Outcomes of a technique combining diaphyseal impaction grafting and metaphyseal cones for severe bone loss in revision total knee arthroplasty.

AIMS: Metaphyseal cones with cemented stems are frequently used in revision total knee arthroplasty (TKA). However, if the diaphysis has been previously violated, the resultant sclerotic canal can impair cemented stem fixation, which is vital for bone ingrowth into the cone, and long-term fixation. We report the outcomes of our solution to this problem, in which impaction grafting and a cemented stem in the diaphysis is combined with an uncemented metaphyseal cone, for revision TKA in patients with severely compromised bone. METHODS: A metaphyseal cone was combined with diaphyseal impaction grafting and cemented stems for 35 revision TKAs. There were two patients with follow-up of less than two years who were excluded, leaving 33 procedures in 32 patients in the study. The mean age of the patients at the time of revision TKA was 67 years (32 to 87); 20 (60%) were male. Patients had undergone a mean of four (1 to 13) previous knee arthroplasty procedures. The indications for revision were aseptic loosening (80%) and two-stage reimplantation for prosthetic joint infection (PJI; 20%). The mean follow-up was four years (2 to 11). RESULTS: Survival free from revision of the cone/impaction grafting construct due to aseptic loosening was 100% at five years. Survival free from any revision of the construct and free from any reoperation were 92% and 73% at five years, respectively. A total of six patients (six TKAs, 17%) required a further revision, four for infection or wound issues, and two for periprosthetic fracture. Radiologically, one unrevised TKA had evidence of loosening which was asymptomatic. In all unrevised TKAs the impacted diaphyseal bone graft appeared to be incorporated radiologically. CONCLUSION: When presented with a sclerotic diaphysis and substantial metaphyseal bone loss, this technique combining diaphyseal impaction grafting with a metaphyseal cone provided near universal success in relation to implant fixation. Moreover, radiographs revealed incorporation of the bone graft and biological fixation of the cone. While long-term follow-up will be important, this technique provides an excellent option for the management of complex revision TKAs. Cite this article: Bone Joint J 2020;102-B(6 Supple A):116-122.

The Radial Aspect of the Distal Radial Metaphysis/Diaphysis as a Source of Cortical Bone Graft.

Cortical bone grafting is commonly required in the finger, hand, and carpus when managing bony trauma. A donor site that can provide a small or large amount of cortical bone graft that is easily accessible and within the same surgical field would be the ideal donor site. In high-energy injuries, a long cortical graft may be needed to reconstruct massive bony defects. In low-energy injuries such as scaphoid nonunions in which a wedge graft is needed, a reliable and easily accessible source of bone grafting would be beneficial. Although the traditional iliac bone grafting can be used, this option requires a separate sterile field to be prepared and may lead to donor site pain and morbidity. We propose an option that places the donor source close to the hand and wrist. The radial aspect of the distal radius metaphysis/diaphysis is superficial, which makes access and closure simpler than other alternatives. Furthermore, the technique only partly violates 1 of the 3 surfaces of the radius so that there is minimal weakening of the integrity of the bone and the likelihood of fracture is low. In this article, we describe the indications, contraindications, surgical technique, and postoperative management of the radial aspect of the distal radius metaphysis/diaphysis as a source of bone grafting.

Effect of rhBMP-2 and VEGF in a vascularized bone allotransplant experimental model based on surgical neoangiogenesis.

We have demonstrated survival of living allogeneic bone without long-term immunosuppression using short-term immunosuppression and simultaneous creation of an autogenous neoagiogenic circulation. In this study, bone morphogenic protein-2 (rhBMP-2), and/or vascular endothelial growth factor (VEGF), were used to augment this process. Femoral diaphyseal bone was transplanted heterotopically from 46 Dark Agouti to 46 Lewis rats. Microvascular repair of the allotransplant nutrient pedicle was combined with intra-medullary implantation of an autogenous saphenous arteriovenous (AV) bundle and biodegradable microspheres containing buffer (control), rhBMP-2 or rhBMP-2 + VEGF. FK-506 given daily for 14 days maintained nutrient pedicle flow during angiogenesis. After an 18 weeks survival period, we measured angiogenesis (capillary density) from the AV bundle and cortical bone blood flow. Both measures were greater in the combined (rhBMP-2 + VEGF) group than rhBMP-2 and control groups (p < 0.05). Osteoblast counts were also higher in the rhBMP-2 + VEGF group (p < 0.05). A trend towards greater bone formation was seen in both rhBMP2 + VGF and rhBMP2 groups as compared to controls (p = 0.059). Local administration of VEGF and rhBMP-2 augments angiogenesis, osteoblastic activity and bone blood flow from implanted blood vessels of donor origin in vascularized bone allografts.

The clinical outcomes of extracorporeal irradiated and re-implanted cemented autologous bone graft of femoral diaphysis after tumour resection.

PURPOSE: We report the outcome of intercalary resection of the femoral diaphysis and extracorporeal irradiated autologous bone graft reconstruction, without the use of vascularized fibular graft. METHODS: Six patients with Ewing sarcoma of the mid-shaft femur who were treated by limb sparing tumour resection and reconstruction with extracorporeal irradiated autologous bone graft with intramedullary cement between 2002 and 2010 were studied. RESULTS: Mean age at the time of surgery was ten years (range, four-23). The length of resected femoral bone averaged 23 cm (15-32 cm). The ratio of bone resection length to total femoral length averaged 60 % (56-66 %). The patients had been followed up for between 16 and 79 months (mean, 41 months) at the time of the study. There was no infection nor fracture in this series. Primary union of the distal and proximal osteotomy sites was achieved in three patients. Delayed union of the proximal osteotomy site occurred in one patient that was successfully treated with iliac crest bone grafting. One patient developed non-union at the distal osteotomy site which failed to heal with bone grafting and was therefore converted to endoprosthetic replacement, and another patient was converted to rotationplasty at five months post-surgery because of contaminated margins. Function was excellent in all patients with surviving re-implanted bone. Local recurrence arose in one patient. CONCLUSION: Our experience suggests that cement augmentation of extracorporeal irradiated and re-implanted bone autografts offer a useful method of reconstructing large femoral diaphyseal bone defects after excision of primary malignant bone tumours.

[New surgical procedures in musculoskeletal sarcomas of the child]. / Nouveautés chirurgicales dans les sarcomes de l'appareil locomoteur de l'enfant.

The role of surgery remains central in the management of malignant bone tumors in children and adolescents. The current chemotherapies have demonstrated their efficiency (and limits) and made possible to avoid amputation in more than 90% of cases without worsening the prognosis. Advances in imaging (MRI) and understanding the mechanisms of tumor progression have led to more accurate resections with more frequent epiphyseal conservations. At the same time, new techniques have emerged that allows to consider more "organic" reconstructions. Therefore, we can better and more often preserve growth, hoping for a better long-term functional outcome. Experience also allows to review older techniques (arthroplasties…). The choice of reconstruction depends on many factors (age, presence of secondary localizations, chemotherapy tolerance, socioeconomic context…) and can only be conceived as part of multidisciplinary evaluations.

Fibular centralisation for the reconstruction of defects of the tibial diaphysis and distal metaphysis after excision of bone tumours.

We evaluated the results of fibular centralisation as a stand alone technique to reconstruct defects that occurred after resection of tumours involving the tibial diaphysis and distal metaphysis. Between January 2003 and December 2006, 15 patients underwent excision of tumours of the tibial diaphysis or distal metaphysis and reconstruction by fibular centralisation. Their mean age was 17 years (7 to 40). Two patients were excluded; one died from the complications of chemotherapy and a second needed a below-knee amputation for a recurrent giant-cell tumour. A total of 13 patients were reviewed after a mean follow-up of 29 months (16 to 48). Only 16 of 26 host graft junctions united primarily. Ten junctions in ten patients needed one or more further procedure before union was achieved. At final follow-up 12 of the 13 patients had fully united grafts; 11 walked without aids. The mean time to union at the junctions that united was 12 months (3 to 36). The mean Musculoskeletal Tumor Society Score was 24.7 (16 to 30). Fibular centralisation is a durable reconstruction for defects of the tibial diaphysis and distal metaphysis with an acceptable functional outcome. Stable osteosynthesis is the key to successful union. Additional bone grafting is recommended for patients who need postoperative radiotherapy.

Host-derived neoangiogenesis with short-term immunosuppression allows incorporation and remodeling of vascularized diaphyseal allogeneic rabbit femur transplants.

The purpose of this study was to demonstrate that living bone allotransplants can incorporate, remodel, and maintain mechanical properties without long-term immunosuppression in a fashion comparable to living autotransplants. For this, viability is maintained by repair of nutrient vessels and neovascularization from implanted host-derived vasculature. Microsurgically revascularized femoral diaphysis allotransplants were transferred from young male New-Zealand-White (NZW) into 4 groups of male Dutch-Belted (DB) rabbits. Short-term immunosuppression by tacrolimus (IS, groups 4 and 5) and host-derived neovascularization (NV) from implanted fascial flaps was used to maintain viability (groups 3 and 5) as independent variables. Group 2 received neither IS nor NV. Vascularized pedicled autotransplants were orthotopically transplanted in group 1. After 16 weeks, transplants were evaluated using radiologic, histologic, biomechanical, and histomorphometric parameters. Vascularized bone allotransplants treated with both short-term IS and host-derived NV (group 5) healed in a fashion similar to pedicled autotransplants (group 1). Their radiographic scores were higher than other groups. Groups with patent fascial flaps (3 and 5) showed significantly greater neoangiogenesis than ligated controls (2 and 4). Tacrolimus administration did not affect neoangiogenesis. Elastic modulus and ultimate stress were significantly greater in autogenous bone than in allotransplanted femora. Biomechanical properties were not significantly different among allotransplants. Bone turnover was decreased with IS, but increased with NV by the implanted fascial flaps. Living allogeneic femoral allotransplants treated with short-term IS and host-derived neoangiogenesis can lead to stable transplant incorporation in this rabbit model. The combination of both factors optimizes bone healing. Transplant mineralization is improved with neoangiogenesis but diminished with IS.

Vascular basis of free transfer of proximal epiphysis and diaphysis of fibula: an anatomical study.

INTRODUCTION: Transfer of proximal epiphysis and diaphysis of fibula is a treatment of bony defects in children. Although there are few reports of this procedure, different arteries or combination of arteries have been used as supplying pedicle and the reported success rates are different. This is an anatomical study to clarify the vascular anatomy of this region. MATERIALS AND METHODS: A total of 16 fresh cadavers were enrolled. An incision was made in the popliteal fossa to find the popliteal artery, which was dissected distally and the lateral inferior genicular artery, anterior tibial artery, tibioperoneal trunk and its bifurcation were located. In eight subjects popliteal artery was cannulated above the level of femoral condyles and injected by latex. In the next eight cases the same material was injected in the anterior tibial artery. The next steps of dissection were done by 4.3-loupe magnification. Lateral inferior genicular artery was dissected from its origin to the fibular head and branches of anterior tibial artery were also dissected. In three specimens, the fibula and its supplying arteries were removed after dissection and put in diluted hydrochloric acid to be opened for studying the medullary vasculature. RESULTS: This study confirms the existence of not only periosteal but also intramedullary anastomosis between artery of the neck and peroneal artery. Artery of the neck was usually a branch of anterior tibial artery and in 24% of the subjects a branch of popliteal artery. In the latter condition the pedicle would be too short to permit the surgeon to do this surgery. Therefore preoperative angiography is mandatory to identify the origin of the artery of the neck. CONCLUSION: According to these dissections, a classification system of arterial supply of proximal fibular epiphysis is introduced in this article.

Transplantation of a vascularized rabbit femoral diaphyseal segment: mechanical and histologic properties of a new living bone transplantation model.

A new vascularized bone transplantation model is described, including the anatomy and surgical technique of isolating a rabbit femoral diaphyseal segment on its nutrient vascular pedicle. The histologic and biomechanical parameters of pedicled vascularized femoral autotransplants were studied following orthotopic reimplantation in the resulting mid-diaphyseal defect. Vascularized femur segments were isolated in 10 rabbits on their nutrient pedicle, and then replaced orthotopically with appropriate internal fixation. Postoperative weightbearing and mobility were unrestricted, and the contralateral femora served as no-treatment controls. After 16 weeks, the bone flaps were evaluated by x-ray (bone healing), mechanical testing (material properties), microangiography (quantification of intraosseous vasculature), histology (bone viability), and histomorphometry (bone remodeling). Bone healing occurred by 2 weeks, with further callus remodeling throughout the survival period. Eight transplants healed completely, while two had a distal pseudarthrosis. Microangiography demonstrated patent pedicles in all transplants. Intraosseous vessel densities were comparable to nonoperated (control) femora. We found ultimate strength and elastic modulus to be significantly reduced when compared to normal controls. Viable bone, increased mineral apposition rate, and bone turnover were demonstrated in all transplants. The method described, and the data provided will be of value for the further study of isolated segments of living bone, and in particular, for investigations of reconstruction of segmental bone loss in weight-bearing animal models. This study also provides important normative data on living autologous bone flap material properties, vascularity, and bone remodeling. We intend to use this method and data for comparison in subsequent studies of large bone vascularized allotransplantation.

Periosteal donor site regeneration in rats.

Periosteal regeneration was investigated in two periosteal donor sites of the femur. The periosteum was taken from the femur epiphyses and diaphyses of 32 rats. The animals were sacrificed 1, 2, 3, 4 and 8 weeks after periosteal stripping. Intense cell proliferation occurred in the first week. After two weeks, a thick tissue layer formed by osteoblasts and undifferentiated cells was seen at the two donor sites. Eight weeks after, the periosteum had the same aspect as that from the right femur, which was used as control. Histomorphometric analysis showed that periosteal regeneration was significantly different between epiphyses and diaphyses. Periosteal regeneration at donor site located in epiphyses presented greater proliferation and better osteogenic activity than that observed in diaphyses.

Allogeneic vascularized transplantation of human femoral diaphyses and total knee joints--first clinical experiences.

This article has presented the preliminary results of three patients who received vascularized allogeneic femoral diaphyses and three patients having undergone vascularized transplantation of fresh and perfused total human knee joints. The large osseous defects in the femora followed osteomyelitis and chondrosarcoma. The three knee joints were lost due to various trauma mechanisms. All grafts were harvested within 25 hours from multiorgan donors perfused with 4 L of UW solution. All osteosyntheses were performed employing intramedullary nails. Vascular pedicles of the grafts were anastomosed end-to-side to the superficial femoral artery and vein in the adductorial canal of the recipient thigh. Immunosuppression was based mainly on two drugs: CyA and AZA. Perfusion of the grafts was demonstrated by DSA, and bone metabolism in the graft by SPECT scintigraphy. Six months after the operation all osteotomies demonstrated callus formation and osseous consolidation in conventional radiographs. Biopsies of the grafted bone revealed intact osteocytes, and arthroscopy of the transplanted knee joints demonstrated intact synovial, chondral, and ligamentous structures. From the surgical aspect, the vascularized transplantation of the femoral diaphyses and total knee joints is technically feasible. The main problems are immunologic. All transplantations were performed with respect to ABO compatibility, but with a large HLA mismatch. Therefore, acute and chronic rejection crises were observed. In total synovial joints, lifelong immunosuppression of graft recipients seems to be currently unavoidable.

Importance of arterial blood supply to the femur and tibia for transplantation of vascularized femoral diaphyses and knee joints.

The role of the periosteal and intraosseous blood supply to the femur and the proximal tibia was investigated to improve the operating technique for transplantation of allogenic vascularized femoral diaphyses and knee joints in humans. Altogether 48 limbs were injected with gelatin, red latex milk, or Revertex and macroscopically prepared; 41 limbs were studied for the variation and division of the truncus profundo-circumflexus. In 200 femurs and 200 tibias the location of the nutrient foramen was determined. The arteries supplying the periosteum of the distal femur and the proximal tibia have defined nutritive areas. The following technique should be followed: If the femoral artery alone is prepared as the vascular pedicle, the optimal section for resection of the femur in knee joint transplantations is 6 to 12 cm above the level of the femur condyles and 5 to 7 cm below the tibial plateau. For the transplantation of femoral diaphyses, the deep femoral artery can be used if the lateral femoral circumflex artery is protected. The Proximal line of resection is defined between the greater and lesser trochanter. For shorter grafts one must consider the number and location of nutrient foramens. For longer grafts the distal branches of the femoral artery must be respected as the intraosseous blood supply reaches distally down to the level of about 8 cm above the femoral condyles. In all these operations of the variation of the truncus profundo-circumflexus and the trifurcation of the popliteal artery must be considered.

Allogenic grafting of vascularized bone segments under immunosuppression. Clinical results in the transplantation of femoral diaphyses.

Trauma surgery lack, substitute, for the reconstruction of large defects of the long bones. Encouraged by the promising results of bone allotransplantation in animal models, we successfully performed vascularized bone transplantation in humans. Vascularized femoral diaphyses were allogenically transplanted into three patients suffering from chondrosarcoma or post-traumatic osteomyelitis with postoperative immunosuppression. The bone segments were harvested from multi-organ donors and perfused with UW solution. After back-table preparation, the grafts were transplanted into the defect zone. Interlocking devices were used in these operations. Vascular anastomoses were performed in end-to-side technique. The early clinical course of the patients was not free of anatomical, technical, or immunological complications. However, all patients are currently free of malignancy and infection. They are also free of pain and full weight bearing. We conclude that allogenic grafting of vascularized bone segments has the potential to become an alternative for the replacement of large bone defects.

Inorganic pyrophosphate-phosphohydrolytic activity associated with rat osseous plate alkaline phosphatase.

Purified membrane-bound alkaline phosphatase from rat osseous plate hydrolyzed pyrophosphate in the presence of magnesium ions, with a specific activity of 92.7 U/mg. Optimal apparent pH for pyrophosphatase activity was 8.0 and it remained unchanged on increasing the pyrophosphate concentration. In the absence of magnesium ions the enzyme had a Km = 88 microM and V = 36.7 U/mg for pyrophosphate and no inhibition by excess substrate was observed. Pyrophosphatase activity was rapidly destroyed at temperatures above 40 degrees C, but magnesium ions apparently protected the enzyme against denaturation. Sodium metavanadate (Ki = 1.0 mM) was a competitive inhibitor of pyrophosphatase activity, while levamisole (Ki = 8.2 mM) and theophylline (Ki = 7.4 mM) were uncompetitive inhibitors. Magnesium ions (K0.5 = 1.7 microM) stimulated pyrophosphatase activity, while cobalt (Ki = 48.5 microM) and zinc (Ki = 22.0 microM) ions were non-competitive inhibitors. Manganese and calcium ions had no effect on pyrophosphatase activity. The Mw of the pyrophosphatase protein was 130 kDa by gel filtration, but a value of 65 kDa was obtained by dissociative gel electrophoresis, suggesting that it was a dimer of apparently identical subunits. These results suggested that pyrophosphatase activity stems from the membrane-bound osseous plate alkaline phosphatase and not from a different protein.

Incorporation of devitalised autografts in dogs.

Segments of the tibial diaphysis from 24 adult dogs were reimplanted after extracorporeal autoclaving or gamma-irradiation. Fixation was by interlocking intramedullary nailing, or plating. The dogs were killed after 36 weeks and the tibias examined. Bony union was seen in 46 of the 48 contact areas. Microangiography and Tc-perfusion scans demonstrated complete revascularisation of all the grafts. Biomechanical tests showed defective union with increased bending and decreased stiffness compared to normal controls. Fluorescent microscopy confirmed restitution of Haversian systems and slow replacement of the graft by lamellar bone containing viable osteocytes.

The anatomic basis of a free vascularized bone graft based on the canine distal ulna.

The anatomy of the canine distal ulna was evaluated to determine its potential as a free vascularized bone graft. Twelve cadavers were studied by gross dissection and nonselective and selective angiography. The caudal interosseous artery consistently served as a source artery to the distal ulnar periosteal vasculature in all dogs. The diameters of the caudal interosseous artery and venae comitantes were large enough to permit microvascular anastomoses. Nonselective perfusions of the brachial artery demonstrated large barium-filled vessels within soft tissues surrounding the ulna with anastomotic connections between medullary and periosteal vasculature. Grafts selectively perfused through the caudal interosseous artery (periosteal circulation only) had barium-filled vessels within the muscular cuff, periosteum, cortical bone, and medullary canal of the ulna. A surgical approach to remove the distal ulna along with an intact musculoperiosteal cuff and its associated vasculature is described.