Enhancing Vascularized Composite Allograft Supercooling Preservation: A Multifaceted Approach with CPA Optimization, Thermal Tracking, and Stepwise Loading Techniques.

Vascularized composite allografts (VCAs) present unique challenges in transplant medicine, owing to their complex structure and vulnerability to ischemic injury. Innovative preservation techniques are crucial for extending the viability of these grafts, from procurement to transplantation. This study addresses these challenges by integrating cryoprotectant agent (CPA) optimization, advanced thermal tracking, and stepwise CPA loading strategies within an ex vivo rodent model. CPA optimization focused on various combinations, identifying those that effectively suppress ice nucleation while mitigating cytotoxicity. Thermal dynamics were monitored using invasive thermocouples and non-invasive FLIR imaging, yielding detailed temperature profiles crucial for managing warm ischemia time and optimizing cooling rates. The efficacy of stepwise CPA loading versus conventional flush protocols demonstrated that stepwise (un)loading significantly improved arterial resistance and weight change outcomes. In summary, this study presents comprehensive advancements in VCA preservation strategies, combining CPA optimization, precise thermal monitoring, and stepwise loading techniques. These findings hold potential implications for refining transplantation protocols and improving graft viability in VCA transplantation.

Fresh osteochondral allograft transplantation for knee full-thickness articular cartilage lesions using femoral head of living donors: short-term results.

BACKGROUND: Fresh osteochondral allograft transplantation is a good treatment option of cartilage defects. However, this treatment option is not available in all countries due to limited graft availability and tissue banks limitations. The purpose of this study is to assess the short term functional and imaging outcomes of fresh osteochondral allograft transplantation in the knee using the femoral head of living donors. HYPOTHESIS: Fresh osteochondral allografts from the femoral heads of living donors is a valid graft source for management of distal Femur cartilage defects. This technique can improve functional knee scores with good radiological outcomes. STUDY DESIGN: Prospective case series. METHODS: Fifteen patients with full thickness cartilage defects of the distal femur underwent osteochondral allograft transplantation from the femoral heads of living donors. Grafts were transplanted by both shell and multiple dowels techniques. The average follow up duration was 18.3 months (range, 12-25 months). Patients were evaluated by Lysholm and International Knee Documentation Committee (IKDC) scores, radiography and MR imaging using Osteochondral Allograft MRI Scoring System (OCAMRISS). RESULTS: There was a statistically significant improvement (P < 0.001) in both Lysholm and IKDC average scores at 6 months and 12 months postoperative. Postoperative MRI was done at an average 6.8 months (range, 5-11 months) postoperative. The mean total OCAMRISS score was 3.4 (range, 1-7). A second look arthroscopy was done in four patients and showed intact articular cartilage in all three patients. CONCLUSION: Femoral head of living donors is a valid new source for fresh osteochondral allograft transplantation of knee osteochondral lesions. Short term results showed improvement in clinical assessment scores. Follow up imaging showed graft incorporation and good MRI scores.

Predicting in vivo therapeutic efficacy of CelTrac1000-labeled hair follicle epidermal neural crest stem cells in models of repairing rat facial nerve defects via second near-infrared fluorescence imaging.

AIMS: To detect the therapeutic efficacy of CelTrac1000-labeled hair follicle epidermal neural crest stem cells (EPI-NCSCs) on repairing facial nerve defects by second near-infrared (NIR-II) fluorescence imaging. MATERIALS AND METHODS: Firstly, CelTrac1000-labeled EPI-NCSCs were microinjected into the acellular nerve allografts (ANAs) to bridge a 10-mm-long gap in the buccal branch of facial nerve in adult rats. Then, Celtrac1000-labeled EPI-NCSCs were detected by NIR-II fluorescence imaging system to visualize the behavior of the transplanted cells in vivo. Additionally, the effect of the transplanted EPI-NCSCs on repairing facial nerve defect was examined. KEY FINDINGS: Through 14 weeks of dynamic observation, the transplanted EPI-NCSCs survived in the ANAs in vivo after surgery. Meanwhile, the region of the NIR-II fluorescence signals was gradually limited to be consistent with the direction of the regenerative nerve segment. Furthermore, the results of functional and morphological analysis showed that the transplanted EPI-NCSCs could promote the recovery of facial paralysis and neural regeneration after injury. SIGNIFICANCE: Our research provides a novel way to track the transplanted cells in preclinical studies of cell therapy for facial paralysis, and demonstrates the therapeutic potential of EPI-NCSCs combined with ANAs in bridging rat facial nerve defects.

Safety and Effectiveness of Bone Allografts for Mastoid Obliteration After Mastoidectomy: A Pilot Study.

Background and Objectives: : Various materials are used to perform post-mastoidectomy mastoid obliteration (MO) to reduce the risk of recurrent infections, stasis of secretions, or caloric dizziness. Autologous materials used as fillers for MO tend to be insufficient owing to shrinkage over time or inadequate volume of these substances. Synthetic materials are unsatisfactory for MO because of the risk of rejection and extrusion. We investigated the safety and effectiveness of bone allografts for post-mastoidectomy MO. Subjects and Methods: : We reviewed the medical records of patients who underwent mastoidectomy with MO between January 2013 and January 2021. In the MO group, bone allografts were additionally used to fill the residual mastoid cavity. In the canal wall down (CWD) group, all patients underwent CWD mastoidectomy with use of additional inferiorly based mucoperiosteal flaps. Results: : The study included the MO group (23 ears) and the CWD group (53 ears). In the MO group, compared with the preoperative status, we observed a decrease in the tendency of the air-bone gap postoperatively. Compared with the CWD group, the total complication rate showed a decreasing tendency in the MO group. Conclusions: : No patient showed post-MO shrinkage of the grafted bone allograft or otorrhea. Further large-scale studies are warranted to confirm the advantages of bone allografts for MO, including maintenance with time and sufficient amount.

Comparison of Interbody Fusion Strategies in Anterior Cervical Discectomy and Fusion: A Network Meta-analysis and Systematic Review.

OBJECTIVE: The optimal choice for fusion strategy in Anterior Cervical Discectomy and Fusion (ACDF) remains an unresolved issue. This study aims to perform a network meta-analysis and systematic review of fusion rate and complication rate of various fusion strategies used in ACDF. METHODS: This study followed Prisma guidelines, and we searched PubMed, Embase, Cochrane Library, and Web of Science from inception to November 11, 2022, for RCTs comparing the efficacy and safety of fusion modalities in ACDF. The primary outcome was the fusion rate and complication rate. The PROSPERO number is CRD42022374440. RESULTS: This meta-analysis identified 26 RCT studies with 1789 patients across 15 fusion methods. The cage with autograft + plating (CATG + P) showed the highest fusion rate, surpassing other methods like iliac crest autograft (ICAG) and artificial bone graft (AFG). The stand-alone cage with autograft (SATG) had the second highest fusion rate. Regarding complication rate, the cage with artificial bone graft (CAFG) had the highest rate, more than other methods. The ICAG had a higher complication rate compared to ICAG + P, AFG, SAFG, SATG, and CALG. The SATG performed well in both fusion and complication rate. CONCLUSION: In this study, we conducted the first network meta-analysis to compare the efficacy and safety of various fusion methods in ACDF. Our findings suggest that SATG, with superior performance in fusion rate and complication rate, may be the optimal choice for ACDF. However, the results should be interpreted cautiously until additional research provides further evidence.

Ciprofloxacin prophylaxis during haematopoietic cell transplantation: a role for use in patients with germ cell tumours?

Introduction. Fluoroquinolone prophylaxis during haematopoietic cell transplantation (HCT) can lead to antimicrobial resistance (AMR). Identifying the groups of patients that have the highest likelihood of benefiting from prophylactic antimicrobials is important for antimicrobial stewardship (AMS).Hypothesis. We aimed to identify groups of HCT recipients that have the highest likelihood of benefiting from prophylactic fluroquinolones.Methods. All admissions for HCT in a tertiary centre between January 2020 and December 2022 (N = 400) were retrospectively studied. Allogeneic HCT (allo-HCT) recipients had prophylaxis with ciprofloxacin during the chemotherapy-induced neutropenia, while autologous HCT (auto-HCT) recipients did not. Bacteraemias were recorded when non-contaminant bacterial pathogens were isolated in blood cultures.Results. Allo-HCT was performed for 43.3 % (173/400) of patients and auto-HCT was performed for 56.7 % (227/400). A bacteraemia was documented in 28.3 % (113/400) of cases. Allo-HCT recipients were more likely to have a Gram-positive bacteraemia (20.8%, 36/173, vs 10.1%, 23/227, P = 0.03), while a difference was not observed for Gram-negative bacteraemias (18.5%, 32/173 vs 18.1%, 41/227, P = 0.91). Among auto-HCT recipients not receiving ciprofloxacin prophylaxis, patients with germ cell tumours had the highest probability (P for trend 0.09) of recording any bacteraemia (43.5%, 10/23) followed by patients with lymphomas (32.5%, 13/40), other auto-HCT indications (22.2%, 2/9), multiple myeloma (22.1%, 29/131) and multiple sclerosis (12.5%, 3/24). The higher number of bacteraemias in patients with germ cell tumours was primarily driven by Gram-negative pathogens.Conclusions. Ciprofloxacin prophylaxis was associated with a reduced incidence of Gram-negative bacteraemias in allo-HCT recipients. Auto-HCT recipients due to germ cell tumours, not receiving ciprofloxacin prophylaxis, recorded the highest incidence of bacteraemias and represent a possible target group for this intervention.

LONG-TERM OUTCOMES OF USING VARIOUS GRAIN ALLOGRAFT SIZES IN PAPROSKY TYPE 3.

Introduction: Severe acetabular bone defects can pose challenges in revision total hip replacement. The use of structural allografts and various sizes of grain allografts has been proposed as an alternative surgical technique for treating Paprosky type 3 acetabular defects. This study aimed to evaluate the long-term outcomes and potential complications associated with this approach. Methods: A retrospective review was performed on 102 hip reconstructions in patients with major acetabular bone loss, including 81 cases of type 3A and 21 cases of type 3B according to Paprosky's classification. Surgical procedures involved the use of structural allografts and various sizes of grain allografts in both reinforcement ring group and cementless cups group. Results: At a mean follow-up of 82.75 months, 76% of hips had no complications, while The others experienced pain changes in the cup position, post-operative dislocations, and infections. The mean pre-operative Modified Harris Hip Score improved in both groups at the last follow-up. Conclusion: The use of structural allografts and various sizes of grain allografts for treating type 3 acetabular defects in revision total hip replacement showed promising long-term outcomes and a low rate of complications. Level of Evidence IV; Retrospective Case Series.

Introdução: Defeitos ósseos acetabulares graves podem representar desafios na revisão da artroplastia total do quadril. O uso de aloenxertos estruturais e aloenxertos de grãos de vários tamanhos foram propostos como uma técnica cirúrgica alternativa para o tratamento de defeitos acetabulares Paprosky tipo 3. O objetivo deste estudo foi avaliar os resultados de longo prazo e as possíveis complicações associadas a essa abordagem. Métodos: Foi realizada uma revisão retrospectiva de 102 reconstruções de quadril em pacientes com grande perda óssea acetabular, incluindo 81 casos do tipo 3A e 21 casos do tipo 3B de acordo com a classificação de Paprosky. Os procedimentos cirúrgicos envolveram o uso de aloenxertos estruturais e aloenxertos de grãos de vários tamanhos, tanto no grupo do anel de reforço quanto no grupo das próteses sem cimento. Resultados: Em um acompanhamento médio de 82,75 meses, 76% dos quadris não apresentaram complicações, enquanto os demais apresentaram dor, alterações na posição da prótese, luxações pós-operatórias e infecções. A pontuação média pré-operatória do escore de quadril modificado de Harris melhorou em ambos os grupos no último acompanhamento. Conclusão: O uso de aloenxertos estruturais e aloenxertos de grãos de vários tamanhos para o tratamento de defeitos acetabulares do tipo 3 na substituição total do quadril de revisão mostrou resultados promissores em longo prazo e uma baixa taxa de complicações. Nível de Evidência IV; Série de Casos Retrospectivos.

Internal Allo-Cortical Tenting: A Modified Ridge Split Technique in Three-Dimensional Ridge Augmentation.

BACKGROUND: Three-dimensional (3D) alveolar ridge deficiencies necessitate horizontal and vertical bone reconstruction for optimal implant positioning. Despite several available techniques, achieving desired augmentation outcomes remains challenging. This case study aims to present a modified ridge split technique for bone reconstruction in both horizontal and vertical dimensions. METHODS AND RESULTS: The proposed technique was used to reconstruct the horizontal and vertical ridge defect from removing a previously failed implant. This technique includes placing a cortical allograft plate as an internal tent in the split ridge. A portion of the plate was inserted into the ridge, while the other part was placed in the coronal of the vertical defect. Additional guided bone regeneration (GBR) was performed around the tented plate on both the buccal and lingual sides. After five months, cone beam computed tomography (CBCT) revealed sufficient bone formation in horizontal and vertical dimensions. CONCLUSIONS: Within the limitations of the present case study, internal cortical tenting would be a reliable method for 3D bone reconstruction in cases where the ridge split is feasible.

The effect of platelet-rich fibrin (PRF) versus freeze-dried bone allograft (FDBA) used in alveolar ridge preservation on the peri-implant soft and hard tissues: a randomized clinical trial.

BACKGROUND: The effectiveness of alveolar ridge preservation on bone regeneration and tissue healing has been thoroughly documented in the literature. This study aimed to evaluate the peri-implant soft and hard tissue changes after alveolar ridge preservation using either platelet-rich fibrin (PRF) or freeze-dried bone allograft (FDBA) over a 12-month period following the prosthetic loading of implants. METHODS: In this randomized clinical trial, 40 individuals were recruited for alveolar ridge preservation using (1) FDBA or (2) PRF in incisal/premolar areas. At two follow-up sessions (six- and 12-months post-implant insertion), radiographic imaging and clinical examinations assessed marginal bone loss and soft tissue factors, including gingival recession and bleeding on probing. The differences between study groups were analyzed using Generalized estimating Equations, the Binary logistic regression model, and Cochran's Q test. RESULTS: There was a statistically significant difference regarding gingival recession at both follow-up evaluations; values in the PRF group were considerably lower compared to the FDBA group (p < 0.05). The mean values for vertical marginal bone loss and bleeding on probing showed no significant differences between the two study groups (p > 0.05). CONCLUSIONS: Except for gingival recession, applying PRF yielded comparable clinical results to FDBA after one year of implant loading and could be recommended as a potential biomaterial for alveolar ridge preservation following tooth extractions. CLINICAL TRIAL REGISTRATION: The research protocol was registered in the Protocol Registration and Results System on 13/08/2021, available at https://clinicaltrials.gov/ (NCT05005377).

Porosity and surface curvature effects on the permeability and wall shear stress of trabecular bone: Guidelines for biomimetic scaffolds for bone repair.

Scaffolds are an essential component of bone tissue engineering to provide support and create a physiological environment for cells. Biomimetic scaffolds are a promising approach to fulfill the requirements. Bone allografts are widely used scaffolds due to their mechanical and structural characteristics. The scaffold geometry is well known to be an important determinant of induced mechanical stimulation felt by the cells. However, the impact of allograft geometry on permeability and wall shear stress distribution is not well understood. This information is essential for designing biomimetic scaffolds that provide a suitable environment for cells to proliferate and differentiate. The present study investigates the effect of geometry on the permeability and wall shear stress of bone allografts at both macroscopic and microscopic scales. Our results concluded that the wall shear stress was strongly correlated with the porosity of the allograft. The level of wall shear stress at a local scale was also determined by the surface curvature characteristics. The results of this study can serve as a guideline for future biomimetic scaffold designs that provide a mechanical environment favorable for osteogenesis and bone repair.

Comparison of three techniques for decellularization of porcine bone-tendon-bone grafts.

Anterior cruciate ligament injuries are frequent afflictions related to sports or physical trauma. Autograft reconstruction strategies cause secondary injury to the patient. One alternative, supported by clinical evidence, is porcine xenografts. For clinical use, xenografts must be conditioned to avoid immune rejection. The most widely accepted procedure is tissue decellularization. We analyzed three decellularization strategies: the application of the anionic detergent sodium dodecyl sulfate (SDS), sonication, and freezing and thawing cycles. The treated tissues were evaluated histologically using H&E, Masson's trichrome, Verhoeff-van Gieson staining, and DAPI for fluorescent staining of nuclei. Finally, collagen fiber preservation was evaluated by quantifying this protein by colorimetry. The most efficient decellularization techniques were sonication and SDS. Collagen fibers were preserved in all experimental conditions.

Dose-dependent effects of gamma radiation sterilization on the collagen matrix of human cortical bone allograft and its influence on fatigue crack propagation resistance.

Fatigue crack propagation resistance and high-cycle S-N fatigue life of cortical bone allograft tissue are both negatively impacted in a radiation dose-dependent manner from 0 to 25 kGy. The standard radiation sterilization dose of 25-35 kGy has been shown to induce cleavage of collagen molecules into smaller peptides and accumulation of stable crosslinks within the collagen matrix, suggesting that these mechanisms may influence radiation-induced losses in cyclic fracture resistance. The objective of this study was to determine the radiation dose-dependency of collagen chain fragmentation and crosslink accumulation within the dose range of 0-25 kGy. Previously, cortical bone compact tension specimens from two donor femoral pairs were divided into four treatment groups (0 kGy, 10 kGy, 17.5 kGy, and 25 kGy) and underwent cyclic loading fatigue crack propagation testing. Following fatigue testing, collagen was isolated from one compact tension specimen in each treatment group from both donors. Radiation-induced collagen chain fragmentation was assessed using SDS-PAGE (n = 5), and accumulation of pentosidine, pyridinoline, and non-specific advanced glycation end products were assessed using a fluorometric assay (n = 4). Collagen chain fragmentation increased progressively in a dose-dependent manner (p < 0.001). Crosslink accumulation at all radiation dose levels increased relative to the 0 kGy control but did not demonstrate dose-dependency (p < 0.001). Taken together with our previous findings on fatigue crack propagation behavior, these data suggest that while collagen crosslink accumulation may contribute to reduced notched fatigue behavior with irradiation, dose-dependent losses in fatigue crack propagation resistance are mainly influenced by radiation-induced chain fragmentation.

Advancements in alveolar bone reconstruction: A systematic review of bone block utilization in dental practice.

Alveolar reconstructive surgery employs a variety of surgical techniques and biomaterials, with a particular focus on bone blocks as a crucial methodology for restoring and augmenting deficient bone structures. Bone blocks are often employed to support periodontal health or as a foundation for future prosthetic rehabilitation with dental implants. This systematic review investigated recent advances in bone blocks for alveolar bone reconstruction, comparing autologous, allogeneic and xenogeneic types. A search of PubMed identified 56 records, of which 21 were included in the qualitative analysis. The studies involved 685 patients in total. Bone blocks are pivotal for three-dimensional bone regeneration, providing a stable scaffold for achieving the desired bone volume during healing. Autologous bone, harvested from the patient, boasts high biocompatibility, excellent osteogenic properties and minimal immunologic risks. However, its drawbacks include the need for an additional surgical site and extended procedural times. Allogeneic bone blocks involve transferring bone between individuals, offering increased graft availability and customization options without requiring a second surgical site. However, they exhibit moderate resorption rates and carry a heightened risk of immunologic reactions and disease transmission. Innovative techniques, such as tunneling, laser osteotomy, graft customization, and platelet-rich fibrin (PRF) application on wound during surgical treatment show promise in enhancing alveolar bone reconstruction efficacy. In conclusion, despite the traditional preference for autologous bone, the review suggests that alternative materials, particularly individualized allogeneic bone blocks, coupled with modern techniques, could emerge as a standard procedure for regenerating alveolar bone defects due to their satisfactory results and potential advantages.

Depletion of donor dendritic cells ameliorates immunogenicity of both skin and hind limb transplants.

Acute cellular rejection remains a significant obstacle affecting successful outcomes of organ transplantation including vascularized composite tissue allografts (VCA). Donor antigen presenting cells (APCs), particularly dendritic cells (DCs), orchestrate early alloimmune responses by activating recipient effector T cells. Employing a targeted approach, we investigated the impact of donor-derived conventional DCs (cDCs) and APCs on the immunogenicity of skin and skin-containing VCA grafts, using mouse models of skin and hind limb transplantation. By post-transplantation day 6, skin grafts demonstrated severe rejections, characterized by predominance of recipient CD4 T cells. In contrast, hind limb grafts showed moderate rejection, primarily infiltrated by CD8 T cells. Notably, the skin component exhibited heightened immunogenicity when compared to the entire VCA, evidenced by increased frequencies of pan (CD11b-CD11c+), mature (CD11b-CD11c+MHCII+) and active (CD11b-CD11c+CD40+) DCs and cDC2 subset (CD11b+CD11c+ MHCII+) in the lymphoid tissues and the blood of skin transplant recipients. While donor depletion of cDC and APC reduced frequencies, maturation and activation of DCs in all analyzed tissues of skin transplant recipients, reduction in DC activities was only observed in the spleen of hind limb recipients. Donor cDC and APC depletion did not impact all lymphocyte compartments but significantly affected CD8 T cells and activated CD4 T in lymph nodes of skin recipients. Moreover, both donor APC and cDC depletion attenuated the Th17 immune response, evident by significantly reduced Th17 (CD4+IL-17+) cells in the spleen of skin recipients and reduced levels of IL-17E and lymphotoxin-α in the serum samples of both skin and hind limb recipients. In conclusion, our findings underscore the highly immunogenic nature of skin component in VCA. The depletion of donor APCs and cDCs mitigates the immunogenicity of skin grafts while exerting minimal impact on VCA.

Acute Rejection Rates in Vascularized Composite Allografts: A Systematic Review of Case Reports.

INTRODUCTION: Vascularized Composite Allografts (VCA) are usually performed in a full major histocompatibility complex mismatch setting, with a risk of acute rejection depending on factors such as the type of immunosuppression therapy and the quality of graft preservation. In this systematic review, we present the different immunosuppression protocols used in VCA and point out relationships between acute rejection rates and possible factors that might influence it. METHODS: This systematic review was performed according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. We systematically searched Medline (PubMed), Embase, and The Cochrane Library between November 2022 and February 2023, using following Mesh Terms: Transplant, Transplantation, Hand, Face, Uterus, Penis, Abdominal Wall, Larynx, and Composite Tissue Allografts. All VCA case reports and reviews describing multiple case reports were included. RESULTS: We discovered 211 VCA cases reported. The preferred treatment was a combination of antithymocyte globulins, mycophenolate mofetil (MMF), tacrolimus, and steroids; and a combination of MMF, tacrolimus, and steroids for induction and maintenance treatment, respectively. Burn patients showed a higher acute rejection rate (P = 0.073) and were administered higher MMF doses (P = 0.020). CONCLUSIONS: In contrast to previous statements, the field of VCA is not rapidly evolving, as it has encountered challenges in addressing immune-related concerns. This is highlighted by the absence of a standardized immunosuppression regimen. Consequently, more substantial data are required to draw more conclusive results regarding the immunogenicity of VCAs and the potential superiority of one immunosuppressive treatment over another. Future efforts should be made to report the VCA surgeries comprehensively, and muti-institutional long-term prospective follow-up studies should be performed to compare the number of acute rejections with influencing factors.

Enhancing sciatic nerve regeneration with osteopontin-loaded acellular nerve allografts in rats: Effects on macrophage polarization.

Osteopontin (OPN) is a multifunctional matrix glycoprotein with neuroprotective and immunomodulatory properties. This study explored the potential of OPN-loaded acellular nerve allografts (ANAs) to repair sciatic nerves in male Wistar rats. The research also delved into the impact of OPN on macrophage phenotypes. We reconstructed a 10 mm nerve gap with ANAs containing OPN at 2 nM and 4 nM. The sciatic functional index (SFI) and paw withdrawal reflex latency (WRL) showed the significant efficacy of ANA/OPN (2 nM) in enhancement of target organ reinnervation and subsequent sensorimotor recovery compared to other groups. Electrophysiological and histomorphometric analyses further supported the regenerative properties of ANA/OPN (2 nM). Additionally, ANA/OPN (2 nM) promoted macrophage polarization towards an M2 phenotype and reduced proinflammatory cytokines at the injury site. In conclusion, the study suggested that ANA loaded with 2 nM OPN effectively repaired transected sciatic nerves in rats, potentially through enhancing axonal sprouting and exerting anti-inflammatory effects.

Sinus floor augmentation using mineralized freeze-dried bone allograft combined with recombinant human bone morphogenetic protein-2 (rhBMP-2): A long-term retrospective study.

Background/purpose: The combination of recombinant human bone morphogenetic protein-2 (rhBMP-2) with a carrier material has not been extensively studied. This study aimed to evaluate the clinical, radiological, and histomorphometric outcomes of sinus floor augmentation using a 3:7 mixture of cancellous and cortical freeze-dried bone allografts (mixed AG) combined with rhBMP-2. Materials and methods: Mixed AG was used for sinus floor augmentation in a total of 21 patients with a residual alveolar bone height <5 mm. Among the total 47 sites, augmentation with and without rhBMP-2 was performed in 26 and 21 sites, respectively. Radiographic parameters were assessed using cone-beam computed tomography. After a six-month healing period, core biopsies were harvested for histomorphometric analysis. Results: The bone gain after healing was 13.36 ± 3.9 mm and 12.07 ± 3.8 mm in the mixed AG alone and mixed AG with rhBMP-2 groups, respectively. The survival rate of implants in both groups was 100% during the follow-up period. The proportion of newly formed bone was 24.6 ± 10.2% and 39.7 ± 18.3% in the mixed AG alone and mixed AG with rhBMP-2 groups, respectively (P < 0.05). Moreover, the percentage of residual graft material was 21.0 ± 12.2% and 9.6 ± 10.0% in the mixed AG alone and mixed AG with rhBMP-2 groups, respectively (P < 0.05). Conclusion: Mixed AG combined with rhBMP-2 could be a suitable material for sinus floor augmentation. This combination may reduce the treatment time and improve the predictability of implant placement.