed or standing). Knowledge and accurate observation of the correct steps in performing this surgery and the role of the components of the prosthesis can lead to favorable therapeutic outcomes for patients with knee osteoarthritis.

The use of functionalized nanoparticles to treat Staphylococcus aureus-based surgical-site infections: a systematic review

Staphylococcus aureus-based surgical site infections have become the leading cause of failure for total joint arthroplasty operations and remain a major issue across surgical specialties. Moreover, S. aureus-based infections are becoming drastically more difficult to treat due to the development of antibiotic resistant strains and due to the bacteria's propensity to produce biofilms. The emergence of highly resistant S. aureus infections has created the need for a novel antimicrobial treatment. Functionalized nanoparticles have recently been suggested as being a viable option to fill this void due to their strong antimicrobial and antibiofilm properties. However, said research remains a novel and developing field. The presented systematic review aimed to synthesize the best and most recent evidence available to accurately direct new research towards a viable treatment mechanism. In doing so, the authors performed a comprehensive literature search as directed by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The results showed that nanoparticles-particularly those including an iron-oxide component or acidic capping agent-are a viable treatment for S. aureus infections both in vivo and in vitro, and show even greater efficacy when combined with exposure to a magnetic field and irradiation.

Diagnostic Accuracy of the Synovial Fluid α-Defensin Lateral Flow Test in Periprosthetic Joint Infection: A Meta-analysis

Objectives

There is a controversy on the diagnostic reliability and accuracy of synovial fluid α‐defensin in periprosthetic joint infection (PJI). We performed this meta‐analysis to evaluate the diagnostic accuracy of the α‐defensin lateral flow test in PJI.

Methods

PubMed, Embase, and the Cochrane library were systematically searched, and articles (up to January 2020) on the diagnosis of hip and knee PJIs using the α‐defensin Synovasure lateral flow test were included. The diagnostic accuracy of the α‐defensin lateral flow test in PJI was evaluated using meta‐analysis. The pooled sensitivity, specificity, accuracy, positive and negative likelihood ratio, diagnostic odds ratio, and post‐test probabilities were calculated.

Results

Seventeen studies including 1443 cases were included. Meta‐analysis showed the pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and a diagnostic odds ratio was 0.83 (95% CI 0.77, 0.88), 0.95 (95% CI 0.93, 0.97), 16.86 (95% CI 11.67, 24.37), 0.17 (95% CI 0.13, 0.24) and 85.30 (95% CI 47.76, 152.35), respectively. The area under the hierarchical summary receiver operating characteristic curve was 0.97 (95% CI 0.95, 0.98). Subgroup analysis also confirmed the high efficiency of α‐defensin Synovasure lateral flow test in diagnosing PJIs, irrespective of ethnicity. Fagan's nomogram analysis there was a high positive post‐test probability of 94% and a low negative post‐test probability of 15%.

Conclusions

We indicated that the α‐defensin lateral flow test had a high accuracy for diagnosing PJI. Large‐scale studies are needed to validate its significance in PJI diagnosis.

Engineered photo-chemical therapeutic nanocomposites provide effective antibiofilm and microbicidal activities against bacterial infections in porous devices

Today, prosthetic joint infection (PJI) is still a relatively rare but devastating complication following total hip and/or knee arthroplasty. The treatment of PJI is difficult due to a number of obstacles, such as microbial drug resistance, biofilm protection, and insufficient immune activity, which dramatically diminish the cure rate of PJI to <50%. To efficiently eradicate the bacteria hiding in the implant, photo-chemical joint antibacterial therapeutics based on indocyanine green (ICG) and rifampicin (RIF) co-loaded PLGA nanoparticles (IRPNPs) were developed in this study. The IRPNPs were first characterized as a spherical nanostructure with a size of 266 ± 18.2 nm and a surface charge of -28 ± 1.6 mV. In comparison with freely dissolved ICG, the IRPNPs may confer enhanced thermal stability to the encapsulated ICG and are able to provide a comparable hyperthermic effect and increased production of singlet oxygen under 808 nm near infrared (NIR) exposure with an intensity of 6 W cm-2. Based on the spectrophotometric analysis, the IRPNPs with ≥20-/3.52 μM ICG/RIF were able to provide remarkable antibiofilm and antimicrobial effects against bacteria in a porous silicon bead upon NIR exposure in vitro. Through the analysis of the microbial population index in an animal study, ≥70% Staphylococcus capitis subsp. urealyticus grown in a porous silicon bead in vivo can be successfully eliminated without organ damage or inflammatory lesions around the implant by using IRPNPs + NIR irradiation every 72 h for 9 days. The resulting bactericidal efficacy was approximately three-fold higher than that resulting from using an equal amount of free RIF alone. Taken together, we anticipate that IRPNP-mediated photochemotherapy can serve as a feasible antibacterial approach for PJI treatment in the clinic.

Circulating D-Dimer versus Fibrinogen in the Diagnosis of Peri-Prosthetic Joint Infection: A Meta-Analysis

Background: Circulating D-dimer and fibrinogen are both emerging as promising biomarkers for the diagnosis of peri-prosthetic joint infection (PJI), but their clinical values still remain disputable. This study aims to evaluate and compare the accuracy of circulating D-dimer and fibrinogen in the diagnosis of suspected PJI. Methods: We conducted a comprehensive literature search in PubMed, EMBASE, and the Cochrane Library to retrieve diagnostic accuracy studies in which PJI was investigated with circulating D-dimer or fibrinogen from the time of database inception to August 1, 2019. The pooled sensitivity, specificity, likelihood ratios and diagnostic odds ratio (DOR), summary receiver operating characteristic (sROC) curves, and area under the sROC curve (AUC) were constructed using a meta-analysis framework. Results: Seven eligible studies (1,374 patients) were included in the quantitative analysis. The mean levels of circulating D-dimer and fibrinogen were all significantly higher in patients with PJI. The plasma fibrinogen illustrated relatively higher sensitivity (0.84, 95% confidence interval [CI]: 0.78-0.98) and specificity (0.80, 95% CI: 0.76-0.84) than circulating D-dimer (0.74, 95% CI: 0.69-0.78; 0.66, 95% CI: 0.62-0.69, respectively) for the diagnosis of PJI. The pooled DOR of D-dimer, fibrinogen, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) to diagnose PJI was 7.00 (95% CI, 2.50-19.59), 12.40 (95% CI, 5.85 to 26.28), 10.71 (95% CI, 7.76 to 14.78) and 16.22 (95% CI 11.71-22.46), respectively, while the pooled AUC was 0.84 (95% CI, 0.77-0.90), 0.87 (95% CI, 0.85-0.89), 0.82 (95% CI, 0.78-0.85) and 0.87 (95% CI, 0.86-0.88), respectively. Conclusions: This meta-analysis reveals that it could be concluded that plasma fibrinogen is an excellent biomarker for diagnosing PJI, comparable to serum CRP and ESR, while the diagnostic value of circulating D-dimer is only moderate. Large-scale, prospective studies are still needed to confirm current findings.

Development of a Preoperative Risk Calculator for Reinfection Following Revision Surgery for Periprosthetic Joint Infection

BACKGROUND

A recent systematic review demonstrated that reinfection rates following eradication of hip and knee periprosthetic joint infection (PJI) may be as high as 29%. This study aimed to develop a preoperative risk calculator for assessing patient's individual risk associated with reinfection following treatment of PJI in total joint arthroplasty (TJA).

METHODS

A total of 1081 consecutive patients who underwent revision TJA for PJI were evaluated. In total, 293 patients were diagnosed with TJA reinfection. A total of 56 risk factors, including patient characteristics and surgical variables, were evaluated with multivariate regression analysis. Analysis of the area under the receiver operating characteristics curve was performed to evaluate the strength of the predictive model.

RESULTS

Of the 56 risk factors studied, 19 were found to have a significant effect as risk factor for TJA reinfection. The strongest predictors for TJA reinfection included previous PJI treatment techniques such as irrigation and debridement, the number of previous surgical interventions, medical comorbidities such as obesity, drug abuse, depression and smoking, as well as microbiology including the presence of Enterococcus species. The combined area under the receiver operating characteristics curve of the risk calculator for periprosthetic hip and knee joint reinfection was 0.75.

CONCLUSIONS

The study findings demonstrate that surgical factors, including previous PJI surgical treatment techniques as well as the number of previous surgeries, alongside microbiology including the presence of Enterococcus species have the strongest effect on the risk for periprosthetic THA and TKA joint reinfection, suggesting the limited applicability of the existing risk calculators for the development of PJI following primary TJA in predicting the risk of periprosthetic joint reinfection.

Acute Renal Failure After the First Stage of a 2-Stage Exchange for Periprosthetic Joint Infection

BACKGROUND

Two-stage exchange using antibiotic-loaded spacers is a common approach in treating periprosthetic joint infections. Acute kidney injury (AKIN) can be a systemic complication of this procedure. This study investigates the prevalence of AKIN and identifies potential risk factors.

METHODS

This is a single-center retrospective analysis of patients undergoing 2-stage exchange using a spacer in 285 patients treated between 2010 and 2017. Risk factors were evaluated using parametric and nonparametric analyses and a multivariate, binary logistic regression model.

RESULTS

Thirty-three percent of patients (95/285) developed an AKIN postoperatively. Twenty-four percent (23/95) of these patients had an acute on chronic kidney failure with a previously impaired renal function. In multivariate analysis, a higher age (hazard ratio [HR], 1.034; 95% confidence interval [CI], 1-1.068; P = .046) and a higher baseline creatinine level (HR, 1.94; 95% CI, 1.237-3.052; P = .004) were risk factors for AKIN. Treatment with vancomycin in the spacer or systemically was not associated with AKIN while a high vancomycin blood level (HR, 1.91; 95% CI, 0.913-3.992; P = .086) and fungal infections were (HR, 3.482; 95% CI, 0.968-12.521; P = .056). Furthermore, in univariate analysis, a higher median Charlson comorbidity index (4 vs 3, P = .007), a lower preoperative hemoglobin (10.9 vs 11.7 g/dL, P = .008), and a higher number of blood transfusions (1 vs 0, P = .004) were associated with AKIN.

CONCLUSION

AKIN is common in patients undergoing 2-stage exchange. Associated patient factors, particularly in patients with chronic renal dysfunction, should be optimized. The general use of glycopeptide antibiotics was no risk factor for AKIN.

Benefits and Adverse Events Associated With Extended Antibiotic Use in Total Knee Arthroplasty Periprosthetic Joint Infection

BACKGROUND

Total knee arthroplasty (TKA) periprosthetic joint infection (PJI) can be managed with debridement, antibiotic therapy, and implant retention (DAIR). Oral antibiotics can be used after DAIR for an extended time period to improve outcomes. The objective of this study was to compare DAIR failure rates and adverse events between an initial course of intravenous antibiotic therapy and the addition of extended treatment with oral antibiotics.

METHODS

A multicenter observational study of patients diagnosed with a TKA PJI who underwent DAIR was performed. The primary outcome of interest was the failure rate derived from the survival time between the DAIR procedure and future treatment failure.

RESULTS

One hundred eight patients met inclusion criteria; 47% (n = 51) received an extended course of oral antibiotics. These patients had a statistically significant lower failure rate compared to those who received only intravenous antibiotics (hazard ratio, 2.47; P = .009). Multivariable analysis demonstrated that extended antibiotics independently predicted treatment success, controlling for other variables. There was no significant difference in failure rates between an extended course of oral antibiotics less or more than 12 months (P = .23). No significant difference in the rates of adverse events was observed between patients who received an initial course of antibiotics alone and those who received a combination of initial and extended antibiotic therapy (P = .59).

CONCLUSIONS

Extending therapy with oral antibiotics had superior infection-free survival for TKA PJI managed with DAIR. There was no increase in adverse events, demonstrating safety. After 1 year, there appears to be no significant benefit associated with continued antibiotic therapy.

International Organism Profile of Periprosthetic Total Hip and Knee Infections

BACKGROUND

There is scarce literature describing pathogens responsible for periprosthetic joint infections (PJIs) around the world. Therefore, we sought to describe periprosthetic joint infection causative organisms, rates of resistant organisms, and polymicrobial infections at 7 large institutions located in North/South America and Europe.

METHODS

We performed a retrospective study of 654 periprosthetic hip (n = 361) and knee (n = 293) infections (January 2006 to October 2019) identified at Cleveland Clinic Ohio/Florida in the United States (US) (n = 159), Hospital Italiano de Buenos Aires in Argentina (n = 99), Hospital Asociación Española in Uruguay (n = 130), Guy's and St Thomas' Hospital in the United Kingdom (UK) (n = 103), HELIOS Klinikum in Germany (n = 59), and Vreden Institute for Orthopedics in St. Petersburg, Russia (n = 104). Analyses were performed for the entire cohort, knees, and hips. Alpha was set at 0.05.

RESULTS

Overall, the most frequent organisms identified were Staphylococcus aureus (24.8%) and Staphylococcus epidermidis (21.7%). The incidence of organisms resistant to at least one antibiotic was 58% and there was a significant difference between hips (62.3%) and knees (52.6%) (P = .014). Rates of resistant organisms among countries were 37.7% (US), 66.7% (Argentina), 71.5% (Uruguay), 40.8% (UK), 62.7% (Germany), and 77.9% (Russia) (P < .001). The overall incidence of polymicrobial infections was 9.3% and the rates across nations were 9.4% in the US, 11.1% in Argentina, 4.6% in Uruguay, 4.9% in UK, 11.9% in Germany, and 16.3% in Russia (P = .026).

CONCLUSION

In the evaluated institutions, S aureus and S epidermidis accounted for almost 50% of all infections. The US and the UK had the lowest incidence of resistant organisms while Germany and Russia had the highest. The UK and Uruguay had the lowest rates of polymicrobial infections.

Single-Stage Revision of the Infected Total Knee Arthroplasty Is Associated With Improved Functional Outcomes: A Propensity Score-Matched Cohort Study

BACKGROUND

Single-stage revision is an alternative to the standard 2-stage revision, potentially minimizing morbidities and improving functional outcomes. This study aimed at comparing single-stage and 2-stage revision total knee arthroplasty (TKA) for chronic periprosthetic joint infection (PJI) with regard to patient-reported outcome measures (PROMs) and complication rates.

METHODS

A total of 185 consecutive revision TKA patients for chronic PJI with complete preoperative and postoperative PROMs were investigated. A total of 44 patients with single-stage revision TKA were matched to 88 patients following 2-stage revision TKA using propensity score matching, yielding a total of 132 propensity score-matched patients for analysis. Patient demographics and clinical information including reinfection and readmission rates were evaluated.

RESULTS

There was no significant difference in preoperative PROMs between propensity score-matched single-stage and 2-stage revision TKA cohorts. Postoperatively, significantly higher PROMs for single-stage revision TKA were observed for Knee disability and Osteoarthritis Outcome Score physical function (62.2 vs 51.9, P < .01), physical function short form 10A (42.8 vs 38.1, P < .01), PROMIS SF Physical (44.8 vs 41.0, P = .01), and PROMIS SF Mental (50.5 vs 47.1, P = .02). There was no difference between propensity score-matched single-stage and 2-stage revision TKA cohorts for clinical outcomes including reinfection rates (25.0% vs 27.2%, P = .78) and 90-day readmission rates (22.7% vs 25.0%, P = .77).

CONCLUSION

This study illustrated that single-stage revision TKA for chronic PJI may be associated with superior patient-reported outcomes compared to 2-stage revision for the infected TKA using a variety of PROMs. Improved PROMs were not accompanied by differences in complication rates between both cohorts, suggesting that single-stage revision TKA may provide an effective alternative to 2-stage revision in patients with chronic TKA PJI.

Revision knee replacement for prosthetic joint infection: Epidemiology, clinical outcomes and health-economic considerations

Prosthetic joint infection (PJI) is a devastating complication of knee replacement surgery. Recent evidence has shown that the burden of disease is increasing as more and more knee replacement procedures are performed. The current incidence of revision total knee replacement (TKR) for PJI is estimated at 7.5 cases per 1000 primary joint replacement procedures at 10 years. Revision TKR for PJI is complex surgery, and is associated to a high rate of post-operative complications. The 5-year patient mortality is comparable to some common cancer diagnoses, and more than 15% of patients require re-revision by 10 years. Patient-reported outcome measures (PROMs) including joint function may be worse following revision TKR for PJI than for aseptic indications. The complexity and extended length of the treatment pathway for PJI places a significant burden on the healthcare system, highlighting it as an area for future research to identify the most clinically and cost-effective interventions.

Controlling Antibiotic Release from Polymethylmethacrylate Bone Cement

Bone cement is used as a mortar for securing bone implants, as bone void fillers or as spacers in orthopaedic surgery. Antibiotic-loaded bone cements (ALBCs) have been used to prevent and treat prosthetic joint infections by providing a high antibiotic concentration around the implanted prosthesis. High antibiotic concentrations are, on the other hand, often associated with tissue toxicity. Controlling antibiotic release from ALBCS is key to achieving effective infection control and promoting prosthesis integration with the surrounding bone tissue. However, current ALBCs still need significant improvement in regulating antibiotic release. In this review, we first provide a brief introduction to prosthetic joint infections, and the background concepts of therapeutic efficacy and toxicity in antibiotics. We then review the current state of ALBCs and their release characteristics before focusing on the research and development in controlling the antibiotic release and osteo-conductivity/inductivity. We then conclude by a discussion on the need for better in vitro experiment designs such that the release results can be extrapolated to predict better the local antibiotic concentrations in vivo.

Systematic Review and Meta-Analysis of Tobacco Use as a Risk Factor for Prosthetic Joint Infection After Total Hip Replacement

Background

A prosthetic joint infection (PJI) is one of the possible complications after total hip arthroplasty (THA). Several studies, but not all, have reported smoking as a risk factor of PJIs in orthopaedic surgery. This study summarizes the most recent evidence using a systematic review of whether tobacco use (not only tobacco smoking) is a risk factor in developing PJIs, specifically after THA.

Methods

Ovid Medline, EMBASE, Scopus, Web of Science, and Cochrane databases were searched from inception to July 2019 to identify case-control studies that examined the PJI risk in tobacco users and tobacco nonusers undergoing THA. Publication bias was also assessed through funnel plots.

Results

Searches identified 2689 articles, and 10 of these, involving a total of 20,640 patients, met the inclusion criteria. The overall odds ratio (pooled odds ratio) to develop either a superficial infection, a deep infection, or an infection requiring revision surgery for tobacco users vs nonusers was 1.54 (95% confidence interval: 1.25-1.91) when a fixed-effect model was used and 1.56 (95% confidence interval: 1.10-2.21) when a random-effect model was used. No publication bias was observed among the identified studies.

Conclusions

The findings of the study indicated that tobacco use is associated with a higher risk of PJIs in patients undergoing THA.

Gastrocnemius Muscle Flaps for Soft Tissue Coverage in Periprosthetic Knee Joint Infection

BACKGROUND

Soft tissue deficiency in total knee arthroplasty infection is a potentially devastating complication. Gastrocnemius muscle flaps can be used to address this problem. We aim at reporting survival rates of these reconstructions and identify risk factors for failure.

METHODS

A retrospective evaluation of all flaps performed at a single center between 2006 and 2019 was performed. Clinical and microbiological results were assessed in 43 cases after a median follow-up period of 53 months (25%-75% interquartile range 18-79). Function was assessed using the Oxford Knee Score. We analyzed the infection-free survival and identified risk factors using survival comparison and (non-)parametric testing.

RESULTS

Infection-free survival was 71% at 2 years and 63% at 5 years. The rate of subsequent amputation was 16% with a mortality rate of 26% during follow-up. Four patients did not undergo reimplantation and 11 patients received an arthrodesis implant. There were no failures of the flap itself. The Charlson Comorbidity index was the only relevant risk factor for reinfection. Coagulase-negative staphylococci were most common organisms identified. Postoperative function was limited with a mean Oxford Knee Score of 20.

CONCLUSION

Gastrocnemius flap coverage is a valid option for soft tissue reconstruction in periprosthetic infections to retain a functioning limb despite a high complication rate and the risk of subsequent amputation.

Revision total knee arthroplasty longer term outcome and comparison between infection and aseptic loosening at mean follow-up of 10 years

Background:

Although the majority of total knee arthroplasty cases have good outcome and survival, some arthroplasty eventually required revision. While early outcomes of revision knee arthroplasty are well reported, there is relatively fewer literatures reporting on the longer term outcome of revision knee arthroplasty. This study aims to review the outcome of revision knee arthroplasty for a longer term, and also make comparison between the two common indications for revision arthroplasty of infection and aseptic loosening.

Methods:

This study reviews all total knee arthroplasty revision performed at a single center over a 11 year period. Of the 48 cases found, 35 cases not lost to follow-up had a mean follow-up duration of 10.6 years (SD 2.9) for aseptic loosening, and 10.1 years (SD 2.6) for infection. Data of initial arthroplasty, revision arthroplasty, demographics, follow-up outcome were obtained, analyzed and compared.

Results:

Revision arthroplasty due to infection had more cases that required use of varus/valgus constraints (p ∼ 0.008) and extensile surgical exposure of quadriceps snip (p ∼ 0.005) compared to aseptic loosening. The survival at 10 years for this study is 91% overall (aseptic loosening 93.3%, infection 89.3%). Infection cases had significant initial improvement for range of motion (p ∼ 0.001) and use of walking aid (p ∼ 0.04) at post-operation 1 year, but no significant differences between the infection and aseptic loosening cases at 5 years and 10 years follow-up. Comparison between the two groups on other factors including initial arthroplasty, operative details, demographics, post-operative details and X-rays showed no statistically significant difference.

Alpha-Defensin versus Leukocyte Esterase in Periprosthetic Joint Infection: An Updated Meta-Analysis

Periprosthetic joint infection (PJI) is a devastating complication after arthroplasty. Prompt establishment of an infection diagnosis is critical but can be very challenging at present. In order to evaluate the diagnostic accuracy of alpha-defensin or leukocyte esterase for PJI, we performed systematic research in PubMed, Embase, and Cochrane Library to retrieve relevant studies. Data extraction and quality assessment were performed by two reviewers independently. A total of thirty-one eligible studies were finally included in the quantitative analysis. The pooled sensitivity and specificity of alpha-defensin (21 studies) for the diagnosis of PJI were 0.89 (95% confidence interval (CI), 0.83 to 0.93) and 0.96 (95% CI, 0.95 to 0.97), respectively. The value of the pooled diagnostic odds ratios (DOR) of alpha-defensin for PJI was 209.14 (95% CI, 97.31 to 449.50), and the area under the curve (AUC) was 0.98 (95% CI, 0.96 to 0.99). The pooled sensitivity and specificity of leukocyte esterase (17 studies) for the diagnosis of PJI were 0.90 (95% CI, 0.84 to 0.95) and 0.96 (95% CI, 0.93 to 0.97), respectively. The value of the DOR of leukocyte esterase for PJI was 203.23 (95% CI, 96.14 to 429.61), and the AUC was 0.98 (95% CI, 0.96 to 0.99). Based on the results of our meta-analysis, we can conclude that alpha-defensin and leukocyte esterase are valuable synovial fluid markers for identifying PJI with comparable high diagnostic accuracy.

Completeness and capture rate of publicly funded arthroplasty procedures in the New Zealand Joint Registry

BACKGROUND

Registry-based studies have become more common due to the availability of a large study cohort. However, the validity of findings is dependent on the completeness of the registry. This study aimed to validate the capture rate of the New Zealand Joint Registry (NZJR) by matching procedures that have been recorded separately via clinical coding by the New Zealand Government's National Surgical Site Infection Improvement Programme (SSIIP).

METHODS

The National Health Index, a unique identification code for all patients, was combined with the arthroplasty procedure performed (primary total knee arthroplasty (TKA), primary total hip arthroplasty (THA), revision TKA or revision THA) and operation side. Publicly funded procedures recorded in the NZJR were matched with procedures recorded by the SSIIP on a record-by-record basis. This identified the total number of arthroplasty procedures performed in New Zealand, which was used as the denominator value to calculate the procedure capture rate of the NZJR.

RESULTS

Between 2013 and 2018, 24 556 primary TKA, 28 970 primary THA, 2107 revision TKA and 4263 revision THA procedures were recorded by both datasets. The NZJR recorded 95.5% of primary TKA procedures, 96.3% of primary THA procedures, 97.1% of revision TKA procedures and 95.2% of revision THA procedures.

CONCLUSION

The NZJR recorded >95% of publicly funded arthroplasty procedures. In contrast, there were inaccuracies in clinical coding by hospitals, particularly with revision procedures, demonstrating the benefits of an arthroplasty registry. However, data recorded by an infection surveillance programme may supplement arthroplasty registry data to strengthen the quality of research.

Elevated ESR/CRP Ratio Is Associated With Reinfection After Debridement, Antibiotics, and Implant Retention in Chronic Periprosthetic Joint Infections

BACKGROUND

Ratios of established inflammatory markers, erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP), have been used for diagnostic purposes in the surgical field; however, the ESR:CRP ratio (ECR) has not been evaluated as a marker for predicting infection resolution in patients with periprosthetic joint infections (PJIs). This study aimed to evaluate the diagnostic accuracy of ECR in predicting postoperative reinfection in patients who underwent debridement, antibiotics, and implant retention (DAIR).

METHODS

This is a retrospective review of 179 consecutive patients who underwent DAIR revision total joint arthroplasty for PJI. Patients were stratified by acuity of their infection: acute PJI, acute hematogenous PJI, and chronic PJI. The area under the receiver operating characteristic curve was calculated to evaluate ECR as diagnostic marker for predicting postoperative reinfection in patients who underwent DAIR.

RESULTS

Statistically significant differences in ECR were found in patients who underwent DAIR revision total joint arthroplasty for chronic infection (1.23 vs 2.33; P = .04). There was no significant difference in ECR in patients who underwent DAIR for acute infection (P = .70) and acute hematogenous infection (P = .56). In patients who underwent DAIR for chronic PJI, ECR demonstrated a sensitivity and specificity of 75% and 84%, respectively, for the prediction of postoperative reinfection, which was significantly higher than that of ESR (sensitivity, 67%; specificity, 47%; P < .001) and CRP (sensitivity, 50%; specificity, 26%; P < .001).

CONCLUSION

Elevated ECR was associated with an increased reinfection risk in patients who underwent DAIR for chronic PJI, suggesting that preoperative ECR may be a useful predictor to identify patients at increased risk of reinfection after DAIR for chronic PJIs.

Do Positive Cultures at Second Stage Re-Implantation Increase the Risk for Reinfection in Two-Stage Exchange for Periprosthetic Joint Infection?

BACKGROUND

Intraoperative cultures are important in the diagnosis and targeted treatment of periprosthetic joint infection (PJI). Positive cultures at reimplantation during a two-stage exchange are discussed as a risk factor for reinfection. The aim of this study is the investigation of the incidence and risk factors for positive cultures during reimplantation.

METHODS

We retrospectively identified 204 patients (111 knees, 93 hips) who were treated between 2012 and 2016 for PJI using a two-stage exchange protocol at a median follow-up of 42 months. PJI was diagnosed using the criteria of the musculoskeletal infection society (MSIS) of 2011. All cultural findings from first and second stage surgery were recorded. The primary endpoint was revision for infection. Risk factors for positive cultures and reinfection were analyzed.

RESULTS

During reimplantation 25% (51/204) of patients had at least one positive culture, in 19.1% (39/204) only a single culture. Patients with culture-negative infections had a higher risk for positive cultures at reimplantation (HR 2.946 (95% CI 1.247-6.961), P = .014) and patients with infected total hip arthroplasty (THA) (HR 3.547 (95% CI 1.7-7.4), P = .001). Patients with positive cultures during reimplantation had a higher risk for reinfection (HR 2.27 (95% CI 1.181-4.363), P = .014) as well as patients with a single positive culture (HR 2.421 (95% CI 1.139-5.143), P = .021).

CONCLUSION

As positive cultures are common and increase reinfection risk irrespective of their numbers, longer antibiotic therapy following reimplantation can be an option. Single positive cultures in reimplantation surgery should not be considered contamination.

Antibiotic Stewardship for Total Joint Arthroplasty in 2020

Projections indicate an increase in primary and revision total joint arthroplasties (TJAs). Periprosthetic joint infections (PJIs) are one of the most common and devastating causes of failure after TJA. Perioperative administration of systemic and/or local antibiotics is used for both prophylaxis and treatment of PJI. Antibiotic stewardship is a term that has been met with clinical acceptance and success in other specialties of medicine. Identifying antibiotic best practice use in the fight against PJI is limited by studies that are extremely heterogeneous in their design. Variations in studies include antibiotic selection and duration, surgical débridement steps, type of antibiotic delivery (intra-articular, local, intravenous, and prolonged oral), mix of primary and revision surgery cohorts, both hip and knee cohorts, infecting organisms, and definitions of treatment success/failure. This review highlights the current challenges of antibiotic stewardship in TJA.

Fungal Periprosthetic Knee Joint Infection in a Patient with Metamizole-Induced Agranulocytosis

We present the case of a 55-year-old female patient with metamizole-induced agranulocytosis after total knee arthroplasty, leading to septic periprosthetic joint infections (PJIs). Owing to metamizole-induced agranulocytosis, the synovial leukocyte count was negative. Here, we discuss the diagnostic challenges evolving from sepsis and neutropenia in patients with suspected PJIs. We suggest an urgent surgical approach, mainly focusing on the clinical presentation preoperatively. Later, our patient developed candidemia and periprosthetic tissue samples were positive for Candida albicans. For fungal PJIs, long-term follow-up studies are lacking and therapeutic recommendations differ. Here, we present our therapeutic approach, including staged revision and 12 weeks of systemic antifungal therapy, and discuss recent findings regarding the therapy of fungal PJIs.

The Effect of Time Spent with a Dynamic Spacer on Clinical and Functional Outcomes in Two-Stage Revision Knee Arthroplasty

INTRODUCTION

The present study aimed to evaluate the effect of a longer interval between the first and second stages of infected total knee arthroplasty (TKA) revision on the clinical and functional outcome.

METHODS

This study included a total of 56 patients who underwent two-stage revision TKA with a dynamic spacer with a minimum of 2 years of follow-up. Patients were categorized into two groups according to time with the spacer: < 3 months (Group 1, 31 patients) or > 3 months (Group 2, 25 patients). Clinical outcome and quality of life were assessed by knee range of motion (ROM), Knee Society Score for Knee (KSS-K), Knee Society Score for Function (KSS-F) and Short Form 36 (SF-36).

RESULTS

The mean follow-up period was 48 ± 19.1 months (range, 24-84 months). The KSS-K, KSS-F, and ROM values were significantly higher in Group 1 than in Group 2 (p < 0.05). The SF-36 scores for general health, physical function, and bodily pain were significantly higher in Group 1 (p < 0.05). Re-infection occurred in 10 patients (17.8%). Time with spacer was not associated with re-infection development (Group 1, n = 6, 19% vs. Group 2, n = 4, 16%; p > 0.05).

CONCLUSION

Increased duration with a spacer is associated with poorer clinical and functional outcomes as well as higher treatment costs in two-stage revision knee arthroplasty. Surgeons can attempt to reduce the time patients spend in a spacer to obtain better postoperative functional outcomes, as well as a better quality of life.

LEVEL OF EVIDENCE

3.

Comparison of a Comprehensive Set of Fibrinolytic Markers With C-Reactive Protein and Erythrocyte Sedimentation Rate for the Diagnosis of Periprosthetic Joint Infection

BACKGROUND

The diagnosis of periprosthetic joint infection (PJI), a serious complication after primary total joint arthroplasty, remains challenging. Recently, fibrinolytic activities have been shown to be closely related to infections and inflammation. However, data assessing the value of fibrinolytic markers for the diagnosis of PJI have been sparse until now.

METHODS

We retrospectively enrolled 157 patients undergoing revision for aseptic loosening (n = 106, group A) or revision for chronic PJI (n = 51, group B) from January 2014 to August 2019. PJI was defined using the Musculoskeletal Infection Society criteria. Erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), D-dimer, fibrin degradation product (FDP), and fibrinogen were measured preoperatively. The diagnostic values of each biomarker were analyzed and compared using receiver operating characteristic curves, sensitivity, and specificity.

RESULTS

Compared with group A, group B had significantly higher levels of CRP, ESR, D-dimer, FDP, and fibrinogen (P < .001). The area under the curve of fibrinogen was 0.914, which was slightly lower than that of CRP (0.924). FDP and D-dimer had area under the curve values of 0.808 and 0.784, respectively. The optimal threshold, sensitivity, and specificity were 3.56 g/L, 86.27%, and 83.96% for fibrinogen; 1.22 mg/L, 66.67%, and 85.85% for D-dimer; and 3.98 μg/mL, 72.55%, and 80.19% for FDP, respectively.

CONCLUSION

Fibrinolytic markers provided promising diagnostic support for PJI, especially fibrinogen, which had a diagnostic efficiency similar to that of CRP and ESR.

Does Adherence to Preoperative Surgical Selection Criteria Reduce the Rate of Prosthetic Joint Infection in Primary and Revision Total Knee Arthroplasties?

BACKGROUND

There has been recent increased focus on the importance of modifiable risk factors that can affect the risk of potentially avoidable complications such as prosthetic joint infection (PJI). We aimed to assess the relationship between adherence to a preoperative optimization protocol at our institution and its influence on the rate of PJI after primary and revision total knee arthroplasty (TKA).

METHODS

A single-institution, retrospective study was conducted on all elective primary and revision TKAs performed over a 2-year period. PJI was diagnosed using the 2011 Musculoskeletal Infection Society criteria. Surgical outcomes and PJI were assessed relative to adherence to preoperative optimization criteria. Compliance was set as a binary variable with any case that did not meet all criteria deemed noncompliant.

RESULTS

A total of 669 TKAs met inclusion criteria, including 510 primary and 159 revision TKAs. Overall compliance was 61.3%. There were 26 PJIs (3.9%) in total. The PJI rate was 1.2% (6) among primary and 14.4% (20) among revision TKAs. The rate of PJI among cases that met the preoperative optimization criteria was 2.4% (5), and the rate among cases that did not was 6.2% (21) (P < .05).

CONCLUSIONS

Adherence to preoperative optimization criteria may decrease the incidence of PJI after primary and revision TKA, but further study is needed to confirm the findings of this study.

Outcome of Revision Surgery for Infection After Total Knee Arthroplasty: Results of 3 Surgical Strategies

BACKGROUND

Periprosthetic joint infection (PJI) after knee arthroplasty surgery remains a serious complication, yet there is no international consensus regarding the surgical treatment of PJI. This study aimed to assess prosthesis survival rates, risk of revision, and mortality rate following different surgical strategies (1-stage versus 2-stage implant revision and irrigation and debridement with implant retention) that are used to treat PJI.

METHODS

The study was based on 644 total knee arthroplasties (TKAs) that were revised because of a deep infection (i.e., surgically treated PJI) and reported to the Norwegian Arthroplasty Register (NAR) from 1994 to 2016. Kaplan-Meier and multiple Cox regression analyses were performed to assess implant survival rate and risk of revision. We also studied mortality rates at 90 days and 1 year after revision for PJI.

RESULTS

During the follow-up period, 19% of the irrigation and debridement cases, 14% of the 1-stage revision cases, and 12% of the 2-stage revision cases underwent a subsequent revision because of a PJI. The 5-year Kaplan-Meier survival rate with revision for infection as the end point was 79% after irrigation and debridement, 87% after 1-stage revision, and 87% after 2-stage revision. There were no significant differences between 1-stage and 2-stage revisions with subsequent revision for any reason as the end point (relative risk [RR], 1.7; 95% confidence interval [CI], 0.9 to 3.5) and no difference with revision because of infection as the end point (RR, 1.6; 95% CI, 0.7 to 3.7). In an age-stratified analysis, however, the risk of revision for any reason was 4 times greater after 1-stage revision than after 2-stage revision in patients over the age of 70 years (RR, 4.3; 95% CI, 1.3 to 14.8). Age had no significant effect on the risk of subsequent revision for knees that had been revised with the irrigation and debridement procedure. The 90-day and 1-year mortality rates after revision for PJI were 1.2% and 2.5%, respectively.

CONCLUSIONS

Irrigation and debridement yielded good results compared with previous published studies. Although the 1-stage revisions resulted in a fourfold increase in risk of subsequent revision compared with the 2-stage revisions in older patients, the overall outcomes after 1-stage and 2-stage revisions were similar.

LEVEL OF EVIDENCE

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

Increases in the rates of primary and revision knee replacement are reducing: a 15-year registry study across 3 continents

Background and purpose - Rates of knee replacement (KR) are increasing worldwide. Based on population and practice changes, there are forecasts of a further exponential increase in primary knee replacement through to 2030, and a corresponding increase in revision knee replacement. We used registry data to document changes in KR over the past 15 years, comparing practice changes across Sweden, Australia, and the United States. This may improve accuracy of future predictions.Patients and methods - Aggregated data from the Swedish Knee Arthroplasty Register (SKAR), the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR), and the Kaiser Permanente Joint Replacement Registry (KPJRR) were used to compare surgical volume of primary and revision KR from 2003 to 2017. Incidence was calculated using population census statistics from Statistics Sweden and the Australian Bureau of Statistics, as well as the yearly active membership numbers from Kaiser Permanente. Further analysis of KR by age < 65 and ≥ 65 years was carried out.Results - All registries recorded an increase in primary and revision KR, with a greater increase seen in the KPJRR. The rate of increase slowed during the study period. In Sweden and Australia, there was a smaller increase in revision surgery compared with primary procedures. There was consistency in the mean age at surgery, with a steady small decrease in the proportion of women having primary KR. The incidence of KR in the younger age group remained low in all 3 registries, but the proportional increases were greater than those seen in the ≥ 65 years of age group.Interpretation - There has been a generalized deceleration in the rate of increase of primary and revision KR. While there are regional differences in KR incidence, and rates of change, the rate of increase does not seem to be as great as previously predicted.

Mycobacterium mageritense Prosthetic Joint Infection

Prosthetic joint infections (PJI) complicate up to 2% of arthroplasties and are usually caused by typical bacterial agents (e.g., staphylococci and streptococci). Although an infrequent cause of PJI, mycobacterial species are difficult to eradicate, as they adhere to hardware, form biofilms, and have high rates of antimicrobial resistance. Mycobacterium mageritense is a rapidly growing Mycobacterium that has been infrequently described as a cause of surgical and device-related infections. We herein described a case of prosthetic knee infection due to M. mageritense. The patient was treated with removal of hardware, antimicrobials, and prosthetic knee reimplantation with a good outcome. To our knowledge, M. mageritense has not been previously described as a cause of PJI in the medical literature.

Total knee arthroplasty: A single centre review at 10 years of follow-up

Background:

Total knee arthroplasty is a common procedure for treatment of various non-infective arthritis. This study reviewed total knee arthroplasty cases up to 10 years of follow-up for the survival rate, reasons of revision and associated perioperative risk factors for revision.

Methods:

All cases to total knee arthroplasty performed in a single centre in the years 2007 and 2008 were reviewed. A total of 227 cases of total knee arthroplasty were performed during the 2-year period, with 156 cases followed up to 10 years. Perioperative information, follow-up information and information of possible complications were obtained.

Results:

The survival rate of total knee arthroplasty in this study is 98.2% at 5 years and 94.2% at 10 years of follow-up. The early post-operative complication rate was low, and majority of cases had improvement of function at 1 year after the operation. Early post-operative infection rate was low at 0.4%, and overall infection up to 10 years of follow-up was also low at 4.4%. Ten cases had undergone revision of arthroplasty by 10 years after operation.

Conclusion:

The survival rate of total knee replacement was high. The revision rate and infection rates were low up to 10 years of follow-up. The most common reasons of revision arthroplasty were infection and aseptic loosening. Cases which required revision arthroplasty had significantly longer operative duration compared with cases without revision at 10 years of follow-up ( p = 0.01).