Infected Total Hip Arthroplasty Research Articles

THE INFLUENCE OF BEARING SURFACE ON PERIPROSTHETIC JOINT INFECTION IN TOTAL HIP ARTHROPLASTY

BackgroundIncreasing evidence suggests a link between the bearing surface used in total hip arthroplasty (THA) and the occurrence of infection. It is postulated that polyethylene has immunomodulatory effects and may influence bacterial function and survival, thereby impacting the development of periprosthetic joint infection (PJI). This study aimed to investigate the association between polyethylene type and revision surgery for PJI in THA using data from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR). We hypothesized that the use of XLPE would demonstrate a statistically significant reduction in revision rates due to PJI compared to N-XLPE.MethodsData from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) spanning September 1, 1999, to December 31, 2021, were used to compare the infection revision rates between THA using N-XLPE and XLPE. We calculated the Cumulative Percentage Revision rate (CPR) and Hazard Ratio (HR) while controlling for factors like age, sex, body mass index (BMI), American Society of Anesthesiologists’ (ASA) grade, and head size.ResultsFrom the total 361,083 primary THAs, 26,827 used N-XLPE and 334,256 used XLPE. Excluding data from the first 6 months post-surgery, 220 revisions occurred in the N-XLPE group and 1,055 in the XLPE group for PJI. The HR for infection revision was significantly higher in N-XLPE compared to XLPE, at 1.64 (95% CI, 1.41–1.90, p<0.001).ConclusionsThis analysis provides evidence of an association between N-XLPE and revision for infection in THA. We suspect that polyethylene wear particles contribute to the susceptibility of THA to PJI, resulting in a significantly higher risk of revision for infection in N-XLPE hips compared to those with XLPE.Level of EvidenceTherapeutic Level III.

Interleukin-1β Polymorphisms Are Genetic Markers of Susceptibility to Periprosthetic Joint Infection in Total Hip and Knee Arthroplasty.

Periprosthetic joint infections (PJIs) are serious complications of prosthetic surgery. The criteria for the diagnosis of PJI integrate clinical and laboratory findings in a complex and sometimes inconclusive workflow. Host immune factors hold potential as diagnostic biomarkers in bone and joint infections. We reported that the humoral pattern-recognition molecule long pentraxin 3 (PTX3) predicts PJI in total hip and knee arthroplasty (THA and TKA, respectively). If and how genetic variation in PTX3 and inflammatory genes that affect its expression (IL-1β, IL-6, IL-10, and IL-17A) contributes to the risk of PJI is unknown. We conducted a case-control study on a Caucasian historic cohort of THA and TKA patients who had prosthesis explant due to PJI (cases) or aseptic complications (controls). Saliva was collected from 93 subjects and used to extract DNA and genotype PTX3, IL-1β, IL-6, IL-10, and IL-17A single-nucleotide polymorphisms (SNPs). Moreover, the concentration of IL-1β, IL-10, and IL-6 was measured in synovial fluid and plasma. No association was found between PTX3 polymorphisms and PJI; however, the AGG haplotype, encompassing rs2853550, rs1143634, and rs1143627 in IL-1β, was linked to the infection (p = 0.017). Also, synovial levels of all inflammatory markers were higher in cases than in controls, and a correlation emerged between synovial concentration of PTX3 and that of IL-1β in cases only (Spearman r = 0.67, p = 0.004). We identified a relationship between rs2853550 and the synovial concentration of IL-1β and PTX3. Our findings suggest that IL-1β SNPs could be used for the early identification of THA and TKA patients with a high risk of infection.

Utilizing an antibiotic-eluting articulated cemented spacer in the two-stage management of infected total hip arthroplasty: a technical note.

Two-stage revision is generally preferred to eradicate chronic periprosthetic infections after total hip arthroplasty (THA) because of its good infection control and promising results. During two-stage revision, a temporary antibiotic-impregnated cement spacer was initially used for the local delivery of antibiotics, thereby reducing the risk of infection recurrence. Many researchers have reported various techniques for fabricating cemented spacers; however, there is no established standard technique. We share our cost-effective and easily reproducible technique for creating an articulated cemented spacer for managing infected THA.

Latent infections in conversion total hip arthroplasty following internal fixation of femoral neck fractures: a systematic review and meta-analysis of diagnostic methods.

Accurate diagnosis of latent infections prior to conversion total hip arthroplasty (THA) following internal fixation of femoral neck fractures is crucial for successful surgical outcomes. This systematic review aimed to provide a comprehensive evaluation of the current literature regarding the diagnosis of latent infections before conversion THA. Systematic search of PubMed, EMBASE, and Cochrane (CENTRAL) databases was conducted, and the diagnostic accuracy of various markers and techniques was assessed. The quality of the included studies was evaluated using the QUADAS-2 instrument. Five studies comprising 661 patients were included in the review. Pooled analysis using C-reactive protein (CRP) as a diagnostic marker resulted in a sensitivity and specificity of 72% and 76%, respectively, while using erythrocyte sedimentation rate (ESR) yielded a sensitivity and specificity of 75% and 78%, respectively. Fibrinogen and platelet count showed lower sensitivity and specificity compared to CRP and ESR. The best combined markers were CRP and serum platelet count, with a sensitivity of 76% and specificity of 86% based on one study. Our review underscored the limitations and inconsistencies present in current diagnostic methods for latent infections in conversion surgery. Future research needs to focus on standardizing threshold values, exploring the potential of synovial fluid analysis, imaging techniques, and molecular methods, as well as developing tailored diagnostic algorithms. CRD42023394757.

Role of Preoperative Intra-Articular Corticosteroid Injections on Periprosthetic Joint Infection in Total Hip Arthroplasty and Its Association With Preoperative Timing: A Single-Center Series of 5,909 Hips

BackgroundPreoperative intra-articular corticosteroid injections to the hip joint increase the risk of periprosthetic joint infection (PJI) during primary total hip arthroplasty (THA). This study aimed to determine the relationship between preoperative timing of intra-articular corticosteroid injections and PJI risk following THA using data from a single-center hospital. MethodsThis single-center, retrospective cohort study included patients who underwent a THA between 2014 and 2020. Medical records were checked for intra-articular corticosteroid injections and PJI within 1 year of surgery. Patients were categorized into groups based on whether they received “no injection” or “injection 0 to 3 months,” “3 to 6 months,” and “> 6 months prior to THA.” Hazard ratios (HRs) for these groups were calculated using multivariate Cox regression analysis, correcting for potential confounders, and presented with 95% confidence intervals [95% CIs]. ResultsIn total, 4,507 patients (5,909 THAs) were identified. A total of 1,581 patients (27%) received an injection prior to THA. Without considering the timing factor, no increased risk for PJI following an intra-articular injection was noted (P = .19). Comparing the specified groups using multivariate analysis, corticosteroid injection within 3 months of THA showed an increased risk of PJI (HR 2.63, 95% CI 1.18 to 5.87, P = .018), but this effect was not observed for the “injection 3 to 6 months” group (HR 1.51, 95% CI 0.74 to 3.08, P = .264). ConclusionsCorticosteroid injections administered up to 3 months prior to THA increased the risk of PJI within 1 year after THA, with an HR of 2.63; however, injections between 3 and 6 months before surgery did not have a significantly higher infection rate.

The Use of Preoperative CRP and ESR as Predictive Markers of Prosthetic Joint Infection in Primary Total Hip and Knee Arthroplasty

The Use of Preoperative CRP and ESR as Predictive Markers of Prosthetic Joint Infection in Primary Total Hip and Knee Arthroplasty

Validation of the Incidence of Reported Periprosthetic Joint Infections in Total Hip and Knee Arthroplasty in the Dutch Arthroplasty Register

BackgroundArthroplasty registers underreport the incidence of periprosthetic joint infections (PJIs). We validated the incidence of reported PJIs in total hip arthroplasties (THAs) and total knee arthroplasties (TKAs) in the Dutch Arthroplasty Register (LROI) using data from the Dutch National Nosocomial Surveillance Network (PREZIES). MethodsAll primary THAs and TKAs from the LROI and all primary THAs and TKAs performed in consenting hospitals from PREZIES between 2012 and 2018 were matched on date of birth, date of surgery, sex, hospital, and type of procedure (THA n = 91,208; TKA n = 80,304). Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated for PJIs registered in the LROI, using PREZIES as a reference. ResultsThe incidence of registered PJIs in THAs was 1.2% in PREZIES and 0.5% in the LROI. For TKAs, this was 0.7 and 0.4%, respectively. The PJIs in THAs in the LROI had a sensitivity of 0.32 (confidence interval [CI]: 0.29 to 0.35), specificity of 1.00 (CI: 1.00 to 1.00), PPV of 0.74 (CI: 0.70 to 0.78), and NPV of 0.99 (CI: 0.99 to 0.99). In TKAs, the sensitivity, specificity, PPV, and NPV were 0.38 (CI: 0.34 to 0.42), 1.00 (CI: 1.00 to 1.00), 0.65 (CI: 0.59 to 0.70), and 1.00 (CI: 1.00 to 1.00), respectively. ConclusionsThe LROI captures approximately one-third of the PJIs as revision within one year for infection or resection arthroplasty. The capture rate of PJIs can be improved by including all reoperations without component exchange and nonsurgical treatments with antibiotics only.

Periprosthetic joint infection after total hip arthroplasty induces histological degeneration of the gluteus medius tendon.

A revision for periprosthetic joint infection (PJI) in total hip arthroplasty (THA) has a major effect on the patient's quality of life, including walking capacity. The objective of this case control study was to investigate the histological and ultrastructural changes to the gluteus medius tendon (GMED) in patients revised due to a PJI, and to compare it with revision THAs without infection performed using the same lateral approach. A group of eight patients revised due to a PJI with a previous lateral approach was compared with a group of 21 revised THAs without infection, performed using the same approach. The primary variables of the study were the fibril diameter, as seen in transmission electron microscopy (TEM), and the total degeneration score (TDS), as seen under the light microscope. An analysis of bacteriology, classification of infection, and antibiotic treatment was also performed. Biopsy samples from the GMED from infected patients revealed a larger fibril diameter than control patients, as seen in the TEM (p < 0.001). Uninfected patients were slightly older and had their revisions performed significantly later than the infected patients. Histologically, samples from infected patients revealed significantly more vascularity (p < 0.001), the presence of glycosaminoglycans (p < 0.001), and a higher TDS (p = 0.003) than the control patients. The majority of patients had staphylococcal infections of various species. More histological degeneration in the GMED was found in patients undergoing THA revision surgery due to PJI than in patients undergoing THA revision surgery due to other reasons.

THE DIAGNOSTIC ACCURACY OF INTRAOPERATIVE SYNOVIAL FLUID CALPROTECTIN IN SUSPECTED LOW-GRADE PERIPROSTHETIC HIP JOINT INFECTIONS

Pre-operative definitive diagnosis of infection in painful total hip arthroplasty (THA) is not always easy to be established, making the intra-operative decision-making process crucial in management of revision hip surgery. Calprotectin is a promising point-of-care novel biomarker that has displayed high accuracy in detecting PJIs.From November 2020 to December 2022, 105 patients with painful primary THA were treated with revision THA in 3 orthopaedic departments. Pre-operatively, 23 were considered infected and treated with two-stage revision THA. The remaining 82 were likely infected according to the 2019 EBJIS criteria. The suspicion of low-grade infection was based on clinical (rest and/or night pain), laboratory (CRP, ESR, WBC – normal or slightly elevated) and radiological evaluation (loosening). Hip aspiration under CT imaging was performed in these cases and 34 of them yielded positive culture and were treated with two-stage revision. Aspiration was ineffective in the remaining 48 cases (33 negative, 15 unsuccessful attempts). Intra-operatively, calprotectin was measured with lateral flow immunoassay test in these patients. Cases with calprotectin levels ≥ 50 mg/L were treated with 2-stage revision THA; otherwise, they were considered not-infected and one-stage revision was performed. Synovial fluid and tissue samples were collected for analysis. Implants were sent for sonication fluid cultures.Calprotectin was positive (≥ 50 mg/L) in 27 cases and negative in 21 cases. There was 1 false negative case with positive tissue cultures. Out of the 27 positive cases, 25 had positive tissue cultures and sonication. However, 2 cases with high calprotectin levels (&gt;200 mg/L) were not infected. The false positive result was attributed to severe metallosis. Calprotectin sensitivity was 96.2%, specificity 90.9%, PPV 92.6%, NPV 95.2%, AUC 0.935.The results of this ongoing study indicate that calprotectin seems to be a valuable tool in facilitating the intra-operative decision-making process in cases that low-grade infection is suspected and diagnosis cannot be established pre-operatively.

Staged Revision Hip Arthroplasty With Femoral Impaction Bone Grafting for Prosthetic Joint Infections: Radiostereometric Analyses and Clinical Outcomes at Minimum 5-Year Follow-Up

BackgroundThere are ongoing concerns regarding the use of bone graft following prosthetic joint infection and subsequent implant subsidence. The aim of this study was to determine whether the use of a cemented stem combined with femoral impaction bone grafting (FIBG) at second stage revision for infection results in stable femoral stem fixation, determined by accurate methods, and good clinical results. MethodsA prospective cohort of 29 patients underwent staged revision total hip arthroplasty for infection using an interval prosthesis followed by FIBG at the final reconstruction. The mean follow-up was 89 months (range, 8 to 167 months). Femoral implant subsidence was measured with radiostereometric analysis. Clinical outcomes included the Harris Hip Score, Harris Pain score and Société Internationale de Chirurgie Orthopédique et de Traumatologie activity scores. ResultsAt 2-years follow-up the median stem subsidence relative to femur was −1.36 mm (range, −0.31 to −4.98), while the cement subsidence relative to femur was −0.05 mm (range, 0.36 to −0.73). At 5-years follow-up, the median stem subsidence relative to femur was −1.89 mm (range, −0.27 to −6.35), while the cement subsidence relative to femur was −0.06 mm (range, 0.44 to −0.55). There were 25 patients who were confirmed infection-free after the second stage revision with FIBG. The median Harris Hip Score improved from 51 pre-operatively to 79 at 5 years (P = .0130), and Harris Pain score from 20 to 40 (P = .0038). ConclusionsStable femoral component fixation can be achieved with FIBG when reconstructing the femur after revision for infection without compromising infection cure rates and patient-reported outcomes.

One-stage revision hip arthroplasty for infection using primary cementless stems as first-line implants: About 35 cases

IntroductionDuring infected total hip arthroplasty revisions (THAR), the need for systematic antibiotic cementation remains undefined. HypothesisImplantation of a primary cementless stem as first-line implant in 1-stage septic THAR provides results as good as those from a stem cemented with antibiotics in terms of infection resolution. Materials and methodsWe retrospectively examined 35 patients operated on for septic THAR with Avenir® cementless stem placement – between 2008 and 2018 at Besançon University Hospital – with a minimum follow-up of 2 years to define healing in the absence of infectious recurrence. Clinical outcomes were assessed using the Harris, Oxford, and Merle D’Aubigné scores. Osseointegration was analyzed by the Engh radiographic score. ResultsThe median follow-up was 5±2.6 years (2–11). The infection was cured in 32 of 35 (91.4%) patients. The median scores of the following were: Harris 77/100, Oxford 47.5/60 and Merle d’Aubigné 15/18. Of 32 femoral stems, 31 (96.8%) had radiographically stable osseointegration. Age greater than 80 years was a risk factor for failure to cure the infection during septic THAR. DiscussionA primary cementless stem as first-line implant plays a role in 1-stage septic THAR. It confers good results in terms of infection resolution and stem integration in the setting of loss of femoral bone substances rated Paprosky 1. Level of evidenceIV; retrospective case series.

A Retrospective Analysis of the Association Between Male Facial Hair and the Incidence of Peri-Prosthetic Infections.

Background: The wearing of male facial hair has been undergoing something of a renaissance for a number of years, with medical colleagues in the surgical disciplines being no exception. Meanwhile, there are a few reports in the literature that beards might have an increased bacterial colonization. This study aims to determine if wearing a beard leads to an increased rate of infection in total hip or knee arthroplasty. Patients and Methods: A retrospective analysis was performed on 20,394 primary hip and knee replacements that were implanted at a single university hospital. The rate of infections that occurred within one year after surgery and the surgeons performing the surgery were recorded. The surgeons were classified into clean-shaven and beard wearers. The beard wearers were further classified by individual facial hair styles, namely a moustache, chin beard, round beard, or full beard. Results: The overall rate of surgical site infections 365 days after surgery is 0.75%. There was no statistically significant association between surgical site infection and the presence of facial hair (p = 0.774) or specific beard types (p = 0.298). Conclusions: The results presented in this study show no differences in infection rates across different facial hair styles of male surgeons.

What's New in Musculoskeletal Infection.

What's New in Musculoskeletal Infection.

Risk Factors for Periprosthetic Joint Infection in Primary Total Hip Arthroplasty

Ms. Hoffmeister is a freelance medical writer in Camp Hill, Pennsylvania. To earn CME credit, you must read the CME articles and complete the quiz and evaluation assessment survey on the enclosed form, answering at least 70% of the quiz questions correctly. This continuing medical enduring material activity expires April 30, 2025. All authors, faculty, and staff have no relevant financial relationships with any ineligible organizations regarding this educational activity. Lippincott Continuing Medical Education Institute, Inc., is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians. Lippincott Continuing Medical Education Institute, Inc., designates this enduring material for a maximum of 1.5 AMA PRA Category 1 Credits™. Physicians should claim only the credit commensurate with the extent of their participation in the activity. Lippincott's Bone and Joint Newsletter is an independent publication solely owned and published by Wolters Kluwer and has no affiliation with the Journal of Bone & Joint Surgery.

The Fate of the Patient With Superficial Dehiscence Following Direct Anterior Total Hip Arthroplasty

BackgroundDirect anterior approach (DAA) total hip arthroplasty (THA) has been associated with higher rates of superficial incisional dehiscence. However, limited data are available regarding the outcomes following initial treatment of this complication. This study aimed to evaluate patient risk factors, reoperations, and revisions in those who developed superficial wound dehiscence following DAA THA. MethodsWe identified 3,687 patients who underwent a primary DAA THA between 2010 and 2019 from our enterprise total joint registry. Of these, 98 (2.7%) patients developed a superficial wound dehiscence requiring intervention [irrigation and debridement (n = 42) or wound care with or without antibiotics (n = 56)]. Dehiscence was noted at a median of 27 (range, 2-105) days. These patients were compared to patients who did not have a superficial wound complication (n = 3,589). Landmark survivorship analysis was performed to account for immortal time bias with a 45-day landmark time. ResultsPatients who had superficial wound dehiscence compared to those who did not, were more often women (64 versus 53%, P = .02) and had increased mean body mass index (33 versus 29, P < .001). There was no difference in 4-year survivorship free from any revision between cohorts (97 versus 98%, respectively, P = .14). There were 2 (2.0%) revisions in the superficial dehiscence group: 1 for periprosthetic joint infection and 1 for aseptic femoral loosening. ConclusionSuperficial wound dehiscence following DAA THA was associated with higher body mass index and was more common in women. Fortunately, with proper index management, the risk of revision THA and periprosthetic joint infection was not increased for these patients.

Prevention Techniques Have Had Minimal Impact on the Population Rate of Prosthetic Joint Infection for Primary Total Hip and Knee Arthroplasty: A National Database Study

BackgroundSeveral studies over the years have offered modalities that may greatly decrease the rate of periprosthetic joint infection when implemented. As a result, one would expect a drastic decrease in infection rate among the implementing population with its widespread use. The purpose of this study was to assess whether there exists a decrease in infection rate over time, after accounting for available confounding variables, within a large national database. MethodsA large national database from 2005 to 2019 was queried for primary total hip arthroplasty (THA) and total knee arthroplasty (TKA). In total, 221,416 THAs and 354,049 TKAs were performed over the study period. Differences in 30-day infection rate were assessed with time and available preoperative risk factors using multinominal logistic regressions. ResultsRate of infection overall trended downward for both THA and TKA. After accounting for confounding variables, odds of THA infection marginally decreased over time (odds ratio 0.968 [0.952-0.985], P < .0001), while the odds of a TKA infection marginally increased with time (odds ratio 1.037 [1.020-1.054], P < .0001). ConclusionIndividual peer-reviewed publications have presented infection control modalities demonstrating dramatic decreases in infection rate while analysis at a population level shows almost no changes in infection rate over a 15-year time period. This study supports continued investigation for influential modalities in preventing periprosthetic joint infection and care in patient selection for primary hip and knee arthroplasty.

MRI-based artificial intelligence to predict infection following total hip arthroplasty failure

PurposeTo investigate whether artificial intelligence (AI) can differentiate septic from non-septic total hip arthroplasty (THA) failure based on preoperative MRI features.Materials and methodsWe included 173 patients (98 females, age: 67 ± 12 years) subjected to first-time THA revision surgery after preoperative pelvis MRI. We divided the patients into a training/validation/internal testing cohort (n = 117) and a temporally independent external-testing cohort (n = 56). MRI features were used to train, validate and test a machine learning algorithm based on support vector machine (SVM) to predict THA infection on the training-internal validation cohort with a nested fivefold validation approach. Machine learning performance was evaluated on independent data from the external-testing cohort.ResultsMRI features were significantly more frequently observed in THA infection (P < 0.001), except bone destruction, periarticular soft-tissue mass, and fibrous membrane (P > 0.005). Considering all MRI features in the training/validation/internal-testing cohort, SVM classifier reached 92% sensitivity, 62% specificity, 79% PPV, 83% NPV, 82% accuracy, and 81% AUC in predicting THA infection, with bone edema, extracapsular edema, and synovitis having been the best predictors. After being tested on the external-testing cohort, the classifier showed 92% sensitivity, 79% specificity, 89% PPV, 83% NPV, 88% accuracy, and 89% AUC in predicting THA infection. SVM classifier showed 81% sensitivity, 76% specificity, 66% PPV, 88% NPV, 80% accuracy, and 74% AUC in predicting THA infection in the training/validation/internal-testing cohort based on the only presence of periprosthetic bone marrow edema on MRI, while it showed 68% sensitivity, 89% specificity, 93% PPV, 60% NPV, 75% accuracy, and 79% AUC in the external-testing cohort.ConclusionAI using SVM classifier showed promising results in predicting THA infection based on MRI features. This model might support radiologists in identifying THA infection.

Periprosthetic hip infection in octogenarians : a single institution experience of 33 cases.

Periprosthetic joint infection (PJI) in total hip arthroplasty in the elderly may occur but has been subject to limited investigation. This study analyzed infection characteristics, surgical outcomes, and perioperative complications of octogenarians undergoing treatment for PJI in a single university-based institution. We identified 33 patients who underwent treatment for PJIs of the hip between January 2010 and December 2019 using our institutional joint registry. Mean age was 82 years (80 to 90), with 19 females (57%) and a mean BMI of 26 kg/m2 (17 to 41). Mean American Society of Anesthesiologists (ASA) grade was 3 (1 to 4) and mean Charlson Comorbidity Index was 6 (4 to 10). Leading pathogens included coagulase-negative Staphylococci (45%) and Enterococcus faecalis (9%). Two-stage exchange was performed in 30 joints and permanent resection arthroplasty in three. Kaplan-Meier survivorship analyses were performed. Mean follow-up was five years (3 to 7). The two-year survivorship free of any recurrent PJI was 72% (95% confidence interval (CI) 56 to 89; 18 patients at risk). There were a total of nine recurrent PJIs at a mean of one year (16 days to eight years), one for the same pathogen as at index infection. One additional surgical site infection was noted at two weeks, resulting in a 69% (95% CI 52 to 86; 17 patients at risk) survivorship free of any infection at two years. There were two additional revisions for dislocations at one month each. As such, the two-year survivorship free of any revision was 61% (95% CI 42 to 80; 12 patients at risk). In addition to the aforementioned revisions, there was one additional skin grafting for a decubitus ulcer, resulting in a survivorship free of any reoperation of 54% (95% CI 35 to 73; ten patients at risk) at two years. Mean Clavien-Dindo score of perioperative complications was two out of five, with one case of perioperative death noted at six days. Octogenarians undergoing surgery for PJI of the hip are at low risk of acute mortality, but are at moderate risk of other perioperative complications. One in two patients will undergo a reoperation within two years, with 70% attributable to recurrent infections.Cite this article: Bone Joint J2023;105-B(2):135-139.

The synovial fluid calprotectin lateral flow test for the diagnosis of chronic prosthetic joint infection in failed primary and revision total hip and knee arthroplasty

PurposeThe diagnostic criteria of prosthetic joint infection (PJI) recommended by the most commonly used diagnostic algorithms can be obscured or distorted by other inflammatory processes or aseptic pathology. Furthermore, the most reliable diagnostic criteria are garnered during revision surgery. A robust, reliable addition to the preoperative diagnostic cascade is warranted. Calprotectin has been shown to be an excellent diagnostic marker for PJI. In this study, we aimed to evaluate a lateral flow test (LFT) in the challenging patient cohort of a national referral centre for revision arthroplasty.MethodsBeginning in March 2019, we prospectively included patients scheduled for arthroplasty exchange of a total hip (THA) or knee arthroplasty (TKA). Synovial fluid samples were collected intra-operatively.We used the International Consensus Meeting of 2018 (ICM) score as the gold standard. We then compared the pre-operative ICM score with the LFT result to calculate its diagnostic accuracy as a standalone pre-operative marker and in combination with the ICM score as part of an expanded diagnostic workup.ResultsA total of 137 patients with a mean age of 67 (± 13) years with 53 THA and 84 TKA were included. Ninety-nine patients (72.8%) were not infected, 34 (25.0) were infected, and four (2.9%) had an inconclusive final score and could not be classified after surgery.The calprotectin LFT had a sensitivity (95% confidence interval) of 0.94 (0.80–0.99) and a specificity of 0.87 (0.79–0.93). The area under the receiver operating characteristic curve (AUC) for the calprotectin LFT was 0.94 (0.89–0.99). In nine cases with an inconclusive pre-operative ICM score, the calprotectin LFT would have led to the correct diagnosis of PJI.ConclusionsThe synovial fluid calprotectin LFT shows excellent diagnostic metrics both as a rule-in and a rule-out test, even in a challenging patient cohort with cases of severe osteolysis, wear disease, numerous preceding surgeries, and poor soft tissue conditions, which can impair the common diagnostic criteria. As it is available pre-operatively, this test might prove to be a very useful addition to the diagnostic algorithm.

Partial Two-Stage Exchange for Infected Total Hip Arthroplasty: A Treatment to Take into Account.

Two-stage revision is the gold standard for chronic periprosthetic joint infection (PJI). The removal of well-fixed implants, especially the femoral component, can be extremely difficult and additional osteotomies may be needed, which is time-consuming and results in bone stock loss. When the femoral stem is osseointegrated, there is no clear indication for the use of partial two-stage revision. The primary objective was to assess infection eradication after surgery. Retrospective study of specific case series. A total of eight patients with a chronic uncemented PJI, in the setting of complex revision surgeries, were treated with partial two-stage revision, which included selective retention of the well-fixed femoral component and complete acetabular removal. Stem retention was carried out regardless of the bacteria or associated comorbidities. All patients were re-revision cases with at least two previous surgeries (range, 2-4). Complex revisions were performed in five cases (non-articulated spacer) and simple revisions in three cases (articulated spacer). The minimum follow-up time was 24 months (range, 24-132 months). The infection eradication rate at final follow-up was 100%. Partial two-stage reconstruction is a promising technique for the treatment of chronic PJI in patients with a well-fixed stem and complex re-revision acetabular procedures. Further prospective studies and prolonged follow-ups are required to confirm our results.