Objectives. The aim of this systematic literature review was to assess the clinical level of evidence of commercially available demineralised bone matrix (DBM) products for their use in trauma and orthopaedic related surgery. Methods. A total of 17 DBM products were used as search terms in two available databases: Embase and PubMed according to the Preferred Reporting Items for Systematic Reviews and Meta Analyses statement. All articles that reported the clinical use of a DBM-product in trauma and orthopaedic related surgery were included. Results. The literature search resulted in 823 manuscripts of which 64 manuscripts met the final inclusion criteria. The included manuscripts consisted of four randomised controlled trials (level I), eight cohort studies (level III) and 49 case-series (level IV). No clinical studies were found for ten DBM products, and most DBM products were only used in combination with other grafting materials. DBM products were most extensively investigated in spinal surgery, showing limited level I evidence that supports the use Grafton DBM (Osteotech, Eatontown, New Jersey) as a bone graft extender in posterolateral lumbar fusion surgery. DBM products are not thoroughly investigated in trauma surgery, showing mainly level IV evidence that supports the use of Allomatrix (Wright Medical, London, United Kingdom), DBX (DePuy Synthes, Zuchwil, Switzerland), Grafton DBM, or OrthoBlast (Citagenix Laval, Canada) as bone graft extenders. Conclusions. The clinical level of evidence that supports the use of DBM in trauma and orthopaedic surgery is limited and consists mainly of poor quality and retrospective case-series. More prospective, randomised controlled trials are needed to understand the clinical effect and impact of DBM in trauma and orthopaedic surgery. Cite this article: J. van der Stok, K. A. Hartholt, D. A. L. Schoenmakers, J. J. C. Arts. The available evidence on demineralised bone matrix in trauma and orthopaedic surgery: A systemati c review. Bone Joint Res 2017;6:423–432. DOI: 10.1302/2046-3758.67.BJR-2017-0027.R1

Addressing bone defects is a complex medical challenge that involves dealing with various skeletal conditions, including fractures, osteoporosis (OP), bone tumours, and bone infection defects. Despite the availability of multiple conventional treatments for these skeletal conditions, numerous limitations and unresolved issues persist. As a solution, advancements in biomedical materials have recently resulted in novel therapeutic concepts. As an emerging biomaterial for bone defect treatment, graphene oxide (GO) in particular has gained substantial attention from researchers due to its potential applications and prospects. In other words, GO scaffolds have demonstrated remarkable potential for bone defect treatment. Furthermore, GO-loaded biomaterials can promote osteoblast adhesion, proliferation, and differentiation while stimulating bone matrix deposition and formation. Given their favourable biocompatibility and osteoinductive capabilities, these materials offer a novel therapeutic avenue for bone tissue regeneration and repair. This comprehensive review systematically outlines GO scaffolds’ diverse roles and potential applications in bone defect treatment. Cite this article: Bone Joint Res 2024;13(12):725–740

Despite the increasing availability of bone grafting materials, the regeneration of large bone defects remains a challenge. Especially infection prevention while fostering regeneration is a crucial issue. Therefore, loading of grafting material with antibiotics for direct delivery to the site of need is desired. This study evaluates the concept of local delivery using in vitro and in vivo investigations. We aim at verifying safety and reliability of a perioperative enrichment procedure of demineralized bone matrix (DBM) with gentamicin. DBM (DBMputty, DIZG, Germany) was mixed with antibiotic using a syringe with an integrated mixing propeller (Medmix Systems, Switzerland). Gentamicin, as powder or solution, was mixed with DBM at different concentrations (25 −100 mg/g DBM), release and cytotoxicity was analyzed. For in vivo analysis, sterile drill hole defects (diameter: 6 mm, depth: 15 mm) were created in diaphyseal and metaphyseal bones of sheep (Pobloth et al. 2016). Defects (6 – 8 per group and time point) were filled with DBM or DBM enriched with gentamicin (50 mg/g DBM) or left untreated. After three and nine weeks, defect regeneration was analyzed by µCT and histology. The release experiments revealed a burst release of gentamicin from DBM independent of the used amount, the sampling strategy, or the formulation (powder or solution). Gentamicin was almost completely released after three days in all set-ups. Eluates showed an antimicrobial activity against S. aureus over at least three days. Eluates had no negative effect on viability and alkaline phosphatase activity of osteoblast-like cells (partially published Bormann et al. 2014). µCT and histology of the drill hole defects revealed a reduced bone formation with gentamicin loaded DBM. After nine weeks significantly less mineralized tissue was detectable in metaphyseal defects of the gentamicin group. Histological evaluation revealed new bone formation starting at the edges of the drill holes and growing into the center over time. The amount of DBM decreased over time due to the active removal by osteoclasts while osteoblasts formed new bone. Using this mixing procedure, loading of DBM was fast, reliable and possible during surgical setting. In vitro experiments revealed a burst and almost complete release after three days, antimicrobial activity and good biocompatibility of the eluates. Gentamicin/DBM concentration was in the range of clinically used antibiotic-loaded-cement for prophylaxis and treatment in joint replacement (Jiranek et al. 2006). The delayed healing seen in vivo was unexpected due to the good biocompatibility found in vitro. A reduced healing was also seen in spinal fusion where DBM was mixed with vancomycin (Shields et al. 2017), whereas DBM with gentamicin or DBM/bioactive glass with tobramycin had no negative effect on osteoinductivity or femur defect healing, respectively (Lewis et al. 2010, Shields et al. 2016). In conclusion, loading of DBM with gentamicin showed a proper antibiotic delivery over several days, covering the critical phase shortly after surgery. Due to the faster and complete release of the antibiotic compared to antibiotic loaded cement, the amount of antibiotic should be much lower in the DBM compared to cement

Summary Statement. Demineralised bone matrix augmented tendon-bone fixations in the animal model show less scar tissue and an enthesis morphology closer to the physiologic one which may lead to a more resistant repair construct. Introduction. Rotator cuff repair is one of the most common operative procedures in the shoulder. Yet despite its prevalence recurrent tear rates of up to 94% have been reported in the literature. High failure rates have been associated with tendon detachment from bone at the tendon – bone interface. Exogenous agents as biological strategies to augment tendon – bone healing in the shoulder represent a new area of focus to improve patient outcomes. Demineralised bone matrix (DBM) contains matrix bound proteins, exposed through acid demineralization step of DBM manufacture, and has long been recognised for its osteoinductive and osteoconductive properties. We hypothesised that DBM administered to the bone bed prior to the reattachment of the tendon, will upregulate healing and result in enhanced tissue morphology that more closely resembles that of a normal enthesis. An established ovine transosseous equivalent rotator cuff model was used. Methods. Following ethics approval, 10 adult wethers (18 months) were randomly allocated to control, n=4 (without DBM) or DBM, n=6 (DBM administered to bone bed) groups. The infraspinatus tendon was detached from its insertion and repaired in a transosseous equivalent fashion using PEEK suture anchors. In treatment animals 0.25cc of ovine DBM, previously prepared using a modified Urist protocol, was injected into two drill holes within the bony tendon footprint. Animals were culled at 4 weeks following surgery and processed for tissue histology and microcomputed tomography (μCT) endpoints. Results. No infection or tendon detachment following repair was noted in either group. 3D reconstructed images of μCT scans verified correct DBM and suture anchor placement. Histological images demonstrated distinct differences in tissue morphology between the two groups; however there was no evidence of the four – zoned structure characteristic of a healthy tendon bone insertion, in any specimens. In the control group specimens, the tendon midsubstance was highly disorganised with randomly arranged collagen fibres and diminutive areas of fibrocartilage. In the treatment group, large regions between tendon and bone were occupied by fibrocartilage. Within the fibrocartilage region, insertional collagen fibres appeared organised and chondrocytes were orientated in the direction of the insertional collagen fibres. Organised collagen fibre orientation within the tendon midsubstance was observed, though this was not consistent throughout all the specimens. DBM particles were resorbed and trabecular bone occupied the DBM holes. The PEEK anchors were all in direct contact with the ongrowing bone indicating good quality integration and fixation. Discussion. This study showed that DBM augmented tendon to bone repair leads to an upregulated cellular activity resulting in increased amounts of fibrocartilage between the repaired tendon and underlying bone. The upshot of this is an improved tissue organization which more closely resembles the morphology of the normal enthesis. Introduction of osteoinductive DBM at the tendon – bone interface during surgery may reduce failure rates associated with rotator cuff repair and improve clinical outcomes

Autologous bone graft has been used in the treatment of complex bone defects for more than a century. Morbidity associated with the harvest of this bone graft has led orthopaedic surgeons to seek alternative therapies in the treatment of long bone non-unions. The aim of this study was to determine whether the use of demineralised bone matrix as a bone healing adjunct improves clinical outcomes in adult patients with long bone non-union. A systematic search was carried out of the peer-reviewed English language literature to identify all relevant studies. The search strategy returned a total of 47 studies. Five of these studies were relevant to the research question. The studies were critically assessed and where appropriate combined in a meta-analysis. 4 non-comparative studies and one comparative study were reviewed. An overall estimate of the rate of union for the five studies was 86% (95%CI: 71–94%). The one comparative study demonstrated the relative risk (RR) of healing was not significantly better than in patients treated with autologous bone graft; RR=1.03 (95%CI 0.96–1.12). There are limited data to support the use of demineralised bone matrix in the treatment of long bone non-union. Demineralised bone matrix is likely to be similarly effective to other treatments in the management of non-union. This study confirms the clinical and ethical requirements to proceed with a randomised controlled trial to test the effectiveness of this intervention

Background. Re-attachment of tendon to bone is challenging with surgical repair failing in up to 90% of cases. Poor biological healing is common and characterised by the formation of weak scar tissue. Previous work has demonstrated that decellularised allogenic demineralised bone matrix (DBM) regenerates a physiologic enthesis. Xenografts offer a more cost-effective option but concerns over their immunogenicity have been raised. We hypothesised that augmentation of a healing tendon-bone interface with DBM incorporated with autologous mesenchymal stem cells (MSCs) would result in improved function, and restoration of the native enthesis, with no difference between xenogenic and allogenic scaffolds. Methods. Using an ovine model of tendon-bone retraction the patellar tendon was detached and a complete distal tendon defect measuring 1 cm was created. Suture anchors were used to reattach the shortened tendon and xenogenic DBM + MSCs (n=5) and allogenic DBM + MSCs (n=5) were used to bridge the defect. Functional recovery was assessed every 3 weeks and DBM incorporation into the tendon and its effect on enthesis regeneration was measured using histomorphometry. Results. By 12 weeks, DBM augmentation resulted in significantly improved functional weight bearing with no failures in either group. Compared to xenogenic DBM, allogenic DBM was associated with significantly higher functional weight bearing at 6 (P=0.047), 9 (P=0.028) and 12 weeks (P=0.009). This was accompanied by a more direct type of enthesis characterised by significantly more fibrocartilage and mineralised fibrocartilage. Xenograft was also associated with an immunogenic reaction despite preoperative decellularisation. Conclusion. This study shows that DBM enhances tendon-bone healing and may reduce the high failure rates associated with surgery. An immunogenic reaction, and inferior biomechanical and histological results were also associated with the use of xenograft. Allogenic DBM with autologous MSCs may be a suitable scaffold for the enhancement of tendon-bone healing in the clinical setting. Disclosures. Funded by IKC PoC grant awarded by the University of Leeds. Ethical approval. Granted by the study institution (University College London)

Demineralized bone matrix (DBM) is a natural, collagen-based, well-established osteoinductive biomaterial. Nevertheless, there are conflicting reports on the efficacy of this product. The purpose of this study was to evaluate whether DBM collagen structure is affected by particle size and can influence DBM osteoinductivity. Sheep cortical bone was ground and particles were divided in three fractions with different sizes, defined as large (L, 1–2 mm), medium (M, 0.5–1 mm), and small (S, < 0.5 mm). After demineralization, the three DBM samples were characterized by DTA analysis, XRD, ICP-OES, and FTIR. Data clearly showed a particle size-dependent alteration in collagen structure, with DBM-M being altered but not as much as DBM-S. The in vivo study showed that only DBM-M was able to induce new bone formation in a subcutaneous ectopic mouse model. When sheep MSC were seeded onto DBM particles before implantation, all DBM particles were able to induce new bone formation with the best incidence for DBM-M and DBM-S. Gene expression analysis performed on recovered implants supports the histological results and underlines the supportive role of MSC in DBM osteoinduction through the regulation of host cells. In conclusion, our results show a relation between DBM particle size, structural modification of the collagen and in vivo osteoinductivity. The medium particles represent a good compromise between no modification (largest particles) and excessive modification (smallest particles) of collagen structure, yielding highest osteoinduction. We believe that these results can guide researchers to use DBM particles of 0.5–1 mm size range in applications aimed at inducing new bone formation, obtaining results more comparable and reliable among different research groups. Furthermore, we suggest to carefully analyze the structure of the collagen when a collagen-based biomaterial is used alone or in association with cells to induce new bone formation

Introduction: The aim of this study was to develop a technique to decellularise a porcine cartilagebone construct with a view to using this as a biological scaffold for transplantation into human osteochondral defect as a cartilage substitute. Methods: Decellularisation was based on a modification of the technique of Booth et al (2002). Cartilage bone matrix (n=9) were decellularised by exposing the tissue to 2 cycles of dry freeze-thaw followed 2 more cycles with the addition of hypotonic (10mM tris-HCl, pH8.0) buffer. Samples were then cycled through hypotonic buffer, followed by ionic detergent (0.1% [w/v] sodium dodecyl sulphate [SDS]) in the presence of protease inhibitors (aprotinin 10 KIU/ml) and 0.1% (w/v) ethylene diamine tetraacetic acid (EDTA). This was followed by washes in PBS with aprotinin and incubation in nuclease solution containing DNase (50U/ml) and RNase (1U/ml). Decontamination using 0.1% (v/v) peracetic acid in PBS was then incorporated to achieve disinfection of the tissue samples. Finally, samples were washed in PBS. Three decellularisation protocols were used depending on the number of hypotonic/SDS cycles: this was either done once, three or six times referred to as DC1, DC3 and DC6 respectively. Fresh & decellularised cartilage were compared histologically using haematoxylin and eosin staining, to visualize cellular content, sirius red, to visualise collagen fibres & alcian blue, to visualise glycosaminoglycans (GAG). Immunohistochemistry staining for galactose-α-1,3-galactose (α-gal), collagen I, II & VI was performed for fresh and decellularised samples. DNA assay: Genomic DNA was extracted using a DNA isolation kit for tissues (Roche Applied Sciences). Collagen and DMB sulphated sugar assay, as described by Stapleton et al. (2008), were performed to measure collagen and GAG content. The biphasic property of fresh and decellularised cartilage was determined using a pin on plate indentation test. Results: H& E staining revealed the absence of visible whole cells. Sirius red stain gave evidence of the retention of collagen following decellularisation. In contrast, the acellular matrix showed evidence of loss of GAGs. There was no evidence of the expression of α-gal in the acellular scaffold. DNA analysis revealed the absence of genomic DNA in comparison to fresh tissues (ANOVA, p< 0.05). The decellularisation process had minimal effect on the collagen content of the cartilage. Nevertheless there was a significant difference in the sulphated sugar content of the fresh tissue when compared to the decellularised tissue (ANOVA, p< 0.05), indicating loss of 92% GAG. Biomechanical testing of decellularised tissues showed a significant change (ANOVA, p< 0.05) in comparison to the fresh cartilage. Discussion: In conclusion this study has generated data on the production of an acellular cartilage bone matrix scaffold for use in osteochondral defect repair. To our knowledge, this is the first study that has successfully removed whole cells and α-gal from xenogeneic cartilage and bone tissue. Future studies are required to investigate methods to recellularise the acellular matrix using an appropriate cell type and mechanical conditioning and to investigate replenishing GAG loss following decellularisation

Demineralized Bone Matrix (DBM) is currently used in various types of orthopaedic applications because of osteoconductive and osteoinductive properties. Fibrin glue is also used in cardiovascular and thoracic surgery due to its hemostatic, chemotactic and mitogenic properties. There is some possibility of being good biomaterial and biodegradable scaffold with DBM-fibrin glue mixture for bone void filler. After total hip replacement surgery, it takes long time to complete bone fusion. If patients have excess weight load after surgery, the artificial joint may not be adhered with patients’s bone. That is why surgeons have to use any effective treatments for bone fusion for patient’s safety. In order to adapt to these surgical sites, DBMs are shaped in blocks or granules and preferable in porous forms. Combining these DBMs with fibrin glue provides a moldable and self-hardening composite biomaterial. This material will be applied to total hip replacement surgery for the effective fusion between bone and artificial joint. The aim of this work is to study the osteogenic properties of this composite material using in vivo and ex vivo. In radiological study, the DBM composite had been absorbed during one week since implantation surgery and after two weeks, some radio-opaque spots were observed in implantation sites. In histology study, Bone tissue had formed exotically in contact with the surface of the appeared well-mineralized, forming trabeculae between the granules, and had characteristics similar to those of cancellous bone. Bone growth in the tissue engineered filled with DBM and fibrin glue materials increased with implantation time. In summary, these DBM and fibrin glue composites exhibited interesting biological and mechanical properties for filling large bone defect. These composites may be used in total hip replacement surgery for the effective filler between patient’s bone and artificial joint

We report our 4 years’ experience using of demineralized human bone matrix (DBM) in the treatment of complex pathology characterised by bone loss or less regenerating ability, such as congenital or secondary bone mal-union, osteomyelitis, aseptic prosthetic failure, complex bone loss fractures, etc. Considering the known limitations of autologous transplants (limited quantity, infections and fractures of donor sites, operative and bleeding time increase, abdominal herniations, etc.), we have searched in the literature for alternative materials that would be as similar to the osteoconduction and osteoinduction ability of autologous transplant as possible, respecting bio- and immunocompatiblity. Since May 2000 we have used DBM in 50 cases: the first 15 patients with mixed technique (DBM and autologous transplant) and then the other 35 only with DBM. We have controlled each patient clinically and by X-ray: average follow up 34 months. With the same type of pathology and operative technique we have observed a similar recovery with both techniques (DBM with or without autologous transplant); in addition, in patients treated with rigid osteo-synthesis or in patients with osteoporosis we have noted early bone regeneration and no complications with respect to rejection or to osteolysis at the surgical site. In our opinion, this confirms the good osteoconduction and osteoinduction ability of DBM

Despite the widespread use of demineralized bone matrix (DBM) allografts there are few clinical studies comparing DBM to iliac crest bone grafting (ICBG). A comparison of DBM to ICBG is presented in patients who underwent four corner fusions of the wrist by one surgeon using identical operating technique. The senior author’s first fourteen consecutive patients in which DBM was used for four corner fusion were compared with fourteen patients selected from a total of 48 patients in which ICBG was used. The ICBG group was matched for age, indication and healing impairing co-morbidities (mainly smoking). Patient radiographs from the 8th, 12th and 24th postoperative week follow up were digitized and blinded. Three orthopaedic surgeons, not involved in the patients care, rated the degree of bony union in a scale of 0 (no evidence of healing) to 3 (solid bony healing). The operating technique and fixation was identical in all patients. K-wires were removed at a mean of 8.2 weeks for DBM and 7.7 weeks for the ICBG group. All patients had a minimum follow-up of one year. All fusions healed both radiographically and clinically without complications. Review of the radiographs revealed significantly less visible healing at 8 weeks in the DBM group (mean score 1.50 versus 1.74 of the ICBG group, p< .05). Lower scores were also obtained for the DBM group at 12 and 24 weeks but they did not reach statistical significance. In this study both DBM and ICBG were equally effective in achieving solid bone union for intercarpal fusions. However, the statistical power of this series is not adequate to conclude that healing rates are equal between the two graft materials. The radiographic appearance of bridging bone lagged behind in the DBM group. The biological significance of this finding is not clear; it could indicate delayed mineralization at the fusion site. Such a delay may be significant in graft choice for patients with healing impairment

The purpose of this study was to understand the effects of terminal sterilisation and residual calcium on human demineralised bone matrix (DBM) in ectopic bone formation in nude rat. The intramuscular implantation of human DBM prepared by the Queensland Bone Bank (QBB) from four donors into eight male athymic rats was used to assess osteoinductivity. The DBM contained different levels of residual calcium and treated with or without gamma-irradiation at 11kGy. At 6 weeks post-implantation, calcium deposition was assessed by manual palpitation and radiological imaging. Tissue morphology and cellular interactions was analysed using various histological staining methods whilst protein expression of anabolic and catabolic biomarkers were examined through immunohistochemistry. All results were then analysed in qualitative, semi-quantitative and quantitative manners and tested for statistical significance. Bone formation was observed in all specimens at the gross level. This was confirmed by histology which revealed bony capsules surrounded by soft tissue in the muscle pockets and differences in tissue components. On a cellular level, variations in osteoclast expression were found between the two groups as well as amongst individual donors through statistical analysis which resulted in an imbalance of the expression of anabolic and catabolic markers. Furthermore, a positive relationship between residual calcium and new bone formation in gamma irradiated DBM samples was found. To date, no studies have compared the effect of calcium in gamma irradiated DBM. Our results suggest that gamma irradiation even at low doses and residual calcium may affect new bone formation. Taken together, this study stresses the importance of selecting ideal conditions for graft processing and the need to identify an optimal level of irradiation and remaining calcium levels that confers a balance between osteoinductivity and sterility

Introduction. Osteochondral defects (OCDs) of the talus are treated initially by arthroscopic bone marrow stimulation. For both large and secondary defects, current alternative treatment methods have disadvantages such as donor site morbidity or two-stage surgery. Demineralized bone matrix (DBM) was published for the treatment of OCDs of rabbit knees. Autologous platelet-rich plasma (PRP) may improve the treatment effect of DBM. We previously developed a goat model to investigate new treatment methods for OCDs of the talus. The aim of the current study was to test whether DBM leads to more bone regeneration than control OCDs, and whether PRP improves the effectiveness of DBM. Methods. A standardized 6-mm OCD was created in 32 ankles of 16 adult Dutch milk goats. According to a randomized schedule, 8 goats were treated with commercially available DBM (Bonus DBM, Biomet BV, Dordrecht, the Netherlands) hydrated with normal saline, and 8 were treated with the same DBM but hydrated with autologous PRP (DBM+PRP). The contralateral ankles (left or right) were left untreated and served as a control. The goats were sacrificed after 24 weeks and the tali were excised. The articular talar surfaces were assessed macroscopically using the international cartilage repair society (ICRS) cartilage repair assessment, with a maximum score of 12. Histologic analysis was performed using 5-μm sections, and histomorphometric parameters (bone% and osteoid%) were quantified on representative areas of the surface, center, and peripheral areas of the OCDs. Furthermore, μCT-scans of the excised tali were obtained, quantifying the bone volume fraction, trabecular number, trabecular thickness, and trabecular spacing in both the complete OCDs and the central 3-mm cylinders. Results. All goats recovered well and were able to bear full weight within 24 hours after surgery. The mean ICRS-score of the ankles treated with DBM was 8.0 ± 1.0, compared to a score of 8.4 ± 1.5 in the contralateral ankle (NS); those treated with DBM+PRP scored 6.9 ± 2.4, compared to 7.4 ± 2.0 in the contralateral ankle (NS). Histologic analysis showed four different patterns of healing, distributed evenly over the treatment and control groups: type 1 (n = 4), almost completely healed; type 2 (n = 11), restoration of the subchondral bone with a cystic lesion underneath; type 3 (n = 14), superficial defect with regeneration from the margins and bottom; type 4 (n = 3), no healing tendency. Histomorphometry and μCT revealed no statistically significant difference between treatment (DBM or DBM+PRP) and contralateral control or between both treatment groups in any of the parameters investigated. Conclusion. No treatment effect of DBM was found compared to control defects, and the addition of PRP was not beneficial

Aims: The evaluation of the results becoming from the use of demineralized bone matrix (DBM) in the bone defects. Methods: In the present study the above substance was implanted during the period 2000-2002 (28 months) to 24 patients, 11 males and 13 females average age 39,1 for the males and 60 for the females. As a cause was referred in 12 patients the fall, in 3 patients the car crash, in 5 patients the following the removal of osteosynthesis materials, in 2 patients the bone cysts, in 1 patient fracture of ankle joint following fusion and in 1 patient a pseudarthrosis. The implantation of DBM concerned 8 hips, 4 femurs, 6 knees, 1 humerus, 1 forearm, 1 ankle, 2 metacarpal and 1 phalanx. All the fractures as well the fusion were treated through internal fixation. There was a regular post op follow-up and concerned the clinical and x-ray examination per month until the total incorporation of the graft (12 weeks). Results: In all patients the total incorporation of the DBM was accomplished in a brief period of time, depended on the place of implantation without having local or systemic side effects. We have to remark the early signs of bone shadow around the 3rd week, as well the incorporation of the matrix around the 12th week in the x-ray findings. Conclusions: The use of DBM in bone defects could play an important role to the filling of bone defrects due to fractures or benign cysts as a result of its incorporation and without inducing local or systematic side effects

Aims: The evaluation of the results becoming from the use of demineralized bone matrix (DBM) in the bone defects. Methods: In the present study the above substance was implanted during the period 2000–2002 (28 months) to 24 patients, 11 males and 13 females average age 39.1 for the males and 60 for the females. As a cause was referred in 12 patients the fall, in 3 patients the car crash, in 5 patients following the removal of osteosynthesis materials, in 2 patients the bone cysts, in 1 patient fracture of ankle joint following fusion and in 1 patient a pseudarthrosis. The implantation of DBM concerned 8 hips, 4 femurs, 6 knees, 1 humerus, 1 forearm, 1 ankle, 2 metacarpal and 1 phalanx. All the fractures as well the fusion were treated through internal fixation. There was a regular post op follow-up and concerned the clinical and x-ray examination per month until the total incorporation of the graft (12 weeks). Results: In all patients the total incorporation of the DBM was accomplished in a brief period of time, depended on the place of implantation without having local or systemic side effects. We have to remark the early signs of bone shadow around the 3rd week, as well the incorporation of the matrix around the 12th week in the x-ray findings. Conclusions: The use of DBM in bone defects could play an important role to the filling of bone defects due to fractures or benign cysts as a result of its incorporation and without inducing local or systematic side effects

Introduction. Tendon injuries remain challenging, secondary healing and prolonged immobilisation result in suboptimal outcome. Previous study by our group showed that demineralised bone matrix (DBM) can result in faster healing of a tendon enthesis. The aim of this study is to test different ways augmenting tendon with DBM to enhance tendon repair and regeneration. Methods. DBM strips were prepared from tibias of mature ewes. Patella, patellar tendon and tibias were dissected and the distal 1 cm of the patellar tendon was excised. 4 models were designed;. Model-1, DBM strip was used to bridge the gap between the tendon and the tibial tuberosity. The DBM strip was stitched to the tendon using one bone anchor. Model-2, similar to model 1 with the use of 2 anchors. Model-3, similar to model 2, construct was off loaded by continuous thread looped twice through bony tunnels sited in the patella and in the tibial tuberosity. Model-4, similar to model 3 with 3 threads as off loading loop. All models were tested for pullout force and mode of failure. Results. The median failure force for model-1 (N=5) was 250N while for model-2 (N=5) was 290N. In model-3 and model-4 failure of the off loading loop was used as end point, 6 samples were tested in each model. Median failure force of model-3 was 767N and for model-4 was 934N. There was no statistical significance between model-1 and model-2 (p=0.249), however statistical significance was found between other models (p=< 0.006). Discussion. A study published in 1996 proved that cortical DBM can be used as ACL graft with evidence of ligamentisation. DBM provides a biologic scaffold with potential for use as ligament and tendon replacement. Our study shows that a tendon rupture can be augmented with DBM giving intial appropriate mechanical strength suitable for in-vivo use

Introduction. Demineralised Bone Matrix (DBM) is widely used in Orthopaedics and dentistry as a bone graft substitute and may be used to augment bone formation in load bearing applications. In this study we examine the effect of gamma irradiation and freeze drying on the tensile strength of Demineralised Cortical Bone (DCB). Methods. Tibias were harvested from mature ewes and cut into bony strips. Demineralisation was done using 0.6M HCL and confirmed by X-ray. Specimens were washed until a pH of 7.0 +/_ 0.2 was achieved in the washing solutions. Specimens were allocated into 4 groups; group (A) non freeze dried non gamma irradiated, group (B) freeze dried non gamma irradiated, group (C) non freeze dried gamma irradiated mention the level of gamma irradiation and group (D) freeze dried and gamma irradiated. The maximum tensile force and stress were measured. Statistical analysis using the Mann-Whitney U test was carried out. Results. The Median of maximum tensile force for group (A) was 218N, group (B) was 306N, group (C) was 263N and for group (D) was 676N. Group (D) results were statistically higher (p=< 0.05) compared to group (A) and (C), while there was no statistical significance compared to group (B). Conclusion. Previously published studies suggested the possibility of using DCB as ACL graft substitute. We examined the effect of gamma radiation as the most common sterilisation technique in medical field and the freeze drying as a possible technique for long term storage on the tensile strength of the DCB. Freeze drying significantly increases the tensile strength of the DCB while gamma irradiation has no significant effect. Our results indicate that freeze dried gamma irradiated DCB can be used as a ligament substitute

Introduction Experimental heterotopic bone formation in the canine urinary bladder has been observed for more than seventy years without revealing the origin of the osteoinductive signals. In 1931, Huggins demonstrated bone formation in a fascial transplant to the urinary bladder. Through an elaborate set of experiments, it was found that proliferating canine transitional epithelial cells from the urinary system act as a source of osteoinduction. Urist performed a similar series of experiments in guinea pigs as Huggins did in his canine model. After two weeks, mesenchymal cells condensed against the columnar epithelium and membranous bone with haversian systems and marrow began to form juxtapose the basement membrane. At no time was cartilage formation noted, only direct membranous bone formation. They also demonstrated the expression of BMP’s in migrating epithelium and suggested that BMP is the osteoinductive factor in heterotopic bone formation. Method This study was approved by Institutional Animal Ethics Committee. Six dogs underwent a mid-line laparotomy incision followed by mobilisation of a right sided myoperitioneal vascularised flap based on an inferior epigastric artery pedicle. A sagittal cystotomy is made in the dome of the bladder and the vascularised flap was sutured in place with acryl absorbable, continuous suture. The animals were sacrificed at 6 weeks. The bladder samples were removed and assessed by histology and immunohistochemistry. Sections were incubated with optimal dilution of primary antibody for type I collagen, type III collagen, alkaline phosphatase (ALP), bone morphogenetic protein (BMP)-2 and –4, osteocalcin (OCN), osteopontin (OPN), bone sialoprotein (BSP). Results The mechanism for bone formation induced by the epithelial-mesenchymal cell interactions is not clear. We were able to demonstrate mature lamellar bone formation 6 weeks after transplanting a portion of the abdominal smooth muscle into the bladder wall. The bone formed immediately adjacent to the proliferating transitional uroepithelium, a prerequisite for bone formation in Huggins’ model. Here we report evidence of cartilage formation and therefore endochondral ossification as well as membranous bone formation. This is very similar histologically to the process of endochondral ossification at the growth plate in the growing skeleton. We propose a mechanism for the expression of BMP by epithelial cells. Discussion This study demonstrates transitional epithelium induced formation of chondrocytes and osteoblasts in muscle tissue. The sequential expression of bone matrix proteins was related to cell proliferation, differentiation and formation of endochondral and membranous bone. Further information regarding the molecular mechanism of bone formation induced by epithelial-mesenchymal cell interactions will improve understanding of cell differentiation during osteogenesis

Aim: To assess the efþcacy of percutaneous reaming of simple bone cysts followed by administration of a mixture of autologous bone marrow combined with demineralized bone matrix. Material-methods: 10 patients (7 boys aged 10 years on average and 3 girls aged 12 years on average) with a bone cyst (3 patients at the femur, and 7 at the humerus), were treated with the same surgical technique. The diagnosis was based exclusively on imaging methods (X-ray, CT, MRI) and no biopsy was performed. Under general analgesia and image intensi-þer control the cystic cavity was aspirated. Should ßuid was encountered then a mixture of bone marrow and demineralized bone matrix (DBM) was injected after thorough reaming of the canal proximally and distally. None of the patients required overnight hospital stay. The limb was protected till the patient became asymptomatic. Results: The average follow-up time was 24 months (9–29 months). No perioperative complications were noted. All patients were asymptomatic at the last examination, with normal limb movement. All bone cysts were classiþed from an independent observer, according to the Neer classiþcation, as type I and II. Conclusion: Percutaneous administration of DBM combined with autologous bone marrow after restoring the continuity of the medullary canal with reaming is a simple surgical technique requiring no hospitalization and a short period of immobilization while the clinical and radiological outcome is excellent

Background: A common problem achieving lumbar spinal fusion is developing a pseudarthrosis. The current gold standard in achieving fusion is the use of autograft from pelvis or posterior elements of the spine. However the potential limitations of insufficient quantity and donor site morbidity have led to the use of bone graft alternatives such as DBM which contains osteoinductive BMPs. Aims & Methods: A prospective randomized control trial comparing the effectiveness of Demineralised Bone Matrix (DBM Putty)/autograft composite with autograft in lumbar postero-lateral or 270 degree spinal fusion. 35 patients were required for the study. They were randomized to have DBM and autograft on one side of the posterior approach and autograft alone on other side of the same approach. Patients were followed up with interval radiographs for total of 24mons. To date 32 patients have been recruited and with an average follow up a15.3 months. The mineralization of fusion mass lateral to the instrumentation on each side was graded as Absent, Mild (< 50%), Moderate (> 50%) or Complete fusion (100%). The assessment was made by independent orthopaedic consultant and a musculoskeletal radiologist who were blinded to graft assignment. Results: The sex distribution was 17:15 male to females with a mean age of 55.2 (21–87years) and an average follow up of 15.3mons (3–24mons). 50% of patients had single level fusion and the remainder had more than one level fusion. At 12months, on the side of DBM 28% had complete fusion, 65% had moderate fusion, and 7% had no fusion mass. During the same period on the other side (non DBM side) approx 25% did not show any sign of fusion. There was no correlation with number of levels, age or sex. Conclusions: Osteoinductive properties of DBM would appear to enhance the consolidation of the lumbar spinal fusion. DBM reduces the amount of harvested autograft graft and also minimises the morbidity of donor site complications