Massive Bone Allografts Research Articles

Human Leukocyte Antigen Sensitization after Structural Cortical Allograft Implantations

The incidence and significance of a donor-specific human leukocyte antigen antibody response to massive fresh-frozen human bone allograft implantation is not established. This study was a prospective, multicenter study of a cohort of consecutive patients who self-randomized themselves into two groups based on their alloantibody response to allograft bone transplant. The study hypothesis was that donor-directed antibodies are an independent risk factor influencing incorporation of massive frozen bone allografts. Pretransplant and posttransplant human leukocyte antigen alloantibody analysis was performed and correlated to determine pre-existing and graft-induced antibodies. The surgical outcomes of the two groups of patients were compared to determine the relationship between alloantibody response and bone graft incorporation. Preliminary results revealed that donor-specific human leukocyte antigen sensitization occurred in 17 of 32 (53%) of previously nonsensitized patients. A survival analysis of time to healing based on human leukocyte antigen status showed no evidence of an association between human leukocyte antigen status and time to healing. Longer followup in additional patients will be required to determine if this sensitization is correlated with an alteration in the time to union or with the quality or type of bone graft incorporation. Therapeutic study, Level II. See the Guidelines for Authors for a complete description of levels of evidence.

Infection in Massive Bone Allografts

We studied a series of 945 patients who received cadaveric allografts implanted for nonpelvic bone or soft tissue tumor lesions since 1971. We specifically were interested in the role of infection in the graft process, and, more specifically its history, frequency, and affect on outcome. Primary infections (not related to reoperations for nonunions or fractures of the graft) occurred in 75 patients (7.9%), and an additional 46 patients had infections related to reoperations, increasing the total number of patients with infections to 121 (12.8%). The highest frequency of infection occurred in patients with soft tissue tumors, radiated sites, Musculoskeletal Tumor Society Stage IIB tumors, or surgeries consisting of an allograft arthrodesis. Most of the infected grafts failed; however, none of the patients died. One patient had hepatitis C develop, and one patient became HIV positive after receiving the virus from a blood transfusion. A comparison with other series of surgically treated patients, including those receiving metallic devices, suggests that the infection rate may be related to the surgery or the graft's immunologic resistance, rather than the graft. The problem of infection is a major issue for tumor surgeons. Suggestions regarding how to decrease the frequency of this complication are presented.

Kinematic study of a reconstructed hip in paediatric oncology

In 1997, a large portion of the femur of a four-year-old child affected by a Ewing's sarcoma was reconstructed with an innovative technique that used a massive bone allograft, in conjunction with a vascularised fibula autograft that was directly articulated within the acetabulum. The aim of the present study was to assess the kinematic behaviour of the reconstructed hip during flexion, once the acute remodelling process observed after the operation had ceased. A few additional CT slices of the hip joint region, in a flexed position, were taken at month 33 of the follow-up. The helical axes relative to the neutral-flexion motor action were estimated: their relative positions, with respect to the anatomical femoral heads, were compared, and the translation of the anatomical head centres was estimated. The angles spanned by the two femurs were almost equal, as were the translations along the respective helical axis. The main difference between the two femurs was the distance between the estimated femoral head centres and the relative helical axes. This resulted in a non-negligible translation of 2.9 mm of the fibula head inside the acetabulum during flexion, significantly higher than the 0.5 mm found for the intact contralateral femur. The results showed that, although the transplanted fibula grew and remodelled during the follow up, the action of the reconstructed hip joint still cannot be described as a ball-and-socket.

Original biological reconstruction of the hip in a 4-year-old girl

We resected the proximal femur in a 4-year-old child who had Ewing's sarcoma. We reconstructed her hip by an autotransplant of the ipsilateral proximal fibula with its vascular supply, inserted inside a massive bone allograft, and fixed to the residual femur by a plate. Serial postoperative imaging showed the progressive hypertrophy of the transplanted fibula, whose head displayed impressive tridimensional growth inside the acetabulum. 4 years after surgery, hip motility is 100 degrees in flexion, 10 degrees in extension, and 30 degrees in abduction, and the patient's limb is weight bearing.

Massive bone allograft reconstruction in high-grade osteosarcoma.

From 1986 to 1994, 112 bone allograft reconstructions were performed in patients with high-grade osteosarcoma in whom neoadjuvant chemotherapy was administered. The allograft reconstruction was used in arthrodesis in 44 cases (41 knees, three ankles), as an intercalary graft in 39 (28 femurs, 11 tibias), as an osteoarticular graft in 22 (three proximal and/or distal humeri, six distal femurs, 13 proximal tibias), and as an allograft and prosthesis composite in seven (two proximal humeri, one proximal femurs, four proximal tibias). In 20 patients an autologous vascularized fibula was used to augment the allograft. Functional results were excellent or good in 74% of the patients after the primary surgery, and in 83% of the patients after secondary surgery. Complications include delayed union (49%) and fracture (27%), although there were no cases of deep infection. The incidence of delayed union, but not infection or fracture, was increased by the use of chemotherapy.

Versatile Utilization of Massive Bone Allografts in Orthopedic Surgery.

The clinical use of massive bone allografts in orthopaedic surgery has become common practice in tumour operations and primary and revision total joint replacement. In certain special clinical situations associated with large bone loss, such as trauma, limb-length discrepancy repair or even infection, massive bone allografts can be successfully used. We present our treatment results of 47 patients who suffered from major bone loss due either to trauma, limb-length discrepancy repair, or infection. Our results (> 2 years minimum follow-up to allow full-bone allograft incorporation) indicate that the use of massive bone allografts in these special and delicate medical conditions is feasible, and have good functional results.

Human bone allografts can induce T cells with high affinity for donor antigens

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

Human bone allografts can induce T cells with high affinity for donor antigens.

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

Intraepiphyseal Resection of the Proximal Tibia and Its Impact on Lower Limb Growth

From 1989 through 1996, 10 children affected by high grade bone tumors of the proximal tibia underwent an intraepiphyseal intercalary resection. The residual epiphyseal bone segment measured less than 2 cm in thickness in all cases and reconstruction always was performed using the combination of a vascularized fibular autograft and a massive bone allograft. The proximal epiphyseal osteosynthesis was fixed by small fragment screws. The aim of this study was to report the growth pattern of the residual proximal tibial epiphysis and to evaluate any possible lower limb discrepancy and/or deformity after the end of skeletal maturity. At current followup six patients were available for the final evaluation. Radiographic documentation included computed tomography scan of both knees before surgery, a panoramic radiographic view and a computed tomography scan of both lower limbs after the end of skeletal growth. The length of both femurs and tibias, the size of the tibial plateau and of the opposite distal femur, and any possible deformity of femur or tibia were measured and compared with the preoperative data. No patient had a limb length discrepancy greater than 3.5 cm. In all cases the ipsilateral femur had a valgus deformity of the hip develop. In two patients this deformity was associated with an elongation of the femur, partially compensating for the shortening of the tibia. The tibial plateau close to reconstruction grew less than the contralateral one (range 2%-8%) but maintained its normal relationship with the distal femur. None of these patients reported any restriction in recreational activities. They could walk, run, and jump. Their functional result according the International Society of Limb Salvage functional grading system was satisfactory in all cases.

Massive bone allografts in the treatment of pathologic fractures due to bone metastases.

Pathologic fractures due to disseminated metastases are common and often involve major long bones, where the metastasis is responsible for wide bone erosion that is equivalent to major bone loss. Stabilization of these fractures necessitates tumor excision and reconstruction of the destructive metastatic process. Massive allografts were used either as intercalary or "composite" grafts (allografts and regular prostheses) in 17 patients. Fourteen patients could ambulate independently after surgery, and nursing of the remaining three became feasible and less painful. In the event of pathologic fractures due to metastatic bone diseases associated with major bone involvement, massive bone allografts offer an inexpensive, adjustable, simple, solution.

Improved osteoinduction of cortical bone allografts: a study of the effects of laser perforation and partial demineralization.

Massive cortical bone allografts have been found to incorporate slowly into host bone and thus are subject to complications such as nonunion, fatigue fracture, and infection. To better understand and improve the process of osteoinduction in these types of bone grafts, a new experimental model was developed with use of diaphyseal cortical bone grafts from rat tibiae that were prepared by partial demineralization and drilling of 0.33 mm diameter holes with a pulsed, 2.94 microns wavelength, erbium:yttrium-aluminum-garnet laser. Six types of grafts were analyzed: untreated (Type I), demineralized 25 microns deep (Type II), demineralized 150 microns deep (Type III), laser perforated (Type V), laser perforated and then demineralized 25 microns deep (Type V), and laser perforated and then demineralized 150 microns deep (Type VI). The graft was orthotopically transplanted in the tibia of an adult Sprague-Dawley rat and followed for as long as 4 months. Histologic evaluation at 1 and 4 months postoperatively with use of hematoxylin and eosin staining confirmed that there was new bone growth in Types II, III, V, and VI grafts. The amount of growth was estimated by comparing bone mineral density before implantation with values obtained after retrieval of the graft. These measurements were correlated to histomorphometric analysis of graft incorporation. The results show that the processes of partial demineralization (p < 0.000001) and laser perforation with partial demineralization (p < 0.000001) were both significant in enhancing bone growth in this model. New bone growth was significantly increased when the grafts were prepared with extensive demineralization (p < 0.015). This study demonstrates that osteogenesis in cortical bone grafts can be fostered through the process of partial demineralization and laser perforation. To the extent that minimal partial demineralization and laser perforation allow maintenance of structural integrity while altering the osteoinductive properties in such a way as to promote ingrowth of new bone, this experimental model represents an advance in understanding how osteogenesis in cortical bone grafts may be improved.

Foreign Body Granulomatous Response to Particulate Bony Debris

SummaryArchival material was retrieved in order to histologically assess the body’s response to micron-sized, necrotic bony particles. Specimens were obtained from (1) human bone grafts in a subcutaneous or muscular pouch of athymic nude mice, (2) a massive bone allograft replacing a patient’s humerus, (3) rabbits’ healing tibial cortical bone defects littered with finely dispersed bony particles, (4) periprosthetic tissues of patient’s aseptically loosened artificial joints and (5) interfacial membranes of intramedullary nails used for fixation of patients’ fractured long bones. Necrotic bony debris was found to induce a giant celled granulomatous reaction. In sections of undecalcified samples stained by the von Kossa method, small calcific particles were observed to be present within polykaryonic macrophages (foreign body giant cells) and surrounded by mononuclear macrophages. It is concluded that a foreign body-type giant celled granulation tissue participates in the degradation of micron-sized, necrotic bony detritus, whether the disintegrating bone is of the xeno-, alio- or autogenic provenance.Histological examination of von Kossa-stained sections, of undecalcified specimens, revealed a giant celled granulomatous response to bony debris. Irrespective of whether or not the disintegrating bone was of auto-, alio- or xenogeneic provenance, micron-sized bony particles were found to be phagocytosed by polykaryonic macrophages of the granulation tissue.

Human leukocyte antigen matching, radiographic score, and histologic findings in massive frozen bone allografts.

Forty-six patients receiving frozen bone allografts, preoperatively tissue typed for human leukocyte antigen and ABO antigens, were radiographically evaluated according to the Musculoskeletal Tumor Society scoring system at a mean followup of 55 months. Patients who matched for 1 or 2 Class I human leukocyte antigens with the donor scored higher than patients totally mismatched, but differences were not significant. Matching for Class II human leukocyte antigen and ABO antigens seemed not to influence radiographic outcome of allografts. In sixteen patients histologic specimens were obtained. Five of 16 patients who showed histologic parameters of an immune response scored significantly lower than those who did not. Processed frozen bone allografts, because of their lack of viable donor cells, most likely trigger an indirect pathway of alloantigen recognition in the recipient. This type of recognition may generate in the recipient either a chronic type of rejection or an immunologic state of tolerance to grafted antigens that cannot be measured with human leukocyte antigen blood tests. This may explain difficulties in correlating human leukocyte antigen mismatches between the donor and recipient with frozen bone allograft performances.

Magnetic resonance imaging of massive bone allografts with histologic correlation.

The objective of this study was to better understand the MRI appearance of massive bone allografts. The MRI findings of three massive bone allografts imaged in vivo were correlated with the histologic findings following removal of the allografts. A fourth allograft, never implanted, was imaged and evaluated histologically. Allografts were placed for the treatment of primary or recurrent osteosarcoma. The in-vivo allografts have a heterogeneous appearance on MRI which we attribute to the revascularization process. Fibrovascular connective tissue grows into the graft in a patchy, focal fashion, down the medullary canal from the graft-host junction and adjacent of the periosteum. The marrow spacers are initially devoid of normal cellular elements and occupied by fat and gelatinous material. This normal postoperative appearance of massive bone allografts must be interpreted as recurrent neoplasm or infection in the allograft. Recognition of these complications rests on features outside the marrow.

HISTOLOGICAL FEATURES OF LARGE BONE ALLOGRAFTS

We performed biopsies during reoperation for minor complications in two active young patients 9 and 19 months after massive bone allograft implantation for bone tumour. The grafts were dead and resorption-apposition activity, when present, was predominantly in subperiosteal areas. Inflammatory infiltration was very seldom found. Features considered as 'microfractures' or 'microcracks' were noted in the cortical ring together with the formation of woven bone, in areas with remodelling. Such cracks are likely to be of mechanical origin and do not inevitably lead to complications.

Consolidation of massive bone allografts in limb-preserving operations for bone tumours.

This study analysed the influence of several factors affecting the consolidation time of 83 massive bone allografts in 79 patients with malignant bone tumours: osteosarcoma 57; Ewing's sarcoma 8; malignant fibrous histiocytoma 3; chondrosarcoma 4; fibrosarcoma 5; and giant cell tumours 2. The mean age of the patients was 19 years and the mean length of the allografts was 18 cm. The minimum follow up was for 12 months. The mean consolidation time for metaphyseal and diaphyseal osteotomies was 6.5 and 16 months respectively. Fifteen diaphyseal osteotomies required autologous cancellous grafting. There were 8 allograft fractures after consolidation. The following factors which might influence consolidation were analysed: age of the host and donor; allograft length and site; type of osteotomy and osteosynthesis; intra-arterial and systemic chemotherapy; intraoperative and external radio-therapy. In diaphyseal osteotomies there were statistically significant differences in consolidation time with the use of systemic chemotherapy, external radiotherapy and the recipient's age.

Bone scintigraphic appearances of massive bone allograft and local recurrence of sarcoma.

A 12-year-old boy underwent excision of the right distal femur and allograft insertion for right distal femoral osteogenic sarcoma. Eighteen months after allograft placement subcutaneous nodules developed around the right knee. Radionuclide imaging of massive bone allograft and sarcoma recurrence are presented

Infection in massive bone allografts sterilised by radiation

Massive bone allografts sterilised by radiation have been used in our hospital since 1985. The 164 consecutive reconstructions which we carried out before December 1990 were in equal part for tumour resections and revision arthroplasties associated with major bone defects. The allografts were used as intercalary or composite graft-prosthesis reconstructions. Fourteen (8.5%) skin sloughs or infections occurred, all but one after operations for malignant tumours. The grafts never appeared to be responsible. Infection after malignant tumour resection most commonly occurred at the knee when preoperative radiation had been used. Twenty-five reconstructions were performed in the presence of infection, which only recurred in one case. Twelve infections were treated, but 2 other patients died for other reasons within a year. One patient had to have an amputation and one had persistent infection. In the other cases, the infection healed. Only two debridements alone were successful. Removal of the graft and replacement with antibiotic-loaded cement was the most effective treatment.

Clinical use of bone allografts.

Modern techniques of bone allograft surgery provide a treatment modality for management of difficult skeletal defects. In oncological limb-salvage surgery, allograft reconstructions permit re-establishment of skeletal continuity and function after a wide resection of bone tumour. Bone allografts are increasingly used in salvage of difficult bone stock deficiencies following failed total joint replacements. Union between the allograft and the host bone takes place slowly and the use of autogenous bone graft at the graft-host junction is recommended for induction of repair. Internal repair (revascularization and substitution of the original graft bone with new host bone) also progresses slowly and seems to be confined only to the superficial surface and the ends of the graft. Biomechanically, a massive allograft may serve a structural function in the absence of advanced revascularization and creeping substitution processes. Infection of an allograft is a disastrous complication, whereas non-union of the graft-host junction and fracture of the graft are amenable to surgical treatment. Osteochondral allografts tend to show gradual deterioration of the articular cartilage with time, necessitating occasionally late resurfacing arthroplasty. It is evident that there is more active immune response to osteochondral grafts than was thought previously. Bone allografts induce cell-mediated and antibody-mediated cytotoxicity specific for donor antigens similar to that seen after organ transplantations. Not only the basic mechanisms of bone allograft rejection but also the clinical features of bone allograft rejection are poorly characterized. Clinically, new non-invasive imaging techniques should be applied in determining the metabolic activity of bone in order to find the optimal loading of healing allografts. Although the clinical results of massive bone allografts are still not completely predictable, the method has proved to be a technically and biologically feasible alternative for non-biological skeletal reconstructions.

血管柄付同種骨移植の実験的研究 （第３報） 免疫抑制剤長期投与群と短期投与群の比較

A study of vascularized massive bone allograft was performed, using the devised model of inbred rat with cyclosporin A as immunosuppressive drug. This model was designed for making it easy to observe callus formation on both proximal and distal sites of massive interaclary bone allograft and the montitoring of the viability of osteocytes by the bone scan. Cyclosporin A was used postopertively both continuously and short term (14 days after transplant) at 10mg/kg/day (i. m.) as recipient treatment.Bone scintigram indicated remakable difference between continuous cyclosporin group and short term cyclosporin group. High uptake was continuously observed in the continuous cyclosporin groups. In the short term cyclosporin group, howevever, the high uptake was observed during the 3 to 4 weeks. and it changed into the weak or mottled uptake until 6 weeks after transplantation.In the continuous cyclosporin group periosteal new bone formation was observed on both donor and recipient bone, and each of them united until 4 weeks postoperatively at the proximal side and it took one more week to get a union at the distal side. These results were very similar to those of the vascularized bone isograft. On the other hand, in the short term cyclosporin group, the union was remarkably delayed and it took 8 weeks to obtain the union at the proximal side, and failure of the bone union developed in few of models at the distal side.In conculsion, under immunosuppression, viability of he allogratted bone was maintaind and the union of both osteosynthetic side occurred surely as soon as the vasucularized bone isograft. However, in the short term (14 days) cyclosporin group, vascularized allografted bone was rejected after stopping cyclosporin. The union delayed than the continuous cyclosporin group when the cyclosporin was stopped 14 days after transplantation and before union.