Outcomes of Exeter cemented total hip arthroplasty in a county hospital: survivorship of eight hundred and ninety four hips with a minimum ten-year follow up.

PURPOSE: A total of 894 hips were evaluated to describe the survivorship of Exeter cemented femoral stems and report the outcomes and complications of our 'Exeter- era', and there is no study from Central or Eastern Europe demonstrating similar results. METHODS: Between January 2000 and December 2009, a total of 894 hips were included who underwent Exeter universal and V40 femoral stems with a mean follow up of 13 years. Cemented Exeter low profile polyethylene cups were used in 889 patients (99.4%) cups. Harris hip score (HHS) was used and statistical outcome measures were calculated with revision as an endpoint for aseptic loosening of the stem, aseptic loosening of any component, all-cause revision of the stem, and all-cause revision of the hip. RESULTS: A total of 103 patients died and 129 (14.4%) operated hips were lost to follow-up before ten years. Out of the 662, ten stems (1.5%) were revised for aseptic loosening. Aseptic loosening of any component was the reason for revision in 43 cases (6.5%), consisting of 40 cup revisions and ten stem exchanges. Periprosthetic fracture occurred in 17 cases (1.9%) Periprosthetic joint infection occurred in 18 cases (2.01%). Three cups were exchanged for recurrent dislocation, and two stems had broken. CONCLUSION: Exeter hip system has provided reproducible results across different centres worldwide, as it did in our series. Thorough surgical and cementing technique is of utmost importance for achieving these results. The cup is the weak point of the system and use of a hybrid system is worth considering.

Diagnostic utility of open biopsy in patients with two culture-negative aspirations in the diagnostic work-up of periprosthetic joint infection.

INTRODUCTION: Different approaches have been proposed for bacterial identification in patients with a suspected periprosthetic joint infection (PJI). If a one-stage procedure is considered, a higher rate of preoperative bacterial identification can be achieved if biopsy is included in the diagnostic work-up. The performance of open biopsy (OB) in the context of PJI has not been clearly determined yet. The purpose of this study was to determine the value of an OB added to two consecutive culture-negative joint aspirations during PJI workup. MATERIALS AND METHODS: We retrospectively analyzed the OB data from a single institution. Patients under PJI work-up of the hip or knee with two culture-negative periprosthetic aspirations who underwent OB were included. Sensitivity and specificity were calculated using the musculoskeletal infection society (MSIS) criteria as gold standard. Patients undergoing urgent irrigation and debridement and patients with history of surgery to the affected joint in the prior 6 weeks were excluded. RESULTS: 126 patients were included in this study. 62 (49.2%) patients had prior revisions, 48 of them due to PJI. The sensitivity and specificity of OB was 69.4% and 89.1%, respectively. The OB procedure led to the identification of the causative germ in 50 out of 126 (40%) cases so they could undergo one-stage (septic) exchange. CONCLUSION: The OB is a valuable resource if preoperative synovial fluid cultures are negative, a high suspicion of infection persists and a one-stage procedure is preferred. It intends bacteria identification and allows surgeons to evaluate prosthetic complications for further surgical procedures.

Activated polymorphonuclear derived extracellular vesicles are potential biomarkers of periprosthetic joint infection.

BACKGROUND: Extracellular vesicles (EVs) are considered as crucial players in a wide variety of biological processes. Although their importance in joint diseases or infections has been shown by numerous studies, much less is known about their function in periprosthetic joint infection (PJI). Our aim was to investigate activated polymorphonuclear (PMN)-derived synovial EVs in patients with PJI. QUESTIONS/PURPOSES: (1) Is there a difference in the number and size of extracellular vesicles between periprosthetic joint aspirates of patients with PJI and aseptic loosening? (2) Are these vesicles morphologically different in the two groups? (3) Are there activated PMN-derived EVs in septic samples evaluated by flow cytometry after CD177 labelling? (4) Is there a difference in the protein composition carried by septic and aseptic vesicles? METHODS: Thirty-four patients (n = 34) were enrolled into our investigation, 17 with PJI and 17 with aseptic prosthesis loosening. Periprosthetic joint fluid was aspirated and EVs were separated. Samples were analysed by nanoparticle tracking analysis (NTA) and transmission electron microscopy (TEM) and flow cytometry (after Annexin V and CD177 labelling). The protein content of the EVs was studied by mass spectrometry (MS). RESULTS: NTA showed particle size distribution in both groups between 150 nm and 450 nm. The concentration of EVs was significantly higher in the septic samples (p = 0.0105) and showed a different size pattern as compared to the aseptic ones. The vesicular nature of the particles was confirmed by TEM and differential detergent lysis. In the septic group, FC analysis showed a significantly increased event number both after single and double labelling with fluorochrome conjugated Annexin V (p = 0.046) and Annexin V and anti-CD177 (p = 0.0105), respectively. MS detected a significant difference in the abundance of lactotransferrin (p = 0.00646), myeloperoxidase (p = 0.01061), lysozyme C (p = 0.04687), annexin A6 (p = 0.03921) and alpha-2-HS-glycoprotein (p = 0.03146) between the studied groups. CONCLUSIONS: An increased number of activated PMN derived EVs were detected in the synovial fluid of PJI patients with a characteristic size distribution and a specific protein composition. The activated PMNs-derived extracellular vesicles can be potential biomarkers of PJI.

Diagnosis and management of the infected total knee replacement: a practical surgical guide.

PURPOSE: Prosthetic joint infection (PJI) after total knee arthroplasty (TKA) is a significant burden in health care. Diagnosis and proper management are challenging. A standardised procedure for the diagnostic workup and surgical management provides clear benefits in outcome. METHODS: Several diagnostic protocols and definitions for PJI were established in recent years. Proper PJI diagnosis remains critical for success and for choosing the optimal treatment option. A distinct workup of diagnostic steps, the evaluation of the results in a multidisciplinary setup and the meticulous surgical management of the infection are the key factors of successful treatment. RESULTS: The management of PJI after TKA consists of early revision with debridement and implant retention (DAIR) in early cases or staged revision in late infections beyond 30 days postoperative or after onset of acute symptoms. The revision is performed as a two-stage procedure with the use of a fixed or mobile antibiotic spacer, or in selected cases as a single-stage operation with the use of local and systemic antibiotic treatment. CONCLUSIONS: This paper reflects the opinion of two revision surgeons who follow the same protocol for diagnosis and treatment of PJI after TKA, highlighting the key steps in diagnosis and management. LEVEL OF EVIDENCE: Expert's opinion.

Revision Arthroplasty with Total Femur Replacement for the Management of Complex Post-traumatic Bone Defect in a Patient with Dwarfism. / Revisionsendoprothetik mit Totalfemurendoprothese zur Behandlung komplexer posttraumatischer Knochendefekte bei einem Patienten mit Zwergwuchs.

Dwarfism leads to an early onset of osteoarthritis of the joints of the lower limb. Due to bone deformities, arthroplasty is challenging. The incidence of implant-associated complications is higher compared to the normal population and often ends up with multiple revision arthroplasties. We report the first case in the literature of a 48-year-old patient with dwarfism who required implantation of a custom-made total femoral replacement due to aseptic stem loosening and a concomitant valgus gonarthrosis.

Results at 10-24 years after single-stage revision arthroplasty of infected total hip arthroplasty in patients under 45 years of age.

INTRODUCTION: The management of periprosthetic joint infection (PJI) of the hip is a challenging procedure. One-stage exchange is carried out in specialist centres with comparable infection free survival rates. However, there is a paucity of long-term results of this approach in young patients. METHODS: All patients undergoing one-stage exchange due to PJI with a known causative organism ⩽45 years of age with a minimum of 10-year follow-up (mean 15 years; range 10-24 years) were enrolled in this retrospective study. Patients older than 45 years of age or patients with a two-stage procedure were excluded from the study. The primary outcome measure was failure rate with special focus on reinfection at latest follow-up. Failure was defined as revision surgery for infection. Furthermore, functional outcome using the Harris Hip Score was determined initially and at latest follow-up. 26 patients fulfilled the inclusion criteria and were available for final follow-up. RESULTS: The study cohort consists of 16 male and 10 female patients with a mean age of 36.8 years (range 20-45 years) and a mean BMI of 29.8 kg/m2 (range 20.7-40.6 kg/m2). Prior to the single-stage procedure, the patients underwent an average of 3.1 previous surgical interventions (range 1-9). The mean hospital stay after septic revision was 19.7 days (11-33 days). Most infections were caused by Staphylococcus epidermidis (n = 8, 30.8%), followed by Staph. aureus (n = 7, 26.9%) and Propionibacterium acnes (n = 6, 23.1%). At latest follow-up, the overall survival rate was 76.9 %, while infection control could be achieved in 96.2%. At final examination, the mean Harris Hip Score improved from 46.2 to 78.9 (range 18.0-99; SD, 22.6). CONCLUSIONS: Single-stage revision surgery for the management of PJI in patients ⩽45 years is a successful treatment option with high infection control, even after long-term follow-up.

What Is the Dislocation and Revision Rate of Dual-mobility Cups Used in Complex Revision THAs?

BACKGROUND: Dual-mobility cups have been shown to reduce the dislocation risk after THA. Although dual-mobility cups can be a useful strategy to mitigate against recurrent dislocation after revision surgery, few clinical studies have focused on the results of complex revision THAs with extensive bone and soft-tissue loss or in patients who have undergone more than one previous surgical procedure. QUESTIONS/PURPOSES: (1) What is the survival free from revision for dislocation of dual-mobility cups used in complex revision THAs? (2) What is the survival free from any dislocation? METHODS: Between January 1, 2009 and December 31, 2013, 327 patients underwent a complex revision THA that included an acetabular revision, defined as preexisting massive bone loss in the acetabulum (at least Paprosky Type 2B) and/or proximal femur (at least Paprosky Type 3), substantial gluteal soft-tissue involvement, at least two previous surgical procedures or a one-stage septic revision, or history of dislocation. All 327 complex revision patients received a dual-mobility cup. Of those, 34% (111) were lost to follow-up before 5 years and were not known to have reached a study endpoint (revision for dislocation, and any dislocation) before then, leaving 216 patients for analysis. For patients with bilateral hip surgeries only the first operated hip was included for analysis. The median (range) follow-up duration was 69 months (60 to 110). The primary endpoint was dislocation or re-revision for dislocation. Fifty-six percent (120 of 216) of the patients were women and 44% (96 of 216) were men. The mean age of the patients was 69 ± 9 years. The patients underwent a median of four surgical procedures (1 to 4) before the index procedure (the revision evaluated in this study). A survival analysis was performed using the Kaplan-Meier method; any dislocation or revision for dislocation was determined as the endpoint. RESULTS: The dislocation-free survival rates were 96% (95% confidence interval 92 to 98) at 5 years and 82% (95% CI 72 to 89) at 9 years. The overall dislocation rate was 11% (24 of 216 patients) at the final follow-up interval. Survival free of revision for dislocation was 99% (95% CI 96 to 100) at 5 years and 85% (95% CI 75 to 92) at 9 years. CONCLUSIONS: Dual-mobility cups used in complex revision THA in this series had a higher rate of dislocation and revision than expected, based on earlier studies of dislocations of these components. Although we believe dual-mobility cups are still the first choice of implant if the patient has instability, these cups should be used cautiously if severe bone loss or soft-tissue involvement is present. LEVEL OF EVIDENCE: Level III, therapeutic study.

How reliable is the next generation of multiplex-PCR for diagnosing prosthetic joint infection compared to the MSIS criteria? Still missing the ideal test.

INTRODUCTION: Identification of the pathogen in case of a periprosthetic joint infection (PJI) remains 1 of the greatest challenges in septic surgery. Rapid germ identification enables timely, specific, antimicrobial therapy. The first multiplex PCR (polymerase chain reaction) generation (Unyvero-i60) enables germ detection within 5 hours with a sensitivity of 78.8% and a specificity of 100%. The aim of this study is to investigate the performance of the new generation of cartridges (Unyvero-ITI) of multiplex PCR in the case of a PJI. METHODS: In a prospective study, intraoperatively aspirated synovial fluid from 97 patients with aseptic or septic hip or knee revision surgery (49 aseptic, 48 septic) was examined with the multiplex PCR system (Unyvero-ITI) and the results were compared with the MSIS criteria. In addition, the time until the microbiological result was obtained in the event of a germ detection was documented. RESULTS: The multiplex PCR showed a germ detection with a sensitivity of 85.1% and a specificity of 98.0%. In 7 cases a false negative result was found and in one patient a false positive result was found. The general accuracy of this test procedure was 91.8%. The detection of germs was carried out within 5 hours with the multiplex PCR compared to 4.9 days in conventional microbiological diagnostics. CONCLUSIONS: The new generation of multiplex-PCR was able to improve germ detection. The possibility of prompt detection of germs offers the option of faster, targeted antimicrobial therapy. This diagnostic tool offers significant advantages, particularly in the context of an acute periprosthetic infection.

Are Metaphyseal Sleeves a Viable Option to Treat Bone Defect during Revision Total Knee Arthroplasty? A Systematic Review.

Purpose Bone loss is a challenging problem during revision total knee arthroplasty (TKA). Several studies have been published on the use of metaphyseal sleeves during revision TKA. Therefore, the aim of this systematic review was to summarize the clinical and radiographic outcomes of the use of metaphyseal sleeves in the setting of revision TKA. Methods A comprehensive search of PubMed, MEDLINE, CINAHL, Cochrane, EMBASE, and Google Scholar was performed, covering the period between January 1, 2000, and August 12, 2017. Various combinations of the following key words were used: "metaphyseal," "sleeves," "knee," and "revision." A total of 10 studies were included in the present systematic review. Results A total of 904 patients with 928 implants were recorded with a mean age of 69 years. They were evaluated at a mean follow-up of 45 months. Overall 1,413 sleeves, 888 in the tibia and 525 in the femur, were implanted. There were 36 septic re-revisions of the prosthetic components (4%). Five sleeves were found loose during septic re-revision; therefore, the rate of septic loosening of the sleeves was 0.35%. An aseptic re-revision of the prosthetic components was performed 27 times (3%). Ten sleeves were found loose during aseptic re-revision; therefore, the rate of aseptic loosening of the sleeves was 0.7%. Intraoperative fractures occurred 44 times (3.1%). Finally, clinical outcome was improved at final follow-up. Conclusion Metaphyseal sleeves demonstrate high radiographic signs of osteointegration, low septic loosening rate, low intraoperative fractures rate, and a good-to-excellent clinical outcome. Hence, they are a valid option to treat large metaphyseal bone defect during revision TKA. Level of Evidence This is a systematic review of level IV studies.

Risk Factors for Failure After 1-Stage Exchange Total Knee Arthroplasty in the Management of Periprosthetic Joint Infection.

BACKGROUND: One-stage exchange arthroplasty in the management of periprosthetic joint infection was introduced at our institution. The purpose of this study was to analyze the risk factors of failure after periprosthetic joint infection following total knee arthroplasty treated with 1-stage exchange. METHODS: Ninety-one patients who underwent failed treatment following 1-stage exchange total knee arthroplasty due to periprosthetic joint infection from January 2008 to December 2017 were included. From the same period, we randomly selected a 1:1 matched control group without a subsequent revision surgical procedure. Bivariate analyses, including preoperative, intraoperative, and postoperative factors, as well as logistic regression, were performed to identify risk factors for failure. RESULTS: Bivariate analysis yielded 10 predictors (variables with significance at p < 0.05) for failure involving re-revision for any reason and 11 predictors for failure involving re-revision for reinfection. The binary logistic regression model revealed the following risk factors for re-revision for any reason: history of a 1-stage exchange for infection (odds ratio [OR], 26.706 [95% confidence interval (CI), 5.770 to 123.606]; p < 0.001), history of a 2-stage exchange (OR, 3.948 [95% CI, 1.869 to 8.339]; p < 0.001), and isolation of enterococci (OR, 16.925 [95% CI, 2.033 to 140.872]; p = 0.009). The risk factors for reinfection in the binary logistic regression analysis were history of 1-stage or 2-stage exchange arthroplasty, isolation of enterococci, and isolation of streptococci (OR, 6.025 [95% CI, 1.470 to 24.701]; p = 0.013). CONCLUSIONS: We identified several risk factors of failure after 1-stage exchange arthroplasty for periprosthetic joint infection, most of which were not related to the patient comorbidities. Among them, previous exchange due to periprosthetic joint infection and the isolation of Enterococcus or Streptococcus species were associated with a higher risk of failure. Besides a multidisciplinary approach, being aware of the identified risk factors when evaluating patients with periprosthetic joint infection could lead to better outcomes. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

What Is the Diagnostic Accuracy of Alpha-Defensin and Leukocyte Esterase Test in Periprosthetic Shoulder Infection?

BACKGROUND: The diagnosis of periprosthetic joint infection (PJI) after total shoulder arthroplasty (TSA) is challenging, especially in patients with Cutibacterium (formerly Propionibacterium) acnes infection. Despite the increasing number of patients with PJI of the shoulder, there are still no robust data regarding diagnostic tests in detecting shoulder PJI. QUESTIONS/PURPOSES: (1) What are the sensitivity, specificity, and negative- and positive-predictive values for the alpha-defensin enzyme-linked immunosorbent assay test in detecting PJI after TSA? (2) What are the diagnostic accuracies in detecting shoulder PJI for synovial alpha-defensin, leukocyte esterase Test, and serum C-reactive protein (CRP)? METHODS: All patients with painful TSA, who underwent joint aspiration to validate or exclude a PJI, between July 2015 and February 2018 were enrolled in this single-center study. Further indications for aspiration were as follows: planned revision arthroplasty, early loosening and clinical signs of infections, especially serum CRP elevation. A total of 121 patients were aspirated to exclude or verify a PJI, and 16 patients were excluded. In all, 105 patients with a mean age of 68 years (± 12 years) were included for analysis. Patients who underwent TSA were considered aseptic or septic according to the Musculoskeletal Infection Society criteria. Twenty-four patients had a PJI, and the remaining 81 patients were in the aseptic group. The microbiologic evaluation including polymicrobial infection showed C. (formerly P.) acnes in 15 patients (63%). Synovial fluid was then analyzed using microbiology cultures, alpha-defensin immunoassay, and leukocyte esterase. The specificity, sensitivity, and positive-predictive and negative-predictive values were calculated for each test. RESULTS: The overall accuracy for alpha-defensin was 91% (95% confidence interval [CI], 84.4-96); sensitivity was 75% (95% CI, 53-90), specificity was 96% (95% CI, 90-99), negative predictive value was 93% (95% CI, 85-97), and positive predictive value was 86% (95% CI, 64-97). In contrast, the overall accuracy for leukocyte esterase was 76% (95% CI, 61-88), sensitivity was 50% (95% CI, 21-79), specificity was 87% (95% CI, 69-96), positive predictive value 60% (95% CI, 26-88) and negative predictive value was 81% (95% CI, 64-93). CONCLUSIONS: Summarizing the study results, the alpha-defensin ELISA and leukocyte esterase tests had less sensitivity in detecting shoulder PJI than previously reported TKA or THA results. The quality and low amount of joint fluid is the difficult part of the diagnostic. C. (formerly P.) acnes was the most common cause of PJI. Focusing on low-grade infections, alpha-defensin has shown its advantages in diagnosing PJI regardless pathogen virulence. Since the diagnostic of a PJI is always a synopsis of findings, the alpha-defensin and leukocyte esterase test can be used as adjunct diagnostic tool in patients with painful TSA. We propose further prospective studies to improve the diagnostic and confirm the results. LEVEL OF EVIDENCE: Level III, diagnostic study.

Serum C-reactive protein relationship in high- versus low-virulence pathogens in the diagnosis of periprosthetic joint infection.

Little is known about the relationship between the virulence of pathogens in periprosthetic joint infection (PJI) and C-reactive protein (CRP) levels. In this context, we assessed the performance of CRP for PJI. We collected the following data from 987 cases of total joint revision due to PJI and 386 cases of aseptic revision: age, gender, comorbidities, values for serum CRP, leukocytes, microbiology for preoperatively taken aspirations and at least 2 intraoperative biopsies, and presence or absence of a draining sinus. The mean CRP value in the PJI group was 50.2 mg l-1 (sd=62.2), while a lower CRP value of 11.6 mg l-1 (sd=25.3) was found in the control group. There were no significant differences for the CRP values between patients with and without draining sinus (P=0.4423). The difference in CRP between high-virulence and low-virulence micro-organisms was significant for both the hip and the knee (P<0.0001). For the hip, the area under the receiver operating characteristic curve (AUC) of CRP as a diagnostic marker for PJI was 0.830 and, for the knee, the AUC was 0.884. The optimal cutoff point for CRP as a diagnostic marker of PJI, calculated using Youden's index, was 8.90 mg l-1 for the hip and 9.99 mg l-1 for the knee. The study results add valuable new information regarding the organism profile that may help with the diagnostic workup and with the research and development of new strategies for diagnosing and treating PJI.

Ten-Year Results Following One-Stage Septic Hip Exchange in the Management of Periprosthetic Joint Infection.

BACKGROUND: Although 2-stage revision is still considered the gold standard for surgical management of periprosthetic joint infection (PJI), 1-stage revision has been reported to be as effective. Long-term reports for 1-stage revision in hip PJIs are lacking. METHODS: We reviewed our 10-11 years of results of 85 patients who underwent 1-stage exchange of the hip with an antibiotic-loaded bone cemented prosthesis due to PJI to determine the following: (1) What is the infection-free survival? (2) What is the overall survival? and (3) What are the long-term clinical outcomes? All 1-stage revision total hip arthroplasties (THAs) for infection between January 2006 and December 2007, with a minimum 10-year follow-up (range 10-11), were included in this retrospective cohort. Patients from another country or patients who were unable to participate were excluded. Eighty-five patients with a hip PJI were available at the last follow-up. Thirty-seven patients died during the 10-year study. Harris Hip Scores were recorded before the surgery and at last follow-up. Failures are reported as infection-related or aseptic. RESULTS: The 10-year infection-free survival was 94% and the surgery-free survival was 75.9%. The Harris Hip Scores improved from 43 (range 3-91) to 75 (range 10-91) (P < .001). The main indication for re-revision after 1-stage exchange was instability (10/20 patients). CONCLUSION: One-stage exchange of the hip for PJI is a reliable treatment option with high rate of infection control and long-lasting favorable outcomes.

Interprosthetic Femoral Sleeves in Revision Arthroplasty: A 20-Year Experience.

BACKGROUND: Interprosthetic femoral fractures in patients with ipsilateral stemmed total hip arthroplasty (THA) and total knee arthroplasty (TKA) can be technically demanding to treat surgically. Nonunion and implant failure are among the main complications following fixation of interprosthetic femoral (IF) fractures. Total femoral arthroplasty (TFA) is associated with a high incidence of infection and instability. IF sleeves have been designed to avoid the disadvantages of these techniques and to provide a stable construct. The aim of this study was to present the results with this device from a single center. METHODS: We reviewed 26 patients who underwent revision arthroplasty procedures, using custom-made cemented IF sleeves between 1997 and December 2017 in our institution. Two-part sleeves were used in 18 patients and one-part sleeves in 8 patients. The most common indication was an IF fracture (18 patients). Patients were monitored for postoperative complications, implant failure, and re-revision. The minimum follow-up of the survivors with nonrevised sleeves was 12 months. RESULTS: Twenty-three patients were included for the final analysis. The mean survivorship of the IF sleeve was 4.6 years at latest follow-up (mean 48.5 months; range 12 to 156). The overall rate of complications was 47.8%. The rate of mechanical failure was 21.7%. Late infections occurred in 3 patients (13%). At the latest follow-up, the mean Harris Hip Score was 69.9 points (range 39 to 94), and the mean functional Knee Society Score was 42.5 points (range 0 to 90), with average knee flexion of 95° (range 90° to 100°). CONCLUSION: The IF sleeve is a valid technique for the management of selected patients with IF fractures, particularly when a stable fracture fixation is not possible. Hip instability is not a concern, and functional improvement is achievable. Careful planning is required preoperatively to avoid mechanical failure.

The role of alpha defensin in prosthetic joint infection (PJI) diagnosis: a literature review.

Prosthetic joint infection (PJI) management is not standardized worldwide and the outcome is frequently unsatisfactory.More and more arthroplasties are now being performed. An increasing number of highly virulent and antibiotic-resistant bacteria and an ageing population of patients presenting with many comorbidities make it necessary to focus on this important topic.Diagnosis of PJI remains challenging because the clinical signs and symptoms and elevation of systemic biomarkers (C-reactive protein, erythrocyte sedimentation rate) may be unclear.In the last few years, the clinical research has focused on synovial fluid biomarkers as a possible breakthrough in the complex scenario of PJI diagnosis.Synovial biomarkers have shown encouraging results and they should be used as diagnostic adjuncts to synovial white cell count and culture bacteriology. Synovial leukocyte esterase (LE) and synovial C-reactive protein (CRP) have been evaluated as good screening measures; however, the most promising synovial fluid biomarker in terms of sensitivity and specificity for PJI seems to be alpha defensin (AD).The laboratory-based alpha defensin enzyme-linked immunosorbent assay (ELISA) test demonstrated the highest ever reported accuracy for PJI diagnosis. However, an alpha defensin lateral flow test could have its place in ruling in a suspected PJI intraoperatively because of its high specificity and rapid results. Cite this article: EFORT Open Rev 2019;4:10-13. DOI: 10.1302/2058-5241.4.180029.