Aims. To clarify the mid-term results of transposition osteotomy of the acetabulum (TOA), a type of spherical periacetabular osteotomy, combined with structural allograft bone grafting for severe hip dysplasia. Methods. We reviewed patients with severe hip dysplasia, defined as Severin IVb or V (lateral centre-edge angle (LCEA) < 0°), who underwent TOA with a structural bone allograft between 1998 and 2019. A medical chart review was conducted to extract demographic data, complications related to the osteotomy, and modified Harris Hip Score (mHHS). Radiological parameters of hip dysplasia were measured on pre- and postoperative radiographs. The cumulative probability of TOA failure (progression to Tönnis grade 3 or conversion to total hip arthroplasty) was estimated using the Kaplan–Meier product-limited method, and a multivariate Cox proportional hazard model was used to identify predictors for failure. Results. A total of 64 patients (76 hips) were included in this study. The median follow-up period was ten years (interquartile range (IQR) five to 14). The median mHHS improved from 67 (IQR 56 to 80) preoperatively to 96 (IQR 85 to 97) at the latest follow-up (p < 0.001). The radiological parameters improved postoperatively (p < 0.001), with the resulting parameters falling within the normal range in 42% to 95% of hips. The survival rate was 95% at ten years and 80% at 15 years. Preoperative Tönnis grade 2 was an independent risk factor for TOA failure. Conclusion. Our findings suggest that TOA with structural bone allografting is a viable surgical option for correcting severely dysplastic acetabulum in adolescents and young adults without advanced osteoarthritis, with favourable mid-term outcomes. Cite this article: Bone Joint J 2023;105-B(7):743–750

Bone allografts can be used in any kind of surgery involving bone from minor defects to major bone loss after tumour resection. This review describes the various types of bone grafts and the current knowledge on bone allografts, from procurement and preparation to implantation. The surgical conditions for optimising the incorporation of bone are outlined, and surgeon expectations from a bone allograft discussed

Bone infections due to fractures or implants are a big medical problem. In experimental medicine, many experimental models have been created on different animal species to simulate the disease condition and to do experience treatments. The aim of this paper was to present an antibacterial efficacy of using a bone allograft developed according to the Marburg system of bone bank on a model of chronic osteomyelitis induced in rabbits. In research was used 54 rabbits. Osteomyelitis was induced in rabbits by a human strain of St. aureus ATCC 43300, in the rabbit femur. There have been created 3 groups of animals. In 1. st. group used antibiotic impregnated biodegradable material “PerOssal”. In 2. nd. group used antibiotic impregnated whole bone allograft. In 3. rd. group used antibiotic impregnated perforated bone allograft. Evaluation of installation and evolution of the disease was done by microbiological. A separate study of microbiological data is presented here. This study showed, in the 1. st. and 3. rd. groups there is a persistent decrease in CFU by 14 knocks to 120.4 in the 1. st. group and to 3.5 in the 3. rd. group, and in the 2. nd. group, on the contrary, there is an increase in CFU to 237.33. This shows the lack of effectiveness of using a whole bone allograft. The results showed, after 7 days there was no statistically significant difference between the groups. After 14 days the perforated bone allograft impregnated with antibiotic was better than the biodegradable material “PerOssal”

Introduction. Cancellous and cortical bone used as a delivery vehicle for antibiotics. Recent studies with cancellous bone as an antibiotic carrier in vitro and in vivo showed high initial peak concentrations of antibiotics in the surrounding medium. However, high concentrations of antibiotics can substantially reduce osteoblast replication and even cause cell death. Objectives. To determine whether impregnation with gentamycine impair the incorporation of bone allografts, as compared to allografts without antibiotic. Materials and method. Seventy two healthy rabbits (24 rabbits in each group) were used for this study. Bone defects (3-mm diameter, 10-mm depth) were created in the femur. Human femoral head prepared according to the Marburg bone bank system was used as bone allograft. In the experimental groups, in 1 group - the defects were filled with bone allografts, in 2 group – Perforated Gentamycin-impregnated bone allografts. The control group did not receive any filling. The animals were killed after 14, 30 and 60 days. Evaluations consisted of X-ray plain radiography, histology at 14-, 30- and 60-days post-surgery. Results. Active osteoblast activity and active formation of new bones were detected around the defect area in all groups, but the amount of new bone formation was greater in the experimental groups than the control group. We found no statistically significant differences in the rate of bone formation between 1 and 2 groups at 14, 30 and 60 days in any of the parameters studied. X-ray results showed no significant difference in bony callus formation around allografts in 1 and 2 groups. In contrast, no significant callus formation was observed in the control group. Conclusion. The use of gentamycin-impregnated bone allografts may be of value in procedures performed at the site of osteomyelitis which require a second stage reconstruction with impacted bone grafting techniques

Bone allograft use in trauma and orthopaedic surgery is limited by the potential for cross infection due to inadequate acceptable decontamination methods. Current methods for allograft decontamination either put the recipient at risk of potentially pathogenic organisms or markedly reduce the mechanical strength and biological properties of bone. This study developed a technique of sterilization of donor bone which also maintains its mechanical properties. Whole mature rat femurs were studied, as analogous to strut allograft. Bones were inoculated by vortexing in a solution of pathogens likely to cause cross infection in the human bone graft situation. Inoculated bones were subjected to supercritical carbon dioxide at 250 bar pressure at 35 degrees celsius for different experimental time periods until a set of conditions for sterilization was achieved. Decontamination was assessed by vortexing the treated bone in culture broth and plating this on suitable culture medium for 24 hours. The broth was also subcultured. Controls were untreated-, gamma irradiated- and dehydrated bone. Mechanical testing of the bones by precision three-point bending to failure was performed and the dimensions and cross-section digitally assessed so values could be expressed in terms of stress. Mechanical testing revealed bone treated with supercritical carbon dioxide was consistently significantly stronger than that subjected to gamma irradiation and bones having no treatment (due to the minor dehydrating effect of the carbon dioxide). Terminal sterilization of bone is achieved using supercritical carbon dioxide and this method maintains the mechanical properties. The new technique greatly enhances potential for bone allograft in orthopaedic surgery

We retrospectively reviewed 40 hips in 36 patients who had undergone acetabular reconstruction using a titanium Kerboull-type acetabular reinforcement device with bone allografts between May 2001 and April 2006. Impacted bone allografts were used for the management of American Academy of Orthopaedic Surgeons Type II defects in 17 hips, and bulk bone allografts together with impacted allografts were used for the management of Type III defects in 23 hips. A total of five hips showed radiological failure at a mean follow-up of 6.7 years (4.5 to 9.3), two of which were infected. The mean pre-operative Merle d’Aubigné score was 10 (5 to 15) vs 13.6 (9 to 18) at the latest follow-up. The Kaplan-Meier survival rate at ten years, calculated using radiological failure or revision of the acetabular component for any reason as the endpoint, was 87% (95% confidence interval 76.3 to 97.7). A separate experimental analysis of the mechanical properties of the device and the load-displacement properties of bone grafts showed that a structurally hard allograft resected from femoral heads of patients with osteoarthritis should be preferentially used in any type of defect. If impacted bone allografts were used, a bone graft thickness of < 25 mm was acceptable in Type II defects. This clinical study indicates that revision total hip replacement using the Kerboull-type acetabular reinforcement device with bone allografts yielded satisfactory mid-term results

Aims. The aim of this study was to report the medium-term outcomes of impaction bone allograft and fibular grafting for osteonecrosis of the femoral head (ONFH) and to define the optimal indications. Methods. A total of 67 patients (77 hips) with ONFH were enrolled in a single centre retrospective review. Success of the procedure was assessed using the Harris Hip Score (HHS) and rate of revision to total hip arthroplasty (THA). Risk factors were studied, including age, aetiology, duration of hip pain, as well as two classification systems (Association Research Circulation Osseous (ARCO) and Japanese Investigation Committee (JIC) systems). Results. After a mean follow-up period of 8.61 years (SD 1.45), 81.3% (52/64) of enrolled cases had a good or excellent HHS at latest follow-up (declining to 76.0% (38/50) for those with more than eight years of follow-up). Overall survival was 92.1% at eight years’ follow-up (95% CI 83.2% to 96.4%). A total of 12 hips (19.0%) failed (reoperation or HHS < 70 points) at final follow-up. Rate of success was adversely affected by increasing age, duration of pain, and more severe disease as measured using the ARCO and JIC classifications, but not by aetiology of the ONFH. Conclusion. We report favourable medium-term results of this procedure. Best outcomes can be expected in patients matching the following indications: younger than 40 years; less 12-month hip pain before surgery; femoral head collapse being less than 2 mm; and integrated lateral wall of femoral head. Cite this article: Bone Joint J 2020;102-B(7):838–844

The purpose of this study is to enhance massive bone allografts osseointegration used to reconstruct large bone defects. These allografts show >50% complication rate requiring surgical revision in 20% cases. A new protocol for total bone decellularisation exploiting the vasculature can offer a reduction of postoperative complication by annihilating immune response and improving cellular colonization/ osseointegration. The nutrient artery of 18 porcine bones - humerus/femur/radius/ulna - was cannulated. The decellularization process involved immersion and sequential perfusion with specific solvents over a course of one week. Perfusion was realized by a peristaltic pump (mean flow rate: 6ml/min). The benefit of arterial perfusion was compared to a control group kept in immersion baths without perfusion. Bone samples were processed for histology (HE, Masson's trichrome and DAPI for cell detection), immunohistochemistry (IHC : Collagen IV/elastin for intraosseous vascular system evaluation, Swine Leukocyte Antigen – SLA for immunogenicity in addition to cellular clearance) and DNA quantification. Sterility and solvent residues in the graft were also evaluated with thioglycolate test and pH test respectively. Compared to native bones, no cells could be detected and residual DNA was <50ng/mg dry weight. Intramedullary spaces were completely cleaned. IHC showed the preservation of intracortical vasculature with channels bounded by Collagen IV and elastin within Haversian systems. IHC also showed a significant decrease in SLA signaling. All grafts were sterile at the last decellularization step and showed no solvent residue. The control group kept in immersion baths, paired with 6 perfused radii/ulnae, showed that the perfusion is mandatory to ensure complete decellularisation. Our results prove the effectiveness of a new concept of total bone decellularisation by perfusion. These promising results could lead to a new technique of Vascularized Composite Allograft transposable to pre-clinical and clinical models

Bone allograft is the most widely accepted approach in treating patients suffering from large segmental bone defect regardless of the advancement of synthetic bone substitutes. However, the long-term complications of allograft application in term of delayed union and nonunion were reported due to the stringent sterilization process. Our previous studies demonstrated that the incorporation of magnesium ions (Mg2+) into biomaterials could significantly promote the gene up-regulation of osteoblasts and new bone formation in animal model. Hence, our group has proposed to establish an Mg2+ enriched tissue microenvironment onto bone allograft so as to enhance the bone healing. The decellularization and gamma irradiation process were performed on bovine bone allograft and followed by magnesium plasma treatment. To evaluate the biocompatibility and bioactivity, materials characterizations, in vitro and in vivo studies were conducted, respectively. Mg composite layer on bone surface ranged from 500nm to ∼800nm thick. The cell viability on magnesium enriched allograft was significantly higher than that of the control. The ALP gene expression of hTMSCs in the group of PIII&D treated samples was highly up-regulated. The bone regeneration ability of Mg modified bone allograft implanted in animal model was significantly superior than the control after 2-month post-operation

Bone allografts can store and release high levels of vancomycin. We present our results of a two-stage treatment for infected hip arthroplasty with acetabular and femoral impaction grafting using vancomycin-loaded allografts. We treated 29 patients (30 hips) by removal of the implants, meticulous debridement, parenteral antibiotic therapy and second-stage reconstruction using vancomycin-supplemented impacted bone allografts and a standard cemented Charnley femoral component. The mean follow-up was 32.4 months (24 to 60). Infection control was obtained in 29 cases (re-infection rate of 3.3%; 95% confidence interval 0.08 to 17) without evidence of progressive radiolucent lines, demarcation or graft resorption. One patient had a further infection ten months after revision caused by a different pathogen. Associated post-operative complications were one traumatic periprosthetic fracture at 14 months, a single dislocation in two hips and four displacements of the greater trochanter. Vancomycin-supplemented allografts restored bone stock and provided sound fixation with a low incidence of further infection

Impacted bone allograft is often used in revision joint replacement. Hydroxyapatite granules have been suggested as a substitute or to enhance morcellised bone allograft. We hypothesised that adding osteogenic protein-1 to a composite of bone allograft and non-resorbable hydroxyapatite granules (ProOsteon) would improve the incorporation of bone and implant fixation. We also compared the response to using ProOsteon alone against bone allograft used in isolation. We implanted two non-weight-bearing hydroxyapatite-coated implants into each proximal humerus of six dogs, with each implant surrounded by a concentric 3 mm gap. These gaps were randomly allocated to four different procedures in each dog: 1) bone allograft used on its own; 2) ProOsteon used on its own; 3) allograft and ProOsteon used together; or 4) allograft and ProOsteon with the addition of osteogenic protein-1. After three weeks osteogenic protein-1 increased bone formation and the energy absorption of implants grafted with allograft and ProOsteon. A composite of allograft, ProOsteon and osteogenic protein-1 was comparable, but not superior to, allograft used on its own. ProOsteon alone cannot be recommended as a substitute for allograft around non-cemented implants, but should be used to extend the volume of the graft, preferably with the addition of a growth factor

Successful reconstructive surgery with allografts is severely limited by a failure rate of 30 – 40%. Allograft failure is due to nonunion of the graft-host junction. The molecular mechanism by which this occurs is not yet fully elucidated. Using a sheep femoral allograft model, we have investigated the cellular and molecular mechanisms associated with nonunion of bone allografts. Five, from a total of twelve operations, resulted in the development of graft-host nonunion, reflecting a failure rate of 42%. Histological assessment revealed that allograft failure was due to the excessive accumulation of and resorption by, osteoclasts (Ocs) on the surface of the bone allograft. Three distinct layers, lying adjacent to the allograft bone surface, in the nonunion groups, were identified. The outer fibroblastic layer contained abundant fibroblasts and connective tissue. Underlying this layer were synovial-like cells and some multinuclear giant cells. The third layer, opposing the bone surface, consisted of Ocs and round mononuclear cells. Histomorphometric analysis showed that allograft unions, featured a large amount of newly formed bone on the surface, (OS/BS = 47.81%) with a small proportion of eroded surface (ES/BS = 20.59%). The number of osteoclasts associated with the allograft bone surface were few (Oc/B.Pm = 1.7190/mm) and activity (ES/BS = 46.68%) of Ocs with a reduced amount of new bone formation (OS = 6.35%). Both calcitonin receptor and H+ATPase mRNA, characteristically expressed by Ocs, were localised to the multinuclear giant cells, indicating that they were Ocs. Synovial-like cells in the histological layer above the Ocs, expressed gene transcript for the Osteoprotegrin Ligand (OPGL), a membrane bound factor that is critical for the induction of Oc activity and osteoclastogenesis. In conclusion, these findings suggest that failure of bone allografts is partially due to excessive resorption by host Ocs, accompanied by reduced bone formation. The production of OPGL by synovial-like cells, may be responsible for the recruitment and generation of Ocs

The Use of bone allograft in orthopaedic Surgery has been predicted to increase particularly in joint revision surgery. This has led to a potential problem with supply. Questionnaires were distributed to all 146 Consultant orthopaedic Surgeons working in Scotland in 2000. They were asked to indicate their current usage of bone and tissue allograft, any problems encountered with supply and if alternatives to allograft such as processed bone, might be used. The questions asked were very similar to those asked in a survey by the author (GG) in 1995 to enable comparisons to be made. 74% of all bone issued by the SNBTS in 2000 –2001 was used in revision hip arthroplasy. This compares with only 66% of bone issued in 1998–1999. Replies were received from 125 consultants (87%) of whom 93 reported using bone allograft. 41 consultants (46%) predicted an increase in their requirement for bone allograft, and 23 (26%) felt they could currently use more bone if this became available. Sixty percent of Surgeons would consider using processed bone as an alternative. In comparison with figures from a previous study in 1995, an increasing number of surgeons are prepared to use processed bone as an alternative to fresh frozen allograft. As the number of revision THR’ s continues to increase the amount of bone required is likely to continue to increase. The need to increase efficiency in harvest and supply of bone is therefore great. The use of more SNBTS nurses in selection of patients and collection of bone may increase efficiency. More surgeons may have to use processed bone, which would allow more bone to be released. Also processing may help reduce transmission of infective particles such as HIV and new variant CJD. With rising public and medical concerns over these issues this seems most desirable

Major drawbacks associated with autologous bone grafting are the risk of donor site morbidity and its limited availability. Sterilized bone allograft, however, lacking osteoinductive properties, carries the risk of graft failure resulting from insufficient osseointegration of the graft. The aim of this study was to vitalize bone allograft with human osteoprogenitor cells under GMP-conform conditions. For this purpose we investigated proliferation, osteogenic differentiation and large-scale gene expression of human MSCs cultured three-dimensionally on peracetic acid (PAA)-treated spongious bone chips. MSCs were isolated from healthy donors (N=5) and seeded onto PAA-treated spongious bone samples (~5×5×5 mm, DIZG, Germany) under GMP-conform conditions. Proliferation (total protein assay), osteogenic differentiation (cell-specific ALP activity assay, quantitative gene expression analysis of selected osteogenic marker genes), and morphology were assessed. RNA was isolated and microarray analysis was performed using the PIQORTM Stem Cell Microarray system (Miltenyi Biotec) including 942 target sequences. Increasing cellularity was observed during the 42 d observation period while cell-specific ALP activity peaked at day 21. Effective proliferation and adhesion of human MSCs on PAA-treated spongious bone was confirmed by histology, scanning electron and confocal laser scanning microscopy. Gene expression of early (Runx-2), intermediate (ALP), and late (osteocalcin) osteogenic marker genes was present during 42 days of cultivation. Microarray analysis of MSCs cultivated on bone allograft versus 2-D tissue culture demonstrated temporal upregulation of genes involved in extracellular matrix synthesis (e.g., matrix metalloproteases, collagens), osteogenesis (e.g., BMPR1b, Runx-2) and angiogenesis (angiopoietin, VEGF). PAA-treated spongious bone allograft is a biocompatible carrier matrix for long-term ex vivo cultivation of MSCs as observed by favorable proliferation, cell distribution, gene expression profile, and persisting osteogenic differentiation. GMP-grade vitalisation of bone allograft by cultivation with autologous MSCs represents a promising clinical application for the treatment of osseous defects

Metal meshes are used in revision surgery of the hip to contain impacted bone grafts in cases with cortical or calcar defects in order to provide rotational stability to the stem. However, the viability of bone allografts under these metal meshes has been uncertain. We describe the histological appearances of biopsies obtained from impacted bone allografts to the calcar contained by a metal mesh in two femoral reconstructions which needed further surgery at 24 and 33 months after the revision procedure. A line of osteoid and viable new bone was observed on the surface of necrotic trabeculae. Active bone marrow between these trabeculae showed necrotic areas in some medullary spaces with reparative fibrous tissue and isolated reactive lymphocytes. This is interpreted as reparative changes after revascularisation of the cancellous allografts. These pathological findings are similar to those reported in allografts contained by cortical host bone and support the hypothesis that incorporation of morcellised bone under metal meshes is not affected by these devices

Vancomycin-supplemented allografts provide biological restoration of bone stock and sound fixation with a low incidence of re-infection. Experimental incorporation of these grafts is similar to allografts without vancomycin. However, the underlying biology remains unknown. We report the first histological observations of vancomycin-supplemented impacted bone allografts in two reconstructions performed 14 and 20 months after revision surgery because of a periprosthetic fracture. Areas of active bone remodelling (creeping substitution), as well as calcified bone trabeculae and graft particles embedded in dense fibrous tissue, were observed with osteoid and fibroconnective tissue surrounding polymethylmethacrylate particles. These pathological findings are similar to those reported in allografts without vancomycin and support the hypothesis that high levels of vancomycin do not affect the incorporation of bone graft

Background: Early failure of morselized impaction bone allograft is usually due to shear forces. Soil mechanics tells us that in aggregates such as bone allograft, the resistance to these shear forces can be increased by altering the fluid concentration, varying the particle size, and improving the morphology of the graft particle. Finding an idealized concentration of fat and water in bone graft could improve the resistance to interparticle shear and therefore decrease the failure rate of impaction bone graft. Ensuring the quality of the bone source is adequate can also improve the initial strength the bone graft. Furthermore optimizing the graft can be achieved by screening methods and simple intra-operative techniques. Methods: Human femoral heads were retrieved from both total hip arthroplasty and hemiarthroplasty procedures. Bone mineral density was determined by DEXA scanning. The fat and water content of the graft was varied by combinations of squeezing and drying the graft and also by washing the graft using pulse lavaged water and 1:1 mixture of chloroform: methanol. The amount and characteristics of the fat and water in human morselized cancellous bone was quantified by the Karl Fischer extraction techniques, and gas chromatography. The overall shear strength of each graft preparation was determined by the direct shear test, adapted from an accepted protocol in soil mechanics and the optimum mixture which would resist shear forces was determined. Results: An optimum level of fat and water was determined which was 50% stronger than unaltered bone graft. This is most closely approximated in an operating theatre situation by washing the graft with pulse lavaged normal saline and subsequently squeezing the bone graft in a vice with a force of 335kPa for 5 minutes. Whereas osteoarthritic and osteoporotic bone were similar in their fat and water content and initial resistance to shear forces, after processing, the resistance to shear forces of osteoarthritic bone improved by 147% and that of osteoporotic bone only improved by 12% (p< 0.001) Conclusions: Optimizing the fat and water content of bone graft and closely choosing the source of graft produces a stronger graft which is more resistance to shear stresses, protecting the surgical construct until bone growth can occur

Management of bone defects is a common surgical challenge encountered following any high energy trauma. Femur fractures with bone loss account for 22% of all the fractures with bone loss/defect, and 5% to 10% of distal femur fractures are open injuries. It was estimated in 2008, that, more than 4.5 million open fractures occur annually in India. In this retrospective study, patients who received bone allograft from our tissue bank between May 2012 and September 2015 were analysed. Of the 553 allografts issued, at that point in time, 26 were used in patients who underwent reconstruction for distal Femur fractures primarily. Fractures with defect or bone loss from 12 cc (1cm) to 144 cc (12cm) were treated with either Internal or External fixation and bone allograft. Morcellised cancellous, or a cortical strut, were used to fill or reconstruct the defect or void. The radiological outcome in terms of fracture union was assessed and Knee society score was used to assess the functional outcome. Complications such as non- union, infection, stiffness and need of revision or additional procedures were also assessed. Osseous consolidation was achieved in all the 26 patients with a Median time of 24 weeks (16 to 60). The Median Functional Knee Society Score was 80, indicating satisfactory functional outcome. Infection was noted in one patient, but it was not attributed to the allograft. Additional minor procedures like bone marrow infiltration, corticotomy for bone lengthening were required in 10 patients. Our studycomprises the largest group of patients treated primarily with Allograft to reconstruct or fill the void of bone loss encountered with distal Femur fracture. Reconstruction of massive bone defects, in patients of distal Femur fractures, with bone allograft, shows encouraging results. The surgeon can achieve the goal of restoring form and function of these difficult injuries in a single stage and the technique will provide the freedom to reconstruct the bony defect up to 150 cc (12 cm length) and recreate the anatomy to near normal. This allows for early mobilisation of patients and restoration of their daily routine at the earliest

Structural bone allografts are a viable option in reconstructing massive bone defects in patients following musculoskeletal (MSK) tumour resection and revision hip/knee replacements. To decrease infection risk, bone allografts are often sterilised with gamma-irradiation, which consequently degrades the bone collagen connectivity and makes the bone brittle. Clinically, irradiated bone allografts fracture at rates twice that of fresh non-irradiated allografts. Our lab has developed a method that protects the bone collagen connectivity through ribose pre-treatment while still undergoing gamma-irradiation. Biomechanical testing of bone pretreated with our method provided 60–70% protection of toughness and 100% protection of strength otherwise lost with conventional irradiation. This study aimed to determine if the ribose-treated bone allografts are biocompatible with host bone. The New Zealand White rabbit (NZWr) radius segmental defect model was used, in which 15-mm critically-sized defects were created. Bone allografts were first harvested from the radial diaphysis of donor female NZWr, and treated to create 3 graft types: C=untreated controls, I=conventionally-irradiated (33 kGy), R=our ribose pretreated + irradiation method. Recipient female NZWr (n=24) were then evenly randomised into the 3 graft groups. Allografts were surgically fixed with a 0.8-mm Kirschner wire. Post-operative X-rays were taken at 2, 6, and 12 weeks, with bony healing assessed by a blinded MSK radiologist using an established radiographic scoring system. The reconstructed radii were retrieved at 12 weeks and analysed using bone histomorphometry and microCT. Kruskal-Wallis and Mann-Whitney tests were utilised to compare groups, with statistical significance when p<0.05. Radiographic analysis revealed no differences in periosteal reaction and degree of osteotomy site union between the groups at any time point. Less cortical remodeling was observed in R and I grafts compared to untreated controls at 6 weeks (p=0.004), but was no longer evident by 12 weeks. Radiographic union was achieved in all groups by 12 weeks. Histologic and microCT analysis further confirmed union at the graft-host bone interface, with the presence of mineralising callus and osteoid. Histomorphometry also showed the bridging external callus originated from host bone periosteum and a distinct cement line between allograft and host bone was present at the union site. Previous studies have shown that the presence of non-enzymatic glycation end products in bone can impair fracture healing. However, these studies investigated bony healing in the setting of diabetic states. Our findings showed that under normal conditions, ribose pretreated grafts healed at rates similar to controls via mechanisms also seen in retrieved human allografts clinically in use. These findings that grafts pretreated with our method are biocompatible with host bone in the rabbit help to further advance this technology for clinical trials

We reviewed the clinical and radiological results of 131 patients who underwent acetabular revision for aseptic loosening with impacted bone allograft and a cemented acetabular component. The mean follow-up was 51.7 months (24 to 156). The mean post-operative Merle D’Aubigné and Postel scores were 5.7 points (4 to 6) for pain, 5.2 (3 to 6) for gait and 4.5 (2 to 6) for mobility. Radiological evaluation revealed migration greater than 5 mm in four acetabular components. Radiological failure matched clinical failure. Asymptomatic radiolucent lines were observed in 31 of 426 areas assessed (7%). Further revision was required in six patients (4.5%), this was due to infection in three and mechanical failure in three. The survival rate for the reconstruction was 95.8% (95% confidence interval 92.3 to 99.1) overall, and 98%, excluding revision due to sepsis. Our study, from an independent centre, has reproduced the results of the originators of the method

We analysed the histological findings in 1146 osteoarthritic femoral heads which would have been considered suitable for bone-bank donation to determine whether pathological lesions, other than osteoarthritis, were present. We found that 91 femoral heads (8%) showed evidence of disease. The most common conditions noted were chondrocalcinosis (63 cases), avascular necrosis (13), osteomas (6) and malignant tumours (one case of low-grade chondrosarcoma and two of well-differentiated lymphocytic lymphoma). There were two with metabolic bone disease (Paget’s disease and hyperparathyroid bone disease) and four with inflammatory (rheumatoid-like) arthritis. Our findings indicate that occult pathological conditions are common and it is recommended that histological examination of this regularly used source of bone allograft should be included as part of the screening protocol for bone-bank collection

We analysed the histological findings in 1146 osteoarthritic femoral heads which would have been considered suitable for bone-bank donation to determine whether pathological lesions, other than osteoarthritis, were present. We found that 91 femoral heads (8%) showed evidence of disease. The most common conditions noted were chondrocalcinosis (63 cases), avascular necrosis (13), osteomas (6) and malignant tumours (one case of low-grade chondrosarcoma and two of well-differentiated lymphocytic lymphoma). There were two with metabolic bone disease (Paget’s disease and hyperparathyroid bone disease) and four with inflammatory (rheumatoid-like) arthritis. Our findings indicate that occult pathological conditions are common and it is recommended that histological examination of this regularly used source of bone allograft should be included as part of the screening protocol for bone-bank collection

Introduction: Bone grafts are frequently used in orthopaedic operations to augment bone healing. Autologous bone graft is the gold standard for osteogenesis, but the amount available from the patient’s iliac crest is often insufficient to fill the defect and donor site morbidity is a significant complication. Alternatively, allograft can be implanted into patients, however, processing is necessary to reduce the immunicity of the graft and the risk of transmission of infection, but this destroys osteoprogenitor cells and hence reduces the osteogenic properties of the graft. Mesenchymal stem cells (MSCs) are present in bone marrow and have the ability to differentiate into osteoblasts. Therefore our study examined the use of MCSs, from bone marrow, to enhance the osteogenic properties of allograft. Hypothesis: MSCs cultured on freeze-dried ethylene oxide treated bone allograft differentiate into osteoblasts, thereby increasing the osteogenic nature of the graft material. Method: After informed consent, bone marrow aspirates were taken from 10 patients during elective orthopaedic operations. MSCs were characterized using Stro-1 antibody and grown on freeze-dried ethylene oxide treated bone allograft in vitro. The hypothesis was tested on three groups of graft, with eight samples in each group. Firstly, freeze-dried ethylene oxide treated bone graft was tested (group 2). For a negative control, allograft was heated to 70°C to denature the osteogenic proteins (group 1). The final group tested the effect of additional osteogenic supplements (100nM dexamethasone, 0.05mM ascorbic acid and 10mM (-glycerol phosphate) on MSCs on allograft (group 3). Osteoblastic differentiation of MSCs was observed under scanning (SEM) and transmission (TEM) electron microscopy, and by measuring protein levels: alkaline phosphatase (ALP), osteopontin and type I pro-collagen over 14 days. Results: SEM confirmed that MSCs could be successfully cultured on bone allograft. Cells grown in groups 2 and 3 were characteristic of metabolically active osteoblasts and collagen extracellular matrix was observed under TEM. The amount of ALP protein produced by MSCs cultured in groups 2 and 3 increased significantly over 14 days (P< 0.05), but there was no increase in group 1. ALP, osteopontin and type I pro-collagen production was significantly greater for group 2 than for group 1 and for group 3 than for group 2 (P< 0.05). Discussion and Conclusions: ALP, type I pro-collagen and osteopontin proteins are known to be produced by osteoblasts during increasing cell maturation and the levels of each of these proteins increased significantly when MSCs were cultured on allograft for 14 days compared with the negative control. The addition of osteogenic supplements significantly increased production of these proteins. Furthermore, MSCs cultured in groups 2 and 3 produced extracellular collagen matrix. These results are consistent with allograft causing MSCs to differentiate into osteoblasts and that this differentiation increases with additional osteogenic supplements. This study confirms that MSCs, derived from autologous bone marrow, could be used to increase the osteogenic potential of allograft, thereby increasing bony healing in patients

Revision hip surgery is becoming increasingly common, 300 procedures being performed in 2001 at our institution. In order to achieve a good outcome bone stock needs to be of good quantity frequently necessitating the use of impaction bone grafting using allograft bone. Donor bone may frequently take three months before it becomes available for use due to the stringent screening procedure. Donor patients must have a clean bill of health, swabs taken at the time of surgery must obviously demonstrate no growth and blood samples taken at donation and an interval of three months, free from viral infectious diseases. It is thus easy to see the lag from the time of donation to availability and why, with increasing demand, need for allograft bone is rapidly exceeding supply. We need to look for an alternative supply of human bone allograft. We have compared the harvest of bone at the time of primary total knee replacement with that of the femoral head by both mass and volume. Sixty consecutive patients undergoing primary hip or knee arthroplasty were included in the study, and the masses and volume of the femoral heads compared with that of the total bone cuts in knee arthroplasty. The type of knee replacement used was documented as was whether the femoral head had had a bone block removed. It was found that the mass of femoral heads was 81g, that of knee cuts 95g this is a statistically significant difference; the volume of femoral heads 66ml and that of knee cuts 75ml. The volumes of bone available from knee arthroplasty cuts are at least comparable femoral heads obtained using hip replacement and could, perhaps, provide a realistic source of bone allograft

Introduction: We conducted a retrospective study at our institution to see what effect, if any, the use of impacted morsellised bone allograft technique had on the incidence of early and late infection in revision hip arthroplasty where contemporary measures were taken. Patients and Methods: This study included 120 patients. Patients were 36 male and 84 females with the mean age at the time of revision surgery was 71.4 years (range 42 – 89 SD 9.7). In all the patients their indication for revision surgery was aseptic loosening. All the patients had impacted morsellised bone allograft as part of the reconstruction used with cemented prostheses. Clinical and radiological assessments of all patients were conducted for average of four years follow up. Results: At mean follow up period of 4 years the early infection rate was 0.8% and late infection rate was 0%. Conclusion: In our study the use of morsellised bone allograft does not appear to have added risk effect on the incidence of early or late hip joint infection provided contemporary measures are taken

We retrospectively reviewed 101 consecutive patients with 114 femoral tumours treated by massive bone allograft at our institution between 1986 and 2005. There were 49 females and 52 males with a mean age of 20 years (4 to 74). At a median follow-up of 9.3 years (2 to 19.8), 36 reconstructions (31.5%) had failed. The allograft itself failed in 27 reconstructions (24%). Mechanical complications such as delayed union, fracture and failure of fixation were studied. The most adverse factor on the outcome was the use of intramedullary nails, followed by post-operative chemotherapy, resection length > 17 cm and age > 18 years at the time of intervention. The simultaneous use of a vascularised fibular graft to protect the allograft from mechanical complications improved the outcome, but the use of intramedullary cementing was not as successful. In order to improve the strength of the reconstruction and to advance the biology of host–graft integration, we suggest avoiding the use of intramedullary nails and titanium plates, but instead using stainless steel plates, as these gave better results. The use of a supplementary vascularised fibular graft should be strongly considered in adult patients with resection > 17 cm and in those who require post-operative chemotherapy

Purpose of the study: The mechanical and radiological course of bone allografts is often favorable but osteointegration properties could be improved. We associated a safe allograft with mesenchymatous bone marrow stem cells (MSC) with known osteogenic potential. The purpose of this preliminary study was to study the biocompatibility of the treated allograft, assess the osteoblastic differentiation properties of the MSC, and determine the optimal period for colonizing the bone matrix. Material and methods: The support was a safe bone allograft preserved in a collagenic grid (Osteopure™). MSC harvested by adherence were seeded in a medium favoring osteoblastic differentiation by comparison with standard culture medium. Culture conditions varied to study the influence of the presence or not of support, the culture time, or the presence of human serum in the culture medium. For each culture medium, we noted: the number of cells, osteoblastic differentiation using markers: alkaline phosphate and osteocalcin. A histological study was also performed. Results: Peak cell amplification was achieved at three weeks culture. Presence of osteoblastic differentiation markers was clearly identified in cultures grown in the presence of support material. Microscopy demonstrated that cells stimulated by the differentiation medium adhered strongly to the bone network. Histology revealed the presence of osteoblastic activity in differentiation medium with cells taking on the classical cytological aspect of osteoblasts. Cell proliferation was at least equivalent in medium with human serum as with fetal calf serum. Discussion: This study demonstrated that the allogenic matrix does not modify the capacity of human MSC for colonization and differentiation. The cell organization is optimal compared with the absence of supporting material. Use of the patient’s own serum in the culture medium was validated enabling an autologous procedure. Use of a complex cell graft appears to be optimal after three weeks of culture. This first step proves the feasibility of the concept designed to optimize the support with the patient’s own MSC. The next step is to develop an in vivo model

We analysed the cellular immune response in ten transplantations of different massive bone allografts, of which five had a poor clinical outcome. Cytotoxic T lymphocytes (CTL) and T helper lymphocytes (TH) against mismatched donor antigens were found in all patients. More importantly, CTL with a high affinity for donor antigens were found in five cases. High-affinity CTL need no CD8 molecule to stabilise the antigen binding and are strongly associated with rejection of heart and corneal transplants. Even after removal of most of the bone-marrow cells, we found high-affinity CTL and high TH frequencies. This T-cell response could be detected over a period of years. We conclude that frozen bone allografts can induce high-affinity donor-specific CTL. The present assay allows qualification and quantification of the levels of CTL and TH in the blood. This approach may be helpful in studying the effect of the immune response on the outcome of the graft

Femoral impaction bone allografting has been developed as a means of restoring bone stock in revision total hip replacement. We report the results of 75 consecutive patients (75 hips) with a mean age of 68 years (35 to 87) who underwent impaction grafting using the Exeter collarless, polished, tapered femoral stem between 1992 and 1998. The mean follow-up period was 10.5 years (6.3 to 14.1). The median pre-operative bone defect score was 3 (interquartile range (IQR) 2 to 3) using the Endo-Klinik classification. The median subsidence at one year post-operatively was 2 mm (IQR 1 to 3). At the final review the median Harris hip score was 80.6 (IQR 67.6 to 88.9) and the median subsidence 2 mm (IQR 1 to 4). Incorporation of the allograft into trabecular bone and secondary remodelling were noted radiologically at the final follow-up in 87% (393 of 452 zones) and 40% (181 of 452 zones), respectively. Subsidence of the Exeter stem correlated with the pre-operative Endo-Klinik bone loss score (p = 0.037). The degree of subsidence at one year had a strong association with long-term subsidence (p < 0.001). There was a significant correlation between previous revision surgery and a poor Harris Hip score (p = 0.028), and those who had undergone previous revision surgery for infection had a higher risk of complications (p = 0.048). Survivorship at 10.5 years with any further femoral operation as the end-point was 92% (95% confidence interval 82 to 97)

INTRODUCTION. Allograft reconstruction after resection of primary bone sarcomas has a non-union rate of approximately 20%. Achieving a wide surface area of contact between host and allograft bone is one of the most important factors to help reduce the non-union rate. We developed a novel technique of haptic robot-assisted surgery to reconstruct bone defects left after primary bone sarcoma resection with structural allograft. METHODS. Using a sawbone distal femur joint-sparing hemimetaphyseal resection/reconstruction model, an identical bone defect was created in six sawbone distal femur specimens. A tumor-fellowship trained orthopedic surgeon reconstructed the defect using a simulated sawbone allograft femur. First, a standard, ‘all-manual’ technique was used to cut and prepare the allograft to best fit the defect. Then, using an identical sawbone copy of the allograft, the novel haptic-robot technique was used to prepare the allograft to best fit the defect. All specimens were scanned via CT. Using a separately validated technique, the surface area of contact between host and allograft was measured for both (1) the all-manual reconstruction and (2) the robot-assisted reconstruction. All contact surface areas were normalized by dividing absolute contact area by the available surface area on the exposed cut surface of host bone. RESULTS. The mean area of contact between host and allograft bone was 24% (of the available host surface area) for the all-manual group and 76% for the haptic robot-assisted group (p=0.004). CONCLUSIONS. This is the first report to our knowledge of using haptic robot technology to assist in structural bone allograft reconstruction of defects left after primary bone tumor resection. The findings strongly indicate that this technology has the potential to be of substantial clinical benefit. Further studies are warranted

We report the contamination rate in the Cambridge bone bank of 35 consecutive allograft specimens, all harvested in a clean-air environment, using a strict aseptic technique and antibiotic cover. Five of 27 femoral heads taken from living donors and three of eight massive allografts taken from cadavers were found to be contaminated. The contaminated femoral heads were discarded. All massive allografts were rendered sterile by gamma-irradiation. It is important to exclude bacteriological contamination of harvested and banked bone.

Aim: Failed primary hip arthroplasty often results in significant loss of host bone. Revision surgery may require bone grafting to restore bone stock prior to insertion of a new cup. A two to five year follow up of one method of acetabular revision for severe bone stock loss is presented

Materials and Methods: Seventeen patients had acetabular revision with the use of impacted morcellised bone and a cage reconstruction with a cemented cup. The average age at the time of revision was 62. All patients were followed prospectively with regular X-rays. A variety of cages were employed and bone graft was hand morcellised from femoral heads or cadaver distal femurs.

Glenoid replacement is technically challenging. Removal of a cemented glenoid component often results in a large osseous defect which makes the immediate introduction of a revision prosthesis almost impossible. We describe a two-stage revision procedure using a reversed shoulder prosthesis. Freeze-dried allograft with platelet-derived growth factor was used to fill the glenoid defect. Radiological incorporation of the allograft was seen and its consistency allowed the placement of a screwed glenoid component. There were no signs of new mature bone formation on histological examination.

The addition of platelet-derived growth factor to the allograft seems to contribute to an increase in incorporation and hardness, but does not promote the growth of new bone.

Aim: The biological activity of demineralised bone matrix (DBM) led to the discovery of bone morphogenetic proteins (BMP). OP-1 (BMP 7) is an osteoinductive protein and has been demonstrated to be capable of inducing new bone formation in rat subcutaneous tissue and in both orthotopic and heterotopic sites in primates. In this study we have investigated whether demineralisation and addition of osteogenic. protein 1 (OP-1) improves osteoinductive properties of allograft. Methods: A randomised controlled blind trial was performed in 16 rats. One group received two pellets of fresh frozen allograft; the other received two pellets of demineralised bone (DBM) intramuscularly. In each rat one pellet was treated with OP-1 (2mg/25mg of graft). The rats were sacriþced at 28 days and tissue þxed and processed for sectioning with haematoxylin and eosin for morphology and Alcian blue and Sirrus red for collagen types I, II. Qualitative observations were made and each specimen graded 0–5 on the degree of new bone formation and integration by two blind observers. Results & Conclusions: DBM with OP-1 yielded optimal results, being signiþcantly superior to allograft alone and allograft with OP-1. DBM alone was shown to be more effective compared to the allograft preparations. Hence we have shown that demineralization and OP-1 signiþcantly improve the osteoinductive properties of allograft

This study assessed factors responsible for exclusion of patients from bone donation at primary hip arthroplasty in order to improve bone banking.

Fifty-five patients underwent screening in preoperative clinics assessing their suitability for femoral head donation. Records at the bone bank were then reviewed post operatively to check whether bone had been harvested from these individuals during surgery.

Overall, 95% of the patients screened did not proceed to bone banking. After the initial screening stage 60% of patients were excluded. The majority of exclusions (70%) were unacceptable as donors because of their potential risk of transmission of disease to recipients. Although 40% were consented for donation, femoral heads from only 5% were harvested and sent for storage in the bone bank during hip arthroplasty.

Orthopaedic surgeons must take an active part in bone banking and alternative sources of bone grafts require exploration in the future to meet the increasing demand.

Bone grafts are frequently used to augment bone healing. Autologous bone graft is the gold standard for osteogenesis but is limited by availability and donor site morbidity. The processing required to lower the immunogenicity of allograft also reduces the osteogeneic properties. Bone marrow contains mesenchymal stem cells (MSCs) which differentiate into osteoblasts, forming bone. Our study examined the use of bone marrow to enhance the osteogenic properties of allograft.

Bioactive proteins within allogenic bone graft stimulate marrow-derived MSCs to differentiate into osteoblasts, thereby increasing the osteogenic nature of the graft.

After informed consent, bone marrow aspirates were taken from five patients during orthopaedic operations. Freeze-dried ethylene oxide treated allograft, from a number of donors, was obtained from the bone bank. MSCs isolated from each marrow aspirate were grown on eight samples of test allograft. Further allograft was heated to 70°C to denature the osteogenic proteins and MSCs from each aspirate were grown on 8 samples, as a negative control. Osteoblastic differentiation of MSCs cultured on the types of allograft was compared.

Scanning electron microscopy confirmed that MSCs covered the allograft after 14 days. Transmission electron microscopy showed that cells on the test allograft were characteristic of osteoblasts and produced collagen extracellular matrix. The levels of osteoblastic proteins, ALP, osteopontin and Type I pro-collagen, produced by cells on test allograft were significantly greater compared with heat-treated control (P< 0.005), after days 7 and 14.

Our study showed that marrow-isolated MSCs could be successfully cultured on allograft. As the levels of osteoblastic proteins increased significantly when MSCs were grown on allograft, osteogenic proteins within allograft caused MSCs to change into osteoblasts. This confirms that autologous marrow MSCs could be grown on allograft to increase its osteogenic prior to grafting, resulting in increased rate of bony healing.

Introduction: Iontophoresis is a method to introduce antibiotic molecules into allograft bone using an electrical potential; the antibiotics may then be released at therapeutic levels for extended periods of time. This is the first report of iontophoresed allograft implantation into patients. Method: A method of loading tubular sections of cortical bone was used in theatre prior to implantation. Postoperative serum, drain and allograft antibiotic assays were performed. Patients were followed-up clinically and radiologically. All patients who received a bulk segmental allograft from June 1997 were entered into the trial. Results: Since June 1997, 35 patients have received 37 allografts. Indications for allograft insertion were limb salvage for tumour (18), and poor bone stock associated with infection (11), periprosthetic fracture (6), aseptic loosening (1) and recurrent dislocation of total hip replacement (1). Mean follow-up is 3.3 years, and no patients have been lost to follow-up. One patient received two allografts in different sites and one had an allograft exchange. There has been one superficial wound infection and one deep infection. The latter patient was revised to another iontophoresed allograft and has had no recurrence at 34 months. One allograft has been revised to a vascularised fibular graft and allograft exchange following fracture of metal fixation. There was one case of persistent non-union in a knee arthrodesis which was treated after 21 months by removal of the intramedullary fixation and use of an Illizarov frame. The allograft was not revised. All other allografts are in situ with no complications related to the allograft. Eleven patients had pre-existing proven infections. None of these patients have been re-infected to date. Therapeutic gentamicin and flucloxacillin levels were detected in drain fluid samples post-operatively. Conclusions: Iontophoresis is a safe and inexpensive technique that delivers high local dose of antibiotic, which may reduce infection in avascular allograft bone

Introduction and Aims: Iontophoresis is a method to introduce antibiotic molecules into allograft bone using an electrical potential. In-vitro testing has shown that these antibiotics should be released in their bioactive form at therapeutic levels for extended periods of time. This is the first report of iontophoresed allograft implantation into patients. Method: A method of loading tubular sections of cortical bone was used in theatre prior to implantation. The bone was held vertically in an antibiotic bath with a cylindrical outer electrode and a wire electrode down the centre of the bone. An electrical potential of approximately 90V was applied to drive the antibiotics into the bone. Post-operative serum, drain and allograft antibiotic assays were performed. All patients were followed-up clinically and radiologically. Patients who required a bulk segmental allograft from June 1997 to present were entered into the trial and received iontophoresed bone. Results: Since June 1997, 35 patients have received 37 iontophoresed allografts. Indications for allograft insertion were limb salvage for tumor (16), poor bone stock associated with infection (12), periprosthetic fracture (seven), aseptic loosening (one) and recurrent dislocation of total hip replacement (one). One patient had acute complications requiring amputation. No patients were lost to follow-up with a mean follow-up of 3.3 years. Two patients required an allograft exchange for fracture and infection. There were two late allograft infections at 10 and 18 months. One patient was revised to another iontophoresed allograft and has had no recurrence at two years. The other infection required above knee amputation. One allograft was revised with allograft exchange and vascularised fibular graft following fracture of metal fixation. There was one case of persistent non-union in a knee fusion, which was treated after 21 months by removal of the intermedullary fixation and allograft and use of an Ilizarov frame. All other allografts are in-situ with no complications related to the allograft. Twelve patients had pre-existing proven infections. None of these patients have been re-infected to date. Therapeutic gentamicin and flucloxacillin levels were detected in drain fluid samples post-operatively, averaging from 39.9 mg/L at two hours to 5.97mg/L at 48 hours for gentamicin and 16.83mg/L at two hours and 2.23 mg/L at 48 hours for flucloxacillin. This was significantly greater than the minimum inhibitory concentration (MIC) against Staphylococcus aureus for gentamicin (0.25mg/L) and flucloxacillin (0.30mg/L). At the same time, blood levels remained in a safe range. Conclusion: Iontophoresis is a safe and inexpensive method that can be executed in the operating theatre. Iontophoresed bone delivers a high local dose of antibiotic, which may prevent early biofilm formation initiated during allograft handling and exposure to theatre air. With no early infections and no re-infections, further assessment of this technique continues with guarded optimism

Reconstruction acetabular surgery with bone stock loss is still a difficult and challenging problem for the orthopaedic surgeon. The goals of acetabular revision are: stable bone coverage that can support the new acetabular component, restoration of the anatomy and bone stock for future revisions, equalization of leg length and restoration of the centre of hip motion. These goals are difficult to achieve when the pelvic defect is particularly severe. We examine the case of a female 73 years old who underwent a third revision arthroplasty of the hip joint because of extensive bony defect of the acetabular cavity (massive protrusio defect-type III –D’Antonio- combined segmental/cavitary acetabular defect). The femoral component which was revised in a previous operation with a mega stem (type Kotz), was radiologically stable and symptomless. Preoperative radiological assessment was performed using standard radiographic views, Judet views and CT scan. The surgical approach that we used was a slight modification of the previous incision achieving a better visualization of the entire acetabulum and iliac wing. The loose acetabular cup as well as soft tissue and debris were removed from the acetabulum. The large acetabular defect was filled with a massive allograft (tibial plateau) properly cut and shaped. The stability of the allograft was achieved fixing the allograft to the iliac bone with screws. A large amount of particulate allograft bone was placed in the depths of the acetabular defect restoring a proper level of the acetabular floor. Then a Burke-Schneider cage was firmly seated and fixed with screws in the prepared acetabular bed. A polyethylene cup was cemented into the acetabular shell. The superior part of the Kotz femoral prosthesis was also revised with a new one. Postoperatively we din not have any complications, the graft incorporation was successful with a satisfactory functional result. We believe that the use of structural allograft bone is essential for the reconstruction of large segmentalace-tabular defects. The results however are less predictable because of important technical difficulties and sometimes serious complications occur

The Scottish National Blood Transfusion Service is the main provider of bone for grafting in Scotland. Bone is procured only from live donors, following very strict selection criteria, and we have investigated whether the amount being collected was adequate.

Our current harvest of approximately 1700 femoral heads per year is shown not to be enough to meet the future demand for revision surgery of the hip. Many more of these operations are being undertaken, and impaction grafting is being used increasingly.

We have calculated the predicted rates of collection and usage for the next four to five years so that we can expand our service in a controlled fashion.

We studied the calcium content and mechanical strength of cortical bone from rats and dogs after different periods of demineralisation, showing that the rate of demineralisation differed considerably between the species. Specimens from the rat were further treated by chemical extraction and autolysis and tested for osteoinductive properties. We showed that partially demineralised cortical bone retained adequate mechanical strength, while retaining the biological effects of completely demineralised bone. This shows that it is possible to prepare allografts which have adequate mechanical strength and still retain osteo-inductive properties.

Introduction:

This study presents a series of 64 patients undergoing tibio-talo-calcaneal (TTC) fusions with a hindfoot nail to compare the times to union and complications comparing use of allograft with no allograft.

Bone morphogenic proteins (BMPs) are members of the transforming growth factor beta (TGF-beta) family and play a central role in bone formation. These morpho-gens are known to be present in bone matrix however the characteristics of their release during the grafting process has not previously been defined. The aim of this study was to determine the release BMP-7 (osteogenic protein; OP-1) from cancellous allograft that occurs during impaction grafting for revision hip arthroplasty. Forty, 10mm cubes of cancellous bone were accurately cut from the central region of 7 fresh frozen femoral heads. The cubes were centrifuged and washed to remove the marrow contents. The cubes were then individually washed and the fluid assayed for BMP-7 activity using a commercially available enzyme linked immuno-sorbent assay kit (Raybiotech Inc.). The cubes were then divided into 4 groups with samples from each femoral head in each group. Each group was subjected to strain of either 20%, 40%, 60% or 80% using a material testing machine. The cubes were then individually washed again and the wash fluid analysed for BMP-7 activity. BMP-7 activity was found to be present in all groups. Release of BMP-7 was found to increase with increasing strain. At 80% strain the mean concentration of BMP-7 released (830 pg/g) was 58% greater than that released at 60% strain (527 pg/g), 150% greater than the concentration at 40% strain (333 pg/g) and 476% greater than at 20% strain (144 pg/g). The differences between release at 80% and 40% strain and between 80% and 20% strain were statistically significant (p=0.036, p=0.002). Activity of BMP-7 in fresh frozen cancellous allograft bone has not previously been demonstrated. This study shows that the freezing and storage of femoral heads allows some maintenance of biological activity. Furthermore we have shown that BMP-7 may be released in proportion to the strain applied to the bone. This confirms that the process of impaction of bone morsels during revision hip arthroplasty may release BMPs that could aid in the incorporation and remodelling of the allograft

Introduction: Filling of bone defects is a significant challenge in Orthopaedic Surgery. Human fresh-frozen allograft is still the most effective bone graft substitution material («gold standard»), guaranteeing all essential biological and physiochemical demands (osteogenic, osteoinductive, and osteoconductive) when the necessary amount of autologous bone is not available. Using donor screening recommendations, more than 50 % of potential donors have to be excluded. With increasing incidence for revision hip surgery and especially acetabular reconstructions, a hospital associated bone bank has difficulties meeting demand. The aim of this study is to evaluate the balance and resource utilisation of a hospital associated bone bank for fresh-frozen allografts and the correlation to commercial alternatives regarding cost effectiveness.

Method: For evaluation of resource utilisation and cost effectiveness of a hospital associated bone bank, all donation processes and the details of allograft use were analysed and summarized within a period of 30 months. Given the increasing disproportion of demand and availability, the reasons for exclusion, especially for exclusion during the preservation period, were carefully scrutinized. The costs of installation and maintenance of the bone bank, as well as all costs in the screening process were balanced to calculate the «per head»-price. The results were compared to commercial alternatives.

Results: Within the period of evaluation 632 femoral heads were available for donation. Through the screening process 359 femoral heads (56.8%) met at least one criterion for exclusion. At the end of the observation period of six months and after HIV retesting, 246 allografts met all criteria for use. The mean period between inclusion in the bone bank and release was 10.9 5.0 months (range 6.0–30.8).

50.8% of released allografts (125 heads) were used in revision arthroplasty. In spine surgery 83 allografts (33.7%) were implanted in spinal fusions and for cage filling during vertebral body replacement. Thirty-two grafts (13.0%) were used in miscellaneous surgeries with minor bone demand.

The costs per donation were 92, with personnel costs the price per head was 140. The price range for commercial alternatives starts at 100 for 1 cm.

Conclusion: A hospital associated bone bank for fresh-frozen allografts is still an effective and cost effective method to maintain material for bone defect filling. To meet demand, information and communication to donors has to be increased to get the HIV-retests. Additionally, division of donations into smaller portions helps to decrease waste in surgeries where less bone is required.

Aim: This study wants to investigate whether the administration of stromal stem cells (SSC) in a platelet-rich plasma (PRP) scaffold could promote angiogenesis which resulted in a better allograft integration.

Methods: surgery: A monolateral resection of 3cm segment of the metatarsus, was perfomed in 10 adult cross-breed sheep (3–4 years old), weighting 60–70 kg.

Isolation and ex-vivo expansion of SSC: nucleated cells were isolated with density gradient and expanded ex-vivo with alpha-MEM containing 20% FCS.

Radiographic and histomorphometric analysis: Radiographs were made after surgery and after 1, 2 and 4 months. Histomorphometric studies were carried out to study the defect and the new bone formation at the implant site

Results: Union had occurred in all the 5 animals of the SSC group after 4 months as observed radiographically and morphologically, while in the control group the osteotomy line was still visible. Histomorphometric analysis demonstrated a higher % of new-bone formation in both the host (%section quadrant) and the grafted bone in SSC animals.

Conclusions: Results presented suggest that SSC in PRP-based scaffold have improved allograft integration. In conclusion the application of this surgical approach may result in an increased and accelerated bone graft integration, reducing the time required for bone healing and increasing the chances of a successful bone implant.

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.

Periosteal mesenchymal stem cells (PMSC) are an emerging niche of stem cells to enhance bone healing by tissue engineering process. They have to be differentiated into osteoprogenitors in order to synthesize new bone matrix. In vitro differentiation with specific differentiation medium (DM) is not exactly representative of what occurs in vivo. The interaction between PMSC and growth factors (GF) present in biological matrix is somewhat less understood. The goal of this study is to explore the possibility of spontaneous PMSC differentiation in contact with different biological matrices without DM. 500.000 porcine PMSC were seeded on 6-well plates and cultured with proliferation medium (PM). When reaching 80% confluence, biological samples (n=3) of demineralized bone matrix (DBM), decellularized porcine bone allograft (AOp), human bone allograft (AOh), human periosteum (HP) and human fascia lata (HFL) were added. Negative and positive control wells included cells with only PM or DM, respectively. The differentiation progress was assessed by Alizarin Red staining at days 7, 14 and 21. Bone morphogenetic protein content (BMP 2, 4, 5, 6, 7, 8, 9 and 11) of each sample was also investigated by western blot. Alizarin red highlighted bone nodules neoformation on wells containing AOp, AOh and DBM, like positive controls. HP and HFL wells did not show any nodules. These results are correlated to a global higher BMP expression profile in AOp than in HP and HFL but not statistically significant (p=0.38 and p>.99, respectively). The highest expression in each tissue was that of BMP2 and BMP7, which play an important role in osteoinduction. PMSC are well known to participate to bone formation but, despite BMP presence in HP and HFL, they did not permit to achieve osteogenesis alone. The bone contact seems to be essential to induce in vitro differentiation into osteoprogenitors

Various approaches have been implemented to enhance bone regeneration, including the utilization of autologous platelet-rich plasma and bone morphogenetic protein-2. The objective of this study was to evaluate the impact of Marburg Bone Bank-derived bone grafts in conjunction with platelet-rich plasma (PRP), recombinant human bone morphogenetic protein-2 (rhBMP-2), and zoledronic acid (ZA) on osteogenesis within rabbit bone defects. Methodology. Bone defects (5mm in diameter) were created in the femurs of 96 male rabbits. The animals were allocated into five groups: (1) bone graft + PRP (BG + PRP), (2) bone graft + 5μg rhBMP-2 (BG + rhBMP-2), (3) bone graft + 5μg ZA (BG + ZA), (4) bone graft + 10μg rhBMP-2 + 5μg ZA (BG + rhBMP-2 + ZA), and (5) bone graft (BG). Marburg Bone Bank-processed human femoral head allografts were utilized for bone grafting. The rabbits were euthanized at 14-, 30-, and 60-days post-surgery, and their femurs underwent histopathological and histomorphometric assessments. Results. Histomorphometric analysis revealed significantly enhanced de novo osteogenesis within the bone allografts in the BG + PRP and BG + rhBMP-2 groups compared to the BG, BG + ZA, and BG + rhBMP-2 + ZA groups at 14 and 30 days (p < 0.05). However, on day 60, the BG + rhBMP-2 group exhibited elevated osteoclastic activity (early resorption). The local co-administration of ZA with thermally treated grafts impeded both bone graft resorption and new bone formation within the bone defect across all time points. The addition of ZA to BG + rhBMP-2 resulted in diminished osteogenic activity compared to the BG + rhBMP-2 group (p < 0.000). Conclusion. The study findings indicated that the combination of PRP and rhBMP-2 with Marburg bone grafts facilitates early-stage osteogenesis in bone defect healing. Incorporating ZA into the thermally treated bone graft hinders both graft resorption and de novo bone formation

Introduction. AlloStem/Cellular Bone Allograft and autologous bone graft are accepted methods for managing hindfoot degenerative arthritis. The purpose was to evaluate outcomes of AlloStem and autograft in subtalar arthrodesis and compare overall fusion rates. Methods. This study was conducted in IRB compliance. Patients between 18–80 years who qualified for a subtalar fusion were randomized 1:1 to AlloStem or autologous graft. The AOFAS hindfoot ankle scale, FFI-R and SF-12 were collected pre-operatively, 6 weeks, 3 & 6 months, 1 and 2 year. Weight-bearing 3-view ankle X-rays were done at the same intervals. A CT scan was obtained at 6 months. Results. 140 patients were enrolled; 124 patients had surgery(60-AlloStem and 64-Control). Withdrawals included 14 voluntarily before surgery and 2 intra-operative failures. 19 were lost to follow-up. Mean age for AlloStem was 56.69(20.3–79.6) and Autograft was 54.60(20.74–80.07). 59 AlloStem patients completed their 6 month visit and 45 completed 2 years. AOFAS score improved: 40.02 at pre-op to 72.16(6 mo) to 79.51 at 1 year and 80.38 at 2 year. SF-12 improved 58.29 at pre-op to 65.67 at 6 month and 71.59 at 2 year. FFI-R improved 236.88 at pre-op to 203.53 at 6 month 149.93 at 2 year.60 Autograft patients completed their 6 month visit and 51 patients completed their 2 year. AOFAS score improved 42.89 at pre-op to 75.67 (6 mo) to 79.75 at 1 year and 78.62 at 2 year. Autograft SF-12 improved 60.55 at pre-op to 70.40 at 6 month and 75.26 at 2 year. Autograft FFI-R improved 217.16 at pre-op to 166.77 at 6 month and 145.43 at 2 year. AlloStem patients had a mean posterior fusion rate of 28.9% at 6 months whereas the Autograft had 46.3%(p=.049). Non-union rates were AlloStem(9/57)(15.7%) whereas Autograft was 3/60(5%). Conclusion. AlloStem trended to be inferior to Autologous graft

Paediatric musculoskeletal (MSK) disorders often produce severe limb deformities, that may require surgical correction. This may be challenging, especially in case of multiplanar, multifocal and/or multilevel deformities. The increasing implementation of novel technologies, such as virtual surgical planning (VSP), computer aided surgical simulation (CASS) and 3D-printing is rapidly gaining traction for a range of surgical applications in paediatric orthopaedics, allowing for extreme personalization and accuracy of the correction, by also reducing operative times and complications. However, prompt availability and accessible costs of this technology remain a concern. Here, we report our experience using an in-hospital low-cost desk workstation for VSP and rapid prototyping in the field of paediatric orthopaedic surgery. From April 2018 to September 2022 20 children presenting with congenital or post-traumatic deformities of the limbs requiring corrective osteotomies were included in the study. A conversion procedure was applied to transform the CT scan into a 3D model. The surgery was planned using the 3D generated model. The simulation consisted of a virtual process of correction of the alignment, rotation, lengthening of the bones and choosing the level, shape and direction of the osteotomies. We also simulated and calculated the size and position of hardware and customized massive allografts that were shaped in clean room at the hospital bone bank. Sterilizable 3D models and PSI were printed in high-temperature poly-lactic acid (HTPLA), using a low-cost 3D-printer. Twenty-three operations in twenty patients were performed by using VSP and CASS. The sites of correction were: leg (9 cases) hip (5 cases) elbow/forearm (5 cases) foot (5 cases) The 3D printed sterilizable models were used in 21 cases while HTPLA-PSI were used in five cases. customized massive bone allografts were implanted in 4 cases. No complications related to the use of 3D printed models or cutting guides within the surgical field were observed. Post-operative good or excellent radiographic correction was achieved in 21 cases. In conclusion, the application of VSP, CASS and 3D-printing technology can improve the surgical correction of complex limb deformities in children, helping the surgeon to identify the correct landmarks for the osteotomy, to achieve the desired degree of correction, accurately modelling and positioning hardware and bone grafts when required. The implementation of in-hospital low-cost desk workstations for VSP, CASS and 3D-Printing is an effective and cost-advantageous solution for facilitating the use of these technologies in daily clinical and surgical practice

Abstract. Background. Benign osteolytic lesions of bone represent a diverse group of pathological and clinical entities. The aim of this study is to highlight the importance of intraoperative endoscopic assessment of intramedullary osteolytic lesions in view of the rate of complications during the postoperative follow up period. Methods. 69 patients (median age 27 years) with benign osteolytic lesion had been prospectively followed up from December 2017 to December 2018 in a university hospital in Cairo, Egypt and in a level-1 trauma center in United Kingdom. All patients had been treated by curettage with the aid of endoscopy through a standard incision and 2 portals. Histological analysis was confirmed from intraoperative samples analysis. All patients had received bone allografts from different donor sites (iliac crest, fibula, olecranon, etc). None of them received chemo or radiotherapy. Results. Most of lesions were enchondroma (n=29), followed by Aneurysmal bone cyst (ABC) (n=16), Fibrodysplasia (n=13), Chondromyxoid fibroma (n=3), simple bone cyst (n= 3), non-ossifying fibroma (n= 3), giant cell tumour (n= 1) and chondromyxoid fibroma (n = 1). Site of lesion varied from metacarpals (n = 29), femur (n= 1), lower leg (n= 31), and upper limb (n=18). Complications happened only in 9 cases (pathological fractures (n=2), infection (n= 1), recurrence (n=3, all aneurysmal bone cyst), residual pain (n= 3, all in tibia). None of cases developed malignant transformation. Conclusion. Endoscopy is recommended in management of benign osteolytic bone lesions; as it aids in better visualization of the hidden lesions that are missed even after doing apparently satisfactory blind curettage. From our study the recurrence rate is 2% compared to the known 12–18% recurrence rate in the blind technique from literature

Background. Structural bone allografts are an established treatment method for long-bone structural defects arising from such conditions as trauma, sarcoma, and osteolysis following total joint replacement. However, the quality of structural bone allografts is difficult to non-destructively assess prior to use. The functional lifetime of structural allografts depend on their ability to resist cyclic loading, which can lead to fracture even at stress levels well below the yield strength. Because allograft bone has limited capacity for remodeling, optimizing allograft selection for bone quality could decrease long-term fracture risk. Raman spectroscopy biomarkers can non-destructively assess the three primary components of bone (collagen, mineral, and water), and may predict the resistance of donor bone allografts to fracture from cyclic loads. The purpose of this study was to prospectively assess the ability of Raman biomarkers to predict number of cycles to fracture (“cyclic fatigue life”) of human allograft cortical bone. Methods. Twenty-one cortical bone specimens were from the mid-diaphysis of human donor bone tissue (bilateral femurs from 4 donors: 63M, 61M, 51F, 48F) obtained from the Musculoskeletal Transplant Foundation. Six Raman biomarkers were analyzed: collagen disorganization, type B carbonate substitution (a surrogate for mineral maturation), matrix mineralization, and 3 water compartments. Specimens underwent cyclic fatigue testing under fully reversed conditions at 35 and 45MPa (physiologically relevant stress levels for structural allografts). Specimens were tested to fracture or to 30 million cycles (“run-out”), simulating 15 years of moderate activity (i.e., 6000 steps per day). Multivariate regression analysis was performed using a tobit model (censored linear regression) for prediction of cyclic fatigue life. Specimens were right-censored at 30 million cycles. Results. All of the 6 biomarkers that were evaluated were independently associated with cyclic fatigue life (p < 0.05). The multivariate model explained 70% of the variance in cyclic fatigue life (R2=0.695, p<0.001,). Increasing disordered collagen (p<0.001) and loosely collagen-bound water compartments (p<0.001) were associated with decreased cyclic fatigue life. Increasing type B carbonate substitution (p<0.001), matrix mineralization (p<0.001), tightly collagen-bound water (p<0.001), and mineral-bound water (p=0.002) were associated with increased cyclic fatigue life. In the predictive model, 42% of variance in cyclic fatigue life was attributable to degree of collagen disorder, all bound water compartments accounted for 6%, and age and sex accounted for 17%. Conclusions. Raman biomarkers of three bone components (collagen, mineral, and water) predict cyclic fatigue life of human cortical bone. Increased baseline collagen disorder was associated with decreased cyclic fatigue life, and was the strongest determinant of cyclic fatigue life. Increased matrix mineralization and mineral maturation were associated with increased cyclic fatigue life. Bound-water compartments of bone contributed minimally to cyclic fatigue life. These results are complementary with prior Raman studies of monotonic testing of bone that reported decreased toughness and strength with increased collagen disorder and increased stiffness with increased bone mineralization and mineral maturation. This model should be prospectively validated. Raman analysis is a promising tool for the non-destructive evaluation of structural bone allograft quality and may be useful as a screening tool for selection of allograft bone. Acknowledgements. Supported by a grant from the Musculoskeletal Transplant Foundation. The Dudley P. Allen Fellowship (JYD), Wilbert J. Austin Professor of Engineering Chair (CMR) and the Leonard Case Jr. Professor of Engineering Chair (OA) are gratefully acknowledged

Introduction and Objective. In recent years, along with the extending longevity of patients and the increase in their functional demands, the number of annually performed RSA and the incidence of complications are also increasing. When a complication occurs, the patient often needs multiple surgeries to restore the function of the upper limb. Revision implants are directly responsible for the critical reduction of the bone stock, especially in the shoulder. The purpose of this paper is to report the use of allograft bone to restore the bone stock of the glenoid in the treatment of an aseptic glenoid component loosening after a reverse shoulder arthroplasty (RSA). Materials and Methods. An 86-years-old man came to our attention for aseptic glenoid component loosening after RSA. Plain radiographs showed a complete dislocation of the glenoid component with 2 broken screws in the neck of glenoid. CT scans confirmed the severe reduction of the glenoid bone stock and critical bone resorption and were used for the preoperative planning. To our opinion, given the critical bone defect, the only viable option was revision surgery with restoration of bone stock. We planned to use a bone graft harvested from distal bone bank femur as component augmentation. During the revision procedure the baseplate with a long central peg was implanted “on table” on the allograft and an appropriate osteotomy was made to customize the allograft on the glenoid defect according to the CT-based preoperative planning. The Bio-component was implanted with stable screws fixation on residual scapula. We decided not to replace the humeral component since it was stable and showed no signs of mobilization. Results. The new bio-implant was stable, and the patient gained a complete functional recovery of the shoulder. The scheduled radiological assessments up to 12 months showed no signs of bone resorption or mobilization of the glenoid component. Conclusions. The use of bone allograft in revision surgery after a RSA is a versatile and effective technique to treat severe glenoid bone loss and to improve the global stability of the implant. Furthermore, it represents a viable alternative to autologous graft since it requires shorter operative times and reduces graft site complications. There are very few data available regarding the use of allografts and, although the first studies are encouraging, further investigation is needed to determine the biological capabilities of the transplant and its validity in complex revisions after RSA

Osteogenic augmentation is required in various orthopaedic conditions. Autograft is the gold standard but has limitations of increased morbidity and limited amount. Bone graft substitutes are costly and limited and don't integrate with host bone. Deep freezed allografts are a viable option, though not widely used in India and there are sparse reports in literature. This paper studies early efficacy of deep freezed bone allografts in treatment of fractures requiring bone graft. This is a prospective descriptive study. Strict inclusion and exclusion criteria as per standard guidelines were followed. We have a in-house facility of gamma irradiated deep freezed allografts available in hospital. 20 patients with comminuted fracture, delayed / malunion / nonunion, depressed intra articular fractures were operated during one year and followed up for at least 24 weeks. Sloof's Criteria was used for assessing osteointegration of grafts. Efficacy was authenticated by observing complications like serous discharge from surgical site, infection (superficial/deep), rejection of graft, clinical and radiological integration of graft, maintenance of articular reduction etc. Allografts have not only accepted well but fractures have healed and bone integration is at various stages. Only one patients got infected (5%). The overall success rate in terms of adequate osteointegration is 95 %. 19 out of 20 patients in our study group had either attained or at various stages of osteointegration and healing. We concluded that deep freezed bone allografts is a viable option in patients with fractures requiring bone grafts, thus give satisfactory surgical outcome, with no serious side effects

Abstract. Introduction. Osteotomy is a recognised surgical option for the management of unicompartmental knee osteoarthritis. The effectiveness of the surgery is correlated with the accuracy of correction obtained. Overcorrection can potentially lead to excess load through the healthy cartilage resulting in accelerated wear and early failure of surgery. Despite this past studies report this accuracy to be as low as 20% in achieving planned corrections. Aim. Assess the effectiveness of adopting modern osteotomy techniques in improving surgical accuracy. Methodology. A prospective cohort study. Patients were identified who had undergone osteotomy surgery for unicompartmental knee OA using a standardised technique. The surgical techniques adopted to ensure accuracy included digital templating software (Orthoview), Precision saw(Stryker), bone wedge allograft and plate osteosynthesis (Tomofix). Pre and post operative analysis of standardised long leg X-rays was performed and the intended (I) and achieved(A) corrections were calculated. Results. A total of 94 (35F/59M) patients with a mean age of 52 years were identified who fulfilled the inclusion criteria for the study. 62 patients were treated with a tibial osteotomy, 21 with femoral and 11 with a double level osteotomy. Using a 10% acceptable range (AR) for error, in 89% of cases (84 of 94) the target Mikulicz point was achieved. Potential risk factors for overcorrection included female sex and osteotomy type, with a higher incidence of over correction observed with double level osteotomies (27%). Conclusion. This study demonstrates that meticulous digital software planning and surgical technique ensures accurate surgical correction in periarticular knee osteotomy surgery

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

A radiation sterilisation dose (RSD) of 25 kGy is commonly recommended for sterilisation of allograft bone. However, the mechanical and biological performance of allograft bone is gamma dose-dependent. Therefore, this study aimed to apply Method 1 – ISO 11137–2: 2006 to establish a low RSD for frozen bone allografts. Two groups of allograft bones were used: 110 femoral heads (FH) and 130 structural and morselized bones (SMB). The method included the following stages: bioburden determination using 10 FHs and 30 SMBs; verification dose selection using table six in the ISO standard and bioburden; the verification dose was used to irradiate 100 samples from each group; then irradiated bone segments were tested for sterility. The criterion for accepting the RSD as valid is that there must be no more than two non-sterile samples out of 100. The radiation sterilisation dose is then established based on table five, ISO 11137– 2: 2006. The bioburden of both types of frozen allograft was zero. The verification dose chosen was 1.3 kGy. Two hundred bone segments were irradiated at 1.3 kGy. The average delivery gamma dose was 1.23 kGy (with minimum dose of 1.05 kGy maximum dose of 1.41kGy), which is acceptable according to the ISO standard. Sterility tests achieved 100% sterility. Accordingly, 11 kGy was established as a valid RSD for those frozen bone allografts. A reduction in the RSD from 25 kGy to 11 kGy will significantly improve bone allograft mechanical and biological performance because our data show that this dose level improves the mechanical toughness and osteoclast activity of the allograft by more than 10 and 100 percent, respectively, compared with bone allografts irradiated at 25 kGy. A low RSD of 11 kGy was established for allograft bones manufactured at Queensland Bone Bank by applying dose validation method 1 (ISO 11137.2-2006) that is internationally accepted

Objectives. Despite promising results have shown by osteogenic cell-based demineralized bone matrix composites, they need to be optimized for grafts that act as structural frameworks in load-bearing defects. The aims of this study is attempt to assess the effects of laser perforations on osteoinduction in cortical bone allografts. Methods. Sixteen wistar rats were divided into two groups according to the type of structural bone allograft; the first: partially demineralized only (Donly) and the second: partially demineralized laser-perforated (DLP). Trans-cortical holes were achieved by Er:YAG laser at a wave length of 2.94 µm in four rows of three holes approximated cylindrical holes 0.5 mm in diameter, with centres 2.5 mm apart. Histologic and histomorphometric analysis were performed at 12 weeks. Results. Statistical analysis showed significant differences between the 2 groups at 3 months. Results showed that partially demineralized laser-perforated grafts had substantially higher incorporation by woven bone than partially demineralized grafts; yet this difference at the interface gap remained insignificant. In DLP allografts healing at the junction was more complete and a wider area was in contact with host and graft surfaces. Conclusions. Based on the results of this study, it may be concluded that surface changes induced by Er:YAG laser, accelerated bone healing with good osteoinduction results and the process might have improved, if they could have been supplemented with the proper stipulations

Along with prosthetic components, a bone allograft is a major option to be considered in reconstructing a segmental bone loss after a primary malignant bone tumor resection. In most cases of primary bone tumor surgery, segments of long bone will be used as allografts. These are sterilely procured in operating theatre after an organ procurement. To facilitate the reconstruction, the periarticular soft tissues along with the cartilage are also dissected free during the harvest. Bone or osteochondral allografts can be implanted alone with osteosynthetic material or combined with a prosthesis. The allograft can be used as an osteoarticular end, an intercalary construct with or without arthrodesis or be implanted with a prosthesis. The main indication for using bone allograft in 2003 are the intercalary bone loss, an osteoarticular defect at the upper limb, at the proximal tibia and femur if tendon insertions are to be resected and at an anatomical location where no reliable prosthetic material exists such as the scapula or distal fibula. A risk of disease transmission and a high rate of fracture and nonunion are the main disadvantages of this material. An anatomical reconstruction of the skeleton, the possibility to reinsert tendon insertion, the biologic anchorage of the graft with a bony callus, the absence of bone reaction to wear particles and the possibility to recreate a stable joint are among the advantages of using this bone grafting materials. With a bone allograft, virtually any segmental bone loss can be reconstructed. Bone allografts remain a sound material to work with when dealing with a bone tumor. The surgeon must however anticipate the potential complications by performing an appropriate reconstruction

Containment of bone defects is one of the main requisites for using the bone impaction grafting technique. When the proximal femur is absent, circumferential meshes in combination with impacted bone allografts and long stems could be an alternative method. However, the initial stability of this femoral stems has not been evaluated and we were not able to find any series in the literature that includes a group of patients treated with this method. This study has two purposes: one is to analyze the initial resistance in vitro to axial and rotational forces of a fresh frozen bovine model with a complete loss of the proximal femur reconstructed with a circumferential metal mesh containing impacted bone allografts and a long polished cemented stem. The second is to present the short-term clinical and radiographic evaluation in a group of patients with massive bone loss of the proximal femur that were reconstructed with this method. Four femurs with an 8 cm proximal bone defect were reconstructed with a circumferential metal mesh, impacted bone grafts and a cemented long stem (group 1). Results were compared with 4 cases presenting an intact proximal femur in which the same stem was implanted (group 2). Thirteen patients with complete massive proximal femoral bone defects (average 12 cm long) were reconstructed with a circumferential metal mesh, impacted bone allografts and a long cemented stem (average 217 cm long). Failure mode was characterized by subsidence under axial load in group one at 617 kg and by periprosthetic fracture in control group at 1335 kg. Under rotational load, group 1 femurs failed at the cement interface at an average of 79 kg and the intact femurs presented a fracture at an average of 260 kg. At 25 months follow-up, 6 patients had to be reoperated. We observed 2 fractures of the metal mesh at 31 and 48 months in cases reconstructed with a Charnley stem that did not by pass the mesh. Three patients presented one dislocation that needed open reduction in 2 cases. Two acute deep infections were treated with debridement, antibiotics and component retention. This model presented a 50% resistance to axial load and 30% resistance to rotational load compared to an intact femur with the same implant. However, this resistance is by far higher than the physiologic load occurring in a normal femur during gait. Although the incidence of complications in this patients was high, this was related to the complexity of the cases. Failures of the system were not observed except in the 2 cases presenting technical defects. This experimental initial stability and early clinical as well as radiographic results encourage the use of circumferential meshes to contain impacted bone allografts combined with long cemented stems in complex revision hip surgery

Introduction. BAG-S53P4 has similar mechanical properties as cortical bone tissue and can be used as an additive to bone allografts. The aim of this study was to evaluate the effect of adding BAG-S53P4 to chemically treated allografts with controlled grain size distribution. Methods. Allografts were prepared and chemically cleaned under sterile conditions. 30 samples were mixed with BAG-S53P4 additive (BG) and compared to a control group (CG) with similar grain size distribution and composition in weight. All samples underwent a uniaxial compression test after compaction with a dropped weight apparatus. The yield limit was determined by a uniaxial compression test and density was recorded. The two groups were tested for statistical differences with the student's t-Test. Results. Adding BAG-S53P4 to the chemically treated allografts with controlled grain size distribution did not affect the yield limit after compaction. No statistically significant difference regarding the yield limit could be found between CG and BG after compaction (p=0.432).). The yield limit yield limit showed an increase of approximately 96% in CG and 93 % in BG, which confirms the importance of impacting bone chips used for load bearing applications like in hip arthroplasty. Conclusions. Adding BAG-S53P4 seems to have a less profound impact on the yield stress limit. In BG particles smaller than 4 mm were substituted with BAG-S53P4. Achieving a high density may not be the major goal for the bone remodeling process as it may actually obstruct new osteocytes from growing into the allograft material. Adding BAG-S53P4 seems to have limited impact on the yield stress limit. From a biomechanical point of view, BAG-S53P4 can be used as a substitute in total hip replacement if access to bone allograft material is limited

Aims. To evaluate the place of the massive prostheses in the most complex periprosthetic infections cases (PJis). Method. Between 2011 and 2017, 516 hip and knee revisions for periprosthetic infections had been performed in our hospital by the same senior surgeon. We report a prospective series of 58 patients treated between 2011 and the end of 2017. 26 males and 32 females with on average 69,4 years old (38–86). Infection involved TKA in 39 cases (26 TKA revisions, 11 primary TKA), THA in 18 cases (10 revisions, 7 primary THA), a femoral pseudoarthrosis with posttraumatic gonarthrosis in one case and a septic humeral pseudoarthrosis in one case. We used one stage procedures in 38 cases (14 hips, 23 knees, 1 shoulder) and 20 two stages surgeries (16 knees and 4 hips). Additional technics used with massive prostheses, all for TKA PJis: 4 massive extensor systemallografts performed two times in a one stage procedure, two local flaps (medial gastronecmienmuscle). Two perioperative hyperbaric procedures used to limit the risks of wound complications. Results. The average follow-up is 38 months (12–62 months). The rate of sucess to treat the infection at this follow-up is 89,7 %. We report our feedback of the different massive components uses and the qualities/defaults we noted. The most frequent complication was skin events like wound swelling and delayed cicatrisations in 13 cases. 3 cases of one stages needed a complementary debridement in the three weeks after the surgery with always a good local and infectious evolution. This series report 5 failures of two stages TKA revisions. In 4 cases, the initial local soft tissues conditions were compromised. Conclusions. The use of massive prostheses to treat PJIs is a good option for the complex cases. It can be a good alternative of knee arthrodesis. These components must be used, preferentially for oldest patients, in cases of extreme bone loss or extensed osteitis to secure the bone debridement and the quality of the reconstruction. In our series, the one stage procedure is a validated option even by using complementary technics as bone allografts, extensor system allografts or flaps. The two stages procedure is a secondary option, particularly when softtissues status is compromised before or after the debridement, and mostly for the knees

The purpose of our study was to identify possible risk factors of patients with GCT of the long bones after curettage and packing the bone cavity with bone cement or bone allografts. We retrospectively reviewed the records of 249 patients with GCT of the limbs treated at Musculoskeletal Oncology Department of our institution between 1990 and 2013, confirmed histologically and recorded in the Bone Tumor Registry. We reviewed 219 cases located in the lower limb and 30 of the upper limb. This series includes 135 females and 114 males, with mean age 32 years (ranging 5 to 80 yrs). According to Campanacci's grading system, 190 cases were stage 2, 48 cases stage 3, and 11 cases stage 1. Treatment was curettage (intralesional surgery). Local adjuvants, such as phenol and cement, were used in 185 cases; whereas in the remaining 64 cases the residual cavity was filled with allografts or autografts only. Oncological outcome shows 203 patients alive and continuously disease-free (CDF), 41 patients NED1 after treatment of local recurrence (LR), 2 patients NED1 after treatment of lung metastases, 2 AWD with lung metastases. One patient died of unrelated causes (DOD). LR rate was 15.3% (38 pts). Lung metastases rate was 1.6% (4 pts). In patients treated by curettage and cement (185 cases) LR was 12% (22 pts). Conversely, in patients treated curettage and bone allografts it was higher (16/64 cases), with an incidence of 25% of cases (p=0.004). Oncological complications seemed to be related with site, more frequently occurring in the proximal femur (p=0.037). LR occurred only in stage 2 or 3 tumors without statistical significance (p>0.05). The mean interval between the first surgical treatment and LR was 22 months (range: 3–89 mos). However, in the multivariate analysis no significant statistical effect on local recurrence rate could be identified for gender, patient's age, Campanacci's grading, or cement vs allografts. The only independent risk factor related to the local recurrence was the site, with a statistical significance higher risk for patients with GCT of the proximal femur (p= 0.008). Our observation on the correlation of tumor location and risk of local recurrence is new. Therefore, special attention must be given to GCTs in the proximal femur. In fact, primary benign bone tumors in the proximal femur are difficult to treat due to the risk of secondary osteonecrosis of the femoral head or pathologic fracture. Numerous methods of reconstructions have been reported. Among these, total hip arthroplasty (THA) or bipolar hip arthroplasty (BHA) should be avoided when possible as more cases are observed in young patients. Therefore, we do not suggest different approach for the proximal femur. GCT in the proximal femur is much more difficult to treat than in other sites, but if curettage is feasible, the best way is to save the joint with a higher risk of local recurrence, knowing that the sacrifice of the hip articulation in case of recurrence is always possible with THA or BHA

The June 2015 Oncology Roundup. 360 . looks at: Infection in megaprosthesis; Impressive results for mid femoral reconstruction; Revered teaching or old myth? Femoral neck protection in metastatic disease; Megaprosthesis about the knee; Malignant transformation in multiple hereditary exostoses; Fracture of intercalary bone allograft; Comorbidity and outcomes in sarcoma; A worrying turn? Use of denosumab for giant cell tumour of bone

Background. Impaction bone grafting (IBG) using a circumferential metal mesh is one of the options that allow restoration of the femoral bone stock and stability of the implant in hip arthroplasty. Here we examined the clinical and radiographic outcome of this procedure with a cemented stem and analyzed experimentally the initial stability of mesh–grafted bone–cemented stem complexes. Methods. We retrospectively reviewed 6 hips (6 patients) that had undergone femoral revisions with a circumferential metal mesh, impacted bone allografts, and a cemented stem. The mean follow-up period was 2.9 years (range, 1.4–3.8 years). Hip joint function was evaluated with the Japanese Orthopaedic Association hip score, and radiographic changes were determined from radiographs. The initial resistance of cemented stem complexes to axial and rotational force was measured in a composite bone model with various segmental losses of the proximal femur. Results. The hip score improved from 50 (range, 10–84) preoperatively to a mean of 74 (range, 67–88) at the final follow-up. The overall implant survival rate was 100% at 4 years when radiological loosening or revision for any reason was used as the endpoint. No stem subsided more than 3 mm vertically within 1 year after implantation. Computed tomography showed reconstitution of the femoral canal in a metal mesh. In mechanical analyses, there was no influence on the stem stability to axial compression during the repeated axial compression test between IBG reconstruction rates. On the other hand, for IBG reconstruction rate of 66.7%, grafted bone-Sawbone juntion was buckled under the axial breaking force. In contrast, under rotational load, the rotation angles of the stainless mesh were strongly affected by the IBG reconstruction rate. Conclusions. The short-term results show good outcomes for reconstruction of proximal bone loss with impaction bone allografts and a circumferential mesh. The procedure should be applied in cases where the circumferential proximal bone loss is less than half of the stem length implanted

Aims

The duration of systemic antibiotic treatment following first-stage revision surgery for periprosthetic joint infection (PJI) after total hip arthroplasty (THA) is contentious. Our philosophy is to perform an aggressive debridement, and to use a high local concentration of targeted antibiotics in cement beads and systemic prophylactic antibiotics alone. The aim of this study was to assess the success of this philosophy in the management of PJI of the hip using our two-stage protocol.

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Proximal humeral fractures are the third most common fracture among the elderly. Complications associated with fixation include screw perforation, varus collapse, and avascular necrosis of the humeral head. To address these challenges, various augmentation techniques to increase medial column support have been developed. There are currently no recent studies that definitively establish the superiority of augmented fixation over non-augmented implants in the surgical treatment of proximal humeral fractures. The aim of this systematic review and meta-analysis was to compare the outcomes of patients who underwent locking-plate fixation with cement augmentation or bone-graft augmentation versus those who underwent locking-plate fixation without augmentation for proximal humeral fractures.

Management of severe acetabular bone loss at the time of revision total hip replacements (THR) remains has been one of the greater challenges for hip surgeon. Recently, many methods of acetabular reconstruction have been described and various materials are used for supplement of the bone stock deficiency in acetabular revision THR. The purpose of this study was to evaluate the midterm results of the using support ring with bone allografts in acetabular revision THR. From 1990 to 2005, forty-six acetabular revisions using supporting ring with bone allografts were performed at our institution. All patients were followed up for a minimum of three years with a mean follow-up of 7.5 years. Pre-operative radiological acetabular bone defects were assessed and classified by author’s classification (Itoman’s classification). Radiological analysis involved a general qualitative evaluation. The position of the acetabular reinforcement ring was measured on radiograms, taken immediately after revision surgery and again at the time of last follow-up. Using a MEM template, cranio-central migration and cup inclination angle were measured. Kaplan-Meier survivorship analysis was performed. The end point was revision because of mechanical loosening of the acetabular implant. We used thirty-six Ganz rings, six Müller rings, three Kerboull T-plate and two Burch-Schneider anti-protrusion cages. The acetabular bone defects were classified as: 10 hips Type B (central defect), 9 hips Type C (cranial defect), 27 hips Type D (cranial-central defect). Migration of acetabular component was defined as a change of > 5mm in the cranial or central direction of the cup or a change in the cup inclination angle of > 5° at the time of last follow-up. All the Eleven acetabular components which had defined as loose were Type D. One acetabular component was revised because of mechanical loosening, four were revised because of infection, and one was broken polyethylene liner. Kaplan-Meier survivorship of these reconstructions was 96.2 % at 10 years. Allograft reconstruction of acetabular bone defect in revision total hip replacement is beneficial procedure. The remaining pelvic bone is usually in poor condition, therefore, it is necessary to ensure primary fixation with the reinforcement ring with bone allografts

The mean way to fill bone loss, to fix loss of continuity or to correct severe dysplasia in pelvis and in the femur during replacement or revision arthroplasty is the augmentation of the bone stock by mean of bulky or morcellized bone allograft. In order to treat these problems, limiting the possible complications connected to the use of massive bone allograft (bulky or morcellized), and to simplify the surgical procedure we thought to apply in selected cases the platelet’s derived autologous growth factors (AGF), alone or added to Granular Hydroxyapatite. From january 2001 to june 2003 we have applied-autologous growth factors in 10 cases. The diagnosis was: 5 acetabula in primary THR, 2 acetabular and 1 femoral revision after THR, 1 femoral and 1tibial revision after TKR. We applied the pure AGF in 2 cases and AGF plus Granular Hydroxyapatite in 8 cases. We used emispherical, HA coated, uncemented acetabular cup plus screws (6 cases), uncemented revision cup plus screws (1 case), straight HA coated uncemented femoral stem (1 cases), semi-constrained cemented TKR prosthesis (1 cases). The mean age atoperation was 45 years (21–69). The mean follow-up time was 12,5 months (28–6). At the last follow up in all the implants there were no signs of loosening; all the graft seems to be well osteo integrated except in 1 case in which we have had fracture and partial reabsorption of the granular HA, without failure of the implant. We haven’t had any inflammatory reaction or signs of intollerance to the graft. The short term results of our experience seems to be encouraging. If these results will be confirmed in the future the application of AGF should reduce the utilization of massive bone allograft

Aim: This study is describes the clinical and radiological results of 28 hips with Paprosky Type 3 acetabular defects treated by impacted morsellised bone allograft technique and followed up for a mean period of 72 months. Method: The complete cohort of 27patients (28 hips) classiþed as severe acetabular deþciencies (Paprosky type 3) and got treated by impacted morsellised bone allograft technique was available for clinical and radiological review at mean follow up of 72 months (range 48 to 91 months). All the patients were assessed clinically according to the Harris hip-score. All radiographs were digitised using high resolution digitiser. Measurements of subsidence and migration were done using image analysis software. All the radiographs were examined for evidence of radiolucent lines in the three zones of DeLee and Charnley and graft incorporation was assessed from serial radiographs. Results: The results of revision surgery using this technique showed a clinical survival of 96.4% and radiological survival rate 92.85%. Conclusion: Our results have shown that the clinical and radiological results using impacted morsellised allograft technique have been extremely gratifying. The morphological changes seen in these grafts would indicate that the bone grafts utilised have not only incorporated but continue to function in a stable manner. The technique of impaction bone allograft using morsellised fresh frozen allograft appears to be a valuable biological option in revising cases with severe acetabular deþciencies with superior mid-term results

Aims: The purpose of this study is to answer the question, whether local femoral head bone banks are still suitable and how to manage and make them safe. Methods: Surgical donors (THR) are selected by medical history, clinical examination and internationally standardized serological testing. Femoral heads are prucured during THR under OR-sterile conditions. Two different viral and bacterial inactivation methods are performed regularly. Either heads are devided into halves and then autoclaved in an open sterile hot and cold resistant box (121°C,20min,1,4 bar) or entirely processed in a closed sterile box in a water bath (80°C,100min-Marburger bone bank system) and stored in a refrigerator (−80°C). Validation of inactivation has been performed using measurement of the temperature in the center of the bones. Results: 867 bone allografts processed in the described method have been transplanted between 1993 and 2001 in our hospital. Autoclaved grafts have been used in limited bone defects with good surrounding bone stock quality. Water bath treated entire femoral heads have been used in total joint revision surgery. Temperature measurement in autoclaved bones confirmed the biological validation performed by Ph. Chiron (EAMST 1993). Water bath treatment has previously been validated. These grafts proved to be safe, effective and affordable and avoid the higher infection risks of bones procured from organ donors. By the described method we are able to meet a big part of the bone allograft demand in our institution. Conclusions: Using the described method local femoral head bone banks can procure safe and reasonable bone allografts from living surgical donors (THR). Allografts from organ donors cause higher risks and should be used where structural grafts are needed

The conventional method for reconstructing acetabular bone loss at revision surgery includes using structural bone allograft. The disadvantages of this technique promoted the advent of metallic but biocompatible porous implants to fill bone defects enhancing initial and long-term stability of the acetabular component. This paper presents the indications, surgical technique and the outcome of using porous metal acetabular augments for reconstructing acetabular defects. . Cite this article: Bone Joint J 2013;95-B, Supple A:103–8

Aims

The use of a porous metal shell supported by two augments with the ‘footing’ technique is one solution to manage Paprosky IIIB acetabular defects in revision total hip arthroplasty. The aim of this study was to assess the medium-term implant survival and radiological and clinical outcomes of this technique.

Introduction Over recent years the techniques of femoral and acetabular impaction allografting with fresh frozen morsellised bone have become incressingly popular for revision total hip arthoplasty with osseous defects. In many centres lack of availability or legislation has required surgeons to explore alternatives to fresh frozen bone that may have different structural and biological properties. In this study we compare in vitro the load carrying capacity of irradiated morsellised bone against a control non-irradiated sample. Methods Fresh frozen heads were divided in halves with one half irradiated at 25 kGy and the control half left non-irradiated. A custom-built pneumatic loading apparatus applied a force of 1200N at a cycle rate of 1Hz for a total of 1500 cylcles. This loading cycle was chosen to simulate the loads normally experienced by the human femur during walking gait. The reduction in height (subsidence) of each test specimen was measured and statistical analysis performed. Results Results from each treatment group displayed similar patterns of subsidence, with an initial rapid rate of subsidence occurring up to 50 to 100 load cycles, followed by a more gradual, slower rate as the tests progressed. The results for each treatment (mean ± standard deviation) were −3.59 ± 0.91 mm and −2.98 ± 0.812 mm for the irradiated and non-irradiated groups, respectively (P+0.049). The irradiated specimens demonstrated an increased amount of subsidence compared to the non-irradiated specimens. Conclusions This study has shown that gamma irradiation of morsellised bone allograft material decreases its load-carrying capacity, as expressed by an increase in subsidence due to an applied cyclic load. The ability for morsellised bone allograft material to bear applied loads in vivo is an important biomechanical parameter and one indicator of a successful clinical outcome. The clinical implications of this result are important when considering the most appropriate methods of treating human bone allograft material. In relation to the conduct of this study, one or more of the authors is in receipt of a research grant from a commercial source

Aims

Large acetabular bone defects encountered in revision total hip arthroplasty (THA) are challenging to restore. Metal constructs for structural support are combined with bone graft materials for restoration. Autograft is restricted due to limited volume, and allogenic grafts have downsides including cost, availability, and operative processing. Bone graft substitutes (BGS) are an attractive alternative if they can demonstrate positive remodelling. One potential product is a biphasic injectable mixture (Cerament) that combines a fast-resorbing material (calcium sulphate) with the highly osteoconductive material hydroxyapatite. This study reviews the application of this biomaterial in large acetabular defects.

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The aim of this study is to report the long-term outcomes of instrumented femoral revisions with impaction allograft bone grafting (IBG) using the X-change femoral revision system at 30 years after introduction of the technique.

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United Classification System (UCS) B2 and B3 periprosthetic fractures in total hip arthroplasties (THAs) have been commonly managed with modular tapered stems. No study has evaluated the use of monoblock fluted tapered titanium stems for this indication. This study aimed to evaluate the effects of a monoblock stems on implant survivorship, postoperative outcomes, radiological outcomes, and osseointegration following treatment of THA UCS B2 and B3 periprosthetic fractures.

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The aim of this study was to determine the clinical outcomes and factors contributing to failure of transposition osteotomy of the acetabulum (TOA), a type of spherical periacetabular osteotomy, for advanced osteoarthritis secondary to hip dysplasia.

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The benefit of a dual-mobility acetabular component (DMC) for primary total hip arthroplasties (THAs) is controversial. This study aimed to compare the dislocation and complication rates when using a DMC compared to single-mobility (SM) acetabular component in primary elective THA using data collected at a single centre, and compare the revision rates and survival outcomes in these two groups.

Deficiencies of acetabular bone stock at revision hip replacement were reconstructed with two different types of allograft using impaction bone grafting and a Burch-Schneider reinforcement ring. We compared a standard frozen non-irradiated bone bank allograft (group A) with a freeze-dried irradiated bone allograft, vitalised with autologous marrow (group B). We studied 78 patients (79 hips), of whom 87% (69 hips) had type III acetabular defects according to the American Academy of Orthopaedic Surgeons classification at a mean of 31.4 months (14 to 51) after surgery. At the latest follow-up, the mean Harris hip score was 69.9 points (13.5 to 97.1) in group A and 71.0 points (11.5 to 96.5) in group B. Each hip showed evidence of trabeculation and incorporation of the allograft with no acetabular loosening. These results suggest that the use of an acetabular reinforcement ring and a living composite of sterile allograft and autologous marrow appears to be a method of reconstructing acetabular deficiencies which gives comparable results to current forms of treatment

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Biofilm-related infection is a major complication that occurs in orthopaedic surgery. Various treatments are available but efficacy to eradicate infections varies significantly. A systematic review was performed to evaluate therapeutic interventions combating biofilm-related infections on in vivo animal models.

We used a canine intercalary bone defect model to determine the effects of recombinant human osteogenic protein 1 (rhOP-1) on allograft incorporation. The allograft was treated with an implant made up of rhOP-1 and type I collagen or with type I collagen alone. Radiographic analysis showed an increased volume of periosteal callus in both test groups compared with the control group at weeks 4, 6, 8 and 10. Mechanical testing after 12 weeks revealed increased maximal torque and stiffness in the rhOP-1 treated groups compared with the control group. These results indicate a benefit from the use of an rhOP-1 implant in the healing of bone allografts. The effect was independent of the position of the implant. There may be a beneficial clinical application for this treatment

We determined the midterm survival, incidence of peri-prosthetic fracture and the enhancement of the width of the femur when combining struts and impacted bone allografts in 24 patients (25 hips) with severe femoral bone loss who underwent revision hip surgery. The pre-operative diagnosis was aseptic loosening in 16 hips, second-stage reconstruction in seven, peri-prosthetic fracture in one and stem fracture in one hip. A total of 14 hips presented with an Endoklinik grade 4 defect and 11 hips a grade 3 defect. The mean pre-operative Merle D’Aubigné and Postel score was 5.5 points (1 to 8). The survivorship was 96% (95% confidence interval 72 to 98) at a mean of 54.5 months (36 to 109). The mean functional score was 17.3 points (16 to 18). One patient in which the strut did not completely bypass the femoral defect was further revised using a long cemented stem due to peri-prosthetic fracture at six months post-operatively. The mean subsidence of the stem was 1.6 mm (1 to 3). There was no evidence of osteolysis, resorption or radiolucencies during follow-up in any hip. Femoral width was enhanced by a mean of 41% (19% to 82%). A total of 24 hips had partial or complete bridging of the strut allografts. This combined biological method was associated with a favourable survivorship, a low incidence of peri-prosthetic fracture and enhancement of the width of the femur in revision total hip replacement in patients with severe proximal femoral bone loss

AIM. Avascular necrosis (AVN) of the femoral head is a potentially debilitating disease of the hip in young adults. Impaction bone grafting (IBG) of morcellised fresh frozen allograft is used in a number of orthopaedic conditions. This study has examined the potential of skeletal stem cells (SSC) to augment the mechanical properties of impacted bone graft and we translate these findings into clinical practice. STUDY DESIGN. We have examined the effect of SSC density on augmentation of bone formation. An in vitro model was developed to replicate the surgical IBG process. Plain allograft was used as the control, and the SSC's seeded at a density of 5×103, 5×104 and 2×105 cells per cc of allograft for the experimental groups. All samples were cultured for 2 weeks and mechanically tested to determine shear strength using the Mohr Coulomb failure curve. The approach was translated to 3 patients with early avascular necrosis (AVN) of the femoral head. The patient's bone marrow was concentrated in theatre using a centrifugation device and the concentrated fraction of SSC's were seeded onto milled allograft. The patient's necrotic bone was drilled, curetted and replaced with impacted allograft seeded with SSC's. Osteogenic potential of concentrated and unconcentrated marrow was simultaneously compared in vitro by colony forming unit assays. RESULTS. The mechanical properties of the impacted allograft was significantly improved as a function of increasing SSC density. The difference compared to the control plain allograft was highly significant at the 2×105 level (p=0.001). Autologous SCC's on impacted bone allograft was subsequently applied in 3 patient cases and up to two year follow up demonstrates no deleterious effect. Critically the analysis of concentrated marrow demonstrated a higher SSC count in vitro than plain marrow aspirate. DISCUSSION. We have demonstrated the potential of skeletal stem cells to augment the mechanical properties of impacted bone allograft in a laboratory model and subsequently translated these findings into a new technique for the treatment of AVN of the femoral head. Such an approach provides not only improved mechanical support to the overlying cartilage but critically improved biology for new bone formation. The early clinical results are encouraging and indicate potential use also in fracture non-unions and void filling of bone defects

Aims

We wanted to evaluate the effects of a bone anabolic agent (bone morphogenetic protein 2 (BMP-2)) on an anti-catabolic background (systemic or local zoledronate) on fixation of allografted revision implants.

Introduction and Objectives: The success rate of bone allografts in the medium term when used in cancer surgery is 63% to 90% according to the different series. Our aim was to analyze the results and the complication rate seen in bone allografts as used in our center. Materials and Methods: We collected follow-up data from 35 patients who received 37 allografts. The variables analyzed include diagnosis, age, bone and side affected, type of allograft, complications, additional surgery, time of follow-up, and allograft and patient survival. Results: Mean age at surgery: 10.6 years. 48.64% were osteosarcomas, 48.64% were Ewing sarcomas, 2.7% were other diagnoses. 52.94% were strut grafts, 29.41% were osteoarticular, 2.94% were composite, 2.94% were arthrodesis and 11.76% were other types. Of these, 88.88% suffered some type of complication and 81. 48% required additional surgery. We achieved allograft survival in 85.29% of cases with a mean follow-up of 55.45 months. Most frequent complications were non-union (25%), postoperative metastasis (25%) length discrepancy (25%), followed by degenerative arthritis (24%) graft resorption and infection (16.6%). Discussion and Conclusions: Allografts are a reconstructive option with good results in the medium term. In spite of the high complication rate, additional surgeries applying rescue procedures have made it possible to obtain allograft survival similar to that seen in published series

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The aim of this study was to investigate the outcome of periprosthetic fractures of the humerus and to assess the uniformity of the classifications used for these fractures (including those around elbow and/or shoulder arthroplasties) by performing a systematic review of the literature.

We have carried out in 24 patients, a two-stage revision arthroplasty of the hip for infection with massive bone loss. We used a custom-made, antibiotic-loaded cement prosthesis as an interim spacer. Fifteen patients had acetabular deficiencies, eight had segmental femoral bone loss and one had a combined defect. There was no recurrence of infection at a mean follow-up of 4.2 years (2 to 7). A total of 21 patients remained mobile in the interim period. The mean Merle D’Aubigné and Postel hip score improved from 7.3 points before operation to 13.2 between stages and to 15.8 at the final follow-up. The allograft appeared to have incorporated into the host bone in all patients. Complications included two fractures and one dislocation of the cement prosthesis. The use of a temporary spacer maintains the function of the joint between stages even when there is extensive loss of bone. Allograft used in revision surgery after septic conditions restores bone stock without the risk of recurrent infection

Acetabular bone stock loss represents one of the main challenges in revision hip surgery. We present 149 consecutive aseptic acetabular reconstructions with impacted bone allograft technique and a cemented cup followed clinically and radiographically for an average of 52 months (range 24–156 months). Patients requiering reinforcement rings were not included in this series. Seven reconstructions in six patients were lost to follow-up. The average postoperative Merle DAubigne and Postel score was 5.7 points for pain, 4.5 points for mobility and 5.2 points for gait. Radiographic analysis evidenced incorporation of the grafts in all but in four cups with more than 5 mm migration, demonstrating radiographic failure. All of these patients presented clinical failure as well. Non progressive radiolucent lines were observed in 29 non symptomatic patients. mainly in Zone 1 according to De Lee and Charnley. Six patients were reoperated (4.5%), 3 of them because of deep infection and 3 patients for aseptic failure related to massive segmental and cavitary defects. Overall survival rate of the acetabular reconstruction was 95.8% (CI 95%:92.3–99.1). When infected cases were excluded, this rate was 98%. Providing precise indications, acetabular reconstruction with impacted morsellized bone allografts and cemented cups is an excellent biologic reconstructive technique in patients with bone stock deficiency

Several stems have been used for revision of total hip replacement (THR). Moreover, management of proximal femoral bone loss at the time of revision THR remains one of the challenges for hip surgeons. Recently, impaction bone grafting has been suggested to resolve this problem, but it is a demanding technique that results in frequent complications. We have used the Wagner self-locking stem with cancellous chip allograft for reconstruction of proximal femoral bone defect during revision surgery since 1992. This study evaluated the midterm results of using Wagner revision stem with bone allograft for femoral revision of THR. We could evaluate forty-one femoral revisions performed between 1992 and 2005 using Wagner revision stem with bone allograft. All patients had been followed for a minimum of three years with a mean follow-up of 8.6 years. Preoperative radiological femoral bone defects were assessed and classified by Gustillo’s classification. Subsidence of the stem was measured on radiograms taken immediately after revision surgery and again at the latest follow-up. Femoral component fixation was graded as radiographic ingrowth, fibrous stable, or unstable according to the criteria described by Engh et al. The incidence of surgical complications was examined. Allografts were assessed for incorporation into host bone as evidenced by trabecular bridging of the host-graft interface. A clear reduction in density or breakdown of the allograft was defined as bone resorption. Kaplan-Meier survival analysis was performed. The end point was revision because of mechanical loosening of the stem. Bone defects were classified as: 10 hips type I, 20 hips type II, and 7 hips type III and 4 hips were a periprosthetic fracture. Subsidence was measured at the time of last follow-up in six hips (3, 3, 12, 16, 21, 30 mm). At the latest follow-up 37 of 41 stems were stable. Allograft incorporation could clearly be observed in the proximal femoral bone defects of 31 stems. Three stems were defined as showing bone resorption. Surgical complications included 11 intraoperative fractures, two femoral shafts were perforated during reaming, one dislocation postoperatively, and 3 greater trochanter pseudoarthroses. There was one deep infection, and these cases were excluded from survivorship analysis. One unstable stem and one stem with infection had to be revised. Kaplan-Meier survival was 97.1 % at 10 years. Wagner self-locking stem with allograft for reconstruction for proximal femoral bone defect in revision surgery is a beneficial procedure. However, because there is a high incidence of intraoperative fractures, surgery should be performed carefully

We analysed the bacterial contamination of 1999 bone allografts retrieved from 200 cadaver donors under sterile operating conditions. The effect of various factors on the relative risk of contamination was estimated using a multiple logistic regression model. Organisms of low pathogenicity were cultured from 50% of the grafts and of high pathogenicity from 3%. The risk of contamination with low pathogenic organisms (mainly skin commensals) increased by a factor of 1.6 for each member added to the procurement team. The risk of contamination with high pathogenic organisms (mainly contaminants from the gastrointestinal tract) was 3.4 times higher in donors with a traumatic cause of death and 5.2 times higher in those with a positive blood culture. Preceding organ procurement did not significantly influence the risk of contamination. Rinsing the graft with an antibiotic solution was not an effective decontamination method. The major source of contamination is exogenous and is strongly influenced by the procurement team. Contamination from endogenous sources can be controlled by donor selection. We discuss methods that can be used to decrease contamination and the rate of discarding of bone allografts

Background: Rates of around only 40% graft incorporation have been reported when irradiated bone allograft is used during revision hip arthroplasty. In this series we washed fat from irradiated allograft and added 40% by volume of autologous marrow from the iliac crest before impaction grafting. The aim of this study was to determine the rate of graft incorporation in a consecutive series of patients who underwent this modified technique of impaction bone grafting. Methods: 85 consecutive patients, including 51 acetabular and 59 femoral revisions were reviewed. Evidence of graft cortication and or trabeculation was recorded by zone over the period of radiographic follow up. Results: Using washed irradiated allograft with autologous marrow, 96% (49/51) of acetabular and 90% (53/59) of femoral grafts showed incorporation in the majority or all zones. Most of these changes were apparent within 6 months of surgery. The average subsidence of the stem at mean follow up of 45 months was 1.28 mm. Of the 8 patients whose graft failed to incorporate, 2 had grafts removed for post operative infection and 3 had early reoperation for intraoperative fractures. Only 3 out of 85 patients failed to demonstrate bone incorporation in the majority of zones with out an obvious reason why. Conclusions: The addition of autologous marrow to irradiated bone allograft during impaction grafting is a cheap and effective way of increasing the rate of bone incorporation. This series demonstrates over 90% bone incorporation, usually occurring within 6 months after surgery

In revision total hip arthroplasty (THA), it is essential to cope with the bone stock loss. The acetabular bone loss is reconstructed by bulk bone grafts, bone chips, bone cement or jumbo cup. The impaction bone-grafting (IBG) technique is a technique that can restore acetabular bone loss, while enough bone allografts are not easy to obtain and the quality is not always sufficient. Thus we mixed hydroxyapatite (HA) granules into bone chips to supplement the volume and the mechanical strength of allografts. To investigate the dynamic migration of cemented cup fixed with IBG, we made acetabular bone defect models and the migration of the cup was traced by a high-speed photography camera. Composite test blocks were used as synthetic acetabulum models. A hemisphere defect of 60mm in diameter was made. We tested 4 different bone/HA ratio; 100%/0%, 75%/25%, 50%/50% and 0%/100%. Each group consisted of 6 specimens. The grafted materials were impacted using impactors. Then, a 46 mm polyethylene cup was fixed with bone cement. The specimens were clamped to the MTS mechanical tester at an angle of 20 degrees. A dynamic load of 150 N to 1500 N with a frequency of 1 Hz was applied for 15 minutes, followed by a dynamic load of 300 N to 3000 N for the same time period. Then the load was released for 15 minutes. The cup migration was traced by the camera during loading and releasing. This camera captures 15 images per second thus it enables us to trace the migration of the cup during cyclic loading. The cup migration at the end of 3000N loading was measured. Elastic recoil was defined as the difference between the migration at the end of 3000N loading and that when the load reached to 0N. Visco-elastic recoil was defined as the difference between the migration at the release of loading and that after 15 minutes. Data were investigated by Pearson’s correlation coefficient test. A strong negative correlation (r = −0.71) was observed significantly between the amount of the migration and bone/HA ratio. In elastic recoil, statistically significant correlation was (r = −0.55) observed. In visco-elastic recoil, there is no correlation between the amounts of the visco-elastic recoil and bone/HA ratio. In the reconstruction of bone defects, initial stability of the cup is a first step to expect the long term survival. The initial stability depends on the mechanical properties of the grafted materials. To supplement the volume and mechanical strength of bone allografts, we added HA granules to the bone chips. In the current study, the cup migration was smaller by adding HA granules. Elastic recoil was affected, while visco-elastic recoil was not affected. These results indicated that the mixture of HA granules to bone chips stabilized the cup during loading period and load releasing period

The reconstruction of a skeletal defect after resection of a bone tumour represents a challenge for the orthopaedic surgeon. Age, site of the lesion and extension of the disease often limit the choice of surgical technique for a conservative procedure, but several options are available, mainly modular, composite or custom prostheses, massive bone allografts with or without autologous vascularised fibular grafts (AVF), and arthrodeses. An interesting reconstructive technique uses the AVF graft, with microsurgical technique, alone or associated with a massive allograft. The association of a fibular transplant with an allograft increases the mechanical strength of the reconstruction, also promoting more rapid integration. The fibula is a cortical bone and it may provide mechanical strength in the reconstruction of a large segmental bony defect if employed as a viable biological rod. In the present paper the authors discuss their experience with 17 patients treated at the Oncological Orthopaedic Unit of the G.Pini Orthopaedic Institute, for bone tumour resection and reconstruction using AVF graft, almost always combined with a bone allograft. No treatments were performed as augmentation in osteoarticular massive allografts. Subjects’ ages ranged from 7 to 66 years (mean 25.2 years). Most of the patients were referred for a diagnosis of malignancy (15 of 17 cases) and in only two patients were the tumours not aggressive. In 11 patients the AVF was transplanted immediately after tumour resection, while in the others it was used after problems of previous reconstruction. The authors report two cases of deep infection and four mechanical fractures (all healed after a period of cast immobilisation with or without bone bridging). All the AVF survived and healed with a good functional result for the patients except for two recurrences that required an amputation

Use of allograft in orthopaedic surgery is a well-established procedure. Ethylene Oxide sterilization is still controversial in bone banking because of its effect on osteoinductive properties of bone graft. Freeze drying is considered to be the best technique for allograft preparation and storage. High cost of equipment and its maintenance makes this method not feasible option in developing countries like India. This study involved setting up of a bone bank for the first time in JIPMER institute, Pondicherry, India. Cancellous bone was collected from 40 patients (femoral heads removed during joint replacements). They were cleaned thoroughly, chemically processed and sterilized with ethylene oxide gas and stored doubly packed. These were implanted at 11 patients with 14 non-unions, which required cancellous bone grafts. Patients were followed up clinically looking for infection and radiologically for graft incorporation. 85.7 % of grafted sites were united at the end of 12 months. Non-unions took average of 44.8 weeks for the union. Radiological union achieved by 12 months with average time of graft incorporation 44.8 weeks. In 8 cases the allografts were used to pack cavities. Healing occurred at an average of 29 weeks. In 4 patients with arthrodesis following excision of tumor one site failed to unite, one deep infection, which did not resolve with regular chemotherapy had an amputation. The rest of the sites healed at an average 54.8 weeks. This study shows ethylene oxide sterilized cancellous allograft suitable for packing cavities in treatment of benign bone lesions as well as in treatment of non-union. The osteoconductive property of bone allograft may not be affcted by the ethylene oxide sterilization. Achivement of union and a low rate of infection confirms efficacy of ethylene oxide as cost effective and reliable option for bone allograft sterilization

Background. Despite promising results have shown by osteogenic cell-based demineralized bone matrix composites, they need to be optimized for grafts that act as structural frameworks in load-bearing defects. The purpose of this experiment is to determine the effect of bone marrow mesenchymal stem cells seeding on partially demineralized laser-perforated structural allografts that have been implanted in critical femoral defects. Materials and Methods. Thirty-two wistar rats were divided into four groups according to the type of structural bone allograft; the first: partially demineralized only (Donly), the second: partially demineralized stem cell seeded (DST), the third: partially demineralized laser-perforated (DLP), and the fourth: partially demineralized laser-perforated and stem cell seeded (DLPST). Trans-cortical holes were achieved in four rows of three holes approximated cylindrical holes 0.5 mm in diameter, with centres 2.5 mm apart. P3 MSCs were used for graft seeding. Histologic and histomorphometric analysis were performed at 12 weeks. Results. DLP grafts had the highest woven bone formation, where most parts of laser pores were completely healed by woven bone. DST and DLPST grafts surfaces had extra vessel-ingrowth-like porosities. Furthermore, in the DLPST grafts, a distinct bone formation at the interfaces was noted. Conclusion. This study indicated that surface changes induced by laser perforation, accelerated angiogenesis induction by MSCs, which resulted in endochondral bone formation at the interface. Despite non-optimal results, stem cells showed a tendency to improve osteochondrogenesis, and the process might have improved, if they could have been supplemented with the proper stipulations

Primary malignant bone tumor often requires a surgical treatment to remove the tumor and sometimes restore the anatomy using a frozen allograft. During the removal, there is a need for a highest possible accuracy to obtain a wide safe margin from the bone tumour. In case of reconstruction using a bone allograft, an intimate and precise contact at each host-graft junction must be obtained (Enneking 2001). The conventional freehand technique does not guarantee a wide safe margin nor a satisfying reconstruction (Cartiaux 2008). The emergence of navigation systems has procured a significant improvement in accuracy (Cartiaux 2010). However, their use implies some constraints that overcome their benefits, specifically for long bones. Patient-specific cutting guides become now available for a clinical use and drastically simplify the intra-operative set-up. We present the use of pre-operative assistances to produce patient-specific cutting guides for tumor resection and allograft adjustment. We also report their use in the operative room. We have developed technical tools to assist the surgeon during both pre-operative planning and surgery. First, the tumor extension is delineated on MRI images. These MRI images are then merged with Computed Tomography scans of the patient. The tumor and the CTscan are loaded in custom software that enables the surgeon to define target (desired) cutting planes around the tumor (Paul 2009) including a user-defined safe margin. Finally, cutting guides are designed on the virtual model of the patient as a mould of the bone surface surrounding the tumor, materialising the desired cutting planes. When required, a massive bone allograft is selected by comparing shapes of the considered patient's bone and available allografts. The resection planes are transferred onto the selected allograft and a second guide is designed for the allograft cutting. The virtually-designed cutting guides are then manufactured by a rapid prototyping machine using biocompatible material. This procedure has been used to excise a local recurrence of a tibial sarcoma and reconstruct the anatomy using a frozen tibial allograft. The pre-operative planning using virtual models of the patient's bone, tumor and the available allografts enabled the surgeon to localise the tumor, define the desired cutting planes and select the optimal allograft. Patient- and allograft-specific guides have been designed and manufactured. A stable and accurate positioning of guide onto the patient's tibia was made easier thanks to the plate formerly put in place during the previous surgery. An accurate positioning of the allograft cutting guide has been obtained thanks to its design. The obtained reconstruction was optimal with a adjusted allograft that was perfectly fitting the bone defect. The leg alignment was also optimally restored. Computer assistances for tumor surgery are progressively appearing. We have presented at CAOS 2010 an optical navigation system for tumor resection in the pelvis that was promising. However, such a tool is not well adapted for long bones. We have used patient-specific guides on a clinical case to assess the feasibility of the technique and check its accuracy in the resection and reconstruction. The surgeon has benefited from the 3D planning to define his strategy. He had the opportunity to select the optimal transplant for his patient and plan the same cuttings for the allograft and the patient. During the surgery, guide positioning was straightforward and accurate. The bone cuttings were very easy to perform. The use of custom guides decreases the operating time when compared to the conventional procedure since there is no need for measurements between cutting trajectories and anatomical landmarks. Furthermore, the same cutting planes were performed around the tumor and onto the allograft to obtain a transplant that optimally fills the defect. We recommend the use of such an intra-operative assistance for tumor surgery