Late Periprosthetic Infection Research Articles

Effect of Multiantibiotic-Loaded Bone Cement on the Treatment of Periprosthetic Joint Infections of Hip and Knee Arthroplasties-A Single-Center Retrospective Study.

Two-stage septic revision is the prevailing method for addressing late periprosthetic infections. Using at least dual-antibiotic-impregnated bone cement leads to synergistic effects with a more efficient elution of individual antibiotics. Recent data on the success rates of multiantibiotic cement spacers in two-stage revisions are rare. We conducted a retrospective follow-up single-center study involving 250 patients with late periprosthetic hip infections and 95 patients with prosthetic knee infections who underwent septic two-stage prosthesis revision surgery between 2017 and 2021. In accordance with the antibiotic susceptibility profile of the microorganisms, a specific mixture of antibiotics within the cement spacer was used, complemented by systemic antibiotic treatment. All patients underwent preoperative assessments and subsequent evaluations at 3, 6, 9, 12, 18, and 24 months post operation and at the most recent follow-up. During the observation period, the survival rate after two-step septic revision was 90.7%. Although survival rates tended to be slightly lower for difficult-to-treat (DTT) microorganism, there was no difference between the pathogen groups (easy-to-treat (ETT) pathogens, methicillin-resistant staphylococci (MRS), and difficult-to-treat (DTT) pathogens). Furthermore, there were no differences between monomicrobial and polymicrobial infections. No difference in the survival rate was observed between patients with dual-antibiotic-loaded bone cement without an additional admixture (Copal® G+C and Copal® G+V) and patients with an additional admixture of antibiotics to proprietary cement. Employing multiple antibiotics within spacer cement, tailored to pathogen susceptibility, appears to provide reproducibly favorable success rates, even in instances of infections with DTT pathogens and polymicrobial infections.

Periprosthetic infection after total hip arthroplasty in polytrauma victims

Infectious complications during endoprosthesis of large joints are one of the urgent medical and socio-economic problems of modern orthopedics and traumatology. The purpose of the study was to improve the results of treatment of periprosthetic infection in patients after total hip arthroplasty as a result of polytrauma by determining the features of the course and diagnosing it in this category of patients. To carry out the study, a retrospective analysis of 87 cases of periprosthetic infection was conducted in patients undergoing inpatient treatment at the Kyiv City Clinical Hospital of Emergency Medical Care for the period 2012–2020 and divided into observation and control groups. Іn the first group, acute postoperative periprosthetic infection (up to 4 weeks) was detected in 33 victims, which was 71.7% of the group. In the second group, this type of periprosthetic infection was detected in 23 victims, which was 56.1% of the group. Late chronic infection (from 4 weeks to 1 year) among the victims of the first group was found in 10 patients, which was 21.7% of the group. In the second group, there were 11 patients with late periprosthetic infection, which was 24.4% of the group. All patients participating in the study were divided into observation and control groups. Periprosthetic infection after total hip arthroplasty in polytrauma victims develops more often in the early stages, up to 4 weeks. In addition to gram-positive cocci, the causes of periprosthetic infection are often gram-negative enterobacteria, which indicates the prevalence of the endogenous route of infection in this category of patients. Among the etiological factors of periprosthetic infection after total hip arthroplasty in polytrauma victims, Acinetobacter spp. is quite often found, which is a consequence of long-term use of invasive methods of treatment and monitoring performed on the patient during the treatment of traumatic injuries. Keywords: large joints, arthroplasty, microorganisms, complications, multiple trauma.

Обоснование выбора спейсера на первом этапе лечения поздней глубокой перипротезной инфекции коленного сустава

Background Periprosthetic infection develops in 0.5 to 5.0 % of cases after knee replacement, which is a social and economic problem. The most common causes of periprosthetic infection are methicillin-resistant staphylococcus aureus (MRSA) (36 %), gram-negative bacteria, and microbial associations. The study was aimed at improving the results of the sanitizing stage of revision arthroplasty in patients with periprosthetic infection of the knee joint by a developed long-acting antimicrobial composition and improving the designs of articulating spacers of the knee joint. Materials and Methods The treatment results of 121 patients with knee joint periprosthetic infection were analyzed. Nine patients had an early periprosthetic infection and 112 had a late one. Patients in satisfactory condition with stable implant components who had early periprosthetic infection underwent surgical treatment of the purulent focuses, replacement of a polyethylene tibial insert, thorough surgical wound washing using pulse lavage, drainage, and VAC-therapy. Patients with late periprosthetic infection were divided into 3 groups on the basis of the spacer used. An articulating spacer based on the developed antimicrobial composition of prolonged action (RU 191236 patent) was used in 59 patients of the first group. Preformed spacers were implanted in 29 patients of the second group, and 18 patients of the third group got a block-shaped spacer. Results An antibacterial anti-adhesive non-toxic composition with a prolonged action based on bone cement with gentamicin and such antiseptics as poviargol, dioxydine, and high-molecular polyvinylpyrrolidone has been developed. All the patients underwent the sanitizing stage of revision arthroplasty, implant removal, and spacer installation. Periprosthetic infection recurrence developed in 3 patients of the first group, 9 patients of the second group and 7 patients of the third one. The average time from the sanitizing stage to the second final stage of revision was 3-6 (4.8 ± 1.9) months. Discussion According to scientific data, the impregnation of new antibiotics into bone cement with gentamicin does not improve the antimicrobial effect of a spacer, especially in case of antibiotic-resistant strains. Block-shaped and preformed spacers lead to infection recurrence and complications. Antiseptic impregnation with different mechanisms of action is able to affect antibiotic-resistant bacteria, and the polymer is able to prolong the effect. Conclusion The use of articulating spacers for the knee joint, which include an antimicrobial composition, allows preserving the function of the joint and reducing the number of infectious complications, which facilitates the final stage of revision arthroplasty.

Individual megaspacers in two-stage revision of infected total hip arthroplasty-clinical and functional results after 2 years : Individual metal-endoskeleton cement spacer (iMECS)

HintergrundGroße Femurdefekte bei periprothetischem Spätinfekt (PPI) nach Hüfttotalendoprothese (HTEP) erfordern oft den Einsatz großer, individueller Metallendoskelett-armierter Zementspacer (iMECS).Ziel der ArbeitZiele waren die Erfassung der klinischen, radiologischen und funktionellen Ergebnisse (Harris Hip Score [HHS]) 2 Jahre nach Behandlung eines PPI unter Verwendung eines iMECS. Zentrale patientenspezifische Parameter sollten im Hinblick auf das Behandlungsergebnis ausgewertet werden.Material und MethodenDas Kollektiv dieser monozentrischen retrospektiven Kohortenstudie umfasste 29 Patienten. Das Follow-up zum Zeitpunkt der Nachuntersuchung (NU) betrug durchschnittlich 24,4 Monate (23,0–27,6 Monate). Als Behandlungserfolg wurde eine Infektfreiheit nach endoprothetischer Gelenkrekonstruktion gewertet. Die beiden Patientengruppen (mit Erfolg [E]/kein Erfolg [kE]) wurden hinsichtlich Geschlechterverteilung, Komorbiditätenindex nach Charlson (CCI), Anzahl früherer septischer Wechsel, Rate an polymikrobiellen und „difficult-to-treat“-Infekten verglichen.ErgebnisseDer durchschnittliche CCI im Gesamtkollektiv betrug 6,4 Punkte. Bei 23 von 29 Patienten (79 %) war eine Gelenkrekonstruktion möglich. Bei 4 Patienten war 2 Jahre nach operativer PPI-Behandlung keine NU möglich (2 verstorben, 2 nicht teilnahmefähig). Zur NU waren 17 von initial 29 Patienten infektfrei rekonstruiert mit einem durchschnittlichen HHS von 75 Punkten. Es traten keine iMECS-assoziierten revisionsbedürftigen Komplikationen auf. Zwischen den Patientengruppen war nur der initiale CCI (E: 4,1 Punkte; kE: 9,7 Punkte) signifikant unterschiedlich (p < 0,05).DiskussionBei großen Femurdefekten leisten iMECS eine sichere temporäre Stabilisierung. Die Chance auf eine erfolgreiche Gelenkrekonstruktion ist eng mit dem individuellen Komorbiditätenprofil verbunden.Zusatzmaterial onlineDie Online-Version dieses Beitrags 10.1007/s00132-021-04185-7 enthält eine tabellarische Übersicht der individuellen Pathogenlagen

Minimum 10 years clinical results of an anatomical short stem with a proximal hydroxyapatite coating

Objectives The CentPillar stem (Stryker Orthopaedics), an anatomical short stem, was designed to match the proximal femoral canal shape in both patients with normal hips and those with developmental dysplasia of the hip (DDH). The long-term outcomes of the CentPillar stem was examined herein. Methods In total, 222 hips that underwent total hip arthroplasty using the CentPillar stem were analyzed. DDH was the main reason for surgery (79.3%). Implant survivorship was assessed using Kaplan–Meier analysis. For radiographic evaluation, stress shielding was assessed using the Engh classification. For functional evaluation, patients’ ability to perform deep hip bending activities (sit on the floor, squat, and sit straight) was assessed. Results During a median follow-up of 13.1 years, 2 stem revisions were performed (aseptic loosening and late hematogenous periprosthetic infection), and the overall cumulative implant survival rate was 99.0% at 15 years. In the radiographic evaluation, grade >3 stress shielding was found in only one hip. More than 80% of the patients were able to perform each of the three deep hip bending activities. Conclusions Good fixation at the proximal part of the femur was obtained, and the implant survival rate of the CentPillar stem was excellent during a long-term follow-up.

Validity of the KLIC and CRIME80 scores in predicting failure in late acute infection treated by debridement and implant retention

It is very important to treat prosthetic infections correctly in order to ensure a higher success rate. Debridement with implant retention (DAIR) is widely used in acute and late infections, however patients who fail after this surgery are known to have a higher risk of failure in subsequent surgeries. Therefore, it is important to find a scale that enables us to predict the risk of DAIR failure. Hence the KLIC and CRIME80 scores for acute and late acute infections, respectively. This study analysed the validity of both scores in acute late periprosthetic knee infections. We observed that the KLIC score has no predictive value for this type of infection, but the CRIME80 score does.

Validez de las escalas KLIC y CRIME80 en la predicción del fracaso en la infección aguda tardía tratada mediante desbridamiento y retención de implantes

It is very important to treat prosthetic infections correctly in order to ensure a higher success rate. Debridement with implant retention (DAIR) is widely used in acute and late infections, however patients who fail after this surgery are known to have a higher risk of failure in subsequent surgeries. Therefore, it is important to find a scale that enables us to predict the risk of DAIR failure. Hence the KLIC and CRIME80 scores for acute and late acute infections, respectively. This study analysed the validity of both scores in acute late periprosthetic knee infections. We observed that the KLIC score has no predictive value for this type of infection, but the CRIME80 score does.

Importance of the Algorithm for Diagnosis of Late Deep Periprosthetic Hip Infection

Relevance. Late deep periprosthetic infection (PJI) of the hip joint is a serious complication after arthroplasty which takes the lead among the world reasons for revision. Accurate diagnostics allows to achieve good results and select a proper treatment tactics. Purpose of the study — to evaluate the efficiency of diagnostics algorithm for late deep PJI and impact of the microbial landscape on the risk of infection recurrence. Materials and methods. The authors evaluated two groups of patients who underwent revision in the period from 2002 to 2014 and from 2015 to 2018. The first (retrospective) group included 144 patients who were not diagnosed for late deep PJI. The second (prospective) group included 157 patients who underwent detailed diagnostics for late deep PJI based on the algorithm including the analysis of x-rays, pelvic CT, triple evaluation of ESR and CRP, puncturing of affected joint and microbiology examination. The authors assessed the microbial landscape in 51 patients with late deep hip PJI. Results. In the first group 12 patients (8.3%) underwent sanation and spacer insertion during first stage of treatment, 46 patients (59.7%) after revision demonstrated positive intraoperative cultures confirming septic etiology of implant loosening, 19 patients (24.67%) had no flora growth, and no intraoperative microbiological examination was done for remaining 67 patients (46.52%). In the second group after detailed diagnostics 51 patients (32.4%) underwent removal of prosthesis and spacer insertion in the first stage, other 13 patients (8.2%) featured flora growth after revision, remaining 93 patients (59.2%) had no flora growth after revision. Recurrent PJI was observed in 21 patients (14.5%) in the first group, and in 10 patients (6.3%) in the second group. In the second group recurrent PJI was reported in 40% of patients due to microbial associations, in 30% — due to MRSA, in 20% — due to culture negative bacteria and in 10% — due to S. aureus. Conclusion. Triple examination allows to obtain an accurate diagnosis and isolate the pathogen for deep PJI. Application of such diagnostics algorithm allows to reduce 2.1 times the risk of recurrent deep PJI and to scale down 4 times the detection of type IV infection by Coventry–Tsukayama classification.

Tibial Tubercle Osteotomy in Total Knee Arthroplasty: Midterm Results Experience of a Monocentric Study.

Purpose Difficult primary total knee arthroplasty (TKA) and revision TKA may be high demanding, especially during joint exposure. Aim of this article is to evaluate the clinical and radiological outcomes of a series of patients, who underwent TKA and revision TKA, where tibial tubercle osteotomy (TTO) was performed. Methods We retrospectively reviewed a cohort of 79 consecutives TKAs where TTO was performed. Patients were assessed clinically and radiographically at their last follow-up (mean, 7.4 ± 3.7 years). Clinical evaluation included the Knee Society Score (KSS), the pain visual analogue scale (VAS), and range of motion. Radiological assessment included the evaluation of radiolucent lines, osteolysis, cortical bone hypertrophy, time of bone healing of the TTO fragment, and the hardware complication. Results KSS raised from 40.7 ± 3.1 to 75 ± 4.3 ( p < 0.0001). Knee flexion increased from 78.7 ± 9.9° to 95.0 ± 9.5° ( p < 0.0001), and VAS improved from 7.9 ± 0.9 to 3.8 ± 1 ( p < 0.0001). No signs of loosening or evolutive radiolucency lines were found. Osteolytic areas around the stem were detected. No significant association was found between the implant design and the outcomes, while aseptic loosening showed significantly better results. Complications were: 4 painful hardware, 3 late periprosthetic infections, 1 extension lag of 5°, and 3 flexion lag. Conclusion Our experience suggests the use of TTO to improve the surgical approach in difficult primary TKA or revision TKA. A precise surgical technique leads to good results with low risk of complications. Level of Evidence Level IV, therapeutic case series.

Pros and Cons of Spacers in the Treatment of Late Periprosthetic Infections of the Hip

Pros and Cons of Spacers in the Treatment of Late Periprosthetic Infections of the Hip

Characterizing infections in prosthetic breast reconstruction: A validity assessment of national health databases

Current guidelines in the United States require reporting only the 30-day postoperative outcomes to standardized databases, including the National Surgical Quality Improvement Program (NSQIP). Thus, many breast implant-related complications go unreported in standard databases. We sought to characterize late periprosthetic infections following implant-based breast reconstruction. We conducted a retrospective analysis of all women who underwent expander/implant reconstruction from 2005 to 2014 at two institutions. All periprosthetic infections were identified and divided into early and late cohorts (≤30 days or >30 days). Infection was defined as any episode where antibiotics were initiated or a prosthetic device was explanted because of clinical evidence of the infection. In the 1820 patients (2980 breasts) identified, 421 periprosthetic infections occurred (14%). Of these, 173 (41%) were early and 248 (59%) were late (mean time to infection=66.4±101.9 days). Patients with late infections were more likely to be current smokers or have diabetes than patients with early infections (p<0.034 for both). Infections caused by gram-negative bacteria and antimicrobial-resistant strains of Staphylococcus were more common in the early infection group (p<0.001 for both). Implant loss due to infection was more common in the late infection group (p=0.037). Late periprosthetic infections following implant-based breast reconstruction are underestimated in national outcome databases and have unique risk factors and microbiology compared to early infections. A system-level change in reevaluating and redefining a timeline for tracking and treating implant infections is necessary, given the substantial morbidity associated with, and frequency of, late periprosthetic infections.

Total Hip Arthroplasty With a Fully Hydroxyapatite-Coated Stem: A Cohort Study During 23-28 Years

BackgroundLong-term results of a hydroxyapatite (HA)-coated stem are sparse. We have followed a cohort of patients operated with a grit-blasted titanium stem designed for press-fit insertion and entirely plasma-sprayed with HA up to 28 years. MethodsIn the years 1988-1993, we performed 323 primary total hip arthroplasties in 276 patients (189 women). Their mean age was 48 (15-79) years. During the following years, 83 patients with 88 hips have died, and 18 patients did not attend the follow-up examination, but had no major symptoms according to telephone interviews and control examination. Thus, 212 patients (255 hips) were followed up for more than 20 years. ResultsThree patients were revised because of late periprosthetic infection, 1 because of a fall with periprosthetic fracture, and 2 stems were revised due to mechanical failure. Osteolysis was significantly associated with wear, and wear was significantly associated with the size of the femoral head. We found a small amount of proximal bone loss and a low incidence of distal hypertrophy of the bone. The bone changes confirmed a well-fixed femoral component in asymptomatic patients. ConclusionOur findings indicate an essentially physiological weight distribution from the stem to the femoral bone with no significant thigh pain. The changes in the bone confirmed that the femoral component was well-fixed, and we conclude that a fully HA-coated titanium stem designed for press-fit insertion lasts for 23-28 years.

The diagnostic thresholds for synovial fluid analysis in late periprosthetic infection of the hip depend on the duration of symptoms.

We hypothesised that the synovial white blood cell (WBC) count in patients with a late periprosthetic joint infection (PJI) of the hip would depend on the duration of a patient's symptoms, and that the optimal diagnostic threshold would also depend on this period of time. The synovial WBC count and percentage of polymorphonuclear cells (%PMN), and the serum CRP and ESR levels obtained > six weeks after primary THA were compared between 50 infected and 88 non-infected THAs, and in patients with symptoms for more than or less than two weeks. Diagnostic thresholds for the synovial WBC count were calculated using area under the curve calculation. The synovial WBC count was significantly higher in patients with symptoms for ≤ two weeks compared with those with symptoms for > two weeks (p = 0.03). The optimal threshold for diagnosing PJI for the synovial WBC count was 5750 cells/µL (sensitivity 94; specificity 100; PPV 100%; NPV 89%; AUC 99%) and 1556 cells/µL (sensitivity 91; specificity 94; PPV 87% and NPV 97%; AUC 95%), respectively. The thresholds for the cut-offs based on duration of symptoms improved the diagnostic performance of this test. This study shows that the diagnostic thresholds for synovial fluid analysis in late periprosthetic infection following THA may depend on duration of symptoms. Cite this article: Bone Joint J 2016;98-B:1355-9.

Antibiotic-loaded articulating cement spacers in two-stage revision for infected total knee arthroplasty: individual antibiotic treatment and early results of 21 cases

ObjectiveTo detail our early experience and technique of a modified two-stage reimplantation protocol using antibiotic-loaded articulating cement spacers (ALACSs) for treatment of late periprosthetic infection after total knee arthroplasty (TKA). MethodsFrom January 2006 to February 2009, aseries of 21 patients (21 knees) with late infected TKAs were treated by radical debridement and removal of all components and cement, and then articulating spacers were implanted using antibiotic-impregnated bone cement. For this purpose, 4g vancomycin powder was mixed with per 40g cement. Graduated knee motion and partial weight bearing activity were encouraged in the interval period. Each patient received an individual systemic organism-sensitiveantimicrobial therapy for 4.9 (range, 2-8) weeks followed by a second-stage TKA revision. All the patients were regularly followedup using the American Knee Society Scoring System. ResultsEach case underwent a successful two-stage exchange and had infection eradicated, none had recurrent infection after an average of 32.2 (range, 17-54) months of follow-up. Preoperatively, the mean knee score was 53.5 points, function score was 27.3 points, pain score was 25.7 points, range of motion (ROM) was 82.0°, extensor lag was 2°. Between stages, the mean knee score was increased to 61.3 points, function score to 45 points, pain score to 35 points, ROM to 88.2°, and extensor lag to 3.4°. At final follow-up, the mean knee score was further increased to 82.1 points, function score to 74.5 points, pain score to 42.1 points, ROM to 94.3°, and knee extension lag to 1.9°. The interval period was 11.5 (range, 6-32) weeks. The amount of bone loss was unchanged between stages. No patient developed noticeable dysfunction of the liver or kidney or other complications such as impaired wound healing, deep venous thrombosis, pulmonary embolism, cerebrovascular accidents, etc. ConclusionsTreating infected TKA with ALACS avoids spacer-related bone loss, preserves knee function between stages, and eradicates infection effectively without significant complications. The early clinical results are inspiring. The authors believe that radical and repeated (if needed) debridement, individual application of systemic antibiotics, and reasonable timing judgement upon the secondary revision are all key factors related to a successful outcome with two-stage reimplantation procedure for infected TKA.

Outcome after total knee arthroplasty in haemophilic patients with stiff knees.

Advanced haemophilic arthropathy of the knee is associated with progressive joint stiffness. Results after total knee arthroplasty (TKA) in stiff knees are considered to be inferior compared to those with less restricted preoperative range of motion (ROM). There is only very limited data on the results of primary TKA in haemophilic patients with stiff knees. The purpose of this retrospective study was to evaluate the clinical outcome after TKA performed in haemophilic patients with preoperative ROM of 50° or less. Twenty one patients (23 knees) undergoing TKA with stiff knees were retrospectively evaluated. Mean follow-up was 8.3years (range, 2-25). Clinical assessment included ROM, degree of flexion contracture and complication rate. Functional evaluation and pain status were assessed using the Knee Society's Scoring System (KSS). Range of motion improved from 26.7° preoperatively to 73.0° postoperatively. Flexion contracture decreased from 21.7° to 8.3°. KSS increased from 22.9 to 72.9 points. Evaluation of pain revealed a decrease from 8.4 points preoperatively to 2.1 points postoperatively. All these differences were statistically significant (P<0.005). The complication rate was 8.7% including one late periprosthetic infection, and one aseptic implant loosening. Nine patients who required VY-quadricepsplasty for knee exposure developed a mean postoperative extensor lag of 7°. Total knee arthroplasty in haemophilic patients presenting with stiff knees results in significant improvement of function and reduction in pain. Although the clinical outcome is inferior compared to nonstiff knees reported in the literature, joint replacement surgery can be successfully performed in this particular group of patients.

Use of Spacers for the Treatment of Deep Periprosthetic Infection of Hip and Knee Joints

Experience in treatment of 27 patients with deep periprosthetic infection is presented. In 17 patients infectious process was localized in the zone of hip implant, in 10 patients — in the zone of knee implant. Sanitation without implant removal was performed in 2 cases of early deep infection. Two-step revision arthroplasty was performed in 25 patients with late deep infection. First the implant was removed and spacer was inserted, then spacer was changed for a revision implant. In 12 patients individual articulating spacers with antibiotics were used. No relapse was noted in 23 patients at terms up to 58 months. Thus, two-step revision arthroplasty with application of spacers showed its high efficacy in treatment of patients with late deep periprosthetic infection.

Antibiotic-loaded articulating cement spacer in two-stage revision for infected total knee arthroplasty

Objective To detail our early experience on a modified two-stage revison using articulating antibiotic-loaded cement spacer (AALCS) for late periprosthetic infection of total knee arthroplasty (TKA).Methods From January 2006 to February 2009,a series of 21 patients (21 knees) underwent twostage revision knee arthroplasty for late infected TKA.There were 8 males and 13 females,aged from 56 to 83 years (average,64.4 years).In the first stage,each patient underwent radical debridement,removal of all components and cement,and implantation of articulating cement spacer containing vancomycin.Graduated knee motion and partial weight bearing activity were encouraged in the interval period.Each patient received an individual systemic organism-sensitive antimicrobial therapy for 4.9 weeks (range,2-8 weeks) followed by a second-stage revision TKA.All the patients were regularly followed-up using the American Knee Society Scoring System.Results All patients were followed up for 17 to 54 months (average,32.2 months).At final follow-up,the knee society score,function score,pain score and range of motion (ROM) of knee were significantly improved compared with those before operation.Meanwhile,there was no significant increase in the degree of extension lag.The average interval period was 11.5 weeks (range,6-32 weeks).No change of bone defect volume was found between two stages.There were no complications such as recurrent infection,hepatic and renal dysfunction,and deep venous thrombosis.Conclusion Treating infected TKA with AALCS can avoid spacer-related bone loss,preserve knee function between two stages,and eradicate infection effectively without significant complications.The early clinical results are inspiring.Radical debridement,individual application of systemic antibiotics,and reasonable juncture for the second revision are all key factors related to a successful outcome. Key words: Arthroplasty,replacement,knee; Prosthesis-related infections; Reoperation

Late Periprosthetic Joint Infection due toStaphylococcus lugdunensisIdentified by Matrix-Assisted Laser Desorption/Ionisation Time of Flight Mass Spectrometry: A Case Report and Review of the Literature

Staphylococcus lugdunensis, member to the group of coagulase-negative staphylococci, is previously thought to be rarely isolated. Recently other staphylococci have been described, which were supposedly related to S. lugdunensis, such as Staphylococcus pseudolugdunensis and Staphylococcus pettenkoferi. To decrease the rate misidentifications, an accurate identification method, such as matrix-assisted laser desorption ionization time of flight mass spectrometry or molecular methods, should be used. S. lugdunensis is usually associated with severe infections similar to those caused by S. aureus. Moreover, it has been described that skin infections due to S. lugdunensis are severely underreported and could be also underreported in periprosthetic joint infections. Ours is the first case of a late periprosthetic infection of the hip due to S. lugdunensis, identified by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry. A periprosthetic infection due to S. lugdunensis should be treated according to protocols of S. aureus periprosthetic infections, and therefore an accurate species identification is desirable.

Revision of late periprosthetic infections of total hip endoprostheses: pros and cons of different concepts.

Many concepts have been devised for the treatment of late periprosthetic infections of total hip prostheses. A two-stage revision with a temporary antibiotic-impregnated cement spacer and a cemented prosthesis appears to be the most preferred procedure although, in recent times, there seems to be a trend towards cementless implants and a shorter period of antibiotic treatment. Because of the differences in procedure, not only between studies but also within studies, it cannot be decided which period of parenteral antibiotic treatment and which spacer period is the most suitable. The fact that comparable rates of success can be achieved with different treatment regimens emphasises the importance of surgical removal of all foreign materials and the radical debridement of all infected and ischaemic tissues and the contribution of these crucial procedures to the successful treatment of late periprosthetic infections.

Prolonged Bacterial Culture to Identify Late Periprosthetic Joint Infection: A Promising Strategy

The value of microbiological culture to diagnose late periprosthetic infection is limited, especially because standard methods may fail to detect biofilm-forming sessile or other fastidious bacteria. There is no agreement on the appropriate cultivation period, although this period is a crucial factor. This study was designed to assess the duration of culture that is necessary for reliable detection. Ten periprosthetic tissue specimens each were obtained during revision from 284 patients with suspected late hip or knee arthroplasty infection. Five samples were examined by microbiological culture over a 14-day period, and 5 were subjected to histologic analysis. To define infection, a pre-established algorithm was used; this included detection of indistinguishable organisms in >/=2 tissue samples or growth in 1 tissue sample and a positive result of histologic analysis (>5 neutrophils in at least 10 high-power fields). The time to detection of organisms was monitored. Infection was diagnosed in 110 patients. After 7 days (the longest incubation period most frequently reported), the detection rate via culture was merely 73.6%. Organisms indicating infection were found for up to 13 days. "Early"-detected species (mostly staphylococci) emerged predominantly during the first week, whereas "late"-detected agents (mostly Propionibacterium species) were detected mainly during the second week. In both populations, an unequivocal correlation between the number of culture-positive tissue samples and positive results of histologic analysis was noted, which corroborated the evidence that true infections were detected over the entire cultivation period. Prolonged microbiological culture for 2 weeks is promising because it yields signs of periprosthetic infection in a significant proportion of patients that would otherwise remain unidentified.