Bone Graft In Treatment Research Articles

In vivo performance of bilayer hydroxyapatite scaffolds for bone tissue regeneration in the rabbit radius

The objective of this study was to investigate the in vivo biomechanical performance of bone defects implanted with novel bilayer hydroxyapatite (HAp) scaffolds that mimic the cortical and cancellous organization of bone. The scaffolds maintained architectural continuity in a rabbit radius segmental defect model and were compared to an untreated defect group (negative control) and autologous bone grafts (positive control). Micro-CT evaluations indicated total bone and scaffold volume in the experimental group was significantly greater than the defect group but lesser than the autologous bone graft treatment. The flexural toughness of the scaffold and the autograft groups was significantly greater than the flexural toughness of the defect group. Interestingly, the absolute density of the bone mineral as well as calcium to phosphorus (Ca/P) ratio in that mineral for the scaffold and autograft contralateral bones was significantly higher than those for the defect contralaterals suggesting that the scaffolds contributed to calcium homeostasis. It was concluded from this study that new bone regenerated in the bilayer HAp scaffolds was comparable to the empty defects and while the HAp scaffolds provided significant increase in modulus when compared to empty defect and their flexural toughness was comparable to autografts after 8 weeks of implantation.

Enhancement of Bone Formation During Distraction Osteogenesis: Pediatric Applications

Delayed bone healing during distraction osteogenesis negatively affects clinical outcome. In addition to autologous bone grafting, several mechanical, chemical, biologic, and external treatment modalities may be employed to promote bone growth during distraction osteogenesis in the pediatric patient. Mechanical approaches include compressive loading of the distraction regenerate, increased frequency of small increments of distraction, and compression-distraction. Intramedullary nailing and submuscular plating can reduce the time in external fixation; however, these techniques are associated with technical difficulties and complications. Exogenous application of low-intensity pulsed ultrasound or pulsed electromagnetic fields may shorten the duration of external fixation. Other promising modalities include diphosphonates, physician-directed use (off-label use) of bone morphogenetic proteins, and local injection of bone marrow aspirate and platelet gel at the osteotomy site. Well-designed clinical studies are needed to establish safe and effective guidelines for various modalities to enhance new bone formation during distraction osteogenesis in children.

Methods to shorten the duration of an external fixator in the management of tibial infections

Massive segmental bone loss due to chronic osteomyelitis represents a considerable challenge to orthopedic surgeons and is a limb threatening condition. The only option available in such a clinical situation is segment transport using the Ilizarov technique of distraction osteogenesis; yet the most common problem in cases of bone transport with the Ilizarov technique in massive bone loss, is the long duration of the fixator. In addition to autologous bone grafting, several mechanical, biologic, and external physical treatment modalities may be employed to promote bone formation and maturation during segment transport in osteomyelitis patients. Mechanical approaches include compressive loading of the distraction regenerate, increased frequency of small increments of distraction, and compression-distraction. Intramedullary nailing and hemicorticotomy can reduce the time in external fixation; however, these techniques are associated with technical difficulties and complications. Exogenous application of low-intensity pulsed ultrasound or pulsed electromagnetic fields may shorten the duration of external fixation. Other promising modalities include diphosphonates, physician-directed use (off-label use) of bone morphogenetic proteins, and local injection of bone marrow aspirate and platelet gel at the osteotomy site. Well-designed clinical studies are needed to establish safe and effective guidelines for various modalities to enhance new bone formation during distraction osteogenesis after segment transfer.

External skeletal fixation technology to treat refractory nonunion in long bones following prior internal fixation

Objective To observe clinical outcomes of external skeletal fixation technology without bone graft in treatment of complex bone nonunion and defect following prior internal fixation. Methods From April, 2002 to December, 2008 in our hospital, a total of 17 patients with complex bone nonunion and bone defect were treated with external skeletal fixation withont bone graft. They were 12 men and 5 women,aged 11 to 50 years (average, 34. 7 years). The nonunion involved tibia in 10, femur in 5 and humerus in 2 cases. The duration for nonunion ranged from 8 to 21 months (average, 16.3 months). Bone defects ranged from 2. 5 to 11.0 cm (average, 3.5 cm) . End-to-end compression followed by lengthening and segmental bone transport by lengthening were conducted for the management. Twelve cases complicated with bone defect or limb shortening received epiphysiotomy to restore the limb length in the period of compressive fixation. The patients were followed regularly to assess their healing of nonunion and defects. Results According to clinical follow-up, all patients obtained fracture healing after a mean time of 5. 2 months (range, 3 to 21 months). The 12 patients with bone defects sustained a mean bone lengthening of 4. 8 cm, obtaining a balance in limb length. Their healing time ranged from 4 to 11 months (average, 5.2 months). Their mean bone union index was 32 d/cm.Conclusions The plastic external skeletal fixation can promote bone healing. Bone lengthening through epiphysiotomy can restore the balance in limb length without bone graft. Therefore, this tecnology is an effective treatment for complex bone nonunion and defect in long bones. Key words: External fixators; Fractures, ununited; Treatment outcome

Interphalangeal Joint Lengthening Arthrodesis for the Treatment of the Flail Toe

Flail toe is a bothersome complication following PIP resection arthroplasty, usually as a result of excessive bone resection. Patients complain of toe instability and catching on socks or shoes. We describe a PIP joint lengthening arthrodesis using structural bone graft for treatment of this condition. The results of 13 toe lengthening arthrodesis procedures in 13 patients were reviewed. Twelve patients were available for final followup, ranging from 6 to 70 (average, 31) months. Relief of instability symptoms occurred in all of the patients. The union rate was 75% (9/12 toes). Infection occurred in four patients, all treated successfully with oral antibiotics and pin removal when necessary. Two patients presented with ischemic complications in the tip of the toe which resolved spontaneously with good final results. Eleven of 12 patients were satisfied with the procedure and stated that they would do the surgery again. We believe toe lengthening arthrodesis is a good salvage operation for a flail toe following PIP resection arthroplasty.

Use of Distraction Osteogenesis to Change Endocranial Morphology in Unilateral Coronal Craniosynostosis Patients

The endocranial morphology of the skull base is an important factor in determining craniofacial asymmetry. Moreover, although the patency of cranial suture would be the first determining factor, unicoronal, unilambdoid synostosis and deformational plagiocephaly can also be differentiated by means of axis angulation of anterior and posterior cranial fossa. These findings indicate the importance of endocranial morphology in craniofacial asymmetry. The authors hypothesized that distraction of the skull base might cause stress on the skull base that could modify skull base angulation deformities. This study compared the distraction technique with traditional bone repositioning techniques for remodeling skull base axis deformities in synostotic plagiocephaly patients. The study recruited 19 unicoronal craniosynostotic patients, of whom seven underwent distraction treatment and 12 underwent traditional bone graft treatment. The authors found that both approaches resulted in successful outcomes in terms of exocranial morphology correction, but that the distraction technique may offer advantages over traditional methods. Moreover, the authors found that distraction did modify the skull base angulation. Distraction created more changes in the endocranial morphology. The average correction of skull base angulation with distraction was from 164.6 to 174.3 degrees, whereas the correction for the traditional technique was from 165.2 to 166.2 degrees. The amount of change in skull base axis was statistically significant according to the Mann-Whitney test (p < 0.001), but the change in cranial index of asymmetry was not (p = 0.363). The skull base axis in synostotic plagiocephaly, which is composed of the anterior and posterior cranial fossa, underwent greater correction using the distraction method.

Orthodontie Treatment Results following Grafting Autologous Mandibular Bone to the Alveolar Cleft in Patients with a Complete Unilateral Cleft

To analyze orthodontic treatment results following mandibular symphysis bone grafting and postoperative orthodontic treatment. Randomized selection of 75 patients out of 308 with unilateral cleft of lip, alveolus, and palate, operated upon according to protocol between 1990 and 2008 in the Wilhelmina Children's Hospital, Utrecht, The Netherlands. Goslon Yardstick rating changes of dental arch relationship. Significant agreement (p < .001) was observed between the two assessments carried out with an interval of 3 months (Cohen's kappa = .963, p < .001). Following mandibular bone grafting and orthodontic treatment in 65.3% of the patients, the aim of treatment (Goslon Yardstick groups 1 and 2) had been achieved. The applied before/after Goslon allocations showed high improvement significance (p < .001). Postoperative orthodontic treatment in patients following grafting with mandibular symphysis bone showed excellent results.

Ｌｅ Ｆｏｒｔ Ｉ型骨切り術により幅の広い顎裂を閉鎖した成人片側性口唇口蓋裂の１症例

The residual wide alveolar cleft often causes potential risk in bone grafting and prosthodontic treatment for cleft lip and palate patients. While performing cleft reduction, maxillary advancement is required because closure of the cleft space itself with orthodontic/orthognathic treatment will result in a crossbite. In this paper, we report the case of a 21-year 4-month old male with left cleft lip and palate. The patient had undergone orthodontic treatment once at another institute, and he visited our Orthodontic Clinic at the University Hospital of Dentistry, Tokyo Medical and Dental University with a chief complaint of residual cleft space. Overjet and overbite were both 2.0 mm and the intercuspation of the buccal segments was optimal. However, the residual cleft space was 14.5 mm with no history of bone grafting. The right maxillary lateral incisor lacked congenitally, and the left lateral incisor was a lingually malpositioned conical tooth. The midline of the maxillary had right deviation of 6.5 mm. A multibracket appliance was used for the presurgical orthodontic treatment and a Le Fort I osteotomy was performed when the patient was 22-years and 4-months old. During the operation, the left maxillary lateral incisor in the cleft area was extracted. A Twin-Track device was placed along with the maxillary dental arch to guide the surgical movement of the alveolar segments into place. After complete cleft closure was achieved along this splint, maxillary segments were fixed using mini-plates and bone grafting was simultaneously performed. After 2 years of post-surgical orthodontic treatment, acceptable occlusion was achieved and no further prosthetic treatment was required.

Swan-like memory connector combined with composite bone graft in treatment of refractory fracture of clavicle

Swan-like memory connector combined with composite bone graft in treatment of refractory fracture of clavicle

The effect of post heat treatment of hydroxyapatite-coated implants on the healing of circumferential coronal defects in dogs

The purpose of this study was to evaluate the effect of post heat treatment on HA coated implants in healing of circumferential bone defects and to compare the results with those of bone graft treatment. The results presented higher bone to implant contact in both post heat treatment group and bone graft group than no heat treatment group and the controls, with no significance between the groups. The post heat treated HA coated implants seemed to show better osseointegration with bone and produce beneficial effect in resolving the defects as comparable with bone graft treatment.

Dose dependent anabolic and anti-catabolic response after local zoledronate treatment of cancellous bone grafts A bone chamber study in rats

Dose dependent anabolic and anti-catabolic response after local zoledronate treatment of cancellous bone grafts A bone chamber study in rats

Percutaneous reduction combined with bone graft in treatment of displaced intra-articular calcaneal fractures

Objective To introduce the experience and key points of percutaneous reduction combined with bone graft to treat calcaneal fractures. Methods Percutaneous reduction and internal fixation combined with bone graft was performed from April 2004 to April 2006 on 15 cases (16 sides) with intra-articular calcaneal fractures including 13 males (14 feet) and 2 females (2 feet), with average age of 36. 6 years (24–61 years). All patients underwent radiography including lateral and axial views for calcaneus, oblique view for foot and three-dimensional CT imaging reconstruction. According to Sanders classification, there were 12 feet of type II(3 type IIa, 3 type IIb and 8 type IIc) and 2 feet of type IIIac. The length of calcaneus was recovered through traction by Steinmann pin which passed through calcaneal tubercle perpendicularly and the posterior facet was elevated until reduction by a curve scissors through an 0.5 cm incision along the primary fracture line of lateral calcaneus. The calcaneus was fixed with different cannulated cancellous screws according to the type of fractures. Then bone graft was injected to fill the defect of calcaneus through lateral incision. Results All patients were followed up for an average of 18.4 months (ranged, 12 to 34 months). No complication such as wound infection, screw breakage and calcaneum varus was found postoperatively. The average time for bone healing was 10 weeks. The results were excellent in 12 cases, good in 4 cases according to the American Orthopaedic Foot and Ankle Society (AOFAS) hindfoot score. The rate of excellent and good clinical results was 100%. The mean AOFAS hindfoot score in tongue type group (86.5±4.4) was better than in joint depression type group (81.2±1.7, P<0.05). Radiography showed basic restoration of Böhler's angle, Gissane's angle and calcaneal shape. Conclusion The combination of percutaneous reduction and injectable bone graft is suitable for surgical treatment of Sanders II and III type calcaneal fractures, with advantages of simple operation, fewer complications and good clinical results.

New Source of Muscle-Derived Stem Cells with Potential for Alveolar Bone Reconstruction in Cleft Lip and/or Palate Patients

Cleft lip and palate (CLP), one of the most frequent congenital malformations, affects the alveolar bone in the great majority of the cases, and the reconstruction of this defect still represents a challenge in the rehabilitation of these patients. One of the current most promising strategy to achieve this goal is the use of bone marrow stem cells (BMSC); however, isolation of BMSC or iliac bone, which is still the mostly used graft in the surgical repair of these patients, confers site morbidity to the donor. Therefore, in order to identify a new alternative source of stem cells with osteogenic potential without conferring morbidity to the donor, we have used orbicular oris muscle (OOM) fragments, which are regularly discarded during surgery repair (cheiloplasty) of CLP patients. We obtained cells from OOM fragments of four unrelated CLP patients (CLPMDSC) using previously described preplating technique. These cells, through flow cytometry analysis, were mainly positively marked for five mesenchymal stem cell antigens (CD29, CD90, CD105, SH3, and SH4), while negative for hematopoietic cell markers, CD14, CD34, CD45, and CD117, and for endothelial cell marker, CD31. After induction under appropriate cell culture conditions, these cells were capable to undergo chondrogenic, adipogenic, osteogenic, and skeletal muscle cell differentiation, as evidenced by immunohistochemistry. We also demonstrated that these cells together with a collagen membrane lead to bone tissue reconstruction in a critical-size cranial defects previously induced in nonimmunocompromised rats. The presence of human DNA in the new bone was confirmed by PCR with human-specific primers and immunohistochemistry with human nuclei antibodies. In conclusion, we showed that cells from OOM have phenotypic and behavior characteristics similar to other adult stem cells, both in vitro and in vivo. Our findings suggest that these cells represent a promising source of stem cells for alveolar bone grafting treatment, particularly in young CLP patients.

Local treatment of cancellous bone grafts with BMP-7 and zoledronate increases both bone formation and bone density. A bone chamber study in rats

Open Access This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the source is credited. DOI 10.3109/17453674.2011.566138 Background and purpose The remodeling of morselized bone grafts in revision surgery can be enhanced by an anabolic substance such as a bone morphogenetic protein (BMP). On the other hand, BMPs boost catabolism and might cause a premature resorption, both of the graft and of the new-formed bone. Bisphosphonates inactivate osteoclasts and can be used to control the resorption. We studied a combination of both drugs as a local admix to a cancellous allograft. Methods Cancellous bone allografts were harvested and freeze-dried. Either saline, BMP-7, the bisphosphonate zoledronate, or a combination of BMP-7 and zoledronate were added in solution. The grafts were placed in bone conduction chambers and implanted in the proximal tibia of 34 rats. The grafts were harvested after 6 weeks and evaluated by histomorphometry. Results Bone volume/total volume (BV/TV) was 50% in the grafts treated with the combination of BMP-7 and zoledronate and 16% in the saline controls (p < 0.001). In the zoledronate group BV/TV was 56%, and in the BMP group it was 14%. The ingrowth distance of new bone into the graft was 3.5 mm for the combination of BMP-7 and zoledronate and 2.6 mm in the saline control (p = 0.002). The net amount of retained remodeled bone was more than 4 times higher when BMP-7 and zoledronate were combined than in the controls. Interpretation An anabolic drug like BMP-7 can be combined with an anti-catabolic bisphosphonate as local bone graft adjunct, and the combination increases the amount of remaining bone after remodeling is complete.

Patient self‐evaluation of intra‐oral bone grafting treatment to the maxillary frontal region

Bone grafting to the anterior region of the maxilla is a treatment method often used for reconstruction after dental trauma when teeth have been lost. The purpose of this study was to interview patients who underwent bone grafting from the chin or lateral mandible to assess the patients' experiences, especially regarding morbidity of the donor site and their overall assessment of treatment and care. Twenty-six patients who had undergone bone grafting from the chin and lateral mandible regions before implant treatment were interviewed about their experiences of treatment and present status 3-5 years after surgery. The patients rated the quality of presurgical information, quality of care, postoperative discomfort, postoperative pain, present discomfort and satisfaction with the final results. The patients, in general, were positive to the presurgical information and the quality of care. Postoperative pain during the first week was rated higher when grafts were taken from the chin than from the lateral mandible. Patient satisfaction with the outcome was high 3-5 years after surgery. However, patients that underwent bone grafting from the lateral mandible rated discomfort significantly lower and satisfaction significantly higher than patients who underwent chin grafting. More discomfort was reported in patients where wide bone grafts had been taken from the chin. A high degree of patient satisfaction with treatment and outcome can be expected after intra-oral bone grafting. However, surgeons should be cognizant of and patients informed about the risks of morbidity, especially when harvesting wide bone grafts from the chin. If possible, a first-hand choice for the surgeon should be grafting from the lateral mandible before considering chin graft.

Mechanical and radiological assessment of the influence of rhTGFβ‐3 on bone regeneration in a segmental defect in the ovine tibia: Pilot study

Limitations in the use of autologous bone graft, which is the gold standard therapy in bone defect healing, drive the search for alternative treatments. In this study the influence of rhTGFbeta-3 on mechanical and radiological parameters of a healing bone defect in the sheep tibia was assessed. In the sheep, an 18-mm long osteoperiosteal defect in the tibia was treated by rhTGFbeta-3 seeded on a poly(L/DL-lactide) carrier (n = 4). In a second group (n = 4), the defect was treated by the carrier only, in a third group (n = 4) by autologous cancellous bone graft, and in a fourth group (n = 2) the defect remained blank. The healing process of the defect was assessed by weekly in vivo stiffness measurements and radiology as well as by quantitative computed tomographic assessment of bone mineral density (BMD) every 4 weeks. The duration of the experiment was 12 weeks under loading conditions. In the bone graft group, a marginally significant higher increase in stiffness was observed than in the PLA/rhTGFbeta-3 group (p = 0.06) and a significantly higher increase than in the PLA-only group (p = 0.03). The radiographic as well as the computed tomographic evaluation yielded significant differences between the groups (p = 0.03), indicating the bone graft treatment (bone/per area, 83%; BMD, 0.57 g/cm(3)) performing better than the PLA/rhTGFbeta-3 (38%; 0.23 g/cm(3)) and the PLA-only treatment (2.5%; 0.09 g/cm(3)), respectively. Regarding the mechanical and radiological parameters assessed in this study, we conclude that rhTGFbeta-3 has a promoting effect on bone regeneration. However, under the conditions of this study, this effect does not reach the potential of autologous cancellous bone graft transplantation.

Treatment of talar neck fractures with external fixators combined with vascularized bone graft

目的 探讨外固定支架联合带血管骨瓣植骨治疗距骨颈骨折的疗效.方法回顾性分析2004年1月～2005年3月收治的7例距骨颈骨折患者,按Hawkins分型:Ⅱ型6例,Ⅲ型1例,分别采用手法闭合复位(1例)和切开复位(6例)经皮空心螺钉内固定治疗,7例患者均在上述处理后加外固定支架跨关节固定联合带血管的骨瓣植骨治疗.术后观察骨愈合、骨坏死及后足功能情况.结果7例患者均获得随访,随访13～24个月,平均17个月.7例均获骨性愈合,无一例发生缺血性骨坏死.后足功能按Maryland评分系统进行评估,结果:优5例,良2例.1例合并距骨体骨折患者出现明显的胫距关节骨关节炎,最后行胫距关节融合术.结论外固定支架联合带血管骨瓣植骨能有效地防止距骨颈骨折后缺血性骨坏死,但远期效果尚须进一步观察。

Radiological quiz

The aim of this study was to assess fracture union and complications following use of dynamic hip screw (DHS) with internal bone grafting in treatment of unstable delayed presented intracapsular neck femur fractures in patients younger than 65 years of age.Thirty two patients with displaced intracapsular neck femur fractures(Garden III and IV, Pauwels III, with comminution) with delayed presentation (15–60 days) in the 45–65 year age group (mean 54.4±10.2 years) were included in this study. All patients were treated with dynamic sliding hip screw with closed cancellous bone grafting through a tunnel of a triple reamer. The average time to union was 3.8 months (3–5 months). Satisfactory union was achieved in all patients except two. One case developed avascular necrosis of the femoral head. Other complications were coxa vara in two, shortening of less than 10 mm in three cases but there were no cases of infection or implant failure. Excellent results were achieved in 27, good/fair in 4 and poor in 1 patient.Osteosynthesis with DHS and primary cancellous bone grafting in indicated cases is a simple, providing biological stimulation for early union. Failure in a particular case can be treated with any appropriate second procedure.

Additive Enhancement of Implant Fixation Following Combined Treatment with rhTGF- 2 and rhBMP-2 in a Canine Model

Gaps at the interface between implant and bone increase the risk of diminished implant fixation and eventual loosening. The purpose of the present study was to determine if combined use of recombinant human transforming growth factor-beta 2 (rhTGF-beta2) and bone morphogenetic protein 2 (rhBMP-2) led to greater implant fixation strength in the presence of interface gaps than the use of either growth factor alone. Twenty-eight skeletally mature adult male dogs received one porous-coated titanium implant in the proximal part of each humerus, for a total of fifty-six implantation sites. Spacers were used to establish an initial 3-mm gap between the implant and the host bone at all fifty-six sites. Forty-two implants were coated with hydroxyapatite-tricalcium phosphate and were used in three growth-factor-treatment groups in which the implants placed in the left humerus were loaded with 12 microg of rhTGF-beta2 (Group 1, seven animals), 25 microg of rhBMP-2 (Group 2, seven animals), or 12 microg of rhTGF-beta2 combined with 25 microg of rhBMP-2 (Group 3, seven animals). In these animals, the twenty-one implants that were placed in the right humerus were loaded with buffer only to serve as contralateral controls. In Group 4 (seven animals), the implants were not coated with hydroxyapatite-tricalcium phosphate, the gap in the left humerus was lightly packed with autogenous bone graft, and the gap in the right humerus was left empty to serve as a contralateral control. All animals were killed at twenty-eight days. The primary end points included three mechanical variables: fixation strength, interface stiffness, and energy to failure. Secondary end points included bone ingrowth and bone volume and trabecular architecture in the gap and in a region located 2 mm medial to the implantation site. The hydroxyapatite-tricalcium phosphate coating had no effect on implant fixation, bone ingrowth, or bone formation in the 3-mm gap. Individual growth factor treatments led to 2.3 to 3.2-fold increases in fixation strength and stiffness as compared with the values for the contralateral controls (p < 0.05). The combined growth factor treatment led to 5.7-fold increases in fixation strength and stiffness compared with the values for the contralateral controls (p < 0.01). Autogenous bone graft treatment was associated with 4.5 to 6.4-fold increases in implant fixation strength and stiffness as compared with the values for the contralateral controls (p < 0.01). Compared with the relevant contralateral controls, energy to failure was increased 3.5-fold in association with TGF-beta2 alone (p < 0.05), 4.5-fold in association with TGF-beta2 combined with BMP-2 (p < 0.01), and 2.5-fold in association with autogenous bone-grafting. As much as 63% of the variance in the mechanical end points was associated with variance in bone volume and architecture in the 3-mm gap and in the region of interest located 2 mm medial to the implantation site (p < 0.01). In this animal model, the combined use of TGF-beta2 and BMP-2 led to more secure mechanical fixation of the implant than did the use of either growth factor alone and demonstrated results that were similar to those associated with the use of autogenous bone graft.

Biokompatibilitätstestung unterschiedlich sterilisierter bzw. desinfizierter allogener Knochentransplantate im Vergleich zum Goldstandard der autologen Knochenspende - Eine „In-vitro”-Analyse der Immunmodulation

Repair of large skeletal defects using bone allografts has become a routine procedure in orthopaedic and trauma surgery. Different procedures of sterilisation (82.5 degrees C disinfection; 121 degrees C autoclaving; PES; Tutoplast; 25 kGy gamma irradiation) are available to inactivate bacteria and fungi, including their spores, as well as viruses in human bone allografts. The efficiency of these procedures has been proven. However, the effects on the cellular response are rarely investigated. This present in vitro study investigates the immunological answer of human bone marrow cells to human allogenous and autologous bone platelets which were sterilised by different methods. Human bone marrow cells and the bone platelets were harvested from patients undergoing a total hip replacement. All patients provided informed consent. Human bone platelets, 10 mm in diameter, 3 mm in height, were produced from femoral heads which were removed within the scope of total hip replacements. They were sterilised by different procedures or were disinfected (gamma radiotherapy, PES/ethanol treatment, Tutoplast procedure, 121 degrees C autoclaving, > 82.5 degrees C thermodisinfection). In addition, an autologous in vitro bone donation was simulated and compared with the allogenous bone grafts. Endobon was evaluated as a bovine hydroxyapatite ceramic. As control a human bone marrow cell culture without bone platelets was used. Over a period of four weeks the changes of the immunogenic cell populations were analysed in vitro (FACS analysis). Light and scanning microscopy were done to reveal morphological differences. As a vitality test the trypan-blue staining was performed. Light and scanning microscopy demonstrated large differences between the various sterilisation and disinfection methods. After 4 weeks the autologous bone platelets were completely covered with homogenously distributed human osteoblast like cells. The heat-sterilised/disinfected transplants demonstrated similar effects compared to the autologous bone grafts while the irradiated bone platelets demonstrated less cell coverage. 2/3 of the cells were vital on average after four weeks, with the exception of the irradiated bone platelets. The FACS analysis revealed in comparison to the control group provable differences in the immunological answer for the autologous bone donation as well as for the differently sterilised or disinfected allogenous bone grafts. The heat sterilisation or, respectively, disinfection methods compared to the autologous bone donation demonstrated almost similar in vitro effects. By far the worst results, characterised by an excessively increased portion of cytotoxic T-cells and a decreased amount of viable cells, were seen in the 25 kGy gamma irradiation samples. The results demonstrate the influence of the different sterilisation and disinfection procedures on the differentiation of human marrow cells (host). Similar in vitro effects were seen for the autologous and heat-treated bone platelets. The treatment of allogenous bone grafts with PES/ethanol and the Tutoplast procedures showed, just as Endobon, only low differences in comparison with the control cultures. The worse results in the case of the irradiated bone platelets may be explained by the production of free radicals which led to an excessive cell death.