Particle size influence in an impaction bone grafting model. Comparison of fresh-frozen and freeze-dried allografts

BackgroundImpaction bone grafting with large particles is considered as mechanically superior to smaller morsels. Interest of freeze-dried irradiated bone for impaction bone grafting has been observed with small particles. Influence of bone process on other particle sizes still needed to be assessed.Material and methodsTwenty-four osteoarthrotic femoral heads were used to prepare fresh-frozen and freeze-dried irradiated cancellous bone. Each group was divided into four batches of different particle sizes, each batch containing 18 samples. The different particle sizes were obtained with a Retsch Cross Beater Mill SK 100, Noviomagus rotating bone mills with two sizes of rasps and a Luer bone rongeur. Bone grafts were impacted in a contained cylinder. Stiffness was monitored during impaction.ResultsFreeze-dried irradiated grafts showed higher stiffness than fresh-frozen bone whatever the size of the particles. Large particles obtained with the rongeur and the large rasp from the Noviomagus bone mill were mechanically superior than small particles up to 30 impactions.InterpretationLarge particles offer better mechanical performance as a greater magnitude of force would be required to deform and break the particles. Freeze-dried irradiated bone brittleness reduces this advantage after 30 impactions. Large particles embrittlement leads to similar mechanical results as small particles at higher impaction rate. This may account for partial collapse of the graft layer in clinical situation when impaction rate is lower. This model supports the use of small particles obtained with thin rasp bone mill when freeze-dried irradiated bone for impaction bone grafting and large particles obtained with the Rongeur when fresh-frozen bone is available.     

大直径陶瓷假体用于全髋关节置换术的稳定性和安全性

目的:探讨大直径陶瓷-陶瓷假体对髋关节置换患者术后假体磨损,稳定性和髋关节功能的影响。方法:选取我院2010年1月-2014年1月间采用大直径陶瓷-陶瓷假体行关全髋置换的股骨头坏死患者46例作为研究组。另选40例采用标准金属-聚乙烯假体手术患者作为对照组。观察并比较两组患者假体磨损情况、髋关节稳定性和功能评分。结果:研究组患者术后无一例脱位,发生假体松动1例,Harris评分为(82.04±1.92)分;对照组术后发生假体脱位4例,松动4例,Harris评分为(81.37±1.27)分;研究组假体稳定性和磨损程度优于对照组,差异具有统计学意义(P0.05),但两组髋关节功能评分无显著差异(P0.05)。发生假体松动的患者术后血沉、IL-1和IL-6浓度均高于正常值,差异具有统计学意义(P0.05)。结论:与标准假体相比,大直径陶瓷-陶瓷假体稳定性好,磨损率低,是全髋置换手术的良好假体。     

Validation data for periprosthetic bone remodelling theories

Periprosthetic adaptive bone remodelling after total hip arthroplasty (THA) has been frequently simulated in computer models, combining bone remodelling theory with finite element analysis. Unfortunately, there still subsist a lack of clinical data, which are necessary for validation of these simulation results. Therefore, the objective of the current project is to collect prospective volumetric bone density data with a clinical computerized tomography study in seven patients after THA. A retrospective study 12 years after implantation in 11 patients was added. A data set of about 100 000 bone voxels for each femur was collected. In all prospective cases, the predominant change is seen during the first year. The average density reduction in the horizontal slices was between 50 and 150 Hounsfield units (HU) (approx. 10%; p<0.001) after 2 years. Loss of density is particularly strong distal of the minor trochanter and decreases from proximal to distal.

For the 12 years retrospective study, the contralateral femur provided the control. Similar trends comparable to the prospective 2-year follow-up CT density values were seen in most cases with density reductions of up to 400 HU (30%). However, in one of these cases there was no difference between the operated and the control density.

As far as we are aware, this is the first collection of fully prospective 3D validation data in vivo for periprosthetic adaptive bone remodelling theories. The data are also unique as they are suitable for direct patient-specific 3D finite element meshing and individual weight-related loading.     

Mechanical properties of compacted morselized cancellous bone graft using one-dimensional consolidation testing

Failures of orthopaedic procedures that use morselized cancellous bone (MCB) graft for load bearing are often due to gross displacement within the graft material. For this reason the mechanical behavior of MCB must be better understood. Our purpose is to present a detailed testing methodology for the mechanical characterization of MCB, and to illustrate how this methodology can be used to study the influence of water and fat content. Complete one-dimensional consolidation testing was performed on bovine cancellous bone processed to represent MCB typically used in surgery (52% water, 31% fat). The one-dimensional consolidation strain under a stress of 1.09 MPa was 30.9% and the confined modulus was 8.0 MPa. The coefficient of consolidation (rate of consolidation) was 2.2×10⁻⁵ cm²/s and the coefficient of secondary strain (steady-state creep rate) was 1.9%. While reducing the water content alone had some influence on properties, reducing the fat content improved both the static and dynamic behavior. A sample of MCB which had fat intentionally minimized and a lower overall moisture content (56% water, 5% fat) demonstrated 23.1% strain, a confined modulus of 9.6 MPa, a coefficient of consolidation of 3.4×10⁻³ cm²/s, and a coefficient of secondary strain of 0.9%. The test methods described in this technical note can be used to evaluate the influence of fluid content on the mechanical behavior of MCB.     

两种不同术式对老年股骨颈骨折治疗对比

目的：探讨全髋关节置换术与股骨头置换术治疗对比。方法：回顾性的分析对2007年1月-2008年12月年我院接收的70例60岁以上的老年股骨颈骨折的进行股骨头置换和全髋关节置换两组不同手术方式的临床资料。结果：两组股骨颈骨折治疗的手术时间、住院时间及术后并发症及治疗效果无明显统计学差异,两组术后半年到一年半的Harris评分较术前评分有显著的统计学意义。结论：人工股骨头置换术和髋关节置换是治疗老年股骨颈骨折的有效方法,可根据患者的自身情况、疾病特点等选择不同术式。     

Experimental and clinical study of the demineralized bone allografts manufactured in the tissue bank of CITO

The technology for producing demineralized bone allografts (DBA) with definable degree of demineralization and sterilization by high energy electron bean was developed in the tissue bank of Central Institute of Traumatology and Orthopaedics (CITO). The authors consider the technology to be one of the ways of producing demineralized bones. The results of the experiments show that time of demineralization process as well as the absorption dose of radioactive high energy electron beam change substantially mechanical toughness and osteoinductive properties of DBA. Mechanical properties of DBA were tested by the universal testing machine 'Zwick 1464'. Quantitative assessment of DBA osteoinductive properties resulted from the investigation of DBA samples in the culture of stromal precursor bone marrow cells and in the culture of human skin fibroblasts. Cloning efficiency of fibroblasts was considered as indecies of proliferative potential of stromal bone marrow cells, i.e. osteogenic precursor cells. The growth of the cell mass after definite time as well as the index of ³H-timidin marked cells within biological inductor were considered as indecies of proliferative potential of skin fibroblasts. The obtained results showed, that inductive properties of allografts improve when the degree of their demineralization increases whereas the dose of high energy electron radiation decreases. Mechanical toughness of DBA deteriorates when both degree of their demineralization and radiation doses increase. This emphasizes the importance of optimizing technological stages in DBA producing. Since 1998 DBA have been used in Russian clinics for bone plasty in traumatology and orthopaedics, maxilla-facial surgery, ophthalmology, and neurosurgery. The resulting analysis is based on case histories of 257 patients operated from March 1998 to July 2002. The majority of patients were children and teenagers of 3–18 years old with prime tumors, tumor-like and systemic inherited diseases of skeleton, post-traumatic complications. Observation periods were from 1.5 to 5 years and 10 months. Good and satisfactory results were obtained in 93.4% cases. This revised version was published online in July 2006 with corrections to the Cover Date.     

两种不同术式对老年股骨颈骨折治疗对比

目的:探讨全髋关节置换术与股骨头置换术治疗对比。方法:回顾性的分析对2007年1月-2008年12月年我院接收的70例60岁以上的老年股骨颈骨折的进行股骨头置换和全髋关节置换两组不同手术方式的临床资料。结果:两组股骨颈骨折治疗的手术时间、住院时间及术后并发症及治疗效果无明显统计学差异,两组术后半年到一年半的Harris评分较术前评分有显著的统计学意义。结论:人工股骨头置换术和髋关节置换是治疗老年股骨颈骨折的有效方法,可根据患者的自身情况、疾病特点等选择不同术式。     

Development of a bacteriophage model system to investigate virus inactivation methods used in the treatment of bone allografts

Bone allografts are commonly used in a variety of surgical procedures, to reconstruct lost bone stock and to provide mechanical support during the healing process. Due to concerns regarding the possibility of disease transmission from donor to recipient, and of contamination of grafts during retrieval and processing procedures, it is common practice to sterilise bone allografts prior to issue for clinical use. It is vital that the sterilisation processes applied to allografts are validated to demonstrate that they achieve the required level of bioburden reduction, and by extension that validated models are used for these studies. Two common sterilisation protocols applied to bone allografts are gamma irradiation and ethylene oxide gas sterilisation, and there are currently no validated models available for measuring the anti-viral efficacy of ethylene oxide treatment with regard to bone allografts or readily useable models for assessing the anti-viral efficiency of gamma irradiation treatment. We have developed and validated models for both these sterilisation processes, using the bacteriophage ϕ×174, and utilised the models to measure the antiviral activity of the standard ethylene oxide and gamma irradiation sterilisation processes applied to bone allografts by the National Blood Service. For the irradiation model, we also utilised bacterial spores (Bacillus pumilus). Our results show that ethylene oxide sterilisation (which can only be applied to lyophilised grafts) inactivated >6.1log₁₀ of the model virus, and gamma irradiation (at 25–40 kGy and applied to frozen allografts) inactivated 3.6–4.0log₁₀ of the model virus and >4log₁₀ of the bacterial spores. Gamma irradiation at this dosage is therefore not in itself a sterilisation process with respect to viruses.     

Self-healing and injectable hybrid hydrogel for bone regeneration of femoral head necrosis and defect

Background

HA modified by bisphosphonate (BP) (HA-BP) was synthesized by chemical reaction and possessed promising properties such as self-healing, injection ability, and strong adhesion. The main aim of this study was to confirm its role in promoting osteogenic differentiation in vitro and bone regeneration in vivo.

Fresh-frozen human bone graft for repair of defect after adenomatoid odontogenic tumour removal

The aim of this paper was report the clinical, radiographic, and histological case of adenomatoid odontogenic tumour (AOT) in adolescent woman as well as present the reconstructive treatment of AOT using fresh-frozen human bone graft with guided bone regeneration. AOT is a benign, noninvasive lesion with slow but progressive growth. Biopsy and microscopic examination confirmed the presence of an AOT. Treatment was conservative and the prognosis was excellent. The patient has been followed-up for without recurrence. The use of fresh-frozen human bone graft can be a safe choice for reconstruction of the bone defects to treat AOT.     

Evaluation of demineralised,freeze-dried,irradiated bone allografts in the treatment of osseous defects in the oral cavity

Demineralised, freeze-dried bone allografts (DFDBA) have been used extensively by dentists in the treatment of periodontal and periapical osseous defects resulting from inflammatory diseases. Their use in India however, is limited by the availability of quality allografts and the high cost of imported alternatives. A study was conducted to assess the osteogenic potential of DFDBA prepared for the first time in India by the Tata Memorial Hospital (TMH) Tissue Bank. The DFDBA was used in the treatment of osseous defects after removal of periapical lesions associated with devitalised teeth in 10 healthy patients. At the 6-month recall visit all the patients showed a remarkable decrease in the grades of mobility, and 9 out of the 10 patients showed radiographic evidence of complete healing of the osseous defects with evidence of normal bony trabaeculae. These findings indicate that the indigenously prepared DFDBA is a cost effective, biocompatible material with osteogenic potential that can be used effectively in treating osseous defects of periapical lesions associated with non vital teeth.     

Impact of the method of exposure in total hip arthroplasty on the variability of gait in the first 6 months of the postoperative period

Introduction, objectiveGait analysis has provided important information about the variability of gait for patients prior to and after total hip arthroplasty (THA). The objective of this research was to clarify how the method of exposure in total hip arthroplasty affects the variability of gait.Materials and methodGait analysis was performed at 0.8 m/s, 1.0 m/s, and 1.2 m/s on 25 patients with direct-lateral exposure (DL), 22 with antero-lateral exposure (AL) and 25 with posterior exposure (P) during total hip arthroplasty. The control group was represented by 45 healthy subjects of identical age. Gait analysis was performed pre-operatively and 3 and 6 months after the surgery. Gait parameter variability was characterized by the coefficient of variance (CV) of spatial–temporal parameters and by the mean coefficient of variance (MeanCV) of angular parameters.ResultsThe variability of gait tends to reach control values during the first 6 months of the postoperative period in all three patient groups. Six months after THA, in patients operated with DL and AL exposure the variability of gait differs significantly from control values; however, in patients operated with P exposure, the variability of spatial–temporal and angular parameters – except the rotation of pelvis – was similar to that of controls.Discussion, conclusionThe type of surgical technique significantly influences the variability of gait. Difference in the variability of angular parameters predicts gait instability and increased risk of falling after THA without the joint capsule preserved. Joint capsule preservation ensures a recovery of gait variability. It should be taken into account when compiling rehabilitation protocols. Differences related to the method of exposure should be considered when abandoning therapeutic aids.     

Adherent cells in granulocyte-macrophage colony-stimulating factor-induced bone marrow-derived dendritic cell culture system are qualified dendritic cells

A widely-used method for generating dendritic cell (DC) is to culture bone marrow cells in granulocyte-macrophage colony-stimulating factor (GM-CSF)-containing medium for 6-10 days. Usually, non-adherent cells are used as qualified dendritic cells while the adherent ones are discarded as “non-dendritic cells” or macrophages. In this study, we show that the adherent cells are nearly identical to the non-adherent cells in both dendritic cell surface markers expression and main dendritic cell-related functions, hence to prove that these “junk cells” are actually qualified dendritic cells.     

人工全髋关节置换术中Delta陶瓷的界面选择

目的:Delta陶瓷较Forte陶瓷在材料复合方面进步明显,并采用了36 mm大直径球头的设计,其组成的界面具有耐磨性好,关节活动度大,稳定性佳,不易脱位等优点,适合年轻及活动量大的患者,但其价格较其他界面更为高昂.观察采用Delta陶瓷-陶瓷界面与Delta陶瓷-高交联聚乙烯界面假体行全髋关节置换术的患者术后效果的差异.方法:选取2009年10月-2012年10月在我院选择Delta陶瓷-高交联聚乙烯界面行全髋关节置换术的35例患者(A组),以同期在我院选择Delta陶瓷-陶瓷界面26例行全髋关节置换术的患者(B组)作为对照.通过随访影像学复查,以及术后Harris功能评分进行临床效果的评价.结果:所有患者均得到随访,随访时间6个月到2年.所有患者在影像学方面,未发现松动下沉,脱位以及碎裂等现象.假体周围未见骨溶解所致透亮线形成以及异位骨化.两组患者行人工全髋关节置换术后Harris评分较术前均有显著提高,但两组之间无显著差异.结论:Delta陶瓷作为最新一代的生物陶瓷,其优异性能毋庸置疑.采用Delta陶瓷-陶瓷界面及Delta陶瓷-高交联聚乙烯界面在短期内未见明显差异,其中长期效果仍有待进一步随访观察.     

Bone morphogenetic protein-2 enhances bone regeneration mediated by transplantation of osteogenically undifferentiated bone marrow-derived mesenchymal stem cells

We have hypothesized that human bone marrow-derived mesenchymal stem cells (BMMSCs), that are not osteogenically differentiated prior to implantation, would regenerate bone extensively in vivo once exogenous bone morphogenetic protein-2 (BMP-2) was delivered to the implantation site. BMP-2 released from heparin-conjugated poly(lactic-co-glycolic acid) (HCPLGA) scaffolds stimulates osteogenic differentiation of cultured BMMSCs. Upon implantation, undifferentiated BMMSCs on BMP-2-loaded HCPLGA scaffolds induce far more extensive bone formation than either undifferentiated BMMSCs or osteogenically differentiated BMMSCs on HCPLGA scaffolds. These BMP-2-loaded HCPLGA scaffolds could prove invaluable for in vivo regeneration of bone from undifferentiated human BMMSCs.     

Enhancement of ectopic bone formation by bone morphogenetic protein-2 delivery using heparin-conjugated PLGA nanoparticles with transplantation of bone marrow-derived mesenchymal stem cells

This study was performed to determine if a combination of previously undifferentiated bone marrow-derived mesenchymal stem cells (BMMSCs) and exogenous bone morphogenetic protein-2 (BMP-2) delivered via heparin-conjugated PLGA nanoparticles (HCPNs) would extensively regenerate bone in vivo. In vitro testing found that the HCPNs were able to release BMP-2 over a 2-week period. Human BMMSCs cultured in medium containing BMP-2-loaded HCPNs for 2 weeks differentiated toward osteogenic cells expressing alkaline phosphatase (ALP), osteopontin (OPN) and osteocalcin (OCN) mRNA, while cells without BMP-2 expressed only ALP. In vivo testing found that undifferentiated BMMSCs with BMP-2-loaded HCPNs induce far more extensive bone formation than either implantation of BMP-2-loaded HCPNs or osteogenically differentiated BMMSCs. This study demonstrates the feasibility of extensive in vivo bone regeneration by transplantation of undifferentiated BMMSCs and BMP-2 delivery via HCPNs. Sung Eun Kim and Oju Jeon equally contributed to this work     

Mechanotransduction in bone cells proceeds via activation of COX-2, but not COX-1

Cyclooxygenase (COX) is the key enzyme in the production of prostaglandins, which are essential for the response of bone to mechanical loading. We determined which COX-isoform, COX-1 or COX-2, determines loading-induced prostaglandin production in primary bone cells in vitro. Mouse and human bone cells reacted to 1 h of pulsating fluid flow (PFF, 0.6+/-0.3 Pa at 5 Hz) with an increased prostaglandin E(2) production, which continued 24 h after cessation of PFF. Inhibition of COX-2 activity with NS-398 abolished the stimulating effect of PFF both at 1 h and at 24 h post-incubation, while inhibition of COX-1 by SC-560 affected neither the early nor the late response to flow. PFF rapidly stimulated COX-2 mRNA expression at 1 h but did not affect COX-1 mRNA expression. COX-2 mRNA expression was still significantly enhanced 24 h after cessation of PFF. We conclude that COX-2 is the mechanosensitive form of COX that determines the response of bone tissue to mechanical loading.     

Regional program for bone allograft harvesting following multiorgan procurement in Pomeranian Academy of Medicine in Szczecin

In Poland, up to 1999, the bones for allograft preparations had been procured only in mortuaries of forensic medicine departments. The increasing demand for bone transplantations greatly exceeds the supply resulting in a long waiting time for bone allografts. In November 1999, for the first time in Poland, the group of orthopedic surgeons from the Pomeranian Academy of Medicine started the regional program for bone harvesting following vascularized organ procurements. The aim of this paper is to present the technical details and limitations of bone harvesting that occurred in 10 out of 25 multiorgan procurements. This revised version was published online in July 2006 with corrections to the Cover Date.     

Application of Novel Design Bone Grafting for Treatment of Segmental Acetabular Rim Defects During Revision Total Hip Arthroplasty

The study aimed to develop efficient techniques with different novel graft structures to enhance the treatment of acetabular bone deficiency.The inhomogeneous material properties Finite Element Analysis(FEA)model was reconstructed according to computed tomography images based on a healthy patient without any peri-acetabular bony defect according to the Ameri-can Academy of Orthopedic Surgeons(AAOS).The FEA model of acetabular bone deficiency was performed to simulate and evaluate the mechanical performances of the grafts in different geometric structures,with the use of fixation implants(screws),along with the stress distribution and the relative micromotion of graft models.The stress distribution mainly con-centrated on the region of contact of the screws and superolateral bone.Among the different structures,the mortise-tenone structure provided better relative micromotion,with suitable biomechanical property even without the use of screws.The novel grafting structures could provide sufficient biomechanical stability and bone remodeling,and the mortise-tenone structure is the optimal treatment option for acetabulum reconstruction.