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

Allograft materials have been the mainstay in addressing bone deficiencies in knee and hip replacement and revision surgery for decades because of the associated donor site morbidity of autografts. Bone graft substitutes have been developed to address allograft issues including potential contamination, disease transmission, and availability. Although non-autogenous products have no osteogenic potential, they do have a variable degree of osteoinductive and osteoconductive properties.

Unfortunately, there are limited reports regarding use of bone graft substitutes for use in total hip and knee arthroplasty. Bone graft substitutes have most frequently been used as an “extender”, in combination with morsellised allograft, to fill cavitary defects. Incorporation of this bone graft substitute and morsellised allograft combination appears to occur incompletely. Stable implant fixation appears to be a prerequisite for incorporation of bone graft substitutes, as these cannot be relied upon for structural support. Although bone graft substitutes appear to perform satisfactorily as “fillers” for contained cavitary bone defects, ultraporous metal augments have become the preferred method of providing structural support for some defects. In view of their substantial cost, high quality clinical, radiographic and retrieval data regarding performance of bone graft substitutes is needed.

Introduction. Reinforcement ring with allograft bone is commonly used for acetabular reconstruction of bone defects because it can achieve stable initial fixation of the prosthesis. It is not clear whether the allograft bone can function as a viable host bone and provide long-standing structural support. The purpose of this study was to assess to long-term survival of the reinforcement rings and allograft bone incorporation after acetabular revisions. Methods. We retrospectively reviewed 39 hips (37 patients) who underwent reconstruction of the acetabulum with a Ganz reinforcement ring and allograft bone in revision total hip arthroplasty. There were 18 females and 19 males with a mean age of 55.9 years (35–74 years). The minimum postoperative follow-up period was 10 years (10∼17 years). We assessed the acetabular bone defect using the Paprosky's classification. We determined the rates of loosening of the acetabular reconstructions, time to aseptic loosening, integration of the allograft bone, resorption of the allograft bone, and survival rate. Aseptic loosening of the acetabular component was defined as a change in the cup migration of more than 5 mm or a change in the inclination angle of more than 5° or breakage of the acetabular component at the time of the follow-up. Graft integration was defined as trabecular remodelling crossing the graft-host interface. Resorption of the allograft bone was classified as minor (<1/3), moderate (1/3–1/2) or severe (>1/2). Kaplan-Meier survivorship analysis was performed for aseptic loosening of the acetabular component. The results. The acetabular bone defects were classified as follows: 8 type II hips (4 type IIB, 4 type IIC), and 31 type III hips (17 type IIIA, 14 type IIIB). Fourteen (35.9%) of 39 hips was defined as aseptic loosening of an acetabular component. Loosening was more frequent in type IIIB (57.1%) than in type IIIA hips (29.4%). Mean time to aseptic loosening of the acetabular reconstructions was 6.3 years in type IIIA and from 5 years in type IIIB defects, respectively. Allograft bone incorporation was satisfactory in 66.7% of hips. There was minor bone resorption in 14.3% and moderate bone resorption in 10.2%. In 9 hips (23.1%), severe resorption of the allograft bone was observed and early component loosening was observed in these cases. The survival rate of acetabular component at 10 years of follow-up was 63.6% (95% confidence interval, 49–77%) with aseptic loosening as endpoints. Conclusions. The long-term survival rate of acetabular revision using the reinforcement ring and allograft bone in the reconstruction of severe acetabular bone defects was unsatisfactorily low due to loosening of acetabular components. Because of unfavorable graft incorporation into a host bone, an alternative component and structural support may be employed in the reconstruction of severe acetabular bone defects

Summary of background data: Lumbar interbody arthrodesis can be achieved by using autograft or allograft bone. One of the disadvantages of using autograft bone graft is complications related to the iliac crest donor site. Another option is using an allograft bone (ex.-femoral head from bone bank). There are few reports of using allograft bone for instrumented lumbar spinal fusion. Methods: Fifteen patients were treated at our institution by lumbar fusion in various indications. We used allograft bone and evaluated their outcome for an average period of 3 years. The recovery rate, complications and radiographic findings were evaluated. Results: Good radiographic and clinical results were achieved by using allograft bone graft. No complications were detected. Conclusions: The clinical and radiographic results of Allograft bone graft, for lumbar spine arthrodesis, are impressive. One of the advantages of this method, comparing to an autograft is avoiding any donor site complications

Introduction. Hip and knee arthroplasty present surgeons with difficult bone loss. In these cases the use of morselized allograft is a well established way of optimizing early implant fixation. In revisions, the surgical field is potentially infected. The use of allograft bone creates a “dead space” in which the immune system has impaired access, and even a small amount of bacteria may therefore theoretically increase the risk of infection. In vivo studies have shown that allograft bone is suitable as a vehicle of local antibiotic delivery. We hypothesized that the allograft bone could be used as a local antibiotic delivery vehicle without impairing the implant fixation, tested by mechanical push-out. Material and Methods. Following approval of the Institutional Animal Care and use Committee we implanted a cylindrical (10×6 mm) porous-coated Ti implant in each distal femur of 12 dogs observed for 4 weeks. The implants were surrounded by a circumferential gap of 2.5 mm impacted with a standardized volume of morselized allograft. In the two intervention groups, 0.2ml tobramycin solution of high (800mg/ml) and low (200mg/ml) concentration was added to the allograft, respectively. In the control group 0.2ml saline was added to the allograft. ANOVA-test was applied followed by paired t-test where appropriate. A p-value < 0,05 was considered statistically significant. Results. The impregnation of allograft bone revealed a relative decrease in biomechanical fixation. The decrease was higher in the high dose group than in the low dose group. The most extreme difference was a decrease in strength by 18% (P = 0,511), stiffness 15% (P = 0,135) and energy absorption 27% (P = 0,784). Conclusion. The result shows a trend towards a decrease in implant fixation correlating with the antibiotic concentration. Although the results are not statistically significant the use of antibiotic impregnation should be used with caution until further reaserch has been conducted

Objectives. The most concerning infection of allografts and operative procedures is methicillin resistant Staphylococcus aureus (MRSA) and no current iontophoresed antibiotics effectively combat this microbe. It was initially hypothesised that iontophoresis of vancomycin through bone would not be effective due to its large molecular size and lack of charge. The aim of this study was to determine whether this was a viable procedure and to find the optimum conditions for its use. . Methods. An iontophoresis cell was set up with varying concentrations of Vancomycin within the medulla of a section of sheep tibia, sealed from an external saline solution. The cell was run for varying times, Vancomycin concentrations and voltages, to gain information on optimisation of conditions for impregnating the graft. Each graft was then sectioned and dust ground from the exposed surface. The dust was serially washed to extract the Vancomycin and concentrations measured and plotted for all variables tested. Results. Vancomycin was successfully delivered and impregnated to the graft using the iontophoresis technique. The first order fit to the whole data set gave a significant result (p = 0.0233), with a significant concentration (p = 0.02774) component. The time component was the next most significant (p = 0.0597), but did not exceed the 95% confidence level. Conclusions. Iontophoresis is an effective method for delivering Vancomycin to allograft bone. The concentrations of the vancomycin solution affected the bone concentration, but results were highly variable. Further study should be done on the effectiveness of delivering different antibiotics using this method. Cite this article: Bone Joint Res 2014;3:101–7

Abstract. Introduction. Bone grafts are utilised in a range of surgical procedures, from joint replacements to treatment of bone loss resulting from cancer. Decellularised allograft bone is a regenerative, biocompatible and immunologically safe potential source of transplant bone. Objectives. To compare the structural and biomechanical parameters of decellularised and unprocessed (cellular) trabecular bone from the human femoral head (FH) and tibial plateau (TP). Methods. Bone pins were harvested from 10 FHs and 11 TPs (27, 34 respectively). Pins were decellularised (0.1% w/v sodium dodecyl sulphate) or retained as cellular controls. QA testing was carried out to assess protocol efficacy (total DNA and histological analysis). Cellular and decellularised FH (n=7) and TP (n=10) were uCT scanned. Material density (MD); apparent density (BV/TV); trabecular connectivity; trabecular number; trabecular thickness (Tb-t) and trabecular spacing were measured. Pins were then compression tested to determine ultimate compressive stress (UCS), Young's modulus and 0.2% proof stress. Results. Total DNA levels of decellularised bone were below 50 ng.mg. −1. dry weight. Cell nuclei and marrow were largely removed. No significant differences in properties were found between decellularised and cellular bone from either anatomical region (p>0.05, Mann-Whitney). No significant differences in biomechanical properties were found between cellular FH and cellular TP (p>0.05) though significant differences in structural properties were found (MD: TP>FH, p=0.001; BV/TV: FH>TP, p=0.001; and Tb-t: FH>TP, p=0.005). Significant differences were found between decellularised FH and decellularised TP (UCS: FH>TP, p=0.001; Young's modulus: FH>TP, p=0.002; proof stress; FH>TP, p=0.001; MD: TP>FH, p<0.001; BV/TV: FH>TP, p<0.001 and Tb-t: FHT>P p<0.001. Conclusion. Decellularisation did not affect the properties of human trabecular bone. Differences were found between the mechanical and structural properties of decellularised FH and TP which could facilitate stratified bone grafts for different applications. Declaration of Interest. (a) fully declare any financial or other potential conflict of interest

Aim. Aim of this monocentric, prospective study was to evaluate the safety, efficacy, clinical and radiographical results at 24-month follow-up (N = 6 patients) undergoing hip revision surgery with severe acetabular bone defects (Paprosky 2C-3A-3B) using a combination of a novel phase-pure betatricalciumphosphate - collagen 3D matrix with allograft bone chips. Method. Prospective follow-up of 6 consecutive patients, who underwent revision surgery of the acetabular component in presence of massive bone defects between April 2018 and July 2019. Indications for revision included mechanical loosening in 4 cases and history of hip infection in 2 cases. Acetabular deficiencies were evaluated radiographically and CT and classified according to the Paprosky classification. Initial diagnosis of the patients included osteoarthritis (N = 4), a traumatic fracture and a congenital hip dislocation. 5 patients underwent first revision surgery, 1 patient underwent a second revision surgery. Results. All patients were followed-up radiographically with a mean of 25,8 months. No complications were observed direct postoperatively. HHS improved significantly from 23.9 preoperatively to 81.5 at the last follow-up. 5 patients achieved a defined good result, and one patient achieved a fair result. No periprosthetic joint infection, no dislocations, no deep vein thrombosis, no vessel damage, and no complaint about limbs length discrepancy could be observed. Postoperative dysmetria was found to be + 0.2cm (0cm/+1.0cm) compared to the preoperative dysmetria of − 2.4 cm (+0.3cm/−5.7cm). Conclusions. Although used in severe acetabular bone defects, the novel phase-pure betatricalciumphosphate - collagen 3D matrixshowed complete resorption and replacement by newly formed bone, leading to a full implant integration at 24 months follow-up and thus represents a promising method with excellent bone regeneration capacities for complex cases, where synthetic bone grafting material is used in addition to autografts

Posterior spinal fusion is performed for a variety of lumbar spine conditions for relief of low back pain. Success relies on an effective fusion. Autograft is associated with donor site comorbidity and limited supply. Allograft has the potential for infection and has limited osteoinductive activity. Bone morphogenic proteins (BMPs) have been promoted for use in posterior spinal fusion despite considerable cost and limited evidence to their efficacy.

The aim of this study was to compare the clinical response, donor site morbidity and radiologic rates of fusion in patients undergoing posterior spinal fusion looking at the choice of bone graft or substitute. A retrospective review of 141 patients undergoing instrumented posterior lumbar spinal fusion by a single surgeon for degenerative disc disease, degenerative spondylolithesis or lytic spondylolithesis between 2000 and 2005 was undertaken. Patients were contacted and assessed for donor site morbidity and scored with the Oswestry Disability Index (ODI). Radiographs were taken and assessed by an independent blinded radiologist using the Ferguson score. Simple analysis was performed of these results to compare bone grafting techniques.

One hundred and forty-one patients were available for review. Fusions were performed for lytic spondylolithesis in 12.4%, degenerative spondylolithesis in 46% and for degenerative disc disease in 41.6% of patients. BMP-2 was used in 19.6%, allograft in 59.8% and iliac crest bone graft in 20.5% of patients. The BMP-2 and non BMP-2 groups were equally spread between the diagnosis and levels of surgery. The overall Ferguson score radiographic fusion rates for these patients was A in 67.9%, B in 17.9% and C in 11.9%. The BMP-2 group patients scored 76.9% (A group) and 23.1% (B group). The non-BMP-2 group scored 57.1% (A group), 23.8% (B group) and 19.1% (C group). The Oswestry Disability Index for patients with BMP-2 improved from 49.7% to 19%, whereas with no BMP-2 improved from 50.0% to 20.9%. Donor site morbidity was not identified as a problem in patients who had an autograft procedure.

Over the course of several years a single spinal surgeon’s posterior lumbar spinal fusion practice has evolved as a variety of bone grafting techniques have been trialled in an effort to increase the rate of bony fusion. There was no obvious difference in Oswestry Disability Index score but there was a modest difference in the Ferguson radiologic fusion score for the BMP-2 group. Morbidity in the autograft group was not a problem. These results have confirmed the efficacy of both allograft and autograft in fusion.

AIM: To study bone healing and infection incidence using Allograft bone in acute comminuted fractures in elderly. METHOD: 21 cases of comminuted fractures of distal femur and proximal tibia requiring bone grafting at primary fixation between 1999 and 2004 were included. Out of 19 cases of proximal tibial fractures, 7 were Schatzker type III, 6 were type IV and 6 were type V. Mean patient’s age was 74 years. Rigid internal fixation with sterilized human Cadaveric allograft was used to fill the defect. No additional auto-bone grafting was done. All cases had 24 hours postop IV antibiotics and were followed up clinically and radiologically until the end point of union or nonunion. OUTCOME: 20/21 cases had fracture union within expected duration. 83 years old patient with Supracon-dylar fracture of femur with DCS fixation, failed to unite at 12 months post op and required revision surgery. 20/21 cases had no superficial or deep infection. 62 years old patient with Schatzker IV tibial plateau fracture had deep infection requiring wound debridement and removal of implant which revealed unabsorbed allograft at one year post op which also cleared the infection. CONCLUSION: Allograft bone graft can be a safe bone substitute for promoting bone healing in elderly patients in acute fracture management. We recommend using allograft bone in elderly patients to reduce morbidity by avoiding one more surgery of obtaining bone graft. Allograft bone in elderly used with internal fixation also provides a reasonable structural support along with it osteoinductive properties

Summary Statement. Supercritical fluid (SCF) sterilization produces clean and osteoconductive allograft bone capable of healing a critical-sised bony defect. SCF treated graft induces an increased anabolic response and decreased catabolic reponse compared to gamma irradiated graft. Introduction. Clinically, allogeneic bone graft is used extensively because it avoids the donor site morbidity associated with autograft. However, there are concerns over the optimal sterilization method to eliminate immunological risks whilst maintaining the biological efficacy of the graft. This study compared the effect of Supercritical fluid (SCF) sterilization and gamma irradiation on the osteoconductivity of allograft bone in a bilateral critical-sised defect rabbit model. Methods. Cortical-cancellous allograft bone was milled, defatted and terminally sterilised with either gamma irradiation at 25kGy or SCF treatment. The graft was then implanted bilaterally into a critical-sised metaphyseal defect in 10 New Zealand White rabbits (n=5 sites per time point per group). Osteoconductivity was evaluated at 2 and 4 weeks to measure the early inflammatory response and early new bone formation respectively, using X-ray, CT, and both qualitative and quantitative histology and immunohistochemistry (Alkaline Phosphatase and Cathepsin-K). Results. Both grafts were well tolerated and osteoconductive. At 2 weeks, there were significant reductions in bone volume and density in the gamma irradiated graft compared to the SCF treated graft as measured by CT. Inside the defect this corresponded with a greater inflammatory response in the gamma irradiated graft, with a less organised fibrous tissue infiltration and mild granuloma reaction. Conversely, the SCF group had a highly organised and densely packed fibrous tissue infiltration around the allograft chips. Immunohistochemistry results supported these findings with an up-regulation in the expression and distribution of Cathepsin-K in the gamma irradiation group; while Alkaline Phosphatase expression was higher in the SCF group. At 4 weeks, resorptive behavior predominated in both groups. Radiographic and CT results detected no significant difference between groups. Histology at 4 weeks showed larger bone chips were undergoing substantial remodeling with areas of simultaneous osteoclastic resorption and osteoblastic new bone formation. Smaller allograft chips and areas of new bone formation were infiltrated by fibrous tissue and undergoing osteoclastic resorption. Quantitative immunohistochemistry showed an up-regulation of Cathepsin-K expression in both groups from 2 to 4 weeks. At both time points Cathepsin-K expression was higher in the gamma irradiated graft compared to the SCF group. This was greatest at 2 weeks where there was a substantial 82% increase in expression which was reduced to a 38% discrepancy at 4 weeks. Alkaline Phosphatase expression was greater in the SCF group at both time-points. Discussion/Conclusion. Allograft bone sterilised with either gamma irradiation or SCF treatment was osteoconductive and capable of healing a critical-sised defect in a rabbit. Gamma irradiated allografts elicited an acute inflammatory reaction when implanted which increased the amount graft resorption compared to the SCF treated bone. Increased osteoclastic resorption may be a concern for structural graft applications leaving the graft more susceptible to premature failure. SCF sterilization produced a clean, highly biocompatible graft with increased anabolic activity compared to gamma irradiation which may facilitate earlier healing clinically. These results suggest that SCF sterilization has considerable expediency for allograft processing and may facilitate more optimal extraction of the inherent properties of the graft compared to current practices

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

Aims: Irradiated allograft bone may help to reduce the risk of transmission of infectious agents from donor to recipient. The purpose of this study was to establish the results of impaction bone grafting of acetabular defects with froze, irradiated allograft bone. Methods: All patients treated by a single surgeon with impaction bone grafting of acetabular defects at revision total hip replacement were reviewed retrospectively. All operations were performed during the period 1994–2000. The mean follow-up was 50 months (range 30–96 months). Case notes and X rays were reviewed and analysed. The Paprosky grade of acetabular defects was determined from the pre-operative X rays and the surgeonñs operation note. Post-operative X rays were reviewed to establish the extent and rate of new bone in-growth. Functional outcomes were determined by way of self-administered questionnaires. Results: Complete records and X rays were obtained for 33 patients who underwent revision hip arthroplasty with impaction bone grafting of the acetabulum using frozen, irradiated allograft bone. There were no complications associated with the bone grafts and no patient required a re-operation. Review of serial X rays conþrmed in-growth of host bone and the functional outcome was satisfactory. Overall 29 patients (88%) declared themselves satis-þed with the outcome of their operation and 32 patients (97%) improved functionally after the operation. Conclusions: These results indicate that satisfactory results can be achieved with impaction bone grafting using frozen, irradiated allograft bone. The use of irradiated bone graft can potentially reduce the risk of disease transmission from donor to recipient without compromising the surgical results

Aims. Infections of bone usually require multiple surgery and prolonged periods of treatment. One reason for problems is found in the presence of stationary phase bacteria embedded in biofilms that show increased resistance against conventional antibiotic therapy (up to 1000x MIC). Biofilms adhere to surfaces of avital material making radical debridement a prerequisite for cure. Osseous defects are common in such conditions and need to be addressed. To avoid re-infection high local antbiotic concentrations are necessary. Allograft bone may be impregnated with high loads of antibiotics using a special incubation technique. The resulting antibiotic bone compound (ABC) provides high and long lasting concentrations at the site of infection and is likely to restore bone stock simultaneously. Based on this technology we have developed a new surgical technique. Methods. 42 patients (10–67yrs) with chronic osteitis were included into a prospective study using a standardized protocol. Infection was at the humerus (1x), femur (10x), tibia (29x) or femur+tibia (2x), respectively. Treatment consisted of removal of foreign material, radical sequestrectomy and soft-tissue debridement followed by pressurized lavage. Surfaces of sclerotic bone were trimmed down to vital areas. The remaining osseous defects were filled with ABC, using an impaction technique resulting in complete dead space management. The allograft was impregnated with vancomycin, in cases with mixed pathogens combinations with tobramycin were used. Internal fixation was performed the same time whenever applicable. Sites were drained and closed immediately; rehabilitation did not differ from uninfected procedures. Results. 1 patient died shortly after surgery from cardiac failure. 41 could be followed for a minimum of 2 and a maximum of 6years (mean 3,1years). In 2 patients wound healing was unsatisfactory requiring additional coverage with a muscle flap. 2 patients showed material failure after intramedullary nailing, requiring exchange of the implant. In those cases no sign of infection was present at the time of revision. There were 3 cases with recurrence of infection, all originating from foci not detected during the index operation and becoming apparent between 3 and 12 months after surgery. Two could successfully be revised using the same technique; one refused revision and shows continuing fistulation. Radiological incorporation of allografts appeared as after conventional bone grafting, union of pseudarthroses was achieved between 2 and 6 months after (re-) stabilization. 40 patients (95,2%) were fully weight bearing, painfree and without any sign of infection at the latest follow up. Conclusion. Using antibiotic impregnated allograft bone eradication of pathogens, grafting of defects, dead space management and insertion of osteosynthetic material may be accomplished in a one stage procedure. Since the graft gradually is replaced by healthy own bone improved long term results may be expected as well as improved conditions in the case of another revision. The new technique provides for quick rehabilitation, improved results and markedly reduced costs of treatment in cases of bone infection

Implantation of allograft bone continues to be an integral part of revision hip surgery. One major concern with its use is the risk of transmission of infective agents. There are a number of methods of processing bone in order to reduce that risk. One part of that processing can be carried out immediately prior to implantation using pulsed irrigation. We report the incidence of deep bacterial infection in a series of 138 patients undergoing 144 revision hip arthroplasty procedures who had undergone allograft bone implantation. The allograft bone used was fresh-frozen non-irradiated. Allograft femoral heads were milled following removal of any residual soft tissue and sclerotic subchondral bone. The bone chips were then placed in a standard metal sieve and irrigated with Normal Saline (pre-warmed to 60 degrees Centigrade) delivered as pulsed lavage at 7 bar pressure. No antibiotics were used in the irrigation solution. The bone chips were washed until all visible blood and marrow products had been removed. The deep infection rate at a minimum one year follow-up was 0.6%. This method of secondary processing appears to be consistent with a very low risk of allograft related bacterial infection

Irradiated allograft bone may help to reduce the risk of transmission of infectious agents from donor to recipient. The purpose of this study was to establish the results of impaction bone grafting of acetabular defects using irradiated allograft bone. Patients treated with impaction bone grafting of ace-tabular defects between 1994 and 2000 were reviewed retrospectively. The mean follow-up was 50months (range 30–96months). Case notes and Xrays were reviewed and analysed. The Paprosky grade of acetabular defects was determined. Functional outcomes were determined by way of self-administered questionnaires. Complete records and Xrays were obtained for 33 patients who underwent impaction bone grafting of the acetabulum using freeze-dried, irradiated bone. The Paprosky classifications of the defects were as follows: 3 type 1, 10 type 2A, 4 type 2B, 4 type 2C, 10 type 3A and 2 type 3B. There were no complications associated with the bone grafts and no patient required reoperation. Review of serial Xrays confirmed ingrowth of host bone. The functional results obtained were as follows: 17 patients (52%) could walk an unlimited distance. 11 patients (33%) required no walking aids whilst a further 17 (52%) required a single cane to mobilise. 21 patients (64%) were able to use public transport after the operation. 20 patients (61%) reported little or no pain. 9 patients (28%) had no limp and 14 patients (42%) had a slight limp. Overall 29 patients (88%) declared themselves to be satisfied with the outcome of their surgery. 32 patients (97%) improved functionally after their operation. These results indicate that satisfactory results can be achieved with impaction bone grafting using irradiated, frozen allograft bone. The use of irradiated bone graft can potentially reduce the risks of disease transmission from donor to recipient without compromising the surgical results

Background: The use of impacted morselized allograft bone and cement in hip revision arthroplasty has proved to be a useful technique for reconstructing femoral bone stock. Studies that specifically address intraoperative and early postoperative femoral fractures and their relationship with bone deficiency, surgical approach or events, fixation of removed implant as well design of implanted stem have been scarce. Methods: Two hundred and eighty five consecutive hip revision arthroplasties with impacted morselized allograft bone were studied. Clinical and radiographic follow-up evaluation was performed and all kind of femoral fractures and incidental perforations during the surgery and within the first year after were analysed. Results: Sixty four (22,4 %) femurs were affected with an incidental perforation or fracture during the surgery and within the first year after. Intraoperative fracture was present in forty femurs. Twenty three were diaphyseal vertical cracks, eight proximal vertical cracks, four fractures of the greater trochanter and two complete diaphyseal fractures. Incidental femoral perforation was present in twenty five femurs. Six fractures occurred during the first year. Four patients of the femoral incidental perforation group suffered a complete diaphyseal fracture at the perforation level. No patient with a diaphyseal femoral crack suffered a complete diaphyseal fracture. Two additional complete fractures occurred during the first year without previous intraoperative complication. Multivariate analysis showed the risk factors for femoral fractures during or after revision to be grater according to preoperative deficiency of the femoral bone stock, or the presence of an intraoperative femoral perforation. Vertical cracks, surgical approach, removal of a cemented or uncemented stem as well as design of the implanted stem showed no difference regarding this complication. Conclusions: Even though a high rate of femoral complications (22,4 %) was observed we found that vertical cracks regardless their location and trochanteric fractures (12,2%) account for almost all of them but have no clinical relevance. Incidental perforation occurred in 9% of the cases and it was found to be related to complete femoral fractures as well as bone stock deficiency. This serious complication requiring revision occurred in only 2.8% of the cases. Due to this results we encourage the use of this technique

Aim: To investigate the migration and rotation patterns of the socket in hip revisions with impacted morselized allograft bone and cement. Methods: 17 Exeter socket revisions were followed by radiostereometry (RSA) and radiography for 5 years. The surgical procedure described by the Nijmegen group in Netherlands was used. The allograft bone chips were prepared in a bone mill and had an approximate size of 3 mm. Results: All but 1 socket migrated proximally (accuracy 0.2 mm). Five socket revisions with a radiolucent line > 2 mm in at least 1 zone had a migration and a rotation rate 2–5 times larger (broken lines) than 12 socket revisions (unbroken lines) without a radiolucent line > 2 mm. Allograft resorption in at least 2 zones was observed in all these 5 revisions but in 4 of them no progression of the radiolucent line was seen after the 2 years and there was no clinical deterioration or threat to bone stock. In 8 of the revisions radiographic signs of trabecular incorporation or remodeling of the graft were observed. No rerevision was performed. Conclusions: Further follow-up is needed for evaluation of the clinical relevance of radiolucent lines in impaction grafting. As a consequence of these findings a RSA study using larger bone chips has been started

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

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