Re-implantation of autoclaved bone segments in musculoskeletal tumor surgery. Clinical experience in 9 patients followed for 1.1-8.4 years and review of the literature

Mesh patch and anchors can improve clinical results of prosthetic replacement after resection of primary proximal humerus malignant tumor

The purpose of this study was to evaluate the functional results, complications and related factors of prosthesis reconstruction after malignant tumor resection of primary proximal humeral, and also evaluate whether soft tissue reconstruction with mesh patch and anchors can improve clinical results. From 2002 to 2016, forty-one patients were enrolled in this study. The pathological diagnosis contained 27 cases of osteosarcoma, 7 cases of chondrosarcoma and other primary malignant bone tumors. Both mesh patch and anchors were used in the reconstruction of joint capsule and the surrounding soft tissues in 27 cases. The mean postoperative follow-up was 60.6 months. The average active abduction angle and passive abduction angle was 33.5 (5–71) degrees and 72.4 (52–104) degrees. The prosthetic humeral head displacement was over 2 cm in 5 cases (12.2%). The average MSTS score was 23.1. The overall 5-year survival rate of prosthesis was 88.2%. The length of osteotomy, whether preserving deltoid muscle, whether applying mesh patch and anchors had significant effects on the abduction angle of shoulder joint; the length of osteotomy, whether applying mesh patch and anchors had significant effects on the degree of upward displacement of prosthesis. The application of both mesh patch and anchors in prosthesis reconstruction achieved more stable result and better function of shoulder joint. To ensure the stability of shoulder joint and the firm wrapping of surrounding soft tissue are key factors affecting the postoperative function.

Limb Salvage for Musculoskeletal Tumors in the Austere Environment: Review of the Literature With Illustrative Cases Regarding Considerations and Pitfalls

Although there is literature discussing the treatment of acute and chronic trauma in austere environments, no literature or guidelines for the treatment of musculoskeletal tumors exist. This series discusses case examples with considerations and pitfalls of performing limb-salvage surgery in an underserved location.

Cases of limb-salvage surgery performed by the same orthopaedic oncologist in Haiti and the Dominican Republic are discussed with a review of the literature on limb salvage for musculoskeletal tumors in developing nations.

All patients successfully underwent limb-salvage surgery after considering multiple factors including tumor type and location. Patients with metastatic disease, likelihood of substantial blood loss, and poor health were not candidates for limb-salvage surgery.

Medical missions and the development of partnerships with established training programs make limb salvage a greater possibility. Knowledge of the facility, anesthesia support, and instrumentation available is vital. Advanced imaging, blood products, and allograft are likely unavailable or difficult to obtain. Established continuity of care is necessary, and training of the local surgeon should be provided. Surgery should only be considered if it is safe and provides more of a benefit to the patient than an amputation.

Extracorporeal high-pressure therapy (EHPT) for malignant melanoma consisting of simultaneous tumor eradication and autologous dermal substitute preparation

Surgical resection of skin tumors leads to large defects in surrounding normal tissues, which should be reconstructed thereafter using the patient's own tissues taken from the other site. Our challenge is to solve this problem in dermal malignant melanoma (MM) by a novel process, named extracorporeal high pressure therapy (EHPT), in which the tissue containing tumor is resected and pressurized, and the treated tissue is re-transplant back to the same position as a tumor-free autologous dermal substitute. The key points are complete tumor death and preservation of native extra cellular matrix (ECM) by the hydrostatic pressure. We found that high hydrostatic pressure at 200 MPa for 10 min at room temperature is completely cytocidal against MM cells in suspension form, in monolayer form, and even in the solid tumor form. MM tumor-bearing nude mice were established by injected human MM cells intradermally and treated by EHTP. The denaturation of the dermal extra cellular matrices was so mild that the pressurized skin was well engrafted as tumor free autologous dermal tissues, resulting in the complete eradication of the MM without any unnecessary skin reconstruction surgery. This very simple and short pressing treatment was proved to make the tumor tissue to the transplantable and tumor-free autologous dermal substitute, which can be applicable to the other temporally resectable tissues.

Irradiation-Induced Compositional Effects on Human Bone After Extracorporeal Therapy for Bone Sarcoma

The present study investigates Raman scattering of human bone irradiated with 50 Gy single dose during therapeutic treatment of Ewing and Osteosarcoma. Bone quality was evaluated via mineral-to-matrix ratio, degree of crystallinity, change in amount of calcium, and carbonate substitution. Alteration in collagen and its cross-links was quantified through second-derivative deconvolution of Amide I peak. A dose of 50 Gy radiation leads to almost 50% loss of mineral content, while maintaining mineral crystallinity, and small changes in carbonate substitution. Deconvolution of Amide I suggested modifications in collagen structure via increase in amount of enzymatic trivalent cross-linking (p < 0.05). Overall irradiation led to detrimental effect on bone quality via changes in its composition, consequently reducing its elastic modulus with increased plasticity. The study thus quantifies effect of single-dose 50 Gy radiation on human bone, which in turn is necessary for designing improved radiation dosage during ECRT and for better understanding post-operative care.

Stepwise verification of bone regeneration using recombinant human bone morphogenetic protein-2 in rat fibula model

Objectives

The purpose of this study was to introduce our three experiments on bone morphogenetic protein (BMP) and its carriers performed using the critical sized segmental defect (CSD) model in rat fibula and to investigate development of animal models and carriers for more effective bone regeneration.

Materials and Methods

For the experiments, 14, 16, and 24 rats with CSDs on both fibulae were used in Experiments 1, 2, and 3, respectively. BMP-2 with absorbable collagen sponge (ACS) (Experiments 1 and 2), autoclaved autogenous bone (AAB) and fibrin glue (FG) (Experiment 3), and xenogenic bone (Experiment 2) were used in the experimental groups. Radiographic and histomorphological evaluations were performed during the follow-up period of each experiment.

Results

Significant new bone formation was commonly observed in all experimental groups using BMP-2 compared to control and xenograft (porcine bone) groups. Although there was some difference based on BMP carrier, regenerated bone volume was typically reduced by remodeling after initially forming excessive bone.

Conclusion

BMP-2 demonstrates excellent ability for bone regeneration because of its osteoinductivity, but efficacy can be significantly different depending on its delivery system. ACS and FG showed relatively good bone regeneration capacity, satisfying the essential conditions of localization and release-control when used as BMP carriers. AAB could not provide release-control as a BMP carrier, but its space-maintenance role was remarkable. Carriers and scaffolds that can provide sufficient support to the BMP/carrier complex are necessary for large bone defects, and AAB is thought to be able to act as an effective scaffold. The CSD model of rat fibula is simple and useful for initial estimate of bone regeneration by agents including BMPs.

Intercalary reconstructions after bone tumor resections: a review of treatments

An intercalary reconstruction is defined as replacement of the diaphyseal portion of a long bone after segmental skeletal resection (diaphysectomy). Intercalary reconstructions typically result in superior function compared to other limb-sparing procedures as the patient's native joints above and below the reconstruction are left undisturbed. The most popular reconstructive options after segmental resection of a bone sarcoma include allografts, vascularized fibula graft, combined allograft and vascularized fibula, segmental endoprostheses, extracorporeal devitalized autograft, and segmental transport using the principles of distraction osteogenesis. This article aims to review the indications, techniques, limitations, pros and cons, and complications of the aforementioned methods of intercalary bone tumor resections and reconstructions in the context of the ever-growing, brave new field of limb-salvage surgery.

Estudo biomecânico comparativo da resistência de segmentos ósseos de rádios de cães autoclavados ou desvitalizados em nitrogênio líquido

RESUMO O presente estudo comparou, por meio do ensaio de flexão em quatro pontos, a resistência de segmentos de rádios de cães autoclavados e desvitalizados em nitrogênio líquido. Avaliaram-se 40 rádios, que foram divididos em quatro grupos: grupo autoclave (GA), grupo controle autoclave (GCA), grupo nitrogênio (GN) e grupo controle nitrogênio (GCN). Os corpos de prova dos grupos GCA e GCN pertenciam ao lado contralateral dos grupos GA e GN, respectivamente. Os ossos foram autoclavados a 121°C, por 20min a 2atm. A desvitalização em nitrogênio foi realizada por meio da imersão em nitrogênio líquido, por 20min, seguida de descongelamento à temperatura ambiente, sendo finalizada por imersão em solução de NaCL a 0,9%, por mais 15min. Após os testes biomecânicos, foram comparadas as variáveis força máxima, rigidez, altura máxima à secção transversa do corpo de prova, deslocamento do baricentro em relação ao eixo x, flecha, tensão-tração, tensão-compressão e tensão máxima. Não foram encontradas diferenças estatisticamente significantes entre os grupos GN e GCN. Foram encontradas diferenças estatisticamente significantes entre os grupos GA e GCA somente na comparação da variável força máxima. A análise das variáveis tensão-tração, tensão-compressão e tensão máxima evidenciou diferenças estatisticamente significantes entre os grupos GA e GN, sendo os valores maiores para o grupo GA. Também foi realizada comparação entre os deltas (GN menos GCN e GA menos GCA), em que não foram observadas diferenças estatísticas.

Fabrication method, structure, mechanical, and biological properties of decellularized extracellular matrix for replacement of wide bone tissue defects

The present paper was focused on the development of a new method of decellularized extracellular matrix (DECM) fabrication via a chemical treatment of a native bone tissue. Particular attention was paid to the influence of chemical treatment on the mechanical properties of native bones, sterility, and biological performance in vivo using the syngeneic heterotopic and orthotopic implantation models. The obtained data indicated that after a chemical decellularization treatment in 4% aqueous sodium chlorite, no noticeable signs of the erosion of compact cortical bone surface or destruction of trabeculae of spongy bone in spinal channel were observed. The histological studies showed that the chemical treatment resulted in the decellularization of both bone and cartilage tissues. The DECM samples demonstrated no signs of chemical and biological degradation in vivo. Thorough structural characterization revealed that after decellularization, the mineral frame retained its integrity with the organic phase; however clotting and destruction of organic molecules and fibers were observed. FTIR studies revealed several structural changes associated with the destruction of organic molecules, although all organic components typical of intact bone were preserved. The decellularization-induced structural changes in the collagen constituent resulted changed the deformation under compression mechanism: from the major fracture by crack propagation throughout the sample to the predominantly brittle fracture. Although the mechanical properties of radius bones subjected to decellularization were observed to degrade, the mechanical properties of ulna bones in compression and humerus bones in bending remained unchanged. The compressive strength of both the intact and decellularized ulna bones was 125-130 MPa and the flexural strength of humerus bones was 156 and 145 MPa for the intact and decellularized samples, respectively. These results open new avenues for the use of DECM samples as the replacement of wide bone tissue defects.

Which is the best method of sterilization for recycled bone autograft in limb salvage surgery: a radiological, biomechanical and histopathological study in rabbit

Background

Limb salvage surgery is a treatment of choice for sarcomas of the extremities. One of the options in skeletal reconstruction after tumour resection is by using a recycled bone autograft. The present accepted methods of recycling bone autografts include autoclaving, pasteurization and irradiation. At the moment there is lack of studies that compare the effectiveness of various sterilization methods used for recycling bone autografts and their effects in terms of bone incorporation. This study was performed to determine the effects of different methods of sterilization on bone autografts in rabbit by radiological, biomechanical and histopathological evaluations.

Methods

Fresh rabbit cortical bone is harvested from the tibial diaphysis and sterilized extracorporeally by pasteurization (n = 6), autoclaving (n = 6), irradiation (n = 6) and normal saline as control group (n = 6). The cortical bones were immediately reimplanted after the sterilization process. The subsequent process of graft incorporation was examined over a period of 12 weeks by serial radiographs, biomechanical and histopathological evaluations. Statistical analysis (ANOVA) was performed on these results. Significance level (α) and power (β) were set to 0.05 and 0.90, respectively.

Results

Radiographic analysis showed that irradiation group has higher score in bony union compared to other sterilization groups (p = 0.041). ANOVA analysis of ‘failure stress’, ‘modulus’ and ‘strain to failure’ demonstrated no significant differences (p = 0.389) between treated and untreated specimens under mechanical loading. In macroscopic histopathological analysis, the irradiated group has the highest percentage of bony union (91.7 percent). However in microscopic analysis of union, the pasteurization group has significantly higher score (p = 0.041) in callus formation, osteocytes percentage and bone marrow cellularity at the end of the study indicating good union potential.

Conclusions

This experimental study shown that both irradiation and pasteurization techniques have more favourable outcome in terms of bony union based on radiographic and histopathological evaluations. Autoclaving has the worst outcome. These results indicate that extracorporeal irradiation or pasteurization of bone autografts, are viable option for recycling bone autografts. However, pasteurization has the best overall outcomes because of its osteocytes preservation and bone marrow cellularity.

Clinical results of primary malignant musculoskeletal tumor treated by wide resection and recycling autograft reconstruction using liquid nitrogen

AIM

To evaluate the clinical results of primary malignant musculoskeletal tumors treated with wide resection and recycling autograft reconstruction using liquid nitrogen.

METHODS

We reviewed 12 patients who had a primary malignant bone and soft tissue tumor treated by wide resection and recycling autograft reconstruction using liquid nitrogen between March 2006 and March 2013. The results were judged by recurrence, functional status and complications. Functional status was assessed according to the Musculoskeletal Tumor Society Score (MSTSS). Clinical failure was defined as need for reoperation in order to change the type of reconstruction or to amputate, and the presence of local recurrence.

RESULTS

The most common tumor was osteosarcoma (eight cases) followed by Ewing's sarcoma (two cases). The tibia was the most frequently involved skeletal site (six cases) followed by the femur (three cases). The median follow-up period was 32 months. In 12 patients, 7 were still alive without recurrence. There were 3 clinical failures: 1 local recurrence and 2 graft complications at 28, 51 and 20 months after reconstruction, respectively. The main complication was infection (three cases). All osteotomy sites were radiographic unions, and the union time was 8.2 ± 2.7 months. The mean ± SD MSTSS score was 79% ± 11%; excellent functional results were achieved in seven patients.

CONCLUSIONS

Recycling autograft reconstruction using liquid nitrogen had favorable clinical outcomes in terms of functional status and local recurrence. This reconstruction method, therefore, represents a reasonable alternative for limb salvage surgery.

Bone Healing Properties of Autoclaved Autogenous Bone Grafts Incorporating Recombinant Human Bone Morphogenetic Protein-2 and Comparison of Two Delivery Systems in a Segmental Rabbit Radius Defect

Purpose:

This study aims to validate the effect of autoclaved autogenous bone (AAB), incorporating Escherichia coli-derived recombinant human bone morphogenetic protein-2 (ErhBMP-2), on critical-sized, segmental radius defects in rabbits. Delivery systems using absorbable collagen sponge (ACS) and fibrin glue (FG) were also evaluated.

Methods:

Radius defects were made in 12 New Zealand white rabbits. After autoclaving, the resected bone was reinserted and fixed. The animals were classified into three groups: only AAB reinserted (group 1, control), and AAB and ErhBMP-2 inserted using an ACS (group 2) or FG (group 3) as a carrier. Animals were sacrificed six or 12 weeks after surgery. Specimens were evaluated using radiology and histology.

Results:

Micro-computed tomography images showed the best bony union in group 2 at six and 12 weeks after operation. Quantitative analysis showed all indices except trabecular thickness were the highest in group 2 and the lowest in group 1 at twelve weeks. Histologic results showed the greatest bony union between AAB and radial bone at twelve weeks, indicating the highest degree of engraftment.

Conclusion:

ErhBMP-2 increases bony healing when applied on AAB graft sites. In addition, the ACS was reconfirmed as a useful delivery system for ErhBMP-2.

Experimental remodellation of extracorporeal irradiated autogenous and allogenic patellar grafts

BACKGROUND

Irradiated autografts have been used to aid the recovery of bone defects, and the results are well documented. Recently, bone allografts with tendinous attachments have been used to restore the function of joints. Similar reconstructions can be performed with irradiated autografts. However, little information is available on the biology of extracorporeal irradiated tendon autografts.

QUESTIONS/PURPOSES

An experimental rabbit model was used to investigate the quality of healing and remodeling of the irradiated autogenous patellar tendon graft after 3 and 12 weeks using immunohistochemical and morphometric analyses.

METHODS

New Zealand rabbits (n = 40) were randomly divided into autograft and allograft groups. The right knees of all animals served as the control (sham). The patellar tendon graft of the control right knee was reimplanted into its original location without any processing, while the patellar tendon of the left knee in the autograft group was reimplanted into the original location after 50 Gy irradiation. In the allograft group, the patellar tendon was sutured to the knee of another rabbit following 50 Gy irradiation. Five rabbits from each group were sacrificed and examined histologically.

RESULTS

There were significant differences in the number of fibroblasts after 12 weeks between allograft and sham groups (P = 0.002). On the other hand, there were no differences between the allograft and autograft groups at the 12th week (P = 0.139). The difference in fibroblast numbers between autograft and allograft groups was statistically significant after the 3rd week (P < 0.05). Collagen fibril thickness was different between both the allograft and sham groups (P = 0.002) and the allograft and autograft groups at the 12th week (P = 0.000). Collagen fibrils were thicker in the sham and autograft groups compared with the allograft group at the 3rd week of evaluation (P < 0.05). The Ki67 index was significantly different between the allograft and sham groups at the 12th week (P < 0.032), while there was no difference between the allograft and autograft groups (P > 0.05). At the 3rd week, Ki67 reactivity was higher in the allograft group compared with the other two groups (P < 0.05).

Massive bone reconstruction with heat-treated bone graft loaded autologous bone marrow-derived stromal cells and β-tricalcium phosphate composites in canine models

Bone marrow-derived stromal cells (BMSCs) contain mesenchymal stem cells that are capable of forming various mesenchymal tissues. We hypothesized that BMSCs and β-tricalcium phosphate (β-TCP) composites would promote the remodeling of large-sized autologous devitalized bone grafts; therefore, the aim of this study was to evaluate the effects of the composites on the remodeling of autologous devitalized bone grafts. Autologous BMSCs cultured in culture medium containing dexamethasone (10(-7)  M) were loaded into porous β-TCP granules under low-pressure. Theses BMSC/TCP composites were put into the bone marrow cavity of autologous heat-treated bone (femoral diaphysis, 65-mm long, 100°C, 30 min) and put back to the harvest site. In the contralateral side, β-TCP without BMSC were used in the same manner as the opposite side as the control. Treatment with the BMSC/TCP composites resulted in a significant increase in thickness, bone mineral density, and matured bone volume of the cortical bone at the center of the graft compared to the control. Histological analysis showed matured regenerated bone in the BMSC loaded group. These results indicate that BMSC/TCP composites facilitated bone regeneration and maturation at the graft site of large-sized devitalized bone. This method could potentially be applied for clinical use in the reconstruction of large bone defects such as those associated with bone tumors.

Autoclaved autologous bone graft for orbital reconstruction for recurrent temporal bone orbital osteosarcoma

Post-tumor excision and reconstruction of the craniofacial region is a complex and technically demanding process due to its proximity to numerous vital structures and irregularly shaped bony tissue. As such, novel methods are needed when reconstruction of irregularly shaped structures is necessary. Autoclaving of autologous bone grafts is an established practice in orthopedic and neurosurgical practice, but has only been described twice previously for orbital reconstruction. We performed grafting of an autoclaved autologous bone segment as part of surgery on a 30-year-old man to treat his recurrent temporal osteosarcoma with orbital involvement, which is rare. In addition, we went on to highlight key differences between bone autoclaving and pasteurization, an alternative heat treatment technique, for orbital reconstruction post-tumor excision. Although he suffered a second recurrence 8 months later, there was no evidence of recurrence in the autoclaved bone. To treat his second recurrence, he subsequently underwent a modified eyelid-conjunctiva sparing orbital exenteration, also an uncommonly performed procedure. Also, we subsequently examined the novel technique of a lid-sparing and conjunctiva-sparing orbital exenteration and its benefits. He continues to remain under follow-up.

Evaluation of long-term outcomes of pasteurized autografts in limb salvage surgeries for bone and soft tissue sarcomas

BACKGROUND

Pasteurized autografts used in limb salvage operations for malignant musculoskeletal tumors have several advantages, including reduced disease transmission, economic efficiency, accessibility, and anatomical conformation. However, their use has been associated with bone absorption, fracture, and pseudarthrosis. Few studies exist which have assessed the long-term outcomes of pasteurized autografts. The purpose of this study was to investigate the clinical outcomes of patients treated with pasteurized autografts and to compare these outcomes across various graft types.

METHODS

A retrospective analysis of 46 patients treated with pasteurized autografts between 1992 and 2010 was conducted. The analysis included 22 intercalary bone grafts, 17 inlay grafts, 4 composite grafts, and 3 osteochondral grafts, with the mean follow-up period of 8.7 years (2-17 years).

RESULTS

The 10-year survival rate of the 46 pasteurized autograft cases analyzed was 93.5 %, and the average bone union time between host and pasteurized autogenous bone was 9.5 months. Infections were identified in 6 (13 %) patients, fractures in 7 (15 %) patients, non-union in 8 (17 %) patients, and bone absorption in 6 (13 %) patients. Inlay grafts were completely incorporated with the host bone at the follow-up period. Combination with a vascularized fibular graft significantly reduced the risk of non-union and bone absorption (p < 0.05 and p < 0.01, respectively), with an average functional score of 23.1/30 (83.8 %).

CONCLUSION

Our findings show that pasteurized bone grafts in combination with vascularized fibular grafts have improved outcomes and potential clinical indications.

Prosthetic limb salvage surgery for bone and soft tissue tumors around the knee

In this study, we analyzed long-term survival, limb function and associated complications after prosthetic limb salvage treatment in patients with bone and soft tissue tumors around the knee joint. A total of 63 patients treated with prosthetic limb salvage surgery around the knee were reviewed. The bone tumors involved the distal femur in 45 patients, the proximal tibia in 14 patients and the soft tissue tumors of the proximal lower leg in 4 patients. The median follow-up period after the first operation was 8.0 years. The medical records of the patients, surgical reports, radiographs and histological specimens were retrospectively reviewed. The 5-year overall survival rate was 63.2% in the patients with distal femur tumors and 86.2% in those with tumors of the proximal lower leg. The 5‑year prosthetic survival rate was 72.8% in the distal femur and 74.6% in the proximal lower leg. The mean functional score according to the scoring system of the Musculoskeletal Tumor Society (MSTS) was 81% in the patients with distal femur tumors and 82% in the patients with proximal lower leg tumors. Post-operative complications occurred in 27 patients. Limb salvage surgery is considered to be an effective treatment option. However, the high complication rate is a major concern for prosthetic replacement. Future improvements of prostheses are very important.

The outcome of the treatment of diaphyseal primary bone sarcoma by resection, irradiation and re-implantation of the host bone

We analysed the outcome of patients with primary non-metastatic diaphyseal sarcomas who had en bloc resection with preservation of the adjoining joints and reconstruction with re-implantation of sterilised tumour bone after extracorporeal radiation (50 Gy). Between March 2005 and September 2009, 32 patients (16 Ewing’s sarcoma and 16 osteogenic sarcoma) with a mean age of 15 years (2 to 35) underwent this procedure. The femur was the most common site in 17 patients, followed by the tibia in 11, humerus in three and ulna in one. The mean resected length of bone was 19 cm (10 to 26). A total of 31 patients were available at a mean follow-up of 34 months (12 to 74). The mean time to union for all osteotomy sites was 7.3 months (3 to 28): metaphyseal osteotomy sites united quicker than diaphyseal osteotomy sites (5.8 months (3 to 10) versus 9.5 months (4 to 28)). There were three local recurrences, all in soft-tissue away from irradiated graft. At the time of final follow-up, 19 patients were free of disease, one was alive with disease and 11 had died of disease. The mean Musculoskeletal Tumor Society Score for 29 patients evaluated at the last follow-up was 26 (9 to 30).

Extracorporeal irradiation is an oncologically safe and inexpensive technique for limb salvage in diaphyseal sarcomas and has good functional results.

The healing process of intracorporeally and in situ devitalized distal femur by microwave in a dog model and its mechanical properties in vitro

Background

Limb-salvage surgery has been well recognized as a standard treatment and alternative to amputation for patients with malignant bone tumors. Various limb-sparing techniques have been developed including tumor prosthesis, allograft, autograft and graft-prosthesis composite. However, each of these methods has short- and long-term disadvantages such as nonunion, mechanical failures and poor limb function. The technique of intracorporeal devitalization of tumor-bearing bone segment in situ by microwave-induced hyperthermia after separating it from surrounding normal tissues with a safe margin is a promising limb-salvage method, which may avoid some shortcomings encountered by the above-mentioned conventional techniques. The purpose of this study is to assess the healing process and revitalization potential of the devitalized bone segment by this method in a dog model. In addition, the immediate effect of microwave on the biomechanical properties of bone tissue was also explored in an in vitro experiment.

Methods

We applied the microwave-induced hyperthermia to devitalize the distal femurs of dogs in situ. Using a monopole microwave antenna, we could produce a necrotic bone of nearly 20 mm in length in distal femur. Radiography, bone scintigraphy, microangiography, histology and functional evaluation were performed at 2 weeks and 1, 2, 3, 6, 9 and 12 months postoperatively to assess the healing process. In a biomechanical study, two kinds of bone specimens, 3 and 6 cm in length, were used for compression and three-point bending test respectively immediately after extracorporeally devitalized by microwave.

Findings

An in vivo study showed that intracorporeally and in situ devitalized bone segment by microwave had great revitalization potential. An in vitro study revealed that the initial mechanical strength of the extracorporeally devitalized bone specimen may not be affected by microwave.

Conclusion

Our results suggest that the intracorporeal microwave devitalization of tumor-bearing bone segment in situ may be a promising limb-salvage method.

Infected tumor prostheses

Infection of tumor prostheses has been a major concern because of the extensive soft tissue dissection, long operating times, and patients' immunosuppression by cancer and adjuvant treatments. Infections most often present within 2 years postoperatively, with approximately 70% of postoperative deep infections presenting within 12 months after surgery. They are typically low organism burden infections, the pathogenesis of which is related to bacteria growing in biofilms. Staphylococci are the most common pathogens involved in prosthetic joint infections, accounting for approximately 50% of infections overall, followed by streptococci, enterococci, Enterobacteriaceae species, Pseudomonas aeruginosa, and anaerobe species. Multiple pathogens may be isolated in approximately 25% of cases, with the most common combination being coagulase-negative Staphylococcus and group-D Streptococcus. Early diagnosis and appropriate treatment are necessary. However, diagnosis may be challenging because clinical symptoms are highly variable and numerous preoperative and intraoperative diagnostic laboratory tests are nonspecific. In most cases, a 1- or 2-stage revision surgery is necessary for eradicating the megaprosthetic infection. Prevention of infection is important. The future will see technical advances for infections of tumor prostheses in areas such as microbiological diagnostics and biofilm-resistant prostheses.

A reconstruction with extracorporeal irradiated autograft in osteosarcoma around the knee

BACKGROUND AND OBJECTIVES

An extracorporeal irradiated (ECI) autograft was first reported in Israel in 1968 for the treatment of primary malignant bone tumor. However, subsequent reports covered mostly short-term follow up results, and the reported results of reconstruction vary from study to study. We analyze the long-term follow up results of reconstruction using an extracorporeal irradiated (ECI) autograft in osteosarcoma around the knee.

METHODS

We retrospectively reviewed 23 osteosarcoma patients who underwent reconstruction with ECI between December 1995 and April 2005. The 15 males and 8 females had a mean age of 21 years (range: 7-74) and a mean follow-up of 127 months(range: 57-170). Tumors were located in the distal femur in 14 cases, and the proximal tibia in 9 cases. Pathological types were conventional in 22 cases, and parosteal in 1 case. Resection methods were osteoarticular in 18 cases and total joint in 5 cases. Eighteen cases were reconstructed with the ECI autograft and five with ECI autograft-prosthesis composite (APC). The Musculoskeletal Tumor Society (MSTS) score was used for functional evaluation. The overall survival rate, local recurrence, complications were analyzed.

RESULTS

The overall survival rate was 82.6%, and the disease-free survival rate was 69.5%. We found 20 complications, including 6 nonunions, 5 deep infections, 4 joint instabilities, 2 fractures, 1 limb-length discrepancy (LLD), 1 epiphyseal collapse, and 1 vessel occlusion. The average MSTS functional score was 62.6%.

CONCLUSIONS

Reconstruction with an extracorporeal irradiated is not recommended for osteosarcoma around the knee.

Reconstruction of a mandibular defect with autogenous, autoclaved bone grafts and tissue engineering: An in vivo pilot study

Reconstruction of bone defects with autogenous, autoclaved bone grafts has already been described but does have one major insuperable problem-the loss of the ostoinductive potential of the graft. In this study, we investigated if autogenous, autoclaved grafts in combination with tissue engineered bone can overcome this problem. An en-bloc resection was done in the mandible of eight pigs. The grafts were autoclaved and filled with autogenous, osseogen differentiated bone marrow cells and compared with four animals without bone marrow cells. After 120 days, the specimens were qualitatively and quantitatively evaluated by means of microradiography and light microscopy. Within the experimental group, osseous remodeling was detected in all cases and new bone formation was visible. Quantitative assessment of the osseous bridging of the osteotomy sites was significantly higher in the test group in comparison with the control group (p = 0.03). The histological evaluation by means of an osseous integration of the grafts revealed a statistically significant difference between both groups as well (p = 0.01). The results of this study indicate that the method investigated hereby represents a further possibility in the therapy of bony defects, such as those arising as a result of tumor operations.

Which is the best method of sterilization of tumour bone for reimplantation? A biomechanical and histopathological study

Introduction

Sterilization and re-usage of tumour bone for reconstruction after tumour resection is now gaining popularity in the East. This recycle tumour bone needs to be sterilized in order to eradicate the tumour cells before re-implantation for limb salvage procedures. The effect of some of these treatments on the integrity and sterility of the bone after treatment has been published but there has yet been a direct comparison between the various methods of sterilization to determine the one method that gives the best tumour kill without compromising the bone's structural integrity.

Method

This study was performed to evaluate the effect of several sterilization methods on the mechanical behavior of human cortical bone graft and histopathology evaluation of tumour bone samples after being processed with 4 different methods of sterilization. Fresh human cortical tumour bone is harvested from the diaphyseal region of the tumour bone were sterilized by autoclave (n =10); boiling (n =10); pasteurization (n =10); and irradiation (n =10). There were also 10 control specimens that did not receive any form of sterilization treatment. The biomechanical test conducted were stress to failure, modulus and strain to failure, which were determined from axial compression testing. Statistical analysis (ANOVA) was performed on these results. Significance level (α) and power (β) were set to 0.05 and 0.90, respectively.

Results

ANOVA analysis of 'failure stress', 'modulus' and 'strain to failure' demonstrated significant differences (p < 0.05) between treated cortical bone and untreated specimens under mechanical loading.

'Stress to failure' was significantly reduced in boiled, autoclaved and irradiated cortical bone samples (p < 0.05). 'Modulus' detected significant differences in the boiled, autoclaved and pasteurization specimens compared to controls (p < 0.05). 'Strain to failure' was reduced by irradiation (p < 0.05) but not by the other three methods of treatments.

Histopathology study revealed no viable tumour cell in any of four types of treatment group compared to the untreated control group.

Conclusions

Sterilization of cortical bone sample by pasteurization and to a lesser extent, irradiation does not significantly alter the mechanical properties when compared with untreated samples. Mechanical properties degrade with the use of high temperature for sterilization (boiling). All methods of sterilization gave rise to 100 percent tumour kill.

Extracorporeal irradiated tumor bone: A reconstruction option in diaphyseal Ewing's sarcomas

BACKGROUND

Limb salvage in extremity tumors is now established as an oncologically safe option without compromising long-term survival. En bloc resection followed by extracorporeal radiation and reimplantation is a biological reconstruction option in diaphyseal Ewing's sarcomas. We analyzed the results of 12 cases of diaphyseal Ewing's sarcomas treated using this modality.

MATERIALS AND METHODS

Between March 2006 and March 2008, 12 patients with Ewing's sarcoma underwent enbloc resection and reconstruction, with reimplantation of the sterilized tumor bone, after extracorporeal irradiation. There were eight males and four females, with a mean age of 14 years (range 2 to 22 years). The femur was the most common bone involved (n=8) followed by the tibia and the humerus (two cases each). All these patients were non-metastatic at presentation and received chemotherapy as per the existing hospital protocol. The mean length of the bone resected was 20 cm (range 11 to 25 cm). The specimen was irradiated with 50 Gy prior to reimplantation and stabilized with the host bone, using suitable internal fixation. Standard biplanar radiographs were assessed for evidence of union on the follow-up visits. The functional status was assessed using the Musculoskeletal Tumor Society Scoring system at the time of the last follow up. The mean follow up duration was 29 months (range 12 to 57 months).

RESULTS

Two patients (17%) had early infection with graft removal, hence are excluded from any analysis of union, however they are included when analysing complications such as infection. Rest 10 cases were analyzed for bony union at the osteotomy sites. Sixteen (84%) of the 19 osteotomy sites united primarily, without any intervention. Implant failure and non-union was seen at three diaphyseal osteotomy sites. The average time for union of all osteotomy sites was 7.2 months (range 3 to 13 months).The average time for union of the metaphyseal osteotomy sites was 5.9 months (range 3 to 12 months) and of diaphyseal osteotomy sites was 8.3 months (range 4 to 13 months). The mean Musculoskeletal Tumor Society Score was 27 (range 19 to 30) with a mean of 27. Nine of the ten patients with lower limb involvement were independent ambulators without additional aids. At the time of the last review, six patients were free of disease and six patients had died from the disease. There were two recurrences around the operative site. Both were associated with disseminated disease and in both the recurrences were in the soft tissue, away from the irradiated graft.

CONCLUSION

Extracorporeal irradiation is a useful, convenient technique for limb salvage in diaphyseal Ewing's sarcomas when there is reasonable residual bone stock. It is oncologically safe and has good functional results. A radiation dose of 50 Gy for sterilizing the bone ensures adequate tumor kill, while minimizing the deleterious effects on the biomechanical and biological properties of the bone. The use of appropriate implants for adequate internal fixation and supplementary bone grafting at the index surgery may help reduce the need for subsequent additional interventions to achieve union. The limitations of this procedure are that it is not applicable in tumor bones that are structurally weak and in bones with pathological fractures.

Reimplantation of the resected tumour-bearing segment after recycling using liquid nitrogen for osteosarcoma

Reconstruction after en block resection of malignant tumours is still the subject of debate. We questioned the effectiveness of reconstruction by reimplanting the tumour-bearing segment after recycling in liquid nitrogen. Ten patients with osteosarcoma around the knee were included, with a mean age of 21 years. The operative technique included wide en bloc excision, debridement, and management of the resected segment with liquid nitrogen followed by reimplantation and internal fixation. At a mean follow-up of 4.5 years there was no local or systemic recurrence and the mean functional score was 82.4%. The frozen graft united proximally and distally in all but one patient in a period ranging from six to ten months. The effectiveness of this reconstruction technique in properly selected patients with osteosarcoma is comparable to other techniques of biological reconstruction with the added benefit of being simple, cheap and durable.

Extracorporeal irradiation for pelvic reconstruction in Ewing’s sarcoma

We review the treatment of pelvic Ewing’s sarcoma by the implantation of extracorporeally-irradiated (ECI) autografts and compare the outcome with that of other reported methods.

We treated 13 patients with ECI autografts between 1994 and 2004. There were seven males and six females with a median age of 15.7 years (interquartile range (IQR) 12.2 to 21.7). At a median follow-up of five years (IQR 1.8 to 7.4), the disease-free survival was 69% overall, and 75% if one patient with local recurrence after initial treatment elsewhere was excluded. Four patients died from distant metastases at a mean of 17 months (13 to 23). There were three complications which required operative intervention; one was a deep infection which required removal of the graft. The functional results gave a mean Musculoskeletal Tumor Society score of 85% (60% to 97%), a mean Toronto extremity salvage score of 86% (69% to 100%) and a mean Harris hip score of 92 (67 to 100).

We conclude that ECI grafting is a suitable form of treatment for localised and resectable pelvic Ewing’s sarcoma.

Reconstruction of the pelvis after resection of malignant bone tumours in children and adolescents

The predominant tumour of the pelvic region in children and adolescents is Ewing's sarcoma followed by osteosarcoma. Both tumours are treated by chemotherapy and the best chance of survival is offered by wide tumour resection. Compared to surgical treatment on the extremities, the resection and reconstruction of pelvic sarcomas remains challenging. Surgery of pelvic sarcomas shows higher rates of local recurrence and complications and a lower functional outcome than other localisations. Especially in children and adolescents the reconstruction methods have to focus additionally on the growing skeleton. According to the different types of pelvic resections and therefore the need of different reconstruction methods, the following article is based on Enneking's surgical classification of pelvic resections. Type I resections are best reconstructed with autografts implanted between the supracetabular osteotomy and the sacrum. Patients show the best functional results after this reconstruction. Periacetabular resections (type II) in small children do best with iliofemoral arthrodesis or pseudarthrosis; in larger adolescents the use of the pedestal Schoellner cup showed superior results over the prior saddle prosthesis. Type III resections are not reconstructed. Complete internal hemipelvectomy represents the most difficult situation, in children as well as in adults. High complication rates after allograft and endoprosthetic reconstruction have recently favoured the renaissance of a flail hip reconstruction or the hip transpositionplasty.

Methods of biological reconstruction for bone sarcoma: indications and limits

Therapy of bone sarcoma has dramatically changed over the past few decades. Several successful interdisciplinary treatment strategies have led to an increase of the survival rates from 20% to 60%-80%. Consequently new demands on the operative treatment of bone and soft tissue sarcoma have arisen. Nowadays limb salvage can be achieved in 80%-90% using tumour megaprostheses or biological reconstruction procedures. In this article we outline the indications and limitations of biological reconstruction procedures after bone tumour resection. We therefore introduce the different biological approaches such as free autologous bone grafting, reimplantation of extracorporeal devitalized autografts or distraction osteogenesis and summarize the currently available data on the individual procedures. Our analyses demonstrate a wide applicability of biological procedures in tumour situations. Although accompanied by considerable complications in the early postoperative phase, biological reconstructions clearly demonstrate the potential of having excellent long-term durability and functionality.

Intercalary femoral reconstruction with extracorporeal irradiated autogenous bone graft in limb-salvage surgery

Between 1996 and 2003, 16 patients (nine female, seven male) were treated for a primary bone sarcoma of the femur by wide local excision of the tumour, extracorporeal irradiation and re-implantation. An additional vascularised fibular graft was used in 13 patients (81%). All patients were free from disease when reviewed at a minimum of two years postoperatively (mean 49.7 months (24 to 96). There were no cases of infection. Primary union was achieved after a median of nine months (interquartile range 7 to 11). Five host-donor junctions (16%) united only after a second procedure. Primary union recurred faster at metaphyseal junctions (94% (15) at a median of 7.5 months (interquartile range 4 to 12)) than at diaphyseal junctions (75% (12) at a median of 11.1 months (interquartile range 5 to 18)). Post-operatively, the median Musculoskeletal Tumour Society score was 85% (interquartile range 75 to 96) and the median Toronto Extremity Salvage score 94% (interquartile range 82 to 99). The Mankin score gave a good or excellent result in 14 patients (88%). The range of movement of the knee was significantly worse when the extracorporeally irradiated autografts were fixed by plates rather than by nails (p = 0.035). A total of 16 (62%) of the junctions of the vascularised fibular grafts underwent hypertrophy, indicating union and loading. Extracorporeal irradiation autografting with supplementary vascularised fibular grafting is a promising biological alternative for intercalary reconstruction after wide resection of malignant bone tumours of the femur.

Reconstruction of bone defects using rhBMP-2-coated devitalized bone

Massive bone defects often are caused by radical resection of bone tumors. Reconstruction of the defect by reimplantation of the resected bone segment after it has been devitalized is advantageous because of its ability to match the size of the defect. In addition, this technique carries a low risk for local recurrence of the tumor, avoids immunologic reaction, and is low in cost. However, limited osteogenic potential of the devitalized bone often leads to delayed union, gradual resorption, and mechanical weakness of the reimplanted segment. We applied rhBMP-2 in a biodegradable polymer delivery system to the devitalized bone. Middiaphyseal bone defects were created by resection in rat femurs. The resected segments were autoclaved at 135 degrees C for 15 minutes, coated with a rhBMP-2-retaining paste on the outer surface, and then reimplanted into the defects. In a brief time, newly formed bone was seen on the surface of the devitalized bone. After 12 weeks, a solid bone mass encasing the dead bone segments was consistently formed and abundant new bone formation was visible in the segments as they were remodeled. The amount of new bone formed could be regulated by the amount of the rhBMP-2-retaining paste applied to the bone segments. This method presents a new approach for the reconstruction of bone defects.

Pasteurized autograft for intercalary reconstruction: an alternative to allograft

Intercalary resection and reconstruction for tumors have become increasingly popular. We asked whether pasteurized autologous bone graft was comparable to other reported reconstruction methods regarding union rates, complications, and functional outcomes. We retrospectively analyzed the outcome of 21 intercalary pasteurized bones in lower extremities. Ultimate graft survival, union rate, and union time were evaluated as a function of clinical variables, such as age, gender, body mass index, location of intercalary segment, primary tumor type, use of chemotherapy, percentage and length of resected bone, type of junction, method of fixation, and iliac bone graft at index operation. The overall survival rate of pasteurized bone was 74% at 10 years. We identified no clinical variables associated with graft survival or union time. The union rate was related to length or percentage of resected segment and location of osteotomy. The rates of infection, fracture, and nonunion were three of 21, two of 21, and five of 21, respectively. Our results suggest reconstruction with pasteurized autograft is a simple and easily accessible method in limb salvage and an economic alternative to allograft, with low rates of ultimate failure and graft-related complications.

Reconstruction with pasteurized autograft-total hip prosthesis composite for periacetabular tumors

BACKGROUND

With the development of preoperative adjuvant treatment, imaging techniques, and improvement of surgical technique, limb salvage is now possible even in patients with pelvic tumors. However, reconstruction after periacetabular resection is complicated and challenging.

METHODS

We retrospectively evaluated the usefulness of pasteurized autograft-total hip composite in pelvic reconstruction with regard to graft survival, union, graft-related complications, and functional outcome in 14 patients with periacetabular tumor.

RESULTS

The 5-year and 10-year survival rates of the pasteurized bones were 64.3% and 32.1%, respectively. Major complications that necessitated graft removal included infection in three, fracture in two, and loosening in three patients. The average functional score of seven long-term successful patients was 25.6 (85.2%).

CONCLUSIONS

In spite of the high complication rate, pasteurized autograft can be considered as an option for periacetabular reconstruction in the selected patients who meet the following criteria. First, iliopectineal and ilioischial lines are radiologically intact; second, the tumor volume is small (preferably less than 100 ml).

Biomechanical and immunohistochemical analysis of high hydrostatic pressure-treated Achilles tendons

BACKGROUND

Reconstruction of bone defects caused by malignant tumors is carried out in different ways. At present, tumor-bearing bone segments are devitalized mainly by extracorporeal irradiation or autoclaving, but both methods have substantial disadvantages. In this regard, high hydrostatic pressure (HHP) treatment of the bone is a new, advancing technology that has been used in preclinical testing to inactivate normal cells and tumor cells without altering the biomechanical properties of the bone. The aim of this study was to examine the biomechanical and immunohistochemical properties of tendons after exposure to HHP and to evaluate whether preservation of the bony attachment of tendons and ligaments is possible.

METHODS

For this, 19 paired Achilles tendons were harvested from both hindlimbs of 4-month-old pigs. After preparation, the cross-sectional area of each tendon was determined by magnetic resonance imaging (MRI). For each animal, one of the two tendons was taken at random and exposed to a pressure of 300 MPa (n = 9) or 600 MPa (n = 10).

RESULTS

The contralateral tendon served as an untreated control. The biomechanical properties of the tendons remained unchanged with respect to the tested parameters: Young's modulus (MPa) and tensile strength (MPa). This finding is in line with immunohistochemical labeling results, as no difference in the labeling pattern of collagen I and versican was observed when comparing the HHP group (at 600 MPa) to the untreated control group.

CONCLUSIONS

We anticipate that during orthopedic surgery HHP can serve as a novel, promising methodical approach to inactivate Achilles tendon and bone cells without altering the biomechanical properties of the tendons. This should allow one to preserve the attachment of tendon and ligaments to the devitalized bone and to facilitate functional reconstruction.

Surgical options and outcomes in bone sarcoma

Bone sarcomas are challenging to treat. The primary goal of treatment is local control of the disease while, if possible, achieving salvage of the limb and its function. There is no ideal method of reconstruction in limb-salvage surgery but the choice of the method of reconstruction should be individualized based upon many factors including the patient's age, the extent and location of the tumor, the wishes of the patient, and the availability of surgical facilities and expertise, as well as the cost of the procedure. In this review, the authors explore the advantages and disadvantages of the different methods of limb reconstruction. The surgical management of bone sarcomas is a real challenge to the orthopedic surgeon, owing to the diversity of sites in which tumors arise, combined with the extension of the tumor into adjacent soft tissues and their proximity, in many cases, to major neurovascular structures. There have been dramatic improvements in survival for patients with osteosarcoma and Ewing's sarcoma in the past 30 years owing to increasing effectiveness of chemotherapy. This, along with developments in imaging techniques (magnetic resonance imaging in particular) has led to earlier diagnosis and more accurate preoperative staging. Whilst traditional treatment for bone tumors used to be amputation, advances in surgical techniques have made limb-salvage procedures a valid alternative method of treatment to amputation in 80-85% of patients with primary bone sarcomas.

Infections in children and young adults with bone malignancies undergoing limb-sparing surgery

BACKGROUND

The epidemiology, risk factors, and efficacy of therapy for infections complicating limb-sparing surgery (LSS) are not understood completely.

METHODS

The authors conducted a retrospective review of children and adolescents with bone malignancies who underwent LSS.

RESULTS

One hundred three patients underwent 104 LSS procedures. Patients experienced a median of 4 infections (range, 0-13 infections), including focal bacterial infections in 67% of patients and bacteremia in 21% of patients. Infections at the LSS site occurred in 26% of patients, and 21% of patients developed orthopedic device infections (ODIs). Compared with patients without ODIs, patients who developed ODIs were more likely to be African American and to have wound infections, and they were less likely to have tumors of the femur than the tibia. In a multivariate analysis, only African-American race and local infection at the LSS site retained a significant association with ODIs. Among survivors, patients who developed ODIs were more likely to undergo amputation (odds ratio [OR], 24.0; 95% confidence interval [95%CI], 5.1-114.0; P < 0.001) and were less likely to have good functional outcomes (OR, 0.02; 95%CI, 0.002-0.15; P < 0.001) compared with patients who did not have an ODI. Overall, only 1 of 22 patients with an ODI was treated successfully without removal of the orthopedic device or amputation.

CONCLUSIONS

Current treatment for bone malignancies is complicated by an unexpectedly high incidence of infection. ODI was the most common reason for amputation and poor functional outcomes. The identification of risk factors for ODI may allow modifications of therapy that reduce the incidence and severity of infection, but prevention of all ODIs will require novel strategies.

Case report: Reconstruction of an intercalary defect with bone transport after resection of Ewing's sarcoma

We report a 13-year-old girl with Ewing's sarcoma of the tibia who was treated with multiagent chemotherapy, followed by local control tumor surgery consisting of wide resection of the tumor and bone transport with distraction osteogenesis for reconstruction. The bone defect created by resection was 13 cm long and was replaced by bone transport using a monolateral external fixator. Evaluation of the resected specimen revealed wide tumor-free margins with 100% chemonecrosis. A planned Harmon-type autogenous bone grafting between the middle and proximal segments of the tibia (docking site) was done primarily after docking occurred, and a solid union was obtained by 23 months after resection. The bone healing index (treatment index) was 54 days/1 cm distraction, which is indicative of slow healing. Clinical evaluation of the affected extremity using the Musculoskeletal Tumor Society rating system revealed 80% normal functional capability. Indications for bone transport in reconstruction of bone defects created by wide resection of bone sarcomas are discussed. In retrospect, we have concerns regarding the suitability of this technique in the setting of diaphyseal sarcoma reconstruction in patients with Ewing's sarcoma who require aggressive and intense multiagent chemotherapy.

Biomechanical investigation of the effect of high hydrostatic pressure treatment on the mechanical properties of human bone

Several methods are available for reconstruction of bone defects due to malignant tumors. To extracorporally devitalize resected tumor-bearing bone segments two methods, that is, extracorporal irradiation or autoclaving, are available up to now. However, both methods have substantial disadvantages like decrease of bone's mechanical strength. To develop an alternative method for tumor inactivation in skeletal segments, high hydrostatic pressure (HHP) was applied. Previous investigations have shown that human normal and tumor cell lines as well as tumor-afflicted human bone specimens were irreversibly damaged at 350 MPa when subjected to HHP. This study was aimed to examine the alterations of biomechanical properties of human bone after exposure to HHP. Trabecular and cortical bone specimens were harvested from six pair of fresh-frozen human cadaveric femora. The bone specimens from one side were exposed to different pressure values of 300 or 600 MPa over 10 min. Bone samples from the contralateral sites were used as untreated controls. Biomechanical properties were investigated by a quasi-static compression test for trabecular specimens and by a quasi-static four-point bending test for cortical specimens, respectively. Biomechanical properties of the cortical and trabecular bone did not decrease after exposure to 300 MPa regarding the testing parameters Young's modulus and ultimate strength (200.7 +/- 38.7 MPa for HHP treated cortical bone versus 186.5 +/- 34.3 MPa for the untreated control group). After pressure treatment at 600 MPa Young's modulus and ultimate strength respectively remained almost unchanged in trabecular bone and were reduced about 15% in cortical bone (p < 0.001 and p =0.002, respectively). We anticipate that in orthopedic surgery HHP can serve as a novel, promising methodical approach for tumor cell inactivation, which occurs at pressure levels of about 300 MPa. Thereby immediate reimplantation of treated bone segments by preservation of the essential biomechanical properties of bone could become possible. Even after HHP treatment at 600 MPa the strength of bone only decreases up to 15%.

Histological and radiological analysis of autoclaved bone 2 years after extirpation

We examined grafted distal femoral autoclaved bone radiologically and histologically 24 months after surgery. The patient was a 16-year-old boy with osteoblastic-type osteosarcoma in the distal part of the left femur. The patient received pre- and postoperative chemotherapy and underwent limb reconstruction surgery using an autoclaved autograft. He was forced to undergo hip disarticulation because of local recurrence in the soft tissue. Radiologically and histologically, we were able to detect newly formed bone at the site of the distal junction and surrounding the autoclaved autograft, although most of the autoclaved bone remained without substitution even 24 months after implantation. The layer of newly formed bone surrounding the autoclaved autograft was so thin that it seemed to be ineffective for weight-bearing. Drilling into the autoclaved autograft appeared to promote little bone regeneration inside the autoclaved autograft. A bone scintigram showed newly formed bone around the autoclaved autograft, but the scan tended to exaggerate such bone formation beyond that actually confirmed by histological examination. We should be careful when applying autoclaved bone for weight-bearing parts.

Limb salvage using original low heat-treated tumor-bearing bone

Limb salvage, using original low heat-treated tumor-bearing bone and a conventional joint prosthesis, was done in six patients with malignant tumors of the proximal humerus (one patient with chondrosarcoma and five patients with osteosarcoma) and in six patients with tumor of the proximal femur (two patients with malignant spindle cell sarcoma and four patients with osteosarcoma). Wide excision of the lesion was done and the tumor and surrounding soft tissues were removed. The excised bone was treated with heat and the prosthesis was inserted into the treated bone and fixed with cement. This construct was reinserted into the original site and anchored to the host bone with a plate. The overall union rate of the low heat-treated bone with normal host bone was 91.7%, and the mean union time was 4.6 months (range, 3-7 months) after surgery. The functional result of the proximal femur and proximal humerus were 76.7% and 56.8%, respectively, using the Musculoskeletal Tumor Society functional evaluation system. Complications included hip dislocation in one patient, fracture of the low heat-treated bone in two patients, and absorption of the low heat-treated bone of the humerus in four of six patients. The 5-year survival rate of the low heat-treated tumor-bearing bone was 83.3% using Kaplan-Meier survival analysis. Based on the results of this study, limb salvage using original low heat-treated tumor-bearing bone seems to be effective in treating primary bone sarcoma with high survival and acceptable complication rates, circumventing the complications of allograft bone.

Osteosarcoma of the distal radius treated by intraoperative extracorporeal irradiation

Osteoblastic osteosarcoma in the distal radius of a 50-year-old woman was treated by en bloc resection, intraoperative extracorporeal irradiation, and reimplantation. Twenty-three months after surgery finger function was good. No tumor recurrence or distant metastasis was found at the final follow-up examination. Intraoperative extracorporeal irradiation and reimplantation is an easy and convenient reconstructive surgical procedure after en bloc excision of a tumor in the distal radius. A biologic reconstruction with a precise anatomic fit is possible, and long-term endoprosthetic problems and maintenance of bone-banking facilities for allografts are avoided.