A number of techniques have been developed to improve the immediate mechanical anchorage of implants for enhancing implant longevity. This issue becomes even more relevant in patients with osteoporosis who have fragile bone. We have previously shown that a dynamic hip screw (DHS) can be augmented with a calcium sulphate/hydroxyapatite (CaS/HA) based injectable biomaterial to increase the immediate mechanical anchorage of the DHS system to saw bones with a 400% increase in peak extraction force compared to un-augmented DHS. The results were also at par with bone cement (PMMA). The aim of this study was to investigate the effect of CaS/HA augmentation on the integration of a different fracture fixation device (gamma nail lag-screw) with osteoporotic saw bones. Osteoporotic saw bones (bone volume fraction = 15%) were instrumented with a gamma nail without augmentation (n=8) or augmented (n=8) with a CaS/HA biomaterial (Cerament BVF, Bonesupport AB, Sweden) using a newly developed augmentation method described earlier. The lag-screws from both groups were then pulled out at a displacement rate of 0.5 mm/s until failure. Peak extraction force was recorded for each specimen along with photographs of the screws post-extraction. A non-parametric t-test was used to compare the two groups. CaS/HA augmentation of the lag-screw led to a 650% increase in the peak extraction force compared with the controls (p<0.01). Photographs of the augmented samples shows failure of the saw-bones further away from the implant-bone interface indicating a protective effect of the CaS/HA material. We present a novel method to enhance the immediate mechanical anchorage of a lag-screw to osteoporotic bone and it is also envisaged that CaS/HA augmentation combined with systemic bisphosphonate treatment can lead to new bone formation and aid in the reduction of implant failures and re-operations

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

Bone turnover and microdamage are impacted by skeletal metastases which can contribute to increased fracture risk. Treatments for metastatic disease may further impact bone quality. This study aimed to establish an understanding of microdamage accumulation and load to failure in healthy and osteolytic vertebrae following cancer treatment (stereotactic body radiotherapy (SBRT), zoledronic acid (ZA), or docetaxel (DTX)). Forty-two 6-week old athymic female rats (Hsd:RH-Foxn1rnu, Envigo) were studied; 22 were inoculated with HeLa cervical cancer cells through intracardiac injection (day 0). Animals were randomly assigned to four groups: untreated (healthy=5, osteolytic=6), SBRT on day 14 (healthy=6, osteolytic=6), ZA on day 7 (healthy=4, osteolytic=5), and DTX on day 14 (healthy=5, osteolytic=5). Animals were euthanized on day 21. L1-L3 motion segments were compression loaded to failure and force-displacement data recorded. T13 vertebrae were stained with BaSO. 4. and µCT imaged (90kVp, 44uA, 4.9µm) to visualize microdamage location and volume. Damage volume fraction (DV/BV) was calculated as the ratio of BaSO. 4. to bone volume. Differences in mean load-to-failure were compared using three-way ANOVA (disease status, treatment, cells injected). Differences in mean DV/BV between treatment groups were compared using one-way ANOVA. Treatment had a significant effect on load-to-failure (p=0.004) with ZA strengthening the healthy and osteolytic vertebrae. Reduced strength post SBRT seen in the metastatic (but not the healthy) group may be explained by greater tumor involvement secondary to higher cell injection concentrations. Untreated metastatic samples had higher DV/BV (16.25±2.54%) compared to all treatment groups (p<0.05) suggesting a benefit of treatment to bone quality. Focal and systemic cancer treatments were shown to effect load-to-failure and microdamage accumulation in healthy and osteolytic vertebrae. Developing a better understanding of how treatments effect bone quality and mechanical stability is critical for effective management of patients with spinal metastases

Summary Statement. The present study demonstrates the beneficial effects of strontium (Sr) modified calcium phosphate cement to improve new bone formation in a metaphyseal osteoporotic fracture defects in rats compared to calcium phosphate cement and empty defects. Keywords: strontium, fracture, calcium phosphate, bone formation. Introduction. Impaired fracture healing with subsequent implant failure is a dramatic problem in osteoporotic fractures. Biomaterials are of interest to stimulate fracture healing in osteoporotic defects and the objective of the current study is to investigate the effects of Strontium modified calcium phosphate cement (SrCPC) in a critical-size metaphyseal fracture defect of osteoporotic rats compared to calcium phosphate (CPC) and empty defect control group. Methods. 45 female Sprague-Dawley rats were randomized into 3 groups: SrCPC, CPC and empty defect (n=15 for each). A combinatorial approach of multi-deficiency diet for 3 months after bilateral ovariectomy was used for induction of osteoporosis. Left femur of all animals underwent a 4mm wedge-shaped metaphyseal osteotomy that was internally fixed with a T-shaped plate. The defect was then either filled with CPC or SrCPC and internally stabilised with a T shaped mini-plate. Empty defect served as a control. After 6 weeks femora were harvested followed by histological, histomorphometrical, immunohistochemical (bone-morphogenic protein 2, osteocalcin and osteoprotegerin), and molecular biology analysis (alkaline phosphatase, collagen10a1 and osteocalcin) to demonstrate the effects of the biomaterials on new bone formation. Time of flight secondary ion mass spectrometry (TOF-SIMS) technology was used to assess the distribution of released strontium ions and calcium appearance of newly formed bone. Results. Histomorphometric analysis showed a statistically significant increase in the bone formation at the tissue-implant interface in the SrCPC group (p<0.001). A statistically significantly more cartilage and unmineralised bone formation was also seen in the SrCPC group in comparision to the CPC group alone (p<0.05) and also to the empty defect (p<0.05) in the former fracture defect zone. These data were confirmed by the immunohistochemistry results which revealed an increase in bone-morphogenic protein 2, osteocalcin and osteoprotegerin and an increase in expression of genes responsible for bone formation viz. alkaline phosphatase, collagen10a1 and osteocalcin. TOF-SIMs analysis showed a higher release of Sr from the SrCPC into the interface region and related to a higher calcium content in this area compared to CPC. Discussion/Conclusion. SrCPC treatment showed enhanced new bone formation in a metaphyseal osteoporotic fracture defect of rats after 6 weeks compared to CPC-filled and empty defects in histomorphometry, immunochemistry and gene expression analysis. Strontium ranelate is a well-known anti-osteoporotic drug increasing bone formation and reducing bone resorption. As revealed by TOF-SIMS release of Sr out of the the SrCPC cement is most likely attributable for new bone formation. Therefore, Sr seems to be a good candidate not only for systemic treatment in osteoporosis but also in Sr-modification of biomaterials for local stimulation of new bone formation in osteoporotic fracture defects

Background. Multiple Myeloma is a hematological malignancy of terminally differentiated plasma cells associated with increased osteoclast activity and decreased osteoblast functions. Systemic antiproliferative treatment includes proteasome inhibitors such as bortezomib, a clinical potent antimyeloma agent. Local delivery of biological active molecules via biomaterial composite implants to the site of the lesion has been shown to be beneficial for bone and implant-associated infections. In anticancer treatment local delivery of anticancer agents to the neoplasia via biomaterial carriers has never been reported before. The purpose of the current is to present the concepts and the first in vivo results for proteasome inhibitor composite biomaterials for local delivery of bortezomib to proliferative multiple myeloma bone lesions including concentration measurements at different anatomical regions in a rat model. Methods. 80 female Sprague-Dawley rats were randomised into five different treatment groups (n=16/group): 1) Empty (2) Xerogel-granulat: XG (3) Xerogel-granulat+100mgbortezomib [b]: XG100b (4) Xerogel-granulat+500mgb:XG500b (5) Xerogel-granulat+2500mgb:XG2500b. A 2.5 mm drill hole was then created in the metaphysis of the left femur. The defect was then either filled with the previously mentioned substitutes or left empty to serve as a control. After 4 weeks femora were harvested followed by histological, histomorphometrical and immunohistochemical (BMP2; bone-morphogenic protein 2, OPG; osteoprotegerin, RANKL; Receptor activator of nuclear factor kappa-B ligand, ASMA; alpha smooth muscle actin, ED1;CD68 antibody). TOF-SIMS was used to assess the distribution of released strontium ions. Statistical analysis was done using SPSS software. Data was not found normally distributed and hence Mann-Whitney U with bonferroni correction was used. To avoid type I errors due to unequal variances and group sizes Games-Howell test was also performed

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

Introduction. In osteonecrosis of the femoral head (ONFH), progression of collapse is influenced by a repair reaction, especially bone resorptive activity, around the necrotic bone. Alendronate is a potent inhibitor of bone resorption by inhibiting osteoclast activity. We performed a clinical study to test if systemic alendronate treatment would prevent the development of collapse in patients with ONFH. Methods. Thirty-three hips in 22 ONFH patients with initial ARCO Stage 1 to 3 were included. Fourteen patients (20 hips) received daily administration of oral alendronate 5mg/day (alendronate group) and 8 patients (13 hips) did not receive alendronate administration (Control group). Baseline investigations included anteroposterior and lateral plain radiographs, T1-weighted magnetic resonance imaging (MRI), and biochemical markers (urinary NTX and serum BAP). Examination of the biochemical markers were repeated at 3, 6, and 12 months, and MRI imaging was repeated at 12 months. At 3 years, clinical symptoms and findings on plain radiographs were compared between the 2 groups. Advancement of ARCO stages or increase of collapse by more than 2 mm were considered as development of collapse. Results. At baseline, there were no significant differences regarding patients' age, distribution of gender, etiology, ARCO radiographic stage, and extent of necrosis between the 2 groups. In the alendronate group, there was an early decrease of osteoclast activity (NTX) and osteoblastic activity (BAP) at 3 months, with significantly larger decrease in NTX (43%) than BAP (21%) at 12 months. At 3 years, development of collapse was observed in 7 hips (54%) of the Control group, and in 3 hips (15%) of the alendronate group. Hip pain was noted in 9 hips (69%) of the Control group, and in 6 hips (30%) of the alendronate group. There was a significant difference oncollapse development and occurrence of hip pain between the two groups (p<0.05). Signal change around the necrotic region on serial MRI images during the first 1 year was observed in 54 % of the Control group, and only 11% of the alendronate group. Conclusion. Alendronate therapy decreased biochemical markers, especially osteoclast activity, after an early period from start of administration. Several clinical studies have shown promising short-term results for prevention of collapse in ONFH by administration of bisphosphonates. The present study showed a significant preventing effect of collapse development by administration of alendronate which was maintained for 3 years of treatment. Low incidence of signal change on serial MRI images may also reflect decrease of repair activity in the alendronate group. Further studies with longer follow-up, larger numbers of patients, and randomized administration of the drug among patients are required., However, alendronate administration may become one of the effective conservative treatments which might obviate the need for osteotomy or replacement surgery in some populations of ONFH patients

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.

Soaking bone grafts in a bisphosphonate solution before implantation can prevent their resorption and increase the local bone density in rats and humans. However, recent studies suggest that pre-treatment of allografts with bisphosphonate can prevent bone ingrowth into impaction grafts. We tested the hypothesis that excessive amounts of bisphosphonate would also cause a negative response in less dense grafts. We used a model where non-impacted metaphyseal bone grafts were randomised into three groups with either no bisphosphonate, alendronate followed by rinsing, and alendronate without subsequent rinsing, and inserted into bone chambers in rats. The specimens were evaluated histologically at one week, and by histomorphometry and radiology at four weeks. At four weeks, both bisphosphonate groups showed an increase in the total bone content, increased newly formed bone, and higher radiodensity than the controls. In spite of being implanted in a chamber with a limited opportunity to diffuse, even an excessive amount of bisphosphonate improved the outcome. We suggest that the negative results seen by others could be due to the combination of densely compacted bone and a bisphosphonate.

We suggest that bisphosphonates are likely to have a negative influence where resorption is a prerequisite to create space for new bone ingrowth.

In an attempt to increase the life of cementless prostheses, an hydroxyapatite-coated implant which releases a bisphosphonate has been suggested as a drug-delivery system. Our in vitro study was designed to determine the maximum dose to which osteoblasts could be safely exposed.

Our findings demonstrated that zoledronate did not impair the proliferation of human osteoblasts when used at concentrations below 1 μm. Murine cells can be exposed to concentrations as high as 10 μm.

A concentration of 0.01% of titanium particles did not impair the proliferation of either cell line. Zoledronate affected the alkaline phosphatase activity of murine osteoblasts through a chelation phenomenon. The presence of titanium particles strongly decreased the alkaline phosphatase activity of murine osteoblasts. We did not detect any synergic effect of zoledronate and titanium particles on the behaviour of both human and murine osteoblasts.

Ciprofloxacin hydrochloride-loaded microspheres were prepared by a spray-drying method using pectin and chitosan. The effects of different polymers and drug ratios were investigated.

The most appropriate carriers were selected by in vitro testing. A rat methicillin-resistant Staphylococcus aureus osteomyelitis model was used to evaluate the effects of the loaded microspheres.

The drug was released rapidly from the pectin carrier but this was more sustained in the chitosan formulation.

Chitosan microspheres loaded with ciprofloxacin hydrochloride were more effective for the treatment of osteomyelitis than equivalent intramuscular antibiotics.

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.

We evaluated the possible induction of a systemic immune response to increase anti-tumour activity by the re-implantation of destructive tumour tissue treated by liquid nitrogen in a murine osteosarcoma (LM8) model. The tumours were randomised to treatment by excision alone or by cryotreatment after excision. Tissue from the tumour was frozen in liquid nitrogen, thawed in distilled water and then re-implanted in the same animal. In addition, some mice received an immunological response modifier of OK-432 after treatment. We measured the levels of interferon-gamma and interleukin-12 cytokines and the cytotoxicity activity of splenocytes against murine LM8 osteosarcoma cells. The number of lung and the size of abdominal metastases were also measured.

Re-implantation of tumour tissue after cryotreatment activated immune responses and inhibited metastatic tumour growth. OK-432 synergistically enhanced the anti-tumour effect. Our results suggest that the treatment of malignant bone tumours by reconstruction using autografts containing tumours which have been treated by liquid nitrogen may be of clinical value.