Fresh-frozen vs. irradiated allograft bone in orthopaedic reconstructive surgery

The Use of Glenoid Structural Allografts for Glenoid Bone Defects in Reverse Shoulder Arthroplasty

Background: The use of reverse shoulder arthroplasty as a primary and revision implant is increasing. Advances in implant design and preoperative surgical planning allow the management of complex glenoid defects. As the demand for treating severe bone loss increases, custom allograft composites are needed to match the premorbid anatomy. Baseplate composite structural allografts are used in patients with eccentric and centric defects to restore the glenoid joint line. Preserving bone stock is important in younger patients where a revision surgery is expected. The aim of this article is to present the assessment, planning, and indications of femoral head allografting for bony defects of the glenoid. Methods: The preoperative surgical planning and the surgical technique to execute the plan with a baseplate composite graft are detailed. The preliminary clinical and radiological results of 29 shoulders which have undergone this graft planning and surgical technique are discussed. Clinical outcomes included visual analogue score of pain (VAS), American Shoulder and Elbow Surgeons score (ASES), Constant-Murley score (CS), satisfaction before and after operation, and active range of motion. Radiological outcomes included graft healing and presence of osteolysis or loosening. Results: The use of composite grafts in this series has shown excellent clinical outcomes, with an overall graft complication rate in complex bone loss cases of 8%. Conclusion: Femoral head structural allografting is a valid and viable surgical option for glenoid bone defects in reverse shoulder arthroplasty.

Intercalary allograft reconstruction following femoral tumour resection: mid- and long-term results and benefits of adding a vascularised fibula autograft

Purpose

Bone healing in femoral reconstructions using intercalary allografts can be compromised in a tumour context. There is also a high revision rate for non-union, infection, and fractures in this context. The advantages and disadvantages of an associated vascularised fibula graft (VFG) are still a matter of debate.

Methods

In a multicentre study, we retrospectively analysed 46 allograft reconstructions, operated on between 1984 and 2017, of which 18 were associated with a VFG (VFG+) and 28 without (VFG−), with a minimum follow-up of 2 years. We determined the cumulative probability of bone union as well as the mid- and long-term revision risks for both categories by Kaplan-Meier survival analysis and a multivariate Cox model. We also compared the MSTS scores.

Results

Significant differences in favour of VFG+ reconstruction were observed in the survival analyses for the probability of bone union (log-rank, p = 0.017) and in mid- and long-term revisions (log-rank, p = 0.032). No significant difference was observed for the MSTS, with a mean MSTS of 27.6 in our overall cohort (p = 0.060). The multivariate Cox model confirmed that VFG+ was the main positive factor for bone union, and it identified irradiated allografts as a major risk factor for the occurrence of mid- and long-term revisions.

Conclusion

Bone union was achieved earlier in both survival and Cox model analyses for the VFG+ group. It also reduced the mid- and long-term revision risk, except when an irradiated allograft was used. In case of a tumour, we thus recommend using VFG+ from a fresh-frozen allograft, as it appears to be a more reliable long-term option.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12957-022-02650-x.

Application of structural allogenous bone graft in two-stage exchange arthroplasty for knee periprosthetic joint infection: a case control study

Background

Knee prosthetic joint infection (PJI) is a common but devastating complication after knee arthroplasty. The revision surgeries for knee PJI may become more challenging when it is associated with large bone defects. The application of structural bone allograft in knee revision surgeries with large bone defects is not a new technique. However, there is a lack of literature reporting its efficacy in PJI cases. This study aimed to investigate the outcome of structural fresh frozen allogenous bone grafts in treating patients in knee PJI with large bone defects.

Methods

We performed a retrospective cohort analysis of knee PJI cases treated with two-stage exchange arthroplasty at our institution from 2010 to 2016. 12 patients with structural allogenous bone graft reconstructions were identified as the study group. 24 patients without structural allograft reconstructions matched with the study group by age, gender, and Charlson comorbidity index were enrolled as the control group. The functional outcome of the study group was evaluated with the Knee Society Score (KSS). Treatment success was assessed according to the Delphi-based consensus definition. The infection relapse rate and implant survivorship were compared between groups.

Results

Revision knees with structural allograft presented excellent improvement in the KSS (33.1 to 75.4). There was no significant difference between infection relapse-free survival rate and prosthesis survival rate in the two groups. The 8-year prosthesis survival rate was 90.9% in the study group and 91% in the control group (p = 0.913). The 8-year infection relapse-free survival rate was 80 and 83.3% in the study group and control group, respectively (p = 0.377).

Conclusion

The structural fresh frozen allogenous bone graft provided an effective way for bone defect reconstruction in knee PJI with an accountable survival rate. Meanwhile, using structural allografts did not increase the relapse rate of infection.

Biologic Augmentation of Tibiotalocalcaneal Arthrodesis With Allogeneic Bone Block Is Associated With High Rates of Fusion

BACKGROUND

The orthopaedic conditions and systemic comorbidities that occur in patients who require bone block tibiotalocalcaneal (TTC) arthrodesis have made this procedure associated with a higher-than-normal risk of nonunion, graft collapse, hardware failure, and amputation. Here, we present a novel approach to bone block TTC arthrodesis using adjunctive osteoinductive agents and a prolonged course of protected weightbearing to assess if we could improve on historical outcomes. We also evaluated the efficacy of a vascularized medial femoral condyle (MFC) free flap to augment TTC arthrodesis.

METHODS

Fourteen adult patients underwent bone block TTC arthrodesis biologically augmented with fresh-frozen femoral head allograft, bone marrow aspirate concentrate, and demineralized bone matrix cortical fibers. Three patients with soft tissue defects underwent vascularized reconstruction with an MFC free flap. Radiographic union, the Foot Function Index (FFI), and PROMIS pain interference (PI), and physical function (PF) scores were assessed at follow-up.

RESULTS

TTC fusion was documented on plain radiograph in 13 of 14 patients (92.9%) and CT in 10 of 11 patients (90.9%). Mean time to fusion was 183.2 ± 83.2 days. One patient (7.1%) experienced nonunion and persistent infection requiring amputation. Patients who underwent vascularized bone grafting had significantly shorter time to fusion (112.3 ± 31.7 days vs 204.4 ± 82.7 days, P = .05). Patient-reported outcomes revealed mild to moderate pain and dysfunction after 1 year (mean FFI = 41.0% ± 23.1%, PROMIS PI = 58.3 ± 1.8, PROMIS PF = 39.0 ± 2.2).

CONCLUSION

In this relatively small series, the biologic augmentation of bone block TTC arthrodesis with osteoinductive agents and protective weightbearing resulted in excellent rates of fusion, modest pain, and preserved function of the lower extremity in almost all those treated. Osseous healing appears to be enhanced and accelerated with application of an MFC flap. We believe that this approach offers a viable salvage option for these challenging clinical problems.

LEVEL OF EVIDENCE

Level IV, case series.

Skeletal regeneration for segmental bone loss: Vascularised grafts, analogues and surrogates

Massive segmental bone defects (SBD) are mostly treated by removing the fibula and transplanting it complete with blood supply. While revolutionary 50 years ago, this remains the standard treatment. This review considers different strategies to repair SBD and emerging potential replacements for this highly invasive procedure. Prior to the technical breakthrough of microsurgery, researchers in the 1960s and 1970s had begun to make considerable progress in developing non autologous routes to repairing SBD. While the breaktthrough of vascularised bone transplantation solved the immediate problem of a lack of reliable repair strategies, much of their prior work is still relevant today. We challenge the assumption that mimicry is necessary or likely to be successful and instead point to the utility of quite crude (from a materials technology perspective), approaches. Together there are quite compelling indications that the body can regenerate entire bone segments with few or no exogenous factors. This is important, as there is a limit to how expensive a bone repair can be and still be widely available to all patients since cost restraints within healthcare systems are not likely to diminish in the near future. STATEMENT OF SIGNIFICANCE: This review is significant because it is a multidisciplinary view of several surgeons and scientists as to what is driving improvement in segmental bone defect repair, why many approaches to date have not succeeded and why some quite basic approaches can be as effective as they are. While there are many reviews of the literature of grafting and bone repair the relative lack of substantial improvement and slow rate of progress in clinical translation is often overlooked and we seek to challenge the reader to consider the issue more broadly.

FDA-approved bone grafts and bone graft substitute devices in bone regeneration

To induce bone regeneration there is a complex cascade of growth factors. Growth factors such as recombinant BMP-2, BMP-7, and PDGF are FDA-approved therapies in bone regeneration. Although, BMP shows promising results as being an alternative to autograft, it also has its own downfalls. BMP-2 has many adverse effects such as inflammatory complications such as massive soft-tissue swelling that can compromise a patient's airway, ectopic bone formation, and tumor formation. BMP-2 may also be advantageous for patients not willing to give up smoking as it shows bone regeneration success with smokers. BMP-7 is no longer an option for bone regeneration as it has withdrawn off the market. PDGF-BB grafts in studies have shown PDGF had similar fusion rates to autologous grafts and fewer adverse effects. There is also an FDA-approved bioactive molecule for bone regeneration, a peptide P-15. P-15 was found to be effective, safe, and have similar outcomes to autograft at 2 years post-op for cervical radiculopathy due to cervical degenerative disc disease. Growth factors and bioactive molecules show some promising results in bone regeneration, although more research is needed to avoid their adverse effects and learn about the long-term effects of these therapies. There is a need of a bone regeneration method of similar quality of an autograft that is osteoconductive, osteoinductive, and osteogenic. This review covers all FDA-approved bone regeneration therapies such as the "gold standard" autografts, allografts, synthetic bone grafts, and the newer growth factors/bioactive molecules. It also covers international bone grafts not yet approved in the United States and upcoming technologies in bone grafts.

The choice between allograft or demineralized bone matrix is not unambiguous in trauma surgery

In fracture surgery, large bone defects and non-unions often require bone transplantation, and alternatives to autograft bone substitutes in the form of allografts from bone banks and the derivate demineralised bone matrix (DBM) are widely used. With a focus on efficacy, clinical evidence, safety, cost, and patient acceptance, this review evaluated the difference between allogeneic allograft or DBM as a bone substitute in trauma surgery. The efficacy in supporting bone healing from allograft and DBM is highly influenced by donor characteristics and graft processing. Mechanical stability is achieved from a structural graft. Based on the existing literature it is difficult to identify where DBM is useful in trauma surgery, and the level of evidence for the relevant use of allograft bone in trauma is low. The risk of transmitting diseases is negligible, and the lowest risk is from DBM due to the extensive processing procedures. A cost comparison showed that DBM is significantly more expensive. The experiences of dental patients have shown that many patients do not want to receive allografts as a bone substitute. It is not possible to definitively conclude whether it makes a difference if allograft or DBM is used in trauma surgery. It is ultimately the surgeon's individual choice, but this article may be useful in providing considerations before a decision is made.

Subtalar distraction arthrodesis for calcaneal malunion - comparison of structural freeze-dried versus autologous iliac bone graft

BACKGROUND

This study aims to analyze the outcomes of subtalar distraction arthrodesis (SDA) for calcaneal malunion using structural freeze-dried iliac allograft (FDIA) compared to using autologous iliac bone (AIB).

METHODS

We retrospectively evaluated 57 consecutive cases (51 patients) of calcaneal malunion between March 2006 and December 2017. All patients were followed for an average of 22.8 months. All cases were treated by SDA using structural FDIA (17 cases, group 1), or AIB (40 cases, group 2). The outcome measures included the American Orthopaedic Foot and Ankle Society ankle-hindfoot (AOFAS) scores, visual analog scale (VAS) pain scores, and radiographic measurements.

RESULTS

The mean postoperative 3, 6, and 12 months of AOFAS scores and VAS pain score were significantly better in group 2 than those in group 1 (p < 0.05, for all). There were 3 cases (17.6%) of nonunion in the group 1, whereas the group 2 had 2 cases (5.0%), which did not shown significant difference between two groups (p = 0.492). Although the mean pre-, postoperative, and final follow-up radiologic parameters in both groups were similar, (p > 0.05, for all) the difference of talocalcaneal height, talocalcaneal angle, and talar declination angle from postoperative to final follow-up were significantly bigger in the group 1. (p < 0.05, for all).

CONCLUSION

Although union rate was not significantly different between the two groups, we obtained more favorable clinical and radiologic outcomes in the autologous iliac bone group. Using FDIA without any orthobiological agent for SDA, there were significant more loss of radiological parameters due to inferior incorporation and biomechanical properties. When considering the SDA for calcaneal malunion, routine use of FDIA without any orthobiological agents as an interpositional graft for SDA is not recommended.

Volumetric Stability of Fresh Frozen Bone Blocks in Atrophic Posterior Mandible Augmentation

Fresh frozen bone allografts (FFB) have become an alternative for bone augmentation in the past decades, especially because of the absence of recent reports of disease transmission or immunologic reactions when it is used. The aim of this prospective controlled study is to evaluate volumetric changes of newly created bone following reconstruction of the atrophic posterior mandible. Twenty consecutive patients presenting for reconstruction of posterior mandibular alveolar bone ridge width ≤6.0 mm and/or height ≤6.0 who met all inclusion and exclusion criteria were included. FFB blocks were used. The main outcome variable investigated was bone volume dynamics. Vertical, horizontal, and 3-dimensional bone gain data were measured from computerized tomography scans. The main predictor variable was time evaluated at 3 points: immediately after surgery (T1), at implant placement (T2), and 1 year after functional loading (T3). Secondary outcome parameters evaluated were implant survival, histologic findings, and microtomographic morphometry. The study included 28 hemi-mandibles, 50 FFB bone blocks, and 15 female and 5 male patients (mean age, 51.8 years). Block and implant survival rates were 100% and 96%, respectively, after 31.75 months of follow-up. Vertical and horizontal bone gain at T2 was 5.15 and 6.42 mm, respectively. Volumetric resorption was 31% at T2, followed by an additional 10% reduction at T3. Histologic evaluation showed newly formed vital bone in intimate contact with the remaining FFB. Microtomography revealed 31.8% newly formed bone, 14.5% remaining grafted bone, and 53.7% connective tissue and bone marrow. Thus, FFB blocks may lead to new bone formation and consolidation, with satisfactory volumetric bone maintenance, allowing implant-supported rehabilitation with high success rates.

The effects of irradiation on the biological and biomechanical properties of an acellular porcine superflexor tendon graft for cruciate ligament repair

Acellular xenogeneic tissues have the potential to provide ‘off‐the‐shelf’ grafts for anterior cruciate ligament (ACL) repair. To ensure that such grafts are sterile following packaging, it is desirable to use terminal sterilization methods. Here, the effects of gamma and electron beam irradiation on the biological and biomechanical properties of a previously developed acellular porcine superflexor tendon (pSFT) were investigated. Irradiation following treatment with peracetic acid was compared to peracetic acid treatment alone and the stability of grafts following long‐term storage assessed. Irradiation did not affect total collagen content or biocompatibility (determined using a contact cytotoxicity assay) of the grafts, but slightly increased the amount of denatured collagen in and decreased the thermal denaturation temperature of the tissue in a dose dependant fashion. Biomechanical properties of the grafts were altered by irradiation (reduced ultimate tensile strength and Young's modulus, increased failure strain), but remained superior to reported properties of the native human ACL. Long term storage at 4°C had no negative effects on the grafts. Of all the conditions tested, a dose of minimum 25 kGy of gamma irradiation had least effect on the grafts, suggesting that this dose produces a biocompatible pSFT graft with adequate mechanical properties for ACL repair. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 2477–2486, 2017.

Large osteochondral lesions of the femoral condyles: Treatment with fresh frozen and irradiated allograft using the Mega OATS technique

BACKGROUND

The purpose of this study was to review the clinical results of irradiated fresh frozen osteochondral allografts for large osteochondral defects of the knee using the Mega-OATS technique.

METHODS

Nine patients with a mean age of 32.1±6.6 (18 to 44) underwent Mega-OATS transplantation with irradiated (2.5Mrad), fresh frozen distal femur allograft. Three patients also underwent ACL-reconstruction; one patient a high tibial osteotomy. The underlying indication was osteochondrosis dissecans in four and trauma in five patients. The defect size was 25×25mm in three patients and 30×30 in six patients and the depth ranged from eight to 14mm. All OCD lesions were located on the medial femoral condyle; two of the traumatic lesions were located on the lateral femoral condyle. Clinical outcome was assessed using the Lysholm and IKDC scores. Radiographic incorporation was evaluated using serial radiographs and MR imaging at one year post surgery. All patients were reviewed at three, six, 12, and 24months following surgery.

RESULTS

The Lysholm (IKDC) score improved significantly (p=0.02 resp. p=0.007) within and between patients during the follow-up period from 40.9 (37) to 90.9 (87.1) at 2years. Radiographic union was observed in all patients at three months; on MR imaging at one year osseous integration was observed in eight patients. Graft subsidence with loss of the overlying cartilage was observed in one and subchondral cystic changes at the implantation side were seen in another patient.

CONCLUSION

The results of this case series suggest that irradiated osteochondral allograft provides significant medium-term clinical improvement in patients treated for large osteochondral lesions of the femoral condyles.

LEVEL OF EVIDENCE

IV, case series.

Does Repair of a Hill-Sachs Defect Increase Stability at the Glenohumeral Joint?

Background:

The effect of osteoallograft repair of a Hill-Sachs lesion and the effect of allograft fit on glenohumeral translations in response to applied force are poorly understood.

Purpose:

To compare the impact of a 25% Hill-Sachs lesion, a perfect osteoallograft repair (PAR) of a 25% Hill-Sachs lesion, and an “imperfect” osteoallograft repair (IAR) of a 25% Hill-Sachs lesion on glenohumeral translations in response to a compressive load and either an anterior or posterior load in 3 clinically relevant arm positions.

Study Design:

Controlled laboratory study.

Methods:

A robotic/universal force-moment sensor testing system was used to apply joint compression (22 N) and an anterior or posterior load (44 N) to cadaveric shoulders (n = 9) with the skin and deltoid removed (intact) at 3 glenohumeral joint positions (abduction/external rotation): 0°/0°, 30°/30°, and 60°/60°. The 25% bony defect state, PAR state, and IAR state were created and the loading protocol was performed. Translational motion was measured in each position for each shoulder state. A nonparametric repeated-measures Friedman test with a Wilcoxon signed-rank post hoc test was performed to compare the biomechanical parameters (P < .05).

Results:

Compared with the defect shoulder, the PAR shoulder had significantly less anterior translation with an anterior load in the 0°/0° (15.3 ± 8.2 vs 16.6 ± 9.0 mm, P = .008) and 30°/30° (13.6 ± 7.1 vs 14.2 ± 7.0 mm, P = .021) positions. Compared with IAR, the PAR shoulder had significantly less anterior translation with an anterior load in the 0°/0° (15.3 ± 8.2 vs 16.6 ± 9.0 mm, P = .008) and 30°/30° (13.6 ± 7.1 vs 14.4 ± 7.1 mm, P = .011) positions, and the defect shoulder had significantly less anterior translation with an anterior load in the 30°/30° (14.2 ± 7.0 vs 14.4 ± 7.0 mm, P = .038) position.

Conclusion:

PAR resulted in the least translational motion at the glenohumeral joint. The defect shoulder had significantly less translational motion at the joint compared with the IAR. An IAR resulted in the most translational motion at the glenohumeral joint. This demonstrates the biomechanical importance of performing an osteoallograft repair in which the allograft closely matches the Hill-Sachs defect and fully restores the preinjury state of the humeral head.

Clinical Relevance:

This study demonstrates the importance of performing an osteoallograft repair of a Hill-Sachs defect that closely matches the preinjury state and restores normal humeral head anatomy.

Post-operative infection with fresh frozen allograft: reported outcomes of a hospital-based bone bank over 14 years

Femoral head bone allografts have traditionally been used to provide mechanical stability to areas of bony deficiency, or for its osteoinductive and osteoconductive properties. Concerns have been raised over increased infection rates following the use of fresh-frozen graft tissue. This retrospective study aims to investigate the outcomes of fresh frozen femoral heads kept in a regulated, non-commercial bone bank at a university teaching hospital.The local bone bank database was used to identify released femoral heads during a 14 year study period (September 1999-December 2013) whereby a retrospective review of patient records was undertaken to determine clinical outcome. During the observed study period, 427 femoral heads were released from cold storage. Of these, 270 femoral heads had a mean follow-up of 347 days. 157 femoral heads were excluded due to insufficient follow-up data (n = 132) or discarded due to breaks in the cold chain prior to use (n = 25). Of the 270 included femoral heads, 231 (85.6 %) had no reported complications with good graft incorporation. In the remaining 39 with reported complications, only 5 (2.6 %) developed a postoperative infection. Our findings suggest that the use of fresh frozen allograft does not materially increase the risk of post-operative bacterial infection. Our reported post-operative infection rates are comparable with infection rates of other similar studies on fresh frozen allograft use.

A retrospective study on annual evaluation of radiation processing for frozen bone allografts complying to quality system requirements

Bone allografts have been used widely to fill up essential void in orthopaedic surgeries. The benefit of using allografts to replace and reconstruct musculoskeletal injuries, fractures or disease has obtained overwhelming acceptance from orthopaedic surgeons worldwide. However, bacterial infection and disease transmission through bone allograft transplantation have always been a significant issue. Sterilization by radiation is an effective method to eliminate unwanted microorganisms thus assist in preventing life threatening allograft associated infections. Femoral heads procured from living donors and long bones (femur and tibia) procured from cadaveric donors were sterilized at 25 kGy in compliance with international standard ISO 11137. According to quality requirements, all records of bone banking were evaluated annually. This retrospective study was carried out on annual evaluation of radiation records from 1998 until 2012. The minimum doses absorbed by the bones were ranging from 25.3 to 38.2 kGy while the absorbed maximum doses were from 25.4 to 42.3 kGy. All the bones supplied by our UMMC Bone Bank were sterile at the required minimum dose of 25 kGy. Our analysis on dose variation showed that the dose uniformity ratios in 37 irradiated boxes of 31 radiation batches were in the range of 1.003-1.251, which indicated the doses were well distributed.

Horizontal Resorption of Fresh-Frozen Corticocancellous Bone Blocks in the Reconstruction of the Atrophic Maxilla at 5 Months

Background

Reliable implant-supported rehabilitation of an alveolar ridge needs sufficient volume of bone. In order to achieve a prosthetic-driven positioning, bone graft techniques may be required.

Purpose

This prospective cohort study aims to clinically evaluate the amount of resorption of corticocancellous fresh-frozen allografts bone blocks used in the reconstruction of the severe atrophic maxilla.

Materials and Methods

Twenty-two partial and totally edentulous patients underwent bone augmentation procedures with fresh-frozen allogenous blocks from the iliac crest under local anesthesia. Implants were inserted into the grafted sites after a healing period of 5 months. Final fixed prosthesis was delivered ± 4 months later. Ridge width analysis and measurements were performed with a caliper before and after grafting and at implant insertion. Bone biopsies were performed in 16 patients.

Results

A total of 98 onlay block allografts were used in 22 patients with an initial mean alveolar ridge width of 3.41 ± 1.36 mm. Early exposure of blocks was observed in four situations and one of these completely resorbed. Mean horizontal bone gain was 3.63 ± 1.28 mm (p < .01). Mean buccal bone resorption between allograph placement and the reopening stage was 0.49 ± 0.54 mm, meaning approximately 7.1% (95% confidence interval: [5.6%, 8.6%]) of total ridge width loss during the integration period. One hundred thirty dental implants were placed with good primary stability (≥ 30 Ncm). Four implants presented early failure before the prosthetic delivery (96.7% implant survival). All patients were successfully rehabilitated. Histomorphometric analysis revealed 20.9 ± 5.8% of vital bone in close contact to the remaining grafted bone. A positive strong correlation (adjusted R² = 0.44, p = .003) was found between healing time and vital bone percentage.

Conclusions

Augmentation procedures performed using fresh-frozen allografts from the iliac crest are a suitable alternative in the reconstruction of the atrophic maxilla with low resorption rate at 5 months, allowing proper stability of dental implants followed by fixed prosthetic rehabilitation.

Porcine bone grafts defatted by lipase: efficacy of defatting and assessment of cytocompatibility

Defatting is an important procedure for the preparation of bone grafts because lipids in bone grafts strongly influence the osteointegration. Lipases have been widely used in different fields. However, study on the application to defatting process for bone grafts preparation has never been found so far. In this study, bone samples were treated respectively by lipase, NaHCO(3)/Na(2)CO(3), acetone and deionized water. The lipids content of processed bone grafts was calculated in Soxhlet extractor method. Surface morphology of the bone grafts was observed under scanning electron microscope (SEM). DNA content of processed bone grafts was measured. Cytocompatibility was evaluated by co-culturing mouse preosteoblasts (MC3T3-E1) on defatted bone cubes. Proliferation rates of MC3T3-E1 were examined by cell counting kit-8 (CCK-8) assay. No statistically significant difference was found between lipids amount of bone processed by lipase (0.46 ± 0.16 %) and acetone (1.11 ± 0.13 %) (P > 0.05). Both of them were significantly lower than that in groups processed by Na(2)CO(3)/NaHCO(3) (3.46 ± 0.69 %) and deionized water (8.88 ± 0.18 %) (P = 0.000). Only cell debris were discovered over the surface of bone processed by lipase or acetone, while lipid droplets were observed on bone processed by Na(2)CO(3)/NaHCO(3) or water by SEM. The difference of DNA concentration between the bone processed by lipase (3.16 ± 0.81 ng/μl) and acetone (4.14 ± 0.40 ng/μl) is not statistically significant (P > 0.05). Both of them are significantly lower than that groups processed by Na(2)CO(3)/NaHCO(3) (5.22 ± 0.38 ng/μl) and water (7.88 ± 0.55 ng/μl) (P < 0.05). MC3T3-E1 cells maintained their characteristic spreading on the trabecular surfaces of bone processed by lipase. There were no statistically significant differences among absorbance of lipase, acetone groups in CCK-8 assay. The application of lipase to bone tissue defatting appears to be a very promising technique for bone grafts preparation.

Hepatitis B transmission by cell and tissue allografts: How safe is safe enough?

More than 2 million human tissue transplants (bone, tendon, cartilage, skin, cornea, amniotic membrane, stem cells, heart valve, blood vessel, etc.), are performed worldwide every year. Cells and tissues are shared between countries which have different regulations and laboratory equipment and represent a risk of hepatitis B virus (HBV) transmission that has become a global safety concern. While the risk of transfusion-transmitted HBV infection from blood donations has been estimated, the rate of HBV transmission from donors to recipients of allografts is unknown and varies between different tissues. There are various important ways of reducing the transmission risk, but donor screening and donor testing are still the main factors for preventing HBV transmission. HBV detection is included in the routine screening tests for cell and tissue donors. The standard test for preventing transplant-transmitted hepatitis B is the hepatitis B surface antigen. The implementation of methods involving nucleic acid amplification and the new generation of reactives to detect viral antibodies or antigens with an immunoassay, has increased the sensitivity and the specificity of the screening tests. The objective of our research was to review the literature and critically analyse the different steps for avoiding HBV transmission in cell and tissue donors, focusing on the screening tests performed.

Radioprotective effect of N-acetyl-L-cysteine free radical scavenger on compressive mechanical properties of the gamma sterilized cortical bone of bovine femur

Gamma sterilization of bone allografts is used as a gold standard method to provide safety against disease transmission. However, it is well documented that high dose levels of ionizing radiation can degrade bone mechanical properties. This effect, which is attributed to the formation of free radicals through radiolysis of the water content of collagen, can lead to post-implantation difficulties such as pre-failure and/or secondary fractures of bone allografts. Recently, treatment of irradiated allografts with free radical scavengers is used to protect them against radiation-induced damages. This study aimed to investigate the radioprotective role of N-acetyl-L-cysteine (NAC) during the gamma sterilization of the cortical bone of bovine femurs using the compressive test. Totally, 195 cubic specimens with a dimension of 5 × 5 × 3 cubic mm were divided into 13 groups including a control and 12 experimental groups exposed to 18, 36, and 70 kGy at three different NAC concentrations (1.25, 12.5, and 25 mM for 18 kGy; 5, 50, and 100 mM for 36 kGy; 10, 100, and 200 mM for 70 kGy). The mechanical behavior of the sterilized specimens was studied using the uniaxial compressive test. The results indicated a concentration-dependent radioprotection effect of NAC on the plastic properties of the cortical bones. The concentration dependency of NAC was in turn related to radiation dose levels. In conclusion, treatment of bone specimens with a characteristic concentration of NAC during exposure to specific radiation dose levels can provide an efficient radioprotection window for preserving the mechanical stability of gamma sterilized allografts.

Bone graft substitutes for anterior lumbar interbody fusion

The procedure of anterior lumbar interbody fusion (ALIF) is commonly performed on patients suffering from pain and/or neurological symptoms associated with disorders of the lumbar spine caused by disc degeneration and trauma. Surgery is indicated when prolonged conservative management proves ineffective. Because an important objective of the ALIF procedure is solid arthrodesis of the degenerative spinal segment, bone graft selection is critical. Iliac crest bone grafts (ICBG) remain the "gold standard" for achieving lumbar fusion. However, patient dissatisfaction stemming from donor site morbidity, lengthier operating times and finite supply of ICBG has prompted a search for better alternatives. Here presented is a literature review evaluating available bone graft options assessed within the clinical setting. These options include autografts, allograft-based, synthetic and cell-based technologies. The emphasis is on the contentious use of recombinant human bone morphogenetic proteins, which is in widespread use and has demonstrated both significant osteogenic potential and risk of complications.

Morsellised sawbones is an acceptable experimental substitute for the in vitro elastic and viscoelastic mechanical characterisation of morsellised cancellous bone undergoing impaction grafting

Impaction grafting using morsellised bone chips is widely used during surgery to mitigate the effects of bone loss. The technique typically involves the packing of morsellised allograft cancellous bone into bone defects, and has found extensive application in revision hip and knee surgery. In the ideal situation, the presence of the bone graft prevents subsidence of the revised prosthesis in the short term, and integrates with the host bone in the longer term. However, the configuration of particles within the graft remains to be optimised, and is highly likely to vary across potential sites and loading conditions. Human bone, for use in experimental investigation, is often difficult to obtain with properties that are relevant from a clinical point of view. This study, therefore, has explored the mechanical response of a Sawbones based experimental substitute. An established confined compression technique was used to characterise the morsellised Sawbones material. Comparison of the results with published values for bovine and human bone indicate that the mechanical response of the morsellised Sawbones material map well onto the elastic and viscoelastic response of bone of a biological origin.

Autologous double-barrel vascularized fibula bone graft for arthrodesis of the shoulder after tumor resection

INTRODUCTION

Arthrodesis of the shoulder is a straightforward and established alternative to reconstruct the shoulder function after tumor resection of the proximal humerus. In most cases, some kind of intercalary bone graft is used to bridge the bony defect. However, due to low stability of a single fibula autograft and disadvantages of exogenous graft material when performing combined allo- and autograft reconstruction, efforts to develop new surgical techniques, with the intention to lower the complication rates, are ongoing.

MATERIALS AND METHODS

We present a detailed description of the surgical technique and the outcome of three patients with osteosarcomas of the proximal humerus, which were treated with tumor resection and autologous double-barrel vascularized fibula bone graft for arthrodesis of the shoulder. The construct was stabilized using a 4.5-mm pelvic reconstruction plate positioned on the scapular spine and the lateral aspect of the humerus.

RESULTS

A wide surgical margin was achieved in all patients. Two of them could be reintegrated and are able to work with excellent shoulder function. In one patient, who developed metastasis, a deep infection under chemotherapy 16 months after index surgery complicated the postoperative course.

CONCLUSION

The fibula's unique dual endosteal and periosteal blood supply makes it effective as a double-barrel bone graft for major long bone defects, which requires extra bone volume to prevent fractures until bone hypertrophy occurs. Additional bone and scar formation between the two struts are believed to provide a stable and long lasting construct, as seen in our patients.

Porous allograft bone scaffolds: doping with strontium

Strontium (Sr) can promote the process of bone formation. To improve bioactivity, porous allograft bone scaffolds (ABS) were doped with Sr and the mechanical strength and bioactivity of the scaffolds were evaluated. Sr-doped ABS were prepared using the ion exchange method. The density and distribution of Sr in bone scaffolds were investigated by inductively coupled plasma optical emission spectrometry (ICP-OES), X-ray photoelectron spectroscopy (XPS), and energy-dispersive X-ray spectroscopy (EDS). Controlled release of strontium ions was measured and mechanical strength was evaluated by a compressive strength test. The bioactivity of Sr-doped ABS was investigated by a simulated body fluid (SBF) assay, cytotoxicity testing, and an in vivo implantation experiment. The Sr molar concentration [Sr/(Sr+Ca)] in ABS surpassed 5% and Sr was distributed nearly evenly. XPS analyses suggest that Sr combined with oxygen and carbonate radicals. Released Sr ions were detected in the immersion solution at higher concentration than calcium ions until day 30. The compressive strength of the Sr-doped ABS did not change significantly. The bioactivity of Sr-doped material, as measured by the in vitro SBF immersion method, was superior to that of the Sr-free freeze-dried bone and the Sr-doped material did not show cytotoxicity compared with Sr-free culture medium. The rate of bone mineral deposition for Sr-doped ABS was faster than that of the control at 4 weeks (3.28±0.23 µm/day vs. 2.60±0.20 µm/day; p<0.05). Sr can be evenly doped into porous ABS at relevant concentrations to create highly active bone substitutes.

Subtalar distraction arthrodesis using fresh-frozen allogeneic femoral head augmented with local autograft

BACKGROUND

Tricortical autograft has been commonly used in subtalar distraction arthrodesis (SDA) for severe calcaneal malunion. Structural allograft enriched with orthobiological agents is an alternative. This study was performed to evaluate the results of SDA using fresh-frozen allogeneic femoral head without the addition of orthobiological agents.

MATERIALS AND METHODS

We retrospectively reviewed 15 consecutive SDA procedures (13 patients) with allogeneic femoral head augmented with local autograft for the treatment of severe calcaneal malunion. Clinical outcome was evaluated with the American Orthopaedic Foot & Ankle Society (AOFAS) ankle-hindfoot score, visual analog scale (VAS) pain score, Short Form-12 (SF-12), range of motion (ROM) of the ankle joint, and patient satisfaction rate. Radiographic assessment included the talar declination angle (TDA), calcaneal inclination angle (CIA), lateral talocalcaneal angle (LTCA), heel height, calcaneal length, and union time.

RESULTS

At a median follow-up of 36.0 months (range, 24-47 months), all 15 feet (100%) achieved union, at a median of 13.0 weeks (range, 12-18 weeks). The AOFAS score and VAS pain score improved significantly, with a satisfaction rate of 93.3%. The TDA, CIA, LTCA, and heel height improved significantly. The median increase in heel height was 8.6 mm (range, 1.9-20.1 mm). There was a significant reduction in calcaneal length. Complications included 1 varus malalignment, 1 complex regional pain syndrome, 1 hardware irritation, and 1 sural neuralgia.

CONCLUSION

This study found that SDA using fresh-frozen femoral head allograft without an orthobiological agent was cost-effective and may have outcomes comparable to those using autograft or allograft enriched with orthobiological agents.

Mandibular reconstruction using fresh frozen bone allograft after conservative enucleation of a mandibular odontogenic myxoma

The purpose of this article was to report the clinical, radiographic, and histological findings about a case of a young woman affected by a mandibular odontogenic myxoma. Conservative tumor resection was followed by immediate reconstructive treatment using fresh-frozen human bone graft, instead of autologous bone graft, as material for bone regeneration. Odontogenic myxoma, according to the World Health Organization, is classified as a benign tumor of mesenchymal origin whether or not containing odontogenic epithelium. Radiological and histological examination of the lesion confirmed the presence of an odontogenic myxoma, which was 21.2 mm high and 47.6 mm long; the lesion underwent biopsy evaluation before enucleation. According to literature and with the aim of a patient free of disease, conservative enucleation of the lesion was performed. The residual bone defect was filled with fresh-frozen bone allograft. At 6 months after surgery, no evidence of major complications was observed; the computed tomography scan revealed effective bone regeneration through the grafted area. The use of fresh-frozen bone allograft, thanks to its osteoinductive and osteoconductive properties, may represent an optional choice for reconstruction of bone defects after jaw tumor removal.

Modified technique using allograft-prosthetic composite in the distal femur after bone tumor resection

BACKGROUND

The purpose of this retrospective study was to analyze the results of treatment of bone tumor resection of the distal femur with the modified technique of allograft-prosthetic composite.

METHODS

Twelve patients with distal femoral bone tumors were treated with deep-frozen cortical allograft struts and allograft-prosthesis composites. There were five males and seven females with a median age of 29.5y. The minimum follow-up time was 12mo (median, 45.7mo; range, 12-81mo). Diagnoses included osteosarcoma in five patients, chondrosarcoma in three patients, giant cell tumors in three patients, and malignant fibrous histiocytoma in one patient. Five osteosarcoma patients were treated with adjuvant chemotherapy.

RESULTS

At the latest follow-up examination, 11 patients were alive with no evidence of disease, and the limb was preserved in nine patients. One patient died of pulmonary metastases with no evidence of local recurrence. Seven healed without complications. A surgical procedure was performed in four patients because of complications, which included a fracture (one patient), deep infection (one patient), instability (one patient), and local recurrence (one patient).

CONCLUSION

The modified technique of allograft-prosthetic composite is an effective treatment for bone tumor resection of the distal femur. This technique has many advantages, including augmentation of the bone stock, minimizing the risk of allograft fracture and nonunion, and decreasing the need for revision operations.

Severe maxillary atrophy treatment with Le Fort I, allografts, and implant-supported prosthetic rehabilitation

PURPOSE

Recently, several authors have described that autologous and fresh-frozen bones are effective materials to correct jaw bone defects before endosseous implant positioning. The aim of this study was to report a multistep oral rehabilitation of severe atrophic maxilla by means of Le Fort I osteotomy for maxillary downward and forward repositioning, allografts, implant insertion, and prosthetic loading.

METHODS

Patients with severe maxillary atrophy underwent Le Fort I osteotomy associated to fresh-frozen interpositional bone allografts. At 7 months after reconstructive procedure, 2 biopsies for each patient have been taken, and in the same surgical procedure, endosseous implants were placed. Five months afterward, abutments were connected for the final prosthodontic restauration. Each patient was evaluated at 1-year follow-up after prosthetic loading.

RESULTS

At 1-year follow-up after functional prosthetic loading, no infection of the allografts or implant failure has been reported. Clinical and radiologic follow-up showed no sign of bone resorption in all the osteotomic sites and in the grafted areas. Histological analysis showed evidence of allograft osteointegration and healing.

CONCLUSIONS

Multistep oral rehabilitation of severe atrophic maxilla with Le Fort and interpositional bone allografts represents a reliable surgical technique. According to this clinical, radiologic, and histologic reports, interpositional fresh-frozen bone allograft seems to be a valuable material for grafting jaw as it is cheaper than other materials and is safe, and it avoids donor site, decreasing the morbidity of the treatment

Freeze-dried human serum albumin improves the adherence and proliferation of mesenchymal stem cells on mineralized human bone allografts

Mineralized scaffolds are widely used as bone grafts with the assumption that bone marrow derived cells colonize and remodel them. This process is slow and often unreliable so we aimed to improve the biocompatibility of bone grafts by pre-seeding them with human mesenchymal stem cells from either bone marrow or dental pulp. Under standard cell culture conditions very low number of seeded cells remained on the surface of freeze-dried human or bovine bone graft or hydroxyapatite. Coating the scaffolds with fibronectin or collagen improved seeding efficiency but the cells failed to grow on the surface until the 18th day. In contrast, human albumin was a very potent facilitator of both seeding and proliferation on allografts which was further improved by culturing in a rotating bioreactor. Electron microscopy revealed that cells do not form a monolayer but span the pores, emphasizing the importance of pore size and microstructure. Albumin coated bone chips were able to unite a rat femoral segmental defect, while uncoated ones did not. Micro-hardness measurements confirmed that albumin coating does not influence the physical characteristics of the scaffold, so it is possible to introduce albumin coating into the manufacturing process of lyophilized bone allografts.

Acetabular impaction grafting in total hip replacement

BACKGROUND AND PURPOSE

Acetabular impaction grafting has been shown to be very effective, but concerns regarding its suitability for larger defects have been highlighted. We report the use of this technique in a large cohort of patients, and address possible limitations of the technique.

METHODS

We investigated a consecutive group of 339 cases of impaction grafting of the cup with morcellised impacted allograft bone for survivorship and mechanisms for early failure.

RESULTS

Kaplan Meier survival was 89.1% (95% CI 83.2 to 95.0%) at 5.8 years for revision for any reason, and 91.6% (95% CI 85.9 to 97.3%) for revision for aseptic loosening of the cup. Of the 15 cases revised for aseptic cup loosening, nine were large rim mesh reconstructions, two were fractured Kerboull-Postel plates, two were migrating cages, one was a medial wall mesh failure and one had been treated by impaction alone.

INTERPRETATION

In our series, results were disappointing where a large rim mesh or significant reconstruction was required. In light of these results, our technique has changed in that we now use predominantly larger chips of purely cancellous bone, 8-10 mm3 in size, to fill the cavity and larger diameter cups to better fill the aperture of the reconstructed acetabulum. In addition we now make greater use of i) implants made of a highly porous in-growth surface to constrain allograft chips and ii) bulk allografts combined with cages and morcellised chips in cases with very large segmental and cavitary defects.

The role of bone allografts in the treatment of angular malunions of the distal radius

PURPOSE

Two cohorts of patients who had corrective osteotomies and volar platings for malunited fractures of the distal radius were compared retrospectively to determine whether the time to union and the outcome were affected by bone allograft.

METHODS

Patients in the first group (n = 14) did not receive any bone graft; patients in the second group (n = 14) had allograft bone chips following volar plating. Indications for surgery, surgical technique, and postoperative rehabilitation were the same in both groups. Volar cortical contact was maintained using a volar locking plate in all patients. Radiographic parameters of deformity correction, time to union, wrist and forearm range of motion, grip strength, patient-rated wrist evaluation and Disabilities of the Arm, Shoulder, and Hand questionnaire were used to evaluate the outcome before and after the surgery. Average follow-up time was 36 weeks. Patients who had diabetes, who smoked, who had a body mass index of more than 35, and who required lengthening for deformity correction were excluded from the study.

RESULTS

Osteotomies in both groups healed without loss of surgical correction. Final outcome and time to union revealed no significant differences, clinically or statistically, between the 2 groups. The Disabilities of the Arm, Shoulder, and Hand score was improved in both groups.

CONCLUSIONS

When volar cortical contact was maintained using a volar locked plate, bone allograft at the osteotomy site did not improve the final outcome.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic III.

Skeletal tissue regeneration: current approaches, challenges, and novel reconstructive strategies for an aging population

Loss of skeletal tissue as a consequence of trauma, injury, or disease is a significant cause of morbidity with often wide-ranging socioeconomic impacts. Current approaches to replace or restore significant quantities of lost bone come with substantial limitations and inherent disadvantages that may in themselves cause further disability. In addition, the spontaneous repair capacity of articular cartilage is limited; thus, investigation into new cartilage replacement and regeneration techniques are warranted. Along with the challenges of an increasingly aging demographic, changing clinical scenarios and rising functional expectations provide the imperative for new, more reliable skeletal regeneration strategies. The science of tissue engineering has expanded dramatically in recent years, notably in orthopedic applications, and it is clear that new approaches for de novo skeletal tissue formation offer exciting opportunities to improve the quality of life for many, particularly in the face of increasing patient expectations. However, significant scientific, financial, industrial, and regulatory challenges should be overcome before the successful development of an emergent tissue engineering strategy can be realized. We outline current practice for replacement of lost skeletal tissue and the innovative approaches in tissue regeneration that have so far been translated to clinical use, along with a discussion of the significant hurdles that are presented in the process of translating research strategies to the clinic.

Lateral clavicular autograft for repair of reverse hill-sachs defect

Posterior dislocations of the shoulder joint can result in an impression fracture over the anteromedial humeral head, termed the reverse Hill-Sachs lesion, the presence of which can contribute to recurrent dislocations. Methods described to repair this defect include using allografts, iliac crest and coracoid process autografts, and bone graft substitutes. We describe a novel technique using the lateral end of the ipsilateral clavicle as an autograft in a 78 year old man with a reverse Hill Sachs lesion. This graft can be harvested through the same incision and does not compromise the stability of the acromioclavicular joint or any future shoulder arthroplasty.

The concentration of antibiotic in fresh-frozen bone graft

We investigated the antibiotic concentration in fresh-frozen femoral head allografts harvested from two groups of living donors. Ten samples were collected from patients with osteoarthritis of the hip and ten from those with a fracture of the neck of the femur scheduled for primary arthroplasty. Cefazolin (1 g) was administered as a pre-operative prophylactic antibiotic. After storage at -80 degrees C for two weeks the pattern of release of cefazolin from morsellised femoral heads was evaluated by an in vitro broth elution assay using high-performance liquid chromatography. The bioactivity of the bone was further determined with an agar disc diffusion and standardised tube dilution bioassay. The results indicated that the fresh-frozen femoral heads contained cefazolin. The morsellised bone released cefazolin for up to four days. The concentration of cefazolin was significantly higher in the heads from patients with osteoarthritis of the hip than in those with a fracture.Also, in bioassays the bone showed inhibitory effects against bacteria.We concluded that allografts of morsellised bone from the femoral head harvested from patients undergoing arthroplasty of the hip contained cefazolin, which had been administered pre-operatively and they exhibited inhibitory effects against bacteria in vitro.

Bone grafting options for lumbar spine surgery: a review examining clinical efficacy and complications

Background

Iliac crest harvest has been considered the “gold standard” at producing successful arthrodesis of the lumbar spine but is also associated with many donor-site morbidities. Many alternatives have been used to avoid iliac crest harvest, including autologous bone from other donor sites, allogeneic bone, ceramics, and recombinant human bone morphogenetic proteins (rhBMPs). This review will highlight the properties and preparations of these graft types and their potential complications and reported clinical efficacy.

Methods

A Medline search was conducted via PubMed by use of the following terms in various combinations: lumbar fusion, freeze-dried allograft, fresh-frozen allograft, autograft, iliac crest, demineralized bone matrix, rhBMP-2, rhBMP-7, scoliosis, bone marrow aspirate, HEALOS, coralline hydroxyapatite, beta tricalcium phosphate, synthetic, ceramics, spinal fusion, PLF, PLIF, ALIF, and TLIF. Only articles written in English were assessed for appropriate material. Related articles were also assessed depending on the content of articles found in the original literature search.

Conclusions

Although iliac crest remains the gold standard, reported success with alternative approaches, especially in combination, has shown promise. Stronger evidence with limited sources of potential bias is necessary to provide a clear picture of their clinical efficacy.