Primary bone tumors are rare, complex and highly heterogeneous. Its diagnostic and treatment are a challenge for the multidisciplinary team. Developments on tumor biomarkers, immunohistochemistry, histology, molecular, bioinformatics, and genetics are fundamental for an early diagnosis and identification of prognostic factors. The personalized medicine allows an effective patient tailored treatment. The bone biopsy is essential for diagnosis. Treatment may include systemic therapy and local therapy. Frequently, a limb salvage surgery includes wide resection and reconstruction with endoprosthesis, biological or composites. The risk for local recurrence and distant metastases depends on the primary tumor and treatment response. Cancer patients are living longer and bone metastases are increasing. Bone is the third most frequently location for distant lesions. Bone metastases are associated to pain, pathological fractures, functional impairment, and neurological deficits. It impacts survival and patient quality of life. The treatment of metastatic disease is a challenge due to its complexity and heterogeneity, vascularization, reduced size and limited access. It requires a multidisciplinary treatment and depending on different factors it is palliative or curative-like treatment. For multiple bone metastases it is important to relief pain and increases function in order to provide the best quality of life and expect to prolong survival. Advances in nanotechnology, bioinformatics, and genomics, will increase biomarkers for early detection, prognosis, and targeted treatment effectiveness. We are taking the leap forward in precision medicine and personalized care

In chronically infected fracture non-unions, treatment requires extensive debridement to remove necrotic and infected bone, often resulting in large defects requiring elaborate and prolonged bone reconstruction. One approach includes the induced membrane technique (IMT), although the differences in outcome between infected and non-infectious aetiologies remain unclear. Here we present a new rabbit humerus model for IMT secondary to infection, and, furthermore, we compare bone healing in rabbits with a chronically infected non-union compared to non-infected equivalents. A 5 mm defect was created in the humerus and filled with a polymethylmethacrylate (PMMA) spacer or left empty (n=6 per group). After 3 weeks, the PMMA spacer was replaced with a beta-tricalcium phosphate (chronOs, Synthes) scaffold, which was placed within the induced membrane and observed for a further 10 weeks. The same protocol was followed for the infected group, except that four week prior to treatment, the wound was inoculated with Staphylococcus aureus (4×10. 6. CFU/animal) and the PMMA spacer was loaded with gentamicin, and systemic therapy was applied for 4 weeks prior to chronOs application. All the animals from the infected group were culture positive during the first revision surgery (mean 3×10. 5. CFU/animal, n= 12), while at the second revision, after antibiotic therapy, all the animals were culture negative. The differences in bone healing between the non-infected and infected groups were evaluated by radiography and histology. The initially infected animals showed impaired bone healing at euthanasia, and some remnants of bacteria in histology. The non-infected animals reached bone bridging in both empty and chronOs conditions. We developed a preclinical in vivo model to investigate how bacterial infection influence bone healing in large defects with the future aim to explore new treatment concepts of infected non-union

Treatment of bone infection often includes a burdensome two-stage revision. After debridement, contaminated implants are removed and replaced with a non-absorbable cement spacer loaded with antibiotics. Weeks later, the spacer is exchanged with a bone graft aiding bone healing. However, even with this two-stage approach infection persists. In this study, we investigated whether a novel 3D-printed, antibiotic-loaded, osteoinductive calcium phosphate scaffold (CPS) is effective in single-stage revision of an infected non-union with segmental bone loss in rabbits. A 5 mm defect was created in the radius of female New Zealand White rabbits. The bone fragment was replaced, stabilized with cerclage wire and inoculated with Staphylococcus aureus (MSSA). After 4 weeks, the infected bone fragment was removed, the site debrided and a spacer implanted. Depending on group allocation, rabbits received: 1) PMMA spacer with gentamycin; 2) CPS loaded with rifampin and vancomycin and 3) Non-loaded CPS. These groups received systemic cefazolin for 4 weeks after revision. Group 4 received a loaded CPS without any adjunctive systemic therapy (n=12 group1-3, n=11 group 4). All animals were euthanized 8 weeks after revision and assessed by quantitative bacteriology or histology. Covariance analysis (ANCOVA) and multiple regression were performed. All animals were culture positive at revision surgery. Half of the animals in all groups had eliminated the infection by end of study. In a historical control group with empty defect and no systemic antibiotic treatment, all animals were infected at euthanasia. There was no significant difference in CFU counts between groups at euthanasia. Our results show that treating an osteomyelitis with segmental bone loss either with CPS or PMMA has a similar cure rate of infection. However, by not requiring a second surgery, the use of CPS may offer advantages over non-resorbable equivalents such as PMMA

Introduction and Objective. Management of bone loss associated with bone contamination or infection represents a double biological and clinical challenge frequent in traumatology. The advent of new biomaterials can allow a different approach in the treatment of bone gap. The purpose of this study was to evaluate the prophylactic and therapeutic effectiveness of addition of a new absorbable bone substitute (BS) eluting different antibiotics in reconstruction of bone defects after infections and fractures with soft tissue damage. Materials and Methods. We conducted a review of patients with contaminated or infected bone defects treated using a new biomaterial, a porous composite of collagen matrices and Beta tricalcium phosphate (β TCP), able to provide a long-term release of different antibiotics. We have included treatment of osteomyelitis and osteosynthesis of exposed fracture (Gustilo Anderson 1–3b) or fractures with soft tissue damage and high risk of contamination. Surgical technique included debridement filling bone defect with BS eluting antibiotics, osteosynthesis (plate, nail, external fixator, kirschner wire), soft tissue coverage, and systemic antibiotic therapy. Radiographic and clinical data including complications (wound dehiscence, superficial or deep infection, osteomyelitis) were collected. Results. We treated 25 patients (21 male, 4 female) with mean age 47 yrs. (range 21–83). The locations treated (for incidence) was: 9 femurs (7 plates, 2 nail), 7 calcanei (one bilateral), 3 tibias, 2 forearms, 2 metatarsi, 2 hands, 1 elbow. 6 patients had large bone loss. 7 patients had bone infections (4 were Cierny Madern 4); 8 patients had osteosynthesis of exposed fractures Gustilo Anderson 1–3b (9 plate, one bilateral calcaneus). 8 patients had treatment for pseudoarthrosis of exposed fractures (6 femurs, 1 forearm, 1 metatarsus) and 3 patients a prophylactic treatment for calcaneal fractures with soft tissue damage. 4 deep infection were treated with multiple surgical debridement and new filling bone defect with BS eluting antibiotic with infection eradication. We have used a combination of vancomycin and gentamicin on 15 cases, vancomycin alone on 4 cases, combination of vancomycin and amikacin on 1 case and amikacin and Linezolid in a targeted multi drug resistance. At final follow-up functional outcome was good in all cases with bone healing. Conclusions. Extensive debridement is a fundamental requisite for eradication of bone infections and contamination. Filling of the bone void with loaded bio-composite eluting diversifiable local antibiotics with synergistic anti-biofilm activity is desirable. Treatment of this bone defects are advantaged when combining his reconstruction with BS and the possibility of release high antibiotic concentration at least for 10 days. This is an important complementing prophylactic and therapeutic antimicrobial option with adjuvant role to systemic therapy that enlarges the success rate

Fracture related infection remains a major challenge in musculoskeletal trauma surgery. Despite best practice, treatment strategies suffer from high failure rates due to antibiotic resistance and tolerance. Bacteriophages represent a promising alternative as they retain activity against such bacteria. However, optimal phage administration protocols remain unknown, although injectable hydrogels, loaded with phage and conventional antibiotics, may support conventional therapy. In this study we tested the activity of meropenem, and two newly isolated bacteriophages (ϕ9 and ϕ3) embedded within alginate-chitosan microbeads and a hydrogel. Antibiotic and phage stability and activity were monitored in vitro, over a period of 10 days. In vivo, the same material was tested in treatment of a 5-day old Pseudomonas aeruginosa infection of a tibial plate osteotomy in mice. Treatment involved debridement and 5 days of systemic antibiotic therapy plus: i- saline, ii-phages in saline, iii-phages and antibiotics loaded into a hydrogel (n=7 mice/group). To assess the efficacy of the treatments, the infection load was monitored during revision surgery with debridement of the infected tissue after 5,10 and 13 days (euthanasia) by CFU and PFU quantification. In vitro testing confirmed that the stability of meropenem and activity of ϕ9 and ϕ3, was not affected within the alginate beads or hydrogel over 10 days. The in vivo study showed that all mice receiving phages and antibiotics loaded into a hydrogel survived the infection with a reduction of the bacterial load in the soft tissue. Active phages could be recovered from the infected site at euthanasia (10. 4. PFU/g). The hydrogel loaded with bacteriophages and meropenem showed a positive result in locally reducing the infection load indicating a synergistic effect of the selected antimicrobials. Overall, our new strategy shows encouraging results for improving the treatment of antibiotic-resistant biofilm infections that are related to medical implants

We describe a case series using calcium sulphate bio composite with antibiotics (Cerament/Stimulan) in treating infected metalwork in the lower limb. Eight patients aged 22–74 (7 males, 1 female) presented with clinical evidence of infected limb metal work from previous orthopaedic surgery. Metal work removal with application of either cerement in 5 cases (10–20ml including 175mg–350mg gentamycin) or stimulan in 3 cases (10–20ml including either 1g vancomycin or clindamycin 1.2g or 100mg tigecycline) into the site was performed. Supplemental systemic antibiotic therapy (oral/intravenous) was instituted based on intraoperative tissue culture and sensitivity. Four patients had infected ankle metalwork, 2 patients infected distal tibial metalwork and 2 had infected external fixators. Metal work was removed in all cases. The mean pre operative CRP was 15.8mg/l (range 1–56mg/l). The mean postoperative CRP at 1 month was 20.5mg/l (range 2–98mg/l). The mean pre op WCC was 7.9×10. 9. (range 4.7–10.5 ×10. 9. ). Mean post op WCC at 1 month was 7.1×10. 9. (range 5.0–9.2×10. 9. ). The organisms cultured included enterobacter, staphylococcus aureus, staphylococcus epidermidis, staphylococcus cohnii, stenotrophomonas, acinetobacter, group B streptococcus, enterococcus and escherichia coli. No additional procedures were required in any case. All surgical wounds went on to heal uneventfully. Infection control and union was achieved both clinically and radiologically in all cases. Our results support the use of a calcium sulphate bio composite with antibiotic as an adjuvant for effective local infection control in cases with implant related bone sepsis. The technique is well tolerated with no systemic or local side effects. We believe that implant removal, debridement and local antibiotic delivery can minimise the need for prolonged systemic antibiotic therapy in such cases

Osteoporosis is an international health and financial burden of ever increasing proportions. Current treatments limit the rate of bone resorption and reduce fracture risk, however they are often associated with significant and debilitating side effects. The most commonly used therapies also do not stimulate osteoblast activity . 1,2,3. Much current research focus is aimed at the metabolic and epigenetic pathways involved in osteoporosis. MicroRNAs have been shown to play an important role in bone homeostasis and pathophysiological conditions of the musculoskeletal system. Up-regulation of specific microRNAs has been identified in-vivo in osteoporotic patients . 4,5. It is hypothesized that modulation of specific microRNA expression may have a key role in future targeted therapies of musculoskeletal diseases. The assessment and analysis of their potential therapeutic use in Osteoporosis is of great importance, due to the burden of the disease. We have developed a 3D osteoporotic model from human bone marrow, without the use of scaffold. Magnetic nanoparticles are utilised to form spheroids, which provides a closer representation of the in-vivo environment than monolayer culture. This model will provide the basis for analysing future microRNA experiments to assess the potential up-regulation of osteoblastogenesis without cessation of osteoclast activity. The results of initial monolayer and spheroid experiments will be presented. Optimisation of the osteoporotic bone marrow culture conditions, involving response to differentiation medias, analysis of adipose and bone markers and cell migration in spheroid culture will be displayed. Quantitative and qualitative results, including fluorescence microscopy and in cell western, assessing the monolayer and spheroid cultures will be presented. The development of a pseudo osteoporosis model from healthy bone marrow will also be discussed. This model will form a basis of future work on microRNA targeting. The development of improved therapies for osteoporosis is of great significance due to the predicted rise in incidence of the disease and associated fragility fractures. Targeted therapies, such as the manipulation of microRNA expression, offer the opportunity to increase osteoblastogenesis and decrease osteoclastogenesis, potentially without the associated side effects of older, systemic therapies. We believe our 3D human bone marrow derived osteoporotic model offers the closest relation to the in-vivo environment for assessment and manipulation of microRNA expression

Background. Antibiotic loaded bone cement spacers are used as an adjunct to treatment in 2-stage arthroplasty revisions. If release of the correct choice of antimicrobials is optimised, systemic therapy might be curtailed and emergence of resistance minimised. Aims: To determine the elution period of antimicrobials from bone cement with and without a copolymer, polyvinylpyrrolidone (PVP) and to limit resistance development by the use of two or more antimicrobials. Methods. Triclosan, gentamicin and clindamycin with and without (PVP) in CMW bone cement, was tested against six bacteria using serial plate transfer. Results. While there was little difference between clindamycin and clindamycin with PVP, and between gentamicin and gentamicin with PVP, there was marked enhancement of release of triclosan with PVP. Resistance developed when antimicrobials were used singly but not when used in combination. Conclusion. The addition of water soluble PVP was expected to enhance elution of antimicrobials from bone cement. This occurred with triclosan, a poorly water-soluble agent, but there was no significant difference for gentamicin and clindamycin, which as preferentially water -soluble. Other copolymers are being explored in an attempt to enhance their release. Triclosan used in combination extended the duration of activity against the test bacteria without development of resistance. Combinations of antimicrobials reduce the risk of paradoxical resistance in bone cement

Device-associated infection remains a serious clinical problem in orthopaedic and trauma surgery. The emergence of resistant organisms such as methicillin resistant Staphylococcus aureus (MRSA) has further exacerbated this problem by limiting the range of treatment options. Currently, systemic antibiotic therapy is the cornerstone of treatment, alongside surgical resection of infected tissues and implant removal. The potential for antibiotic loaded biomaterials to support the prevention and treatment of infection is significant, although the currently available options are limited in number and often re-purposed from other applications e.g. antibiotic loading of bone cement. The first part of the talk will cover the basic concepts involved in antibiotic treatment, with an emphasis on the ideal antibiotic release kinetics from biomaterials, and how bacterial biofilms and antibiotic resistance influence antimicrobial efficacy. The next generation of biomaterials for antibiotic delivery should be specifically designed with this knowledge in mind. Regulatory approval of antimicrobial combination devices, however, is an evolving process as regulatory bodies seek more robust and clinically relevant efficacy data. Approval will require preclinical efficacy using standardized animal models that recapitulate the key features of the clinical disease. The second part of this talk will cover best practice in this important stage of development

To prevent infections after orthopedic surgery, intravenous antibiotics are administered perioperatively. Cefazolin is widely used as the prophylactic antibiotic of choice. Systemic antibiotic therapy may however be less effective in longstanding surgery where bone allografts are used. Bone chips have been shown to be an effective carrier for certain types of antibiotics. Bone allografts impregnated with antibiotics may therefore provide the necessary local antibiotic levels for prophylaxis. To be efficient, a prolonged release from these bonechips is required. In contrast to vancomycin, for which prolonged release has clearly been proven effective from Osteomycin®, a commercially available impregnated bone allograft, no prolonged release bone chip preparations have been described so far for cefazolin. We developed a protocol to bind cefazolin in the porous structure of bone chips by means of a hydrogel composed of proteins naturally present in the human body. Three types of bone chips were evaluated: fresh frozen, decellularized frozen and decellularized lyophilized. Bone chips were incubated with 20 mg/ml cefazolin or treated with liquid hydrogel containing either 1 mg/ml fibrin or 1 mg/ml collagen and 20 mg/ml cefazolin. The cefazolin hydrogel was distributed in the porous structure by short vacuum treatment. Bone chips with cefazolin but without hydrogel were either incubated for 20 min- 4h or also treated with vacuum. Cefazolin elution of bone chips was carried out in fetal bovine serum and analyzed by Ultra Performance Liquid Chromatography – Diode Array Detection. Soaking of bone chips without hydrogel resulted in a quick release of cefazolin, which was limited to 4 hours. When vacuum was applied elution of >1 µg/ml cefazolin was measured for up to 36 hours. Combination with collagen hydrogel resulted in a higher cefazolin concentration released at 24 hours (3.9 vs 0.3 µg/ml), but not in a prolonged release. However, combination of decellularized frozen bone chips with fibrin hydrogel resulted in an initial release of 533 µg/ml followed by a gradual decline reaching the minimal inhibitory concentration for S. aureus at 72 hours (1.7 µg/ml), while not measurable anymore after 92 hours. Processed bone chips with hydrogel-cefazolin showed a markedly prolonged cefazolin release. When combined with a fibrin hydrogel, high initial peak levels of cefazolin were obtained, followed by a decreasing release over the following three days. This elution profile is desirable, since high initial levels are important to maximize anti-bacterial action whereas low levels of antibiotic for a limited time may stimulate osteogenesis. It is important that antibiotic release is ending after a few days as prolonged low levels of antibiotics are not clinically helpful and may lead to antibiotic resistance. Further preclinical studies are warranted to show effectiveness of hydrogel-cefazolin impregnated bone chips

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.

We used a goat model of a contaminated musculoskeletal defect to determine the effectiveness of rapidly-resorbing calcium-sulphate pellets containing amikacin to reduce the local bacterial count. Our findings showed that this treatment eradicated the bacteria quickly, performed as well as standard polymethylmethacrylate mixed with an antibiotic and had many advantages over the latter. The pellets were prepared before surgery and absorbed completely. They released all of the antibiotic and did not require a subsequent operation for their removal. Our study indicated that locally administered antibiotics reduced bacteria within the wound rapidly. This method of treatment may have an important role in decreasing the rate of infection in contaminated wounds.