Antibiotic-laden bone cement is an important strategy of treatment for an established bone infection. It was aimed to find the safe antibiotic dose intervals of the antibiotic cements soaked in Phosphate Buffered Saline solution and to determine whether there was a difference in terms of mechanical strength between the prepared samples.

This study was done in our institute Microbiology and Metallurgy laboratories. All samples were prepared using manual mixing technique using 40 g radiopaque Biomet® Bone cement (Zimmer Biomet, Indiana, USA) under sterile conditions at 19 ± 2 ºC.

In this study, vancomycin (4 groups − 0.5, 2, 4, 6 g), teicoplanin (4 groups − 0.8, 1.2, 2, 2.4 g), daptomycin (4 groups − 1, 2, 2.5, 3 g), piperacillin-tazobactam (4 groups − 0.125, 0.5, 1, 2 g) and meropenem (4 groups − 0.5, 2, 4, 6 g) were measured in a assay balance and added to the cement powder. Antibiotic levels ranged from the lowest 0.625% to the highest 15%.

80×10×4 mm rectangle prism-shaped sample for mechanical measurements in accordance to ISO 5833 standart and 12×6×1 mm disc-shaped samples for microbiological assesments were used. Four sample for each antibiotic dose and control group was made. Prepared samples were evaluated macroscopically and faulty samples were excluded from the study. Prepared samples were kept in Phosphate Buffered Saline solution renewed every 24 hours at 37 ºC. At the end of 6 weeks, all samples were tested with Instron ® 3369 (Norwood Massachusetts, USA) four point bending test.

Staphylococcus aureus (ATCC 29213) strain was used for samples of antibiotics containing vancomycin, teicoplanin and daptomycin after the samples prepared for antibiotic release were maintained under sterile conditions and kept in Phosphate Buffered Saline solution as appropriate. For samples containing meropenem and piperacillin - tazobactam antibiotics, Pseudomonas aeruginosa (ATCC 27853) strain was used.

The addition of more than 5% antibiotics to the cement powder was significantly reduced mechanical strength in all groups(p <0.05) however the power of significance was changed depending on the type of antibiotic. In general, adding antibiotics with 2.5% and less for cement amount was not cause significant changes in mechanical measurements. There was a negative correlation between the increase in the amount of antibiotics mixed with cement and the durability of the cement (p: <0.001, r: −0.883 to 0.914).

In this study, especially the antibacterial effects of piperacillin-tazobactam, containing 0.25 gr and 0.5 gr antibiotic doses, were found to be low. There was no bacterial growth in all other groups for 21 days. Considering the mechanical properties of groups containing meropenem, vancomycin, daptomycin and teicoplanin, it was observed that all antibiotic cements remained above the limit value of 50 MPa in the bending test at concentrations containing 2.5% and less antibiotics. This was not achieved for the piperacillin-tazobactam group. The findings of the study showed that each antibiotic has different MPa values at different doses. Therefore, it could be concluded that not only the antibiotic dose but also the type oould change the mechanical properties. In the light of these findings, mixing more than 2.5% antibiotics in cement for the antibiotic types included in the study was ineffective in terms of antibacterial effect and mechanically reduces the durability of cement below the standard value of 50 MPa.

Copal bone cement loaded with gentamicin and clindamicin was developed recently as a response to the emerging occurrence of gentamicin-resistant strains in periprothetic infections. The objective of this study was to compare the in vitro antibiotic release and antimicrobial efficacy of gentamicin/clindamicin-loaded Copal bone cement and gentamicin-loaded Palacos R-G bone cement, as well as biofilm formation on these cements. In order to determine antibiotic release, cement blocks were placed in phosphate buffer and aliquots were taken at designated times for measurement of antibiotic release. In addition, the bone cement discs were pressed on agar to study the effects of antibiotic release on bacterial growth. Biofilm formation on the different bone cements was also investigated after 1 and 7 days using plate counting and confocal laser scanning microscopy (CLSM). Experiments were done with a gentamicin-sensitive S. aureus and a gentamicin-resistant CNS. Antibiotic release after 672 h from Copal bone cement was more extensive (65% of the clindamycin and 41% of the gentamicin incorporated) than from Palacos R-G (4% of the gentamicin incorporated). The higher antibiotic release from Copal resulted in a stronger and more prolonged inhibition of bacterial growth on agar. Plate counting and CLSM of biofilms grown on the bone cements showed that antibiotic release reduced bacterial viability, most notably close to the cement surface. Moreover, the gentamicin-sensitive S. aureus formed gentamicin-resistant small colony variants on Palacos R-G, and therefore, Copal was much more effective in decreasing biofilm formation than Palacos R-G. Biofilm formation on bone cement could be more effectively reduced by incorporation of a second antibiotic, next to gentamicin. Antibiotic release from the cements had a stronger effect on bacteria close to the cement than on bacteria at the outer surface of the bio-film. Clinically, bone cement with two antibiotics may be more effective than cement loaded with only gentamicin. The clinical efficacy of antibiotic loaded bone cements in combination with systemic antibiotics can be explained because antibiotics released from cements kill predominantly the bacteria in the bottom of the biofilm, whereas systemic antibiotics can only deal with bacteria at the outer surface of the biofilm

Aim. One of the most severe complications of primary total knee arthroplasty (TKA) is periprosthetic joint infection (PJI). Nowadays, the use of antibiotic-loaded cement for prevention of infection is still controversial. The aim of the present study is to evaluate the use of an antibiotic-loaded cement to reduce the infection rate in primary total knee arthroplasty. Method. Prospective randomized study, with 2893 cemented total knee arthroplasties performed between 2005 and 2010 in our institution. Two different groups were formed depending on which bone cement was used, without antibiotic (the control group) or loaded with erythromycin and colistin (the study group). All patients received the same systemic prophylactic antibiotics. The patients were followed for a minimum of twelve months. The rate of infection was analyzed according to the criteria of the Centers for Disease Control and Prevention (CDC). Results. In 1452 patients the prosthetic components were fixed using bone cement without antibiotic and in 1441 patients bone cement loaded with erythromycin and colistin was used. There were no differences between both groups in terms of demographic data (age, sex and BMI), either in operating time (p>0,05). The rate of infection was similar in both groups, being 2,0% (n=29) in the control group and 1,7% in the study group (p=0,58) at 8,7 years (SD 5,1) of follow up. In terms of prosthetic revision due to any cause (infected or aseptic), there wasn't differences between groups, performing a total of 61 revision arthroplasties in control group and 68 in study group (p>0,05). Moreover, we analyzed the erythromycin resistance rate, being no differences between both groups (p=0.6). Conclusions. The use of erythromycin and colistin-loaded bone cement in total knee arthroplasty did not lead to a decrease in the rate of infection when systemic prophylactic antibiotics were used, a finding that suggests that its use would not be indicated in the general population

Aim. The current treatment concepts of acute and chronic osteomyelitis are associated with unsolved challenges and problems, underlining the need for ongoing medical research. The invention and prevalence of an absorbable, gentamicin-loaded ceramic bone graft, that is well injectable for orthopedic trauma and bone infections, enlarges the treatment scope regarding the rise of posttraumatic deep bony infections. This substance can be used either for infection, dead-space, or reconstruction management. The bone cement, eluting antibiotics continuously to the surrounding tissue, outperforms the intravenous antibiotic therapy and enhances the local concentration levels efficiently. This study aims to evaluate the power and practicability of bone cement in several locations of bony infections. Method. The occurrence of posttraumatic infections with acute or chronic osteomyelitis increases in trauma surgery along with progression of high impact injuries and consecutively high incidence of e.g. open fractures. We present a case-series of 33 patients (18w/15m; 56,8±19,4 years) with posttraumatic osteomyelitis at different anatomic sites, who were treated in our level I trauma center. All of these patients received antibiotic eluting bone cement (Cerement® G) for infection and reconstruction management. Results. With admission to our trauma-center all patients with obvious or suspected osteomyelitis undergo an interdisciplinary pre-work up, including thorough clinical examination and different measures of diagnostic imaging, ultimately leading to the definition of an individual treatment plan. We diagnosed 33 bone infections anatomically allocated to the proximal and distal femur (12x), the pelvis (2x), distal tibia (3x), tibial diaphysis (10x), the ankle joint (4x) and calcaneus (2x). According to Cierny-Mader we diagnosed grade I (6), II (7), III (13) and IV (7). These 33 patients were treated (1) with surgical debridement, (2) with Cerament G, (3) bone stabilisation (including nail osteosynthesis, arthrodesis nails, plates, or external ring fixation), (4) optionally VAC-conditioning, and (5) optionally soft tissue closure with local or free flaps. The overall number of surgery was 2.9±2.26. We observed very good clinical, functional and radiological results by using bone cement augmented with gentamicin. The overall recurrence rate of infection is low (12%, 4/33). “White fluid” secretion was observed in six cases. Conclusions. Current concepts for treatment of osteomyelitis include radical surgical debridement and additional antibiotic therapy. It could be demonstrated that the usage of an antibiotic biocement with osteoconductive characteristics enlarges the success rate in septic bone surgery. The treatment concepts, however, remain complex, time consuming, require a high patient compliance, and are highly individually

Introduction. Antibiotic-impregnated bone cement (AIBC) has been used for decades to treat and prevent post-operative infections in joint arthroplasty. Local delivery of antibiotics may theoretically have a bactericidal effect, however evidence supporting this is controversial and literature suggests its prophylactic use in primary total knee arthroplasty (TKA) is seldom justified. With evolving standards of care, historical data is no longer relevant in addressing the efficacy of AIBC in the contemporary TKA. The purpose of this study was to evaluate outcomes following primary TKA using AIBC and regular non-AIBC by comparing rates of surgical site infection (SSI) and prosthetic joint infection (PJI). Methods. A retrospective review was conducted of all cemented primary TKA procedures from a large institutional database between January 1, 2015 and December 31st, 2016. This identified 6,073 cases, n=2,613 in which AIBC was used and n=3,460 cases using bone cement without antibiotics. Patients were stratified into low risk and high-risk groups based on age (>65 years), BMI (>40), and Charlson Comorbidity Index (CCI; >3). Medical records were reviewed for diagnoses of SSI (skin and superficial wound infections) and PJI (deep joint infections requiring surgery) over a 2-year postoperative period. Univariate analysis and multivariate regression models were used to ascertain the effects of cement type, patient factors (age, gender, BMI, CCI), operative time, and length of stay on infection rates. Additionally, mixed models (adjusted for gender, age, race, BMI, and CCI) were built to account for surgeon variability. Results. The use of AIBC and risk group distributions were equal across the study period and no collinearity was found between the study variables. The SSI rate was 3.0% and the PJI rate was 0.8% in the total study population. Univariate analysis showed there was no significant difference in SSI rates with AIBC compared to non-AIBC (3.3% vs. 2.8%, p=0.278) or in PJI rates (1.0% vs. 0.7%, p=0.203). Multivariate logistic regression analysis adjusted for patient factors, operative time, and length of stay showed no significant difference in SSI rates with a procedure using AIBC compared to non-AIBC (OR=0.90; 95% CI, 0.66–1.23; p=0.515) and no significant difference in PJI rates (OR=1.01; 95% CI, 0.55–1.84; p=0.984). Mixed models also showed no difference in PJI rates with AIBC use after adjusting for surgeon variability as well as patient factors (gender, race, age, BMI, and CCI). Discussion. Prophylactic use of AIBC in primary TKA is not without consequence when considering the significant increase in cost and its potential side effects, namely organism specific antibiotic resistance and mechanical loosening. This study shows that even when adjusted for patient factors, procedure-related factors, and length of stay, there is no clinically significant decrease in infection rates with the use of AIBC in primary TKAs

Aim. The current treatment concepts of acute and chronic osteitis are associated with unsolved challenges and problems, underlining the need for ongoing medical research. The invention and prevalence of an absorbable, gentamicin-loaded ceramic bone graft, that is well injectable for orthopedic trauma and bone infections, enlarges the treatment scope regarding the rise of posttraumatic deep bone infections. This substance can be used either for infection, dead-space, or reconstruction management. The bone cement, eluting antibiotics continuously to the surrounding tissue, outperforms the intravenous antibiotic therapy and enhances the local concentration levels efficiently. This study aims to evaluate the power and practicability of bone cement in several locations of bone infections. Method. The occurrence of posttraumatic infections with acute or chronic osteitis increases in trauma surgery along with progression of high impact injuries and consecutively high incidence of e.g. open fractures. We present a case-series of 10 patients with posttraumatic osteitis at different anatomic sites, who were treated in our level I trauma center. All of these patients received antibiotic eluting bone cement* for infection and reconstruction management. Results. With admission to our trauma-center all patients with obvious or suspected osteitis undergo an inter-disciplinary pre-work up, including thorough clinical examination and different measures of diagnostic imaging, ultimately leading to the definition of an individual treatment plan. We diagnosed 10 bone infections anatomically allocated to the proximal (2x) and distal femur (3x), distal tibia (3x), tibial diaphysis (1x) and the ankle joint (1x). These ten patients were treated (1) with surgical debridement, (2) with an antibiotic eluting bone cement*, (3) bone stabilisation (including nail osteosynthesis, arthrodesis nails, plates, or external ring fixation), (4) optionally VAC-conditioning, and (5) optionally soft tissue closure with local or free flaps. We observed very good clinical, functional and radiological results by using bone cement augmented with gentamicin. The overall treatment failure rate is low, throughout, all patients showed no signs of acute recurrence of infection. Pain and immobility decreased continuously with time. “White fluid” secretion was observed in one case. Conclusion. Current concepts for treatment of osteitis include radical surgical debridement and additional antibiotic therapy. It could be demonstrated that the usage of an antibiotic biocement with osteoconductive characteristics enlarges the success rate in septic bone surgery. The treatment concepts, however, remain complex, time consuming, require a high patient compliance, and are highly individually. *Cerement® G

Pelvic reconstruction after tumour resection is challenging. Pelvic replacements are usually custom made at considerable expense and then need very careful positioning at the time of surgery. They have a very high rate of complications with up to 30% risk of infection and 10% dislocation. In 2003 we developed a new type of pelvic replacement which would be simple to make, simple to use and which would hopefully avoid the major complications of previous pelvic replacements whist being versatile to use even when there was very little pelvis remaining. The concept is based on the old design of Ring stemmed hip replacement and has become known as the ice-cream cone prosthesis. It is inserted into the remnant of pelvis or sacrum and is surrounded by bone cement containing antibiotics. One of the main advantages is it’s flexibility, allowing insertion after resection at a variety of levels. It is also suitable for patients with metastatic disease. We have inserted 12 of these implants in the past 4 years, resolving very difficult reconstruction problems. There was one case that became infected but was cured with washout and antibiotics. In one patient there was excessive leg lengthening resulting in a sciatic and femoral nerve palsy and the prosthesis had to be revised. All patients can walk with one stick or less. These results are encouraging and suggest that this versatile implant may be the way forward for pelvic reconstruction because of it’s flexibility of use and low complication rate

The use of polymethylmethacrylate (PMMA) bone cement loaded with antibiotics has become increasingly common in orthopaedic surgery. However, bacterial resistance in antibiotics is an increasing and emerging problem. PMMA bone cements containing different antibiotics, such as gentamicin plus vancomycin may be effective in prevention and treatment of infections (particularly from MRSA and MRSE). The purpose of this study was to determine the in vitro elution characteristics of gentamicin and vancomycin when combined in acrylic cement. Three groups of ten cement disks were prepared. Group I (control group) contained 0.5g of gentamicin per 40-g packet of Palacos-R+G powder. Group II contained 0.5g of gentamicin and 1g of powdered vancomycin and group III contained 0.5g of gentamicin and aqueous solution of vancomycin. Each cement disc (25mm x 20mm) was immersed in a 50-mL bath of normal saline at 37oC. Samples were taken at specific sampling intervals (1, 3, 7, 15, 30, 60, 90, 120, 150, 180 days). Antibiotic concentrations were measured using fluorescence polarisation immunoassay. With regards to gentamicin release, high but rapidly decreasing antibiotic levels were detected within the first week and low concentration after the first month. Samples from Group II eluted significantly more gentamicin (120%–20% during the first month). The influence on the gentamicin release was significant but minor when aqueous solution of vancomycin (Group III) was added. With regards to vancomycin release, high antibiotic levels were detected within the first 3 days and low concentrations after the first week. Cement samples from Group II eluted significantly more antibiotic in comparison with samples from Group III. Bone cements loaded with combinations of gentamicin and vancomycin are more effective in releasing gentamicin than bone cements with gentamicin as a single drug. Powdered vancomycin in cement samples has better elution characteristics in comparison with aqueous solution of vancomycin

Introduction: The use of polymethylmethacrylate (PMMA) bone cement loaded with antibiotics has become increasingly common in the treatment of infected knee and hip arthroplasties and also as prophylaxis in primary joint replacement. However bacterial resistance in antibiotics is an increasing and emerging problem. PMMA bone cements containing different antibiotics, such as gentamicin plus vancomycin may be effective in prevention and treatment of infections (particularly from MRSA and MRSE). The purpose of this study was to determine the in vitro elution characteristics of gentamicin and van-comycin when combined in acrylic cement. Material and methods: Three groups of six cement disks were prepared. Group I (control group) contained 0.5g of gentamicin sulphate per 40-g packet of Palacos-R+G powder. Group II contained 0.5g of gentamicin sulphate and 1g of finely powdered vancomycin and Group III contained 0.5g of gentamicin sulphate and aqueous solution of vancomycin (containing 2mL water for injection and 1g vancomycin). All discs were prepared using vacuum mixing technique. Each cement disc (25mm diameter × 20mm thick) was fully immersed in a 50-mL bath of normal saline at 37o C temperature in a covered beaker. At specific sampling intervals (1, 3, 7, 15, 30, 60, 90, 120, 150, 180 days) the discs were removed and placed in fresh 50 ml bath for 24 hours. Then a 2 mL sample of each solution was taken. Samples were frozen at −60° C until they were analyzed. Gentamicin and vancomycin concentrations were measured using fluorescence polarization immunoassay. Results: With regards to gentamicin release, high but rapidly decreasing antibiotic levels were detected within the first week, resulting in an almost steadily low concentration by the end of the first month. Cement samples eluted significantly more gentamicin (120%-20% during the first month) when powdered vancomycin (Group II) was added. The influence on the gentamicin release was significant but minor when aqueous solution of vancomycin (Group III) was added (40%-20% during the same period). With regards to vancomycin release, high antibiotic levels were detected within the first 3 days and low concentrations after the first week. Cement samples from Group II eluted significantly more antibiotic (80%–100%) in comparison with samples from Group III during the first days. Gentamicin and vancomycin are detectable in measurements at 150 and 180 days samples. Conclusions: Bone cements loaded with combinations of gentamicin and vancomycin are more effective in releasing gentamicin than bone cements with gentamicin as a single drug. The presence of powdered vancomycin in cement samples has major influence on the total gen-tamicin release in comparison with cements containing aqueous solution of vancomycin

Background. Much effort has been aimed at strategies for patient optimization, perioperative standards of care, and postoperative risk stratification to reduce the incidence of SSI. Examples include, newer dressing modalities, antibiotic-impregnated bone cement, intra-wound powdered antibiotics, as well as novel suture types and techniques, all of which have shown great potential. However, the question remains as to whether these changes in practice have led to lower overall infections over the past few years. Therefore, the purpose of this study was to track the annual rates and trends of: 1) overall; 2) deep; and 3) superficial SSI following total hip arthroplasty (THA) using the most recent data (2012 to 2016) from a large nationwide database. Methods. The National Surgical Quality Improvement Program database was queried for all primary THAs (CPT code 27130) between 2012 and 2016, yielding 122,451 cases. Cases with reported superficial and/or deep SSIs were combined for an overall rate, and then independently analyzed as deep and superficial SSIs. The infection incidence for each year was calculated. After an overall 5-year correlation and trends, univariate analysis was also performed to compare the most recent year, 2016, with each of the preceding 4 years. Furthermore, a comparison of overall and deep SSI incidences from this study were compared to meta-analysis of pooled data from 2001 to 2011. Pearson correlation coefficients and chi-squared tests were used to determine correlation and statistical significance which was maintained at a p-value less than 0.05. Results. Over the 5-year period, 1,154 cases out of 122,451 (0.94% of all cases) were complicated by any SSI. The lowest incidence was in the latest year, 2016 (n=289, 0.81%), while the greatest was in the earliest year, 2012 (n=163, 1.12%). There was a significant inverse correlation between overall SSI rate and year (p<0.01). A 31% decrease in rate was found between 2016 and 2012 (0.81% vs. 1.12%, p<0.01). For deep SSI, the lowest incidence was in the most recent year, 2016 (n=82, 0.23%). The incidence over 5 years was 0.30% (364 out of 122,451 cases). The mean percent decrease in deep SSI incidence over the 5 years was 31%. There was a 49% decrease in deep SSI rate in 2016 compared to 2015 (0.23% vs. 0.38%, p>0.05). Additionally, there was an inverse correlation between deep SSI rate and year of surgery (p>0.05). The lowest superficial SSI incidence occurred in the most recent year, 2016 (n=204, 0.58%), while 2012 had the greatest incidence (n=121, 0.83%). There were a total of 796 cases out of 122,451 over 5 years, an incidence of 0.65%. A 31% decrease was observed between 2016 and 2012 (0.58% vs. 0.83%, p=0.001). There was a statistically significant inverse correlation between superficial SSI rate and year (p<0.01). A meta-analysis evaluating primary THA SSIs from 2001 to 2011 reported an overall SSI incidence of 2.5% (95% confidence interval [Cl], 1.4%-4.4%; P<.001; n=28,883), substantially higher (309%) than the 2016 incidence of 0.81% found in this study. Furthermore, the meta-analysis reported an incidence for deep SSIs to be 0.9% (95% Cl, 0.4%-2.2%; p<.001; n=28,883), also found to be markedly lower than the 2016 incidence noted here (0.23%), marking a 391% difference. Conclusion. The findings from this study suggest that the evolving standards of care have brought about improvements in SSI prevention following THA over time. Deep SSIs, which can pose substantial threats to implant survivorship, have decreased throughout the years. These results highlight the importance of following up-to-date clinical recommendations to reduce surgical site infections and substantially improve patient outcomes

The use of antibiotic-loaded cement has become a well-accepted method to develop high local antibiotic concentrations in orthopedic surgery. A new surgical technique has been established in our department in order to further increase the local antibiotic concentration, when implanting a prosthesis during revision surgery. By additional superficial vancomycin coating of the bone cement, high local antibiotic concentrations are generated. They should reach inhibiting and bactericidal concentrations of the respective pathogen during the first days after surgery. The aim of this study was to state the safety of this method by analyzing postoperative serum and drain vancomycin concentrations. Attention was focused on possible systemic side effects. To determine nephrotoxicity, creatinine levels were also measured. In total 32 revision operations (hip n=10, knee n=22) with additional superficial vancomycin coating were performed between 05/2013 and 04/2015. Procedures with removal of the prosthesis following temporary spacer implantation were excluded. In nine cases a one-stage procedure was performed, while in the others an arthroplasty or arthrodesis was performed after temporary spacer explantation. Vancomycin powder (2 grams) was added superficially to the surface of the bone cement and pressed onto manually before curing. Postoperative Vancomycin levels were measured in serum and the drain on day 1 to 5 or until the drain has been removed. In total 90 blood serum samples and 100 drain fluid samples were obtained. The highest median vancomycin level from the drain was documented on postoperative day 1 with a value of 555.3 μg/mL (range 66.1 – 1081.8), continually decreasing until postoperative day 4. The highest value was documented on the second postoperative day with 2170.0 μg/mL. On the first postoperative day, a median serum vancomycin level of 3.35 μg/mL was present (range <2.0 – 8.5), while from postoperative day 2 to 5 a median level less than 2.0 μg/mL (range <2.0 – 7.2) was documented. Anaphylactic reaction, red man syndrome or fever and chills were not observed after the surgical procedure. Furthermore, no subjective hearing loss was reported. Only in one case, a creatinine increase of 0.5 mg/dL from baseline value was detected. In this case the patient suffered preoperatively from a chronic kidney insufficiency. In total two reinfections occurred, one after explanting a spacer with subsequent hip total endoprosthesis, the other one after a one-stage hip revision. Superficial Vancomycin Coating of bone cement in orthopedic revision surgery represents a safe method to increase local inhibiting vancomycin concentrations

Despite of improved operative technique, ultra-clean air in the operating theater and systemically administered as well as in bone cement loaded antibiotics, septic complications after replacement arthroplasty of the knee still exist. Depending of the follow-up time in different reported series insidence vary from 0.5 to 5 per cent. Classic clinical symptoms, painful, swollen knee joint, possibly fever, indicate to more accurate examinations. Lesson to learn: . No treatment before adequate diagnosis !. No “homeostatic” antibiotics before accurate examinations. If the very first contact with physician or surgeon happens in such conditions, that adequate diagnostic methods are not available, patient has to be referred to hospital or institution with capable facilities. Prosthetic infection can be classified in many ways. The following classification is useful for the treatment purposes. Classification of infection:. 1. Early postoperative infection less than 4 weeks after surgery. superficial. deep. extensive soft tissue defects due to skin necrosis. 2. Originally patient is operated for aseptic loosening, but intraoperative cultures are positive. 3. Late chronic infection. 4. Acute hematogenous infection. Diagnostic methods:. 1. Clinical examination:. - symptoms can be suppressed by painkillers or immunomodulant drugs. - wound healing problems. - sinuses. - swelling, redness. - pain. - temperature increased. 2. Blood chemistry:. ESR, C-reactive protein and blood white cell count/ differentiation are helpful. Be ware if the patient has such a general disease, which increases fex CRP. 3. Routine x-rays. In early cases no significant signs, in late cases might appear erosions or cysts. 4. Isotope scintigraphy. Technetium- or indium labeled leucosytes are given intravenously. The patient is scanned 24 hours. Extended scintigraphy seems to be more sensitive than routine 6 to 8 hours‘ scintigraphy. 5. Joint aspiration. One has to sure, that the patient is not on antibiotics. If she/he is, antibiotics has to be stopped for two to four weeks, and aspiration performed after that, unless infection is not clinically obvious or situation is not life-threatening. White cell count/differentiation can be for some help. When the cell count is less than 2000/ml, and majority of cells are mononuclear, the result is indicative negative for infection. White cell count over 10000/ml, and majority polymorphonuclear, speaks for infection. When the aspiration has been carried in aseptic condition, positive culture is strong evidence for infection. Adequate handling of sample is important: as little as possible air in the syringe and as short as possible time used for transportation to lab. Treatment protocols. Treatment protocols can rather straight forward: if any sample culture is positive,. Two-stage revision arthroplasty is carried out. But also more conservative opinions are reported. 1.a. Early postoperative, superficial infection:. Surgical débridement of the wound. Careful examination of retinaculum layer. Lavage and wound closure if possible. Systemic antibiotics. Joint puncture and aspiration through healthy skin area, never through open wound. b. Early postoperative, deep infection:. Open débridement and careful lavage with retention of prosthesis. Additional peroperative samples for culture in order to confirm earlier pathogene definition. Systemic antibiotics regarding sensitivity estimation. Arthroscopic debridement and lavage has not proved to be better or neither as good as open. New aspiration 4–6 days after. If white cell count clearly over 10000/ml and possibly culture positive, new debridement and lavage. If third debridement comes necessary, even without bony changes, removal of prosthesis and antibiotics- loaded spacer has to be considered. c. Dehiscense of wound or soft tissue defect due to the necrosis:. Wound débridenent, antibiotics and depending on the extend of defect either partial closure, skin grafting or pedicled gastrocnemius muscle flap is performed. 2. In some cases there is no signs of infection, and the is operated as an aseptic loosening. In all revision, routineously 4 to 5 tissue samples should be taken for culture. If preoperatively there is any doubts about infection, histological examination of frozen sections should be carried out. If there are high count of polymorphonuclear cells, results of culture has to be waited. If later on in minimum two samples same pathogen is growing, the case has to be considered as infected. Two-stage revision protocol is recommended. One positive sample cannot be regarded as a concluding proof. Long term antibiotics is recommended. 3. Late chronic infection has insidious , slowly progressing onset. Symptoms can be confusing mild, and can lead to misdiagnosis. Method of choice is débridement, removal of the prosthesis and all bone cement, and placement of an antibiotics-loaded cement spacer. No dead space is left , but has to be filled with antibiotic-loaded collagen or antibiotic-cement beads. The patient is put on systemic antibiotics, preferably combination of two. Antibiotic therapy is continued six- to eight weeks. Healing process is controlled with ESR and CRP tests. If the blood test normal and clinical situation is normal, delayed revision arthroplasty is performed. Antibiotic loaded-cement is always used. 4. Acute hematogenous infection. Onset is usually acute and symptoms dramatic. Sometimes distant focus can be found. If the history is rather short( less than 14 days) open débridement, retainment of prosthesis, antibiotics-loaded collagen filling of the joint as well systemic antibiotics is recommended. Recovering is monitored by blood chemistry and repeated joint aspiration and cultures. If in aspiration sample there is high polymorphonueclear count and culture possibly positive, new débridemand is carried out. If signs of infection still continue, two-stage exchange to be considered. Pathogenes. Gram-positive. staphylococci are most frequent patogene in total knee replacement infections (95%). Gram-negative. bacilli cover the rest (5%). Coagulase-negative staphylococci has grown up the most important bacteria, and it‘s resistance against antibiotics has turned frightening. Spacers. In cases with short history retainment of prosthesis can be considered. Many authors change of polyethylene bearing. In two-stage revisions static antibiotic-loaded cement spacer was used during. The six to eight weeks‘ interval. Static spacer is connected with extensive bone loss as well as stiff causing problems in secondary revision. Molded cement spacer is used in order to avoid complications and to achieve better functional results. Failure. In some cases treatment of infection is unsuccessful. Arthodesis with method of Ilizarov or intramedullary nail or sometimes above-knee amputation comes necessary

Bone cement with an antibiotic additive is currently widely available, gentamicin being the most common type. However, the high resistance of such organisms as staphylococci to gentamicin has popularised the practice of adding additional antibiotic powders to the cement mix. This study aims to quantify the effects of adding 1g active of seven antibiotics on the viscoelastic properties of the cement from mixing to set time using a robust rheometer, developed at the University of Leeds. CMW1 Radiopaque cement was the base cement selected for its widespread familiarity. Viscosity and elasticity were recorded at two rates of shear until the cements set. Viscosity was found to decrease with shear rate, but the cements were found to have a significant elastic component that greatly increased with shear rate. This indicates that for maximum cement penetration, maintained pressure would be more effective than “hammering”. It should be noted that the effects described above are small compared to other theatre variables, especially temperature and humidity

The visco-elastic behaviour of acrylic bone cement is a key feature of cement-implant performance. The ability of the cement to creep in conjunction with a force-closed design of stem (collarless polished taper) affords protection of the vital bone-cement interface. Most surgeons in the UK use antibiotic-laden PMMA in primary total joint arthroplasty. In revision surgery the use of bespoke antibiotic-cement combinations is common. The aim of this study was to elicit the effect of antibiotics upon the physical properties of bone cement. Methods: The static properties of the cements were assessed following protocols described in ISO 5833: 2002, while the viscoelastic properties of the cement were measured with in-house developed apparatus in quasi-static conditions. Creep tests were performed in four point bending configuration over a 72 hour period in physiological conditions. Porosity was measured on the mid cross section of the creep samples using a digital image technique. The cements used were Palacos R40 and Palacos R with gentamicin. The antibiotics added included fucidin, erythromycin, teicoplanin and vancomycin in 500mg powder aliquots up to a maximum of 1g per 40 g mix. All data were analysed using ANOVA with Bonfer-roni post-hoc test. Pearson’s correlation coefficient was used to investigate the association between physical factors (SPSS). Results: The static and working properties did not vary significantly with antibiotic additions. The mean creep of the cement increased in line with the amount of antibiotic added. The specific antibiotic was not relevant. The differences were statistically significant. Mean porosity also increased with antibiotic mass. There was a linear relationship between cement porosity and creep!. Conclusions: Despite modern mixing techniques the porosity of bone cement increases with antibiotic additions. This increased porosity is related to the greater creep seen in the cement. Surgeons should apply these findings when planning revision hip surgery

The weak points and complications of the classic spacers are eliminated by the construction of an articulated spacer. We did have very good results with the application of a classic spacer and considered the negative properties of the articulated spacer as a foreign matter in the wound. Gradually, the excellent literary results, standardization of the procedure, faster rehabilitation and a significant growth of comfort for the patient convinced us of the fact, that we chose the right way. Therefore we prepared and verified the new implant. In its construction we used the experience from the creation of classic spacers as well as the principle of a drained spacer allowing a drainage of the cavity of the femur. The implant is constructed as a module to be enwrapped by as large amount of the bone cement with an antibiotics as possible. The cup is flat with a diameter of 42 mm, with grooves allowing adhesion of as large a quantity of cement as possible with the articular area for the head of a diameter of 28 mm. For a better stability of the implant, it is constructed as antiluxation one. The implant stem consists of three parts so that a high modularity is secured upon low costs. The body of the stem has a single length and it is furnished in the axis with a drain enabling the use of a flush lavage. For a better modularity, it is possible to fit on the stem body three different lengths of the neck. In 2002 and 2004, the articulated spacer was used to treat 26 patients with a deep infection of a hip joint prosthesis. The treatment of the infection has been successful in all cases. The period of leaving the drained articulated spacer was 12,8 weeks. The result of the Harris hip score when after implantation it reaches on average 94.7 points. The contribution of this method is also supported by an even more average growth of the Harris hip score as opposed to the condition prior to operation, which was 37,5 points. The patients did not feel any pain in between the operations. The only restriction of the quality of life was brought by a recommended necessity of walking with crutches. The technique combines the advantages of a two-stage procedure with flexibility of the reimplanting term and the economic and social profits for the patient