CLASSIFICATION AND ALGORITHM FOR DIAGNOSIS AND TREATMENT OF HIP PROSTHETIC JOINT INFECTION

“Unexpected” Infections in Revision Arthroplasty for Aseptic Loosening

Background. Data from the national registers of arthroplasty showed that about 12% of hip and knee arthroplasty undergo revision within 10 years after the primary surgery. The leading cause of hip revisions is aseptic loosening of components, knee joint periprosthetic infection (PPI). Some of the infectious complications, including those related to mechanical causes, remain out of sight. The aim of the study was to identify the frequency of unexpected infections during revision knee and hip arthroplasty performed for aseptic complications of any etiology. Materials and Methods. 839 cases of revision arthroplasty of knee and hip joints were analyzed, including 485 aseptic revisions in 450 patients. Clinical, X-ray, laboratory (complete blood count and comprehensive metabolic panel, coagulation panel) methods, synovial fluid analysis and microbiological examination of punctures, including intraoperative ones, were used. The ICM and EBJIS (European Bone and Joint Infections Society) consensus recommendations were used as criteria for assessing the presence of infection. Results. The average age of patients at the time of the revision was 61.7 years. The hip joint prevailed (59.4%), knee joint 40.6%. The growth of microorganisms in the intraoperative biomaterial was detected in 2.08% of observations: in 10 out of 287 patients after aseptic revision of the hip joints and in none of the 198 revisions of the knee joints. In 8 out of 10 cases, the causative agents were coagulase-negative staphylococci, including 6 MRSE; in two cases, anaerobic bacteria. All revisions were carried out by a one-stage method. Patients with detected PPI underwent systemic antibacterial therapy. At the stage of catamnesis, reinfection was assumed in one of the 10 identified cases of PPI, the patient did not show up for revision. In control 63% of the group of the other (aseptic) 470 patients, PPI developed in 4 cases, two-stage revisions were carried out. Conclusions. The frequency of infections accidentally detected during aseptic revisions of large joints was 2.08%. Three-time examination of joint punctures, including intraoperative, provides additional opportunities for the diagnosis of PPI during aseptic revision, and also allows you to choose the optimal stage of revision treatment. The experience gained makes it possible in certain cases to perform one-stage revision in the treatment of PPI.

“Unexpected” Infections in Revision Arthroplasty for Aseptic Loosening

Background. Data from the national registers of arthroplasty showed that about 12% of hip and knee arthroplasty undergo revision within 10 years after the primary surgery. The leading cause of hip revisions is aseptic loosening of components, knee joint periprosthetic infection (PPI). Some of the infectious complications, including those related to mechanical causes, remain out of sight. The aim of the study was to identify the frequency of unexpected infections during revision knee and hip arthroplasty performed for aseptic complications of any etiology. Materials and Methods. 839 cases of revision arthroplasty of knee and hip joints were analyzed, including 485 aseptic revisions in 450 patients. Clinical, X-ray, laboratory (complete blood count and comprehensive metabolic panel, coagulation panel) methods, synovial fluid analysis and microbiological examination of punctures, including intraoperative ones, were used. The ICM and EBJIS (European Bone and Joint Infections Society) consensus recommendations were used as criteria for assessing the presence of infection. Results. The average age of patients at the time of the revision was 61.7 years. The hip joint prevailed (59.4%), knee joint 40.6%. The growth of microorganisms in the intraoperative biomaterial was detected in 2.08% of observations: in 10 out of 287 patients after aseptic revision of the hip joints and in none of the 198 revisions of the knee joints. In 8 out of 10 cases, the causative agents were coagulase-negative staphylococci, including 6 MRSE; in two cases, anaerobic bacteria. All revisions were carried out by a one-stage method. Patients with detected PPI underwent systemic antibacterial therapy. At the stage of catamnesis, reinfection was assumed in one of the 10 identified cases of PPI, the patient did not show up for revision. In control 63% of the group of the other (aseptic) 470 patients, PPI developed in 4 cases, two-stage revisions were carried out. Conclusions. The frequency of infections accidentally detected during aseptic revisions of large joints was 2.08%. Three-time examination of joint punctures, including intraoperative, provides additional opportunities for the diagnosis of PPI during aseptic revision, and also allows you to choose the optimal stage of revision treatment. The experience gained makes it possible in certain cases to perform one-stage revision in the treatment of PPI.

Assessing risks of developing and persistence of infectious process in knee joint replacement

Despite of intensive work on improving endoprosthetic replacement constructions, using minimally invasive techniques, developing methods of prevention for and treatment of periprosthetic joint infection, relapse of infection process can reach up to 52 % after treatment.The aim of the study: to show the importance of identifying the risks of development and recurrence of periprosthetic infection after implantation of a knee joint endoprosthesis. A clinical case of the development of a deep periprosthetic infection in a patient after primary knee replacement and successful treatment of the resulting complication was demonstrated. The analysis of this case of an infectious complication using the proposed prognosis for the development of periprosthetic infection showed that before surgical treatment of the patient, the risk of an infectious process was not assessed, and appropriate preventive and therapeutic measures were not carried out.Materials and methods. In the treatment of developed periprosthetic infection of the knee joint, the author’s algorithm for choosing surgical tactics was used, which allowed to determine the high risk of recurrence of periprosthetic infection, evaluate additional criteria and choose the optimal type of surgical intervention – two-stage revision endoprosthetic, which allowed to stop the infectious process.New was the use of the proposed prognosis for the development of periprosthetic infection and the algorithm for choosing surgical tactics for periprosthetic infection, which make it possible to determine the necessary preventive measures to reduce the risk of an infectious complication and to apply the optimal type of surgical intervention to relieve periprosthetic knee infection.

Cell Immunity in Implant-Associated Infections Caused by Biofilm-Forming Microorganisms

High biofilm-forming capacity of Staphylococcus spp. strains isolated from biomaterial of patients with infectious complications after primary knee replacement developed within 6-12 months after surgery was experimentally demonstrated. Differential leukocyte counts and some indicators of cell immunity in these patients were compared with those in patients without purulent complications and healthy volunteers. In patients with implant-associated infection, the relative numbers of T cells (both T-helpers and T-suppressors) B cells were significantly (p<0.05) reduced, while the number of NK cells was significantly increased in comparison with the corresponding parameters in other groups. The revealed changes attest to cell immunity failure in biofilm infection.

[Resection Arthroplasty Using a Vastus Lateralis Muscle Flap in the treatment of patients with recurrent form of the hip prosthetic joint infection]

OBJECTIVE

To evaluate the efficacy of chronic recurrent hip periprosthetic joint infection (PJI) eradication after resection arthroplasty with non-free transplantation of vastus lateralis muscle flap of the thigh.

MATERIAL AND METHODS

There were 38 patients with chronic recurrent hip PJI who underwent resection arthroplasty with non-free transplantation of vastus lateralis muscle flap of the thigh in 2005-2016. The groups were compiled considering the absence or presence of recurrent infection in early postoperative period. Infection duration, number of operations, incidence of recurrent PJI, type of pathogen, laboratory parameters, bone defect size and presence of PJI remission within at least 2 years were investigated.

RESULTS

Uneventful early postoperative period after resection arthroplasty with non-free transplantation of vastus lateralis muscle flap was noted in 81.6% of cases (n=31, group 1). Postoperative wound revision was required in 18.4% of cases (n=7, group 2). Stable remission of infection within 2-8 years (Me - 4 years) was achieved in 36 (94.7%) patients. Relative risk of recurrent PJI increased by more than 4 times (RR 4,364, 95% CI 0,581-32,787) in cases of polymicrobial infection involving Gram-negative bacteria and decreased in cases of monomicrobial infection (RR 0,256, 95% CI 0,034-1,916). Significantly longer duration of surgery and more pronounced laboratory changes were revealed in group 2.

CONCLUSION

High efficacy of resection arthroplasty with non-free transplantation of vastus lateralis muscle flap of the thigh was established in patients with chronic recurrent hip PJI. This procedure might be considered as a stage treatment with the possibility for revision arthroplasty in case of failed initial debridement surgery due to PJI pathogens that are difficult for eradication.

Treatment of Periprosthetic Infection with Silver-Doped Implants Based on Two-Dimensionally Ordered Linear Chain Carbon

Relevance. Formation of pan-resistance microorganisms, microbial biofilms on implants and recurrent infection rate stimulate the search for optimal prosthesis materials for treatment of periprosthetic infection (PJI). Purpose of the study — to compare the efficiency of two stage PJI treatment with simultaneous implantation of a spacer in combination with implants with silver-doped coatings based on two-dimensionally ordered linear chain carbon (TDOLCC+Ag) during the first stage and the conventional revision with a spacer only. Materials and methods. The study included 72 patients with PJI of the knee (n = 42) and hip (n = 30) joints. Control group (conventional revision) consisted of 35 patients and the main group (TDOLCC+Ag coated implant incorporated in a spacer) — 37 patients. Mean age of the patients was 61 years. Temporary components were replaced by the final components during revision at the second stage. Evaluation methods: clinical, X-ray, laboratory, microbiological and follow up history. Results. Inflammation markers and synovial fluid cytosis in the groups at the first revision stage featured equal high base values. During the second stage leucocyte count and cytosis reached normal values, ESR decreased twofold in both groups, CRP decreased five times in the main group. Throat and nasal swabs demonstrated growth of Staphylococcus aureus at 24,3-32,4% in both groups. The leading inducer of PJI was staphylococcal flora with MRSA share of 7,1% and MRSE — from 62,5 to 66,7%. End-points of evaluating treatment outcomes were revision spacer implantation at the second stage of sanation and recurrent PJI. Control group featured implantation of more revision spacers (5) as compared to the main group (1) after the treatment. Two recurrent PJIs were reported for the control group in 11 months while no recurrent infection was reported for the main group. Conclusion. The study demonstrated statistically significant improvement in the outcomes of PJI treatment by spacers with implants coated by TDOLCC+Ag as compared to the conventional treatment option.

Bone Regeneration in the Application of a New Device for Osteosynthesis in the Experiment

Background. Treatment of residual cavities after radical surgery for bone diseases is a vital problem of modern traumatology. Currently, there is an active search for devices both for osteosynthesis and bone-substituting masses. Aims. The purpose of this work was to test a new device for osteosynthesis. It can be used both for fixing bone fragments, and for studying the morphological features of bone regenerate in experiment.

Materials and methods. A device for bone osteosynthesis of tubular bones in an experiment (Patent of the Russian Federation N 20116121487) was applied. The device consisted of two half-bushings, fastened to each other by a fierce clamp. Polypropylene was used as the material for the half-bushings, therefore no immunological reactions were observed. On the inner surface there were silicone cylinders, which directed pressure on the fragments and did not disturb the nutrition of the periosteum. The experiment was performed on Wistar rats. The surgical defect of the femur was filled with hydroxyapatite. Two groups of animals were identified. The bone in the first group was fixed by the device. The wire cerclage was used in the second group.

Results. The study showed that the developed device does not disturb the nutrition of the periosteum, and also tightly fixes the osteoplastic material in the bone defect. Histological examination showed that bone regeneration was faster when the device was used. On the 21st day of the experiment, the regenerate filled the defect in the control group by 62 %, and in the experimental group by 73 %. The regenerate was represented by a woven bone. In all animals, bone regenerate formed a strong osteo-integrative connection with the maternal bone. In both groups, it looked like a mature bone tissue at the end of the experiment (28 days).

Conclusion. The data indicate that the device does not disturb the processes of bone formation and allows for more efficient use osteoplastic material.

Adverse Trends in the Etiology of Orthopedic Infection: Results of 6-Year Monitoring of the Structure and Resistance of Leading Pathogens

Osteomyelitis remains one of the most intractable diseases. The nature of the pathogen and its resistance to antibiotics significantly affect the outcome and cost of treatment.

The aim of the study: to analyze the dynamics of the spectrum and antibiotic resistance of the leading pathogens of orthopedic infection for the period 2012– 2017.

Material and methods. The structure of pathogens isolated from the focus of infection from 2774 patients with periprosthetic infection and chronic osteomyelitis was retrospectively analyzed. Antibiotic resistance of the leading pathogens that occupied more than 4% in the species structure was studied. Comparative analysis of changes in the spectrum of pathogens and antibiotic resistance was carried out for the periods 2012-2013, 2014–2015 and 2016-2017. Epidemiological analysis was performed in the program „microbiological monitoring system” Microbe-2. Statistical processing of the obtained data was carried out using the Z-criterion.

Results.From 2774 patients with orthopedic infection have been isolated 4359 strains, in the structure of which about 73.5% were occupied by S. aureus, S. epidermidis, E. faecalis, E. faecium, P. aeruginosa, Acinetobacter sp. representatives of the family Enterobacteriacea. In 27% of the cases, microorganisms of other species were identified. Microbial associations were identified in 19.4% of cases. In the structure of the leading Gram(+) pathogens, a significant decrease in the incidence of S. aureus was detected, while the share of S. epidermidis increased significantly. Among the leading Gram(-) microorganisms, a significant increase in the proportion of representatives of the fam. Enterobacteriacea was found, against the background of a decrease in the share of Acinetobacter sp. and P. aeruginosa. The level of resistance of MSSA to the studied antibiotics ranged from 0.1 to 8.8%, for MSSE the spread was from 1.9 to 16.7%. Negative dynamics of growth of resistance of non-fermenting bacteria is established. The strains of Acinetobacter sp. demonstrated greater resistance to tested antibiotics in comparison with P. aeruginosa.

Conclusion.An increase in the role of S. epidermidis and K. pneumoniae in the etiology of orthopedic infection was established. The revealed increase in the resistance of microbial pathogens to most tested and used antibiotics should be taken into account in the appointment of empirical antibiotic therapy. The extremely high frequency of resistance of gram-negative bacteria to cephalosporins and fluoroquinolones excludes the possibility of their empirical use, which requires the management of carbapenems in the starting treatment regimens. High resistance to fluoroquinolones limits the ability of oral antibiotic therapy in patients with periprosthetic infection.