The treatment of chronic osteomyelitis often includes surgical debridement and filling the resultant void with antibiotic-loaded polymethylmethacrylate cement, bone grafts or bone substitutes. Recently, the use of bioactive glass to treat bone defects in infections has been reported in a limited series of patients. However, no direct comparison between this biomaterial and antibiotic-loaded bone substitute has been performed. . In this retrospective study, we compared the safety and efficacy of surgical debridement and local application of the bioactive glass S53P4 in a series of 27 patients affected by chronic osteomyelitis of the long bones (Group A) with two other series, treated respectively with an antibiotic-loaded hydroxyapatite and calcium sulphate compound (Group B; n = 27) or a mixture of tricalcium phosphate and an antibiotic-loaded demineralised bone matrix (Group C; n = 22). Systemic antibiotics were also used in all groups. After comparable periods of follow-up, the control of infection was similar in the three groups. In particular, 25 out of 27 (92.6%) patients of Group A, 24 out of 27 (88.9%) in Group B and 19 out of 22 (86.3%) in Group C showed no infection recurrence at means of 21.8 (12 to 36), 22.1 (12 to 36) and 21.5 (12 to 36) months follow-up, respectively, while Group A showed a reduced wound complication rate. Our results show that patients treated with a bioactive glass without local antibiotics achieved similar eradication of infection and less drainage than those treated with two different antibiotic-loaded calcium-based bone substitutes. Cite this article: Bone Joint J 2014; 96-B:845–50

Chronic osteomyelitis is historically treated in a two stage fashion with antibiotic-loaded polymethylmethacrylate (PMMA) as local antibacterial therapy. However, two-stage surgeries are associated with high morbidity, long hospitalization and high treatment costs. In recent years new biomaterials were developed that allow to change this treatment algorithm. S53P4 bioactive glass is such a novel biodegradable antibacterial bone graft substitute that enables a one-stage surgery in local treatment of chronic osteomyelitis. This study aimed to explore the eradication of infection and bone healing capacities of S53P4 bioactive glass in clinical practice. In this prospective longitudinal outcome study, clinical applicability of S53P4 bioactive glass in treatment of patients with chronic osteomyelitis was assessed. All patients with clinically, haematologically and radiologically evident chronic osteomyelitis were included. All patients were treated with an extensive debridement surgery, S53P4 bioactive glass implantation and systemic antibiotic administration. Primary endpoint of this study is eradication of infection. During follow-up eradication was analysed based on clinical outcomes, blood samples (inflammatory parameters) and radiological outcomes. The secondary endpoint, bone healing, is assessed using conventional radiographic images of the treated region. Between 2011 and 2016, 25 patients were included in this study, with a mean follow-up of 23 months (range 4 – 57). Hospital stay was short with a mean of 18 days (range 4 – 40) and patients required an average of 1,4 surgeries (range 1 – 4). The inflammatory parameter C-reactive protein (CRP) showed a normalization after a mean duration of 46 days (range 0 – 211). At the end of follow-up haematological and clinical outcomes showed eradication of infection in 24 (96%) of all patients. Radiologically none of all patients showed persisting signs of infection and bone healing was observed in 22 (88%) patients based on changes on conventional radiographic images. One patient had a persistent infection without any bone healing, this patient had an infected non-union prior to surgery. There were two other patients with an initial infected non-union fracture which was not consolidated at last follow-up, although they had successful infection treatment. Another patient had a femoral fracture after surgery that needed additional surgery which did not interfere with eradication of infection. Four (16%) of all patients had initial wound healing problems related to compromised skin and/or soft tissue prior to surgery. Based on the results of our clinical experience, S53P4 bioactive glass can successfully be used in a one-stage procedure for treatment of chronic osteomyelitis. Eradication of infection was successful in almost all patients and so far no patients required a second surgery due to infection recurrence. Bone healing (incorporation of the bioactive glass) was seen in all patients except for the patients with an initial infected non-union fracture. As a consequence of these results, we changed our institutional protocol for treatment of chronic osteomyelitis to a one-stage approach instead of a two-step approach

Osteomyelitis is an infection of bone or bone marrow with a concomitant inflammation involving the bone marrow and the surrounding tissues. Chronic osteomyelitis is historically treated in a two-stage fashion with antibiotic-loaded polymethylmethacrylate as local antibacterial therapy. Two-stage surgeries are associated with high morbidity, long hospitalization and high treatment costs. Next to antibiotic releasing biomaterials, S53P4 bioactive glass is a biomaterial that enables one-stage surgery in local treatment of chronic osteomyelitis. S53P4 bioactive glass is gaining interests in recent years in clinical treatment of chronic osteomyelitis in a one-stage fashion due to its antibacterial and bone regenerating capacities. By changing local pH and osmotic pressure S53P4 bioactive glass attack bacteria in a different way as compared to antibiotics. In this presentation, we will present current clinical treatment options for osteomyelitis, clinical results and level of evidence of various biomaterials used in osteomyelitis treatment. In addition, the clinical results and health-economic results of S53P4 bioactive glass will be detailed. Thereafter a summary of the current standing across the board in osteomyelitis treatment will be provided

Long-term survival and favourable outcome of implant use are determined by bone-implant osseointegration and absence of infection near the implants. As with most diseases, prevention is the preferred approach. Silver ion doped calcium phosphate based ceramic coating (Silveron®) for implant coating has been shown previously to be a potent antimicrobial agent as indicated by in vitro testing. The present study reports on clinical experience using silver ion doped calcium phosphate based ceramic coated external fixator pins as surgical treatment in the management of chronic osteomyelitis and open fractures. Ten patients had external fixators: six for open fractures of ankle, three for chronic osteomyelitis of the femur, one for tibia pseudoarthrosis. The electrospray method was used for coating the external fixator pins with silver ion doped calcium phosphate-based ceramics. A radiofrequency energy source was used to sinter the coated pins. Microbiological, roentgenographic, toxic and biochemical analyzes of patients were carried out. Wound debridement, and subsequent wound care resulted in control of the infection in three chronic osteomyelitis and in healing of seven fractures after follow-up ranging from three to six months. In total 67 pins were used in 10 patients but only one pin was positive microbiologically in one patient. Collectively, these data clearly illustrate that the toxic effects of silver were not observed at the doses used. Silver ion doped calcium phosphate based ceramic coating (Silveron®) can be used to prevent infection associated with the implant

Bone infections due to fractures or implants are a big medical problem. In experimental medicine, many experimental models have been created on different animal species to simulate the disease condition and to do experience treatments. The aim of this paper was to present an antibacterial efficacy of using a bone allograft developed according to the Marburg system of bone bank on a model of chronic osteomyelitis induced in rabbits. In research was used 54 rabbits. Osteomyelitis was induced in rabbits by a human strain of St. aureus ATCC 43300, in the rabbit femur. There have been created 3 groups of animals. In 1. st. group used antibiotic impregnated biodegradable material “PerOssal”. In 2. nd. group used antibiotic impregnated whole bone allograft. In 3. rd. group used antibiotic impregnated perforated bone allograft. Evaluation of installation and evolution of the disease was done by microbiological. A separate study of microbiological data is presented here. This study showed, in the 1. st. and 3. rd. groups there is a persistent decrease in CFU by 14 knocks to 120.4 in the 1. st. group and to 3.5 in the 3. rd. group, and in the 2. nd. group, on the contrary, there is an increase in CFU to 237.33. This shows the lack of effectiveness of using a whole bone allograft. The results showed, after 7 days there was no statistically significant difference between the groups. After 14 days the perforated bone allograft impregnated with antibiotic was better than the biodegradable material “PerOssal”

Serial section electron microscopy (SSEM) was initially developed to map the neural connections in the brain. SSEM eventually led to the term ‘Connectomics’ to be coined to describe process of following a cell or structure through a volume of tissue. This permits the true three-dimensionality to be appreciated and relationships between cells and structures. The purpose of this study was to utilize this methodology to interrogate S. aureus infected bone. Bone samples were harvested from mice tibia infected with S. aureus and were fixed, decalcified, and osmicated. The samples were paraffin embedded and 5-micron sections were cut to identify regions of bacterial invasion into the osteocyte-lacuna-canalicular-network (OLCN). This area was cut from the paraffin block, deparaffinized, post-fixed and reprocessed into epoxy resin. Serial sections were cut at 60nm and collected onto Kapton tape utilizing the Automated Tape-collecting Ultramicrotome (ATUMtome) system. Samples were mounted onto 4” silicon wafers and post-stained with 2% uranyl acetate followed by 0.3% lead citrate and carbon coated. A ZEISS GeminiSEM 450 scanning electron microscope fitted with an electron backscatter diffusion detector was used to image the sections. The image stack was aligned and segmented using the open-source software, VASTlite. 264 serial sections were imaged, representing approximately 40 × 45 × 15-micron (x, y, z) volume of tissue. 70% of the canaliculi demonstrated infiltration by S. aureus. This study demonstrates that SSEM can be applied to the skeletal system and provide a new solution to investigate the OLCN system. It is feasible that this methodology could be implemented to investigate why some canaliculi are resistant to colonization and potentially opens up a new direction for the prevention of chronic osteomyelitis. In order to make this a realistic target, automated segmentation methodologies utilizing machine learning must be developed and applied to the bone tissue datasets

Osteomyelitis is an inflammatory condition accompanied by the destruction of bone and caused by an infecting microorganism. Open contaminated fractures can lead to the development of osteomyelitis of the fractured bone in 3-25% of cases, depending on fracture type, degree of soft-tissue injury, degree of microbial contamination, and whether systemic and/or local antimicrobial therapies have been administered. Untreated, infection will ultimately lead to non-union, chronic osteomyelitis, or amputation. We report a case series of 10 patients that presented with post-operative infected non-union of the distal femur with or without prior surgery. The cases were performed at Padmashree Dr. D. Y. Patil Hospital, Nerul, Navi Mumbai, India. All the patients’ consents were taken for the study which was carried out in accordance with the Helsinki Declaration. The methodology involved patients undergoing a two-stage procedure in case of no prior implant or a three-stage procedure in case of a previous implant. Firstly, debridement and implant removal were done. The second was a definitive procedure in form of knee arthrodesis with ring fixator and finally followed by limb lengthening surgery. Arthrodesis was planned in view of infection, non-union, severe arthritic, subluxated knee, stiff knee, non-salvage knee joint, and financial constraints. After all the patients demonstrated wound healing in 3 months along with good radiographic osteogenesis at the knee arthrodesis site, limb lengthening surgeries by tibial osteotomy were done to overcome the limb length discrepancy. Distraction was started and followed up for 5 months. All 10 patients showed results with sound knee arthrodesis and good osteogenesis at the osteotomy site followed by achieving the limb length just 1-inch short from the normal side to achieve ground clearance while walking. Our case series is unique and distinctive as it shows that when patients with infected nonunion of distal femur come with the stiff and non-salvage knee with severe arthritic changes and financial constraints, we should consider knee arthrodesis with Ilizarov ring fixator followed by limb lengthening surgery

A retrospective series of 45 cases of chronic osteomyelitis collected over a period of 14 years was histologically classified into tuberculous osteomyelitis (25) and chronic non-granulomatous osteomyelitis (20). The tuberculous osteomyelitis group was divided into three subgroups: a) typical granulomas (13 cases); b) ill-defined granulomas (seven cases), and c) suspected granulomas (five cases). An in-house polymerase chain reaction amplifying the 245 bp nucleotide sequence, and capable of detecting 10 fg of DNA of Mycobacterium tuberculosis, was used on the DNA extracted from the paraffin blocks. The polymerase chain reaction was positive in 72% of cases (18) of tuberculous osteomyelitis, but when typical cases of tuberculous osteomyelitis with confirmed granulomas were considered (13), this increased to 84.6% (11). The chronic non-granulomatous osteomyelitis group gave positive polymerase chain reaction results in 20% of the cases (4). Our preliminary study on tuberculous osteomyelitis shows that the polymerase chain reaction can be a very useful diagnostic tool, since a good correlation was seen between typical granulomas and polymerase chain reaction with a sensitivity of 84.6% and a specificity of 80%. In addition, our study shows that tuberculous osteomyelitis can be diagnosed in formalin-fixed paraffin-embedded tissues in the absence of typical granulomas

Open limb fractures are typically due to a high energy trauma. Several recent studied have showed treatment's superiority when a multidisciplinary approach is applied. World Health Organization reports that isolate limb traumas have an incidence rate of 11.5/100.000, causing high costs in terms of hospitalization and patient disability. A lack of experience in soft tissue management in orthopaedics and traumatology seems to be the determining factor in the clinical worsening of complex cases. The therapeutic possibilities offered by microsurgery currently permit simultaneous reconstruction of multiple tissues including vessels and nerves, reducing the rate of amputations, recovery time and preventing postoperative complications. Several scoring systems to assess complex limb traumas exist, among them: NISSSA, MESS, AO and Gustilo Anderson. In 2010, a further scoring system was introduced to focus open fractures of all locations: OTA-OFC. Rather than using a single composite score, the OTA-OFC comprises five components grades (skin, arterial, muscle, bone loss and contamination), each rated from mild to severe. The International Consensus Meeting of 2018 on musculoskeletal infections in orthopaedic surgery identified the OTA-OFC score as an efficient catalogue system with interobserver agreement that is comparable or superior to the Gustilo-Anderson classification. OTA-OFC predicts outcomes such as the need for adjuvant treatments or the likelihood of early amputation. An orthoplastic approach reconstruction must pay adequate attention to bone and soft tissue infections management. Concerning bone management: there is little to no difference in terms of infection rates for Gustilo-Anderson types I–II treated by reamed intramedullary nail, circular external fixator, or unreamed intramedullary nail. In Gustilo-Anderson IIIA-B fractures, circular external fixation appears to provide the lowest infection rates when compared to all other fixation methods. Different technique can be used for the reconstruction of bone and soft tissue defects based on each clinical scenario. Open fracture management with fasciocutaneous or muscle flaps shows comparable outcomes in terms of bone healing, soft tissue coverage, acute infection and chronic osteomyelitis prevention. The type of flap should be tailored based on the type of the defect, bone or soft tissue, location, extension and depth of the defect, size of the osseous gap, fracture type, and orthopaedic implantation. Local flaps should be considered in low energy trauma, when skin and soft tissue is not traumatized. In high energy fractures with bone exposure, muscle flaps may offer a more reliable reconstruction with fewer flap failures and lower reoperation rates. On exposed fractures several studies report precise timing for a proper reconstruction. Hence, timing of soft tissue coverage is a critical for length of in-hospital stay and most of the early postoperative complications and outcomes. Early coverage has been associated with higher union rates and lower complications and infection rates compared to those reconstructed after 5-7 days. Furthermore, early reconstruction improves flap survival and reduces surgical complexity, as microsurgical free flap procedures become more challenging with a delay due to an increased pro-thrombotic environment, tissue edema and the increasingly friable vessels. Only those patients presenting to facilities with an actual dedicated orthoplastic trauma service are likely to receive definitive treatment of a severe open fracture with tissue loss within the established parameters of good practice. We conclude that the surgeon's experience appears to be the decisive element in the orthoplastic approach, although reconstructive algorithms may assist in decisional and planification of surgery

The treatment of chronic osteomyelitis requires both appropriate surgical and antibiotic management. Prolonged intravenous antibiotic therapy followed by oral therapy is widely adopted. Despite this, the long-term recurrence rate is around 20% to 30%. The aim of this cohort study was to examine the effectiveness of surgical marginal resection in combination with local application of antibiotics (Collatamp G - gentamicin in a collagen fleece). Post-operatively this was followed by a short course of intravenous antibiotics, then oral antibiotics, to 6 weeks in total. A cohort of 50 patients from a 10-year period, 2000 to 2010, with chronic osteomyelitis was identified. Most were male (n= 35, 70%) and the average age is 40.9 years (SD 15.9). The mean follow-up duration was 3.2 years (SD 1.8). The average length of admission was 9.8 days (SD 11.4). 6 patients (12%) suffered recurrence of infection requiring further treatment. We used the Cierny and Mader classification to further stratify the patients. ‘A’ hosts had a shorter duration of admission (7.1 days) than ‘B’ hosts (12.3 days). There was no significant difference between recurrence rates of ‘A’ and ‘B’ hosts. Where available, we found pre-operative C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) levels had no correlation with disease recurrence. Disease-free probability for this cohort compared favourably with a cohort treated with prolonged systemic and oral antibiotics (Simpson and colleagues, JBJS Br 2001). We believe local administration of gentamicin in a collagen fleece is a useful component in the management of chronic osteomyelitis

Bone infection occurring after fractures or orthopedic surgery can progress to the chronic stage and lead to poor results of treatment. Optimal treatment of chronic osteomyelitis are stabilization the fracture, biological recovery of bone defects and destroy bacterial infection. Traditional methods of treatment are systemic administration of antibiotics and surgical treatment of active infection focus. Systemic antibiotics are part of the standard therapy after surgical treatment of infected bone, but their effectiveness is limited due to malnutrition and low absorption at the site of infection. Moreover, long-term treatment and higher doses are associated with serious side effects. The aim of this investigation was to study the results of the complex treatment of patients with chronic osteomyelitis using biodegradable nanomaterials “PerOssal” as antibiotic delivery system. The study was performed at Regional center traumatology and orthopedics, Karaganda, Kazakhstan. A total 20 patient with post-traumatic/post-operative osteomyelitis were included in this open-label, prospective study. Bacteriological examination was taken with the determination of culture and sensitivity test preoperatively, during and postoperatively. After radical surgical debridement and ultrasound cavitation, the bone cavity was full filled with Perosal which can be loaded with different antibiotics depending from the antibiotic sensitivity test. Postoperative wound is completely was sutured. Systemic antibiotic treatment are allowed. The course of infection was monitored by determination leukocyte count and blood sedimentation rate; blood samples were taken befor, 24 hours after surgery, and on days 3, 7, 10, 14. Wound healing was assessed on days 2, 3, 7, 10, and at the time of removal of sutures. Resorption of implanted beads and bone reconstruction were evaluated by X-ray at after operation and at approximately one, three and six months after implantation. A total of 20 patients (mean age 38,1 (26 to 53), 14 male, 6 female) were treated with Perossal pellets (AAP, Germany) from October 2013 to April 2015. Mean leukocyte counts and blood sedimentation rate were within the normal laboratory range and did not indicate infectious complications during the first 21 days after surgery. Primary wound healing occurred in 18 patients and secondary wound healing in two patients. There were two cases of re-infection during the course of the study, one of them related to an incomplete eradication of infected tissue and multidrug-resistant strain occurring during the course of the study, the other is occurred that patient non-compliance. Radiographic analysis six months after surgery showed progressive resorption of the implanted pellets, but only 10 cases have decreasing size of defects on X-ray. This study in adult patients with chronic post-traumatic/post-operative osteomyelitis demonstrated that these biodegradable bone filler pellets which can be loaded with different antibiotics are a clinically useful local antibiotic delivery system and bone substitute which can be used as an alternative to other anti-infective implants. The implantation of the pellets was safety and well tolerated in all patients. This composite can provide adequate protection against bacterial infection during the first weeks after implantation and to support the bone healing process

We have developed a new drug-delivery system using reconstituted bone xenograft to treat chronic osteomyelitis. This material, which has the capabilities of osteoinduction and osteoconduction, was supplemented with up to 2000 times the minimum inhibitory concentration of gentamicin against Staphylococcus aureus to prepare a gentamicin-reconstituted bone xenograft-composite (G-RBX-C). In a rabbit model, we evaluated the release of gentamicin from this composite in vivo, its capability for induction of ectopic bone and the repair of segmental defects of the radius. There was a high level of concentration of antibiotics, which was sustained for at least ten days. In the study of induction of ectopic bone, there was abundant woven bone in the G-RBX-C group two weeks after operation. At 16 weeks after implantation of G-RBX-C the radial defects had been repaired, with the formation of lamellar bone and recanalisation of the marrow cavity. Our findings suggest that G-RBX-C may be useful in the treatment of chronic osteomyelitis

Chronic osteomyelitis (OM) is a progressive, inflammatory infection of bone caused predominantly by S. aureus and requires treatment through surgical debridement and systemic antibiotic administration. We have previously reported the fabrication of an antibiotic-eluting scaffold which is responsive to microbial activity for the treatment of OM. Herein, we ventured to assess the capacity of this antibiotic-eluting scaffold to treat infection in a rabbit model of chronic OM. Infections were established in the radii of New Zealand White rabbits using inoculations of 2×10. 6. CFUs S. aureus JAR 060131 over a period of 4 weeks. Following surgical debridement (6mm), rabbits underwent treatment for a period of 8 weeks until euthanasia. The treatment groups were; 1) empty, 2) antibiotic-eluting scaffold (collagen/hydroxyapatite scaffold loaded with vancomycin) and 3) commercially available antibiotic-eluting fleece (Septocoll E®, collagen fleece loaded with gentamicin). During the treatment period, all groups received systemic antibiotics (Cefazolin 25mg/kg) administered subcutaneously twice daily for 4 weeks. Inoculation of the radius resulted in the development of a sequestrum containing S. aureus, demonstrating the successful establishment of OM. After the 8-week treatment period, 4/5 rabbits in the empty group were still infected, indicating that systemic antibiotic administration following debridement was insufficient to treat the infection. Fewer rabbits in both the antibiotic-eluting scaffold group (2/4) and the antibiotic-eluting fleece group (1/3) were infected. This work demonstrates that the implantation of an antibiotic-eluting biomaterial into a defect following debridement enhances bacterial clearance in conditions of chronic OM

Background. The different biodegradable local antibiotic delivery systems are widely used in recent years. The aim of this study was to evaluate the bactericidal activity antibiotic loaded PerOssal pellet in vitro and its effectiveness in the treatment of Staphylococcus aureus induced chronic osteomyelitis. Material and methods. MALDI-TOF have been applied to microbiological diagnosis in patient with osteomyelitis. In most cases, Staphylococcus aureus was isolated. In vitro Ceftriaxone-Loaded PerOssal pellet were placed in middle agar plate containing a stock strain of Staphylococcus aureus. Plates were incubated at 37ºC for 24 hours. The zones of bacterial inhibition were recorded after 24, 48 and 72 hours of incubation. In vivo evaluation was performed by prospectively studying of 21 patients with a clinically and bacteriologically diagnosed Staphylococcus aureus induced osteomyelitis. Mean age was 38±4,2(26 to 53)). After radical surgical debridement and ultrasound cavitation, the bone cavity was full filled with Perosal pellets loaded with different antibiotics depending from the antibiotic sensitivity test. Endpoints were the absence of clinical manifestation of infection or disease recurrence, no need for further surgery. Results. In vitro showed after 24 hrs inhibition zone was 4,2 х 4,9 cm, after 72 hrs the inhibition zone was increased till 7,6 х 8,4 cm. During the subsequent time, there were no changes. Results of the clinical study evidenced no signs of infection in 18 patients (86% (CI 69,8;100)) (p<0,05) at the follow up, while 3 (14%(CI 0;30,2)) (p<0,05) subjects showed infection recurrence at 6 months from operation and 2 of them needed further surgical procedures. Conclusion. PerOssal as an antibiotic carrier stabilizes the action of the antibiotic. This antibiotic carrier system allows to choose an antibiotic individually for each patient according to the antibiotic sensitivity test and can be successfully used in clinical cases of osteomyelitis

Summary. An in vivo model of implant infection was developed to assess immune response. Titanium and PEEK implants were tested in the presence of an osteotomy and Staphylococcus aureus contamination. Immune response differed yet the outcome of contamination did not. Introduction. The presence of an implant increases infection risk by reducing the number of bacteria required to cause an infection. The nature or magnitude of this risk may be influenced by the implant material. A model of implant associated osteomyelitis was developed based upon the MouseFix. TM. model and the development of infection and immune responses associated with either titanium or PEEK implants was investigated. Methods. MouseFix. TM. titanium plates with or without Staphylococcus aureus contamination were used with a femoral osteotomy in C57bl/6 and BALB/c mice (ethical permission: 2012/15). C57bl/6 mice receiving titanium implants were sacrificed at seven time-points over 35 days after surgery (n=6 per group). In addition, PEEK implants in C57bl/6 mice and both titanium and PEEK implants in BALB/c mice were assessed at 1, 3 and 7 days. Bacteria from the implant, bone and soft-tissue were quantified. Cytokine levels in the bone, soft tissue and spleen were assessed. Lymph node cells were characterised for cytokine production by flow cytometry. Results. Bacterial contamination led to the development of chronic osteomyelitis. The bacterial counts showed an increase at day 1 followed by an initial decrease at early time-points in all conditions. However, after day 21 the bacterial load increased again. The materials caused differences in bacterial counts at day 3. In non-infected bone, IL-4, IL-6, IL-17A and KC production was elevated. In the local lymph node there was an increase of CD3+IL4+ cells. Infected bone presented a decrease in IL-4 levels, an early increase of IL-6 and IL-10 and a late increase in IL-17 and KC; additionally, CD3+IFN-gamma+ cells were increased at early time-points and after day 21. CD3+IL-17+ cells were increased between days 7 and 21. IL-4 and IL-10 producing lymphocytes were also elevated after day 14. When comparing the materials, PEEK stimulated an increase in IL-4 and a decrease in IL-17 type response compared to titanium. Discussion. Our results suggest a Th2-type response in uninfected and a Th17-type response in infected animals. The use of different materials altered the immune response but not the outcome of contamination

Summary Statement. A single, locally-delivered injection of a human placental product containing multipotent stromal cells reduced severity of infection in an immunosuppressed murine osteomyelitis model and eliminated infection in 25% of animals compared with 0% of controls without the use of antibiotics. Introduction. Implant–associated osteomyelitis is a serious orthopaedic condition and is particularly difficult to treat in immunosuppressed individuals. Despite great advancement in the field of biomaterials and pharmaceuticals, emerging patterns of antibiotic resistance, complex biofilm production and penetration of therapeutic concentrations of effective antibiotics into bone continue to represent unmet clinical challenges. The promise of adult multipotent stromal cells (MSCs) for tissue regeneration has been of intense interest in recent years. Among their many potential therapeutic uses, MSCs have also been shown to have direct antimicrobial properties. The objective of this study was to evaluate the efficacy of a locally–delivered human placental-based tissue product containing multipotent stromal cells (hAmSC) to reduce the severity of implant-associated Staphylococcus aureus osteomyelitis in an immunosuppressed murine model. We hypothesised that athymic mice with implant-associated osteomyelitis would have diminished infection following treatment with hAmSC as evidenced by decreased bioluminescence intensity and lower histologic scores for infection and bacterial load when compared to saline-treated controls. Methods. An athymic murine model of chronic implant-associated osteomyelitis was developed using luciferase-transfected Staphylococcus aureus to study the antimicrobial effects of a human placental-based product containing multi-potent stromal cells (hAmSC). Sixteen athymic mice had osteomyelitis established in the right femoral diaphysis. Fifteen days after inducing luc S. aureus osteomyelitis, the mice were randomised to receive a single 0.5 cc injection of hAmSC (n=8) or vehicle (0.9% saline) (n=8) into the soft tissues immediately adjacent to the infected bone. No antibiotics were administered throughout the duration of the study. Mice were imaged with an In Vivo Imaging System (IVIS 1000, PerkinElmer) twice weekly for 30 days to assess change in bioluminescence intensity from baseline immediately prior to treatment with either hAmSC or saline. Radiographs were obtained at days −10, 0, 10, 20 and 30 days post-injection and scored for bone changes secondary to osteomyelitis by a reviewer blinded to treatment group. Mice were sacrificed 30 days after treatment and femurs were examined histologically and scored for bacterial load and degree of inflammation by a pathologist blinded to treatment group. Results. Osteomyelitis was successfully established in all mice as evidenced by baseline bioluminescence imaging and radiographs. Mean bioluminescence intensity decreased from baseline in animals receiving hAmSC and remained below baseline for 28 days, whereas vehicle-treated animals showed an increase in mean bioluminescence intensity throughout the study period. Osteomyelitis resolved in 2/8 hAmSC-treated animals and 0/8 vehicle-treated animals as evidenced by bioluminescence imaging and histological examination for bacteria/inflammation at sacrifice. Radiograph scores for secondary bone changes were lower in mice treated with hAmSC than vehicle at 10, 20 and 30 days post injection. Median inflammatory score was lower in the hAmSC-treated mice than vehicle treated controls. Conclusions. A single injection of hAmSC was effective at reducing the severity of S. aureus infection without the use of antibiotics in this chronic implant associated osteomyelitis immunosuppressed murine model. In addition to reduced bioluminescence intensity below baseline for 28 days during the study period, infection was eliminated in 25% of animals in the hAmSC-treated group

Objectives

We have observed clinical cases where bone is formed in the overlaying muscle covering surgically created bone defects treated with a hydroxyapatite/calcium sulphate biomaterial. Our objective was to investigate the osteoinductive potential of the biomaterial and to determine if growth factors secreted from local bone cells induce osteoblastic differentiation of muscle cells.

We studied the effects of coating titanium implants with teicoplanin and clindamycin in 30 New Zealand White rabbits which were randomly assigned to three groups. The intramedullary canal of the left tibia of each rabbit was inoculated with 500 colony forming units of Staphylococcus aureus. Teicoplanin-coated implants were implanted into rabbits in group 1, clindamycin-coated implants into rabbits in group 2, and uncoated implants into those in group 3. All the rabbits were killed one week later. The implants were removed and cultured together with pieces of tibial bone and wound swabs. The rate of colonisation of the organisms in the three groups was compared.

Organisms were cultured from no rabbits in group 1, one in group 2 but from all in group 3. There was no significant difference between groups 1 and 2 (p = 1.000). There were significant differences between groups 1 and 3 and groups 2 and 3 (p < 0.001). Significant protection against bacterial colonisation and infection was found with teicoplanin- and clindamycin-coated implants in this experimental model.

Platelet-leucocyte gel (PLG), a new biotechnological blood product, has hitherto been used primarily to treat chronic ulcers and to promote soft-tissue and bone regeneration in a wide range of medical fields. In this study, the antimicrobial efficacy of PLG against Staphylococcus aureus (ATCC 25923) was investigated in a rabbit model of osteomyelitis. Autologous PLG was injected into the tibial canal after inoculation with Staph. aureus. The prophylactic efficacy of PLG was evaluated by microbiological, radiological and histological examination. Animal groups included a treatment group that received systemic cefazolin and a control group that received no treatment.

Treatment with PLG or cefazolin significantly reduced radiological and histological severity scores compared to the control group. This result was confirmed by a significant reduction in the infection rate and the number of viable bacteria. Although not comparable to cefazolin, PLG exhibited antimicrobial efficacy in vivo and therefore represents a novel strategy to prevent bone infection in humans.

Curettage and packing with polymethylmethacrylate cement is a routine treatment for giant-cell tumour (GCT) of bone. We performed an in vitro evaluation of the cytotoxic effect of a combination of cement and methotrexate, doxorubicin and cisplatin on primary cell cultures of stromal GCT cells obtained from five patients. Cement cylinders containing four different concentrations of each drug were prepared, and the effect of the eluted drugs was examined at three different time intervals.

We found that the cytotoxic effect of eluted drugs depended on their concentration and the time interval, with even the lowest dose of each drug demonstrating an acceptable rate of cytotoxicity. Even in low doses, cytotoxic drugs mixed with polymethylmethacrylate cement could therefore be considered as effective local adjuvant treatment for GCTs.