Six highly unstable elbows with severe bone loss due to rheumatoid arthritis were replaced by a non-constrained, unlinked prosthesis. Bone defects were filled with autogenous bone grafts. The mean follow-up was 4.5 years (2 to 8). The clinical results were excellent in four elbows and good in two, with good varus-valgus stability in all. Radiological follow-up showed no appreciable signs of loosening, and the bone grafts had retained most of their original size, with minimal resorption. There were no major complications such as dislocation, skin necrosis, infection or ulnar neuropathy. The study has shown that the so-called mutilans elbow can be successfully replaced using a properly selected type of non-constrained, unlinked prosthesis with bone grafting of the major defects

Bone apatite contains carbonate and is therefore not pure hydroxyapatite. We have successfully developed sintered carbonate apatite (CA) with a concentration of carbonate of 6 weight% and have evaluated its osteoconductive and bioresorption characteristics. Cylindrical porous sintered CA and sintered hydroxyapatite (HA) measuring 4 × 4 mm with a porosity of 20% were implanted into surgically-created bone defects in the knees of rabbits. The animals were killed after 1, 3, 6 and 12 months. The defects were evaluated by microfocus CT and histology. Bone growth into and around both materials increased. Newly-formed bone was placed in direct contact with both. Osteoclast-like cells resorbed only CA, and were coupled with osteoblasts. The porosity of sintered CA increased, indicating bioresorption, whereas that of sintered HA did not increase. Our findings indicate that sintered CA may be useful as a bioresorbable bone substitute

1. One hundred and one cases of cancellous chip bone grafting operations for filling of infected bone defects are reviewed. 2. Short-term follow-up showed primary or delayed primary healing in 87 per cent of the cases. 3. Observation after five years revealed a recurrence rate of 20 per cent. The recurrences were successfully overcome by minor procedures except in five patients, who suffer from repeated flare-ups of infection. 4. At the present time, 91 per cent of the lesions are satisfactorily healed with a partial or complete bone graft intact. There have been ten failures. 5. The criteria for successful cancellous chip bone grafting of osteomyelitic cavities are discussed

Aims

The aim of this study was to analyze the effect of a lateral rim mesh on the survival of primary total hip arthroplasty (THA) in young patients, aged 50 years or younger.

1. An experimental study of the healing mechanism in circumscribed defects in femora of albino rats of the Wistar strain is described. 2. Only the outer one-fifth of the defect is repaired by subperiosteal bony callus, the rest of the defect being repaired by endosteal callus. 3. Subperiosteal callus does not bridge the defect until endosteal callus is developed fully. 4. As peripheral callus matures the greater part of the endosteal callus is resorbed, with the exception of trabeculae attached to the margin of the defect. 5. The resorbed area in the medullary part of the defect is gradually obliterated by deposition of inner circumferential lamellae. 6. There appear to be differences between the mechanism responsible for repair of fractures of a long bone and that which heals circumscribed bone defects

Limb salvage after loss of bone and soft tissue may require many operations to obtain soft-tissue cover and bony continuity. We describe a fibula-flexor hallucis longus osteomuscular flap which can provide both soft tissue and bone in a single stage. The flap is based on the peroneal vessels and is covered by a split-thickness skin graft. We report the results in five patients with an average bone defect of 8.3 cm and soft-tissue and skin loss. All regained a normal gait on the donor side; four had clinical and radiological union with excellent soft-tissue cover, but one required later amputation due to diffuse coagulopathy. The flap provides free vascularised bone with muscle cover. It has a dependable, long pedicle with minimal morbidity at the donor site, and allows monitoring of the vascularity of the fibular graft

We have used the Ilizarov technique for the management of subarticular defects after the excision of giant-cell tumours in the proximal tibia in five patients. The defect was reconstructed with a segment of 5 to 6 cm obtained from the diaphysis of the affected tibia and by autogenous bone graft from the iliac crest. The newly developed defect in the diaphysis was reconstructed by distraction using the Ilizarov apparatus. Bone grafting at the docking site was performed soon after positioning the bone segments. The mean length of the bone defect was 5.7 cm and the mean duration of external fixation was 233 days. The relative blood flow in the leg measured by . 99m. Tc angiography increased by 1.7 to 2.3 times that of the control level during distraction and consolidation. When seen at a mean of 43 months all patients showed a normal range of motion in the knee and ankle with no collapse of the articular surfaces

Demineralised homologous bone-matrix implant was used to bridge a large circumferential osteoperiosteal gap in the diaphysis of the ulna of rabbits. Periodic observations of the graft were made clinically, radiologically, histologically and by tetracycline fluorescence up to forty-two weeks. By the twelfth week after operation 81 per cent of the animals revealed bone formation in the implant and complete bridging of the gap. The new bone was laid on the surface and in the substance of the matrix, suggesting that the inductive principle was acting locally. The bone, once formed, remodelled to the texture of a mature tubular bone and did not undergo absorption during a long follow-up period. Demineralise bone-matrix proved to be a highly osteoinductive and readily osteoconductive material. The graft did not evoke any appreciable local foreign-body or immunogenic reaction. The high degree of success in bridging massive bone defects justifies further serious studies and hopes for a useful substitute for massive autologous bone grafts

Objectives

Bone tissue engineering is one of the fastest growing branches in modern bioscience. New methods are being developed to achieve higher grades of mineral deposition by osteogenically inducted mesenchymal stem cells. In addition to well established monolayer cell culture models, 3D cell cultures for stem cell-based osteogenic differentiation have become increasingly attractive to promote in vivo bone formation. One of the main problems of scaffold-based osteogenic cell cultures is the difficulty in quantifying the amount of newly produced extracellular mineral deposition, as a marker for new bone formation, without destroying the scaffold. In recent studies, we were able to show that ^99mTc-methylene diphosphonate (^99mTc-MDP), a gamma radiation-emitting radionuclide, can successfully be applied as a reliable quantitative marker for mineral deposition as this tracer binds with high affinity to newly produced hydroxyapatite (HA).

Extraskeletal bone formation can be induced in rodents by implantation of demineralised bone matrix and such implantation has been used to treat bone defects in man, but it is uncertain if induction or merely conduction occurs. We studied bone induction in primates by excising segments of the fibulae of adult squirrel monkeys, defatting and demineralising them before reimplanting them into the quadriceps of the same animal. As a control experiment, rat matrix was prepared in exactly the same way and implanted in rats. After six weeks the implants were harvested and either ashed and analysed for calcium content or prepared for histology. In the rats, the calcium content indicated that about 20% of the original matrix had been replaced by new bone. In the monkeys the calcium content was about the same as that in normal body fluid and no bone was seen in histological sections. This result casts doubt on the use of demineralised human bone matrix as a bone inductor, although it may function by other mechanisms

In impaction grafting of contained bone defects after revision joint arthroplasty the graft behaves as a friable aggregate and its resistance to complex forces depends on grading, normal load and compaction. Bone mills in current use produce a distribution of particle sizes more uniform than is desirable for maximising resistance to shear stresses. We have performed experiments in vitro using morsellised allograft bone from the femoral head which have shown that its mechanical properties improve with increasing normal load and with increasing shear strains (strain hardening). The mechanical strength also increases with increasing compaction energy, and with the addition of bioglass particles to make good the deficiency in small and very small fragments. Donor femoral heads may be milled while frozen without affecting the profile of the particle size. Osteoporotic femoral heads provide a similar grading of sizes, although fewer particles are obtained from each specimen. Our findings have implications for current practice and for the future development of materials and techniques

We have reviewed retrospectively 68 revisions of the femoral component in arthroplasties of the hip in 65 patients, using impaction bone grafting, at a median of three years (1 month to 6 years). We employed the cemented Exeter X-Change technique in 36 patients and the uncemented Bi-Metric allografting method in 32. The 37 bone defects were grade 3 or grade 4 on the Endo-Klinik classification. The Mayo hip score improved from a mean of 32 (. sd. ± 18) to 62 (. sd. ± 15). Most (25) of the 34 complications occurred in grade-3 and grade-4 defects; nine were intraoperative diaphyseal fractures and eight fractures of the greater trochanter. All the fractures united. The risk of intraoperative fracture was prevented by supporting the bone with wires in 16 hips, with reinforcement mesh in 18 and by a plate in six. Early migration of the stem of more than 10 mm during the first year indicated rotational instability; it occurred in three cases. In difficult revision cases with large defects of the femoral bone, bone-impaction techniques carry a high risk of complications

Aims

Prosthetic joint infections (PJIs) of the hip and knee are associated with significant morbidity and socioeconomic burden. We undertook a systematic review of the current literature with the aim of proposing criteria for the selection of patients for a single-stage exchange arthroplasty in the management of a PJI.

Limited success in regenerating large bone defects has been achieved by bridging them with osteoconductive materials. These substitutes lack the osteogenic and osteoinductive properties of bone autograft. A direct approach would be to stimulate osteogenesis in these biomaterials by the addition of fresh bone-marrow cells (BMC). We therefore created osteoperiosteal gaps 2 cm wide in the ulna of adult rabbits and either bridged them with coral alone (CC), coral supplemented with BMC, or left them empty. Coral was chosen as a scaffold because of its good biocompatibility and resorbability. In osteoperiosteal gaps bridged with coral only, the coral was invaded chiefly by fibrous tissue. It was insufficient to produce union after two months. In defects filled with coral and BMC an increase in osteogenesis was observed and the bone surface area was significantly higher compared with defects filled with coral alone. Bony union occurred in six out of six defects filled with coral and BMC after two months. An increase in the resorption of coral was also observed, suggesting that resorbing cells or their progenitors were present in bone marrow and survived the grafting procedure. Our findings have shown that supplementation of coral with BMC increased both the resorption of material and osteogenesis in defects of a clinical significance

Distraction osteogenesis (callotasis) has been widely used in patients with limb-length inequality or massive bone defects. This procedure, however, may be associated with a high incidence of physical and psychosocial complications. Callotasis telescoping on a locked intramedullary nail has been used to shorten the period of external fixation. Little attention has been given to the use of locked intramedullary nails in the treatment of complications after callotasis. Between 1990 and 1999, we used locked intramedullary nailing in 27 patients for the treatment of complications after distraction osteogenesis. There were 17 men and ten women with a mean age of 33.2 years (16 to 66). The nail was inserted at a mean of 3.4 weeks (0 to 15) after removal of the external fixator. Simultaneous autogenous bone grafting and soft-tissue reconstruction were also undertaken in seven and two patients, respectively. There was consolidation of the callus or docking site in all patients at a mean of 6.4 months (2 to 14) after surgery. The mean shortening of the callus was 0.7 cm (0 to 2.5). Two patients had infection at the site of a distal screw which resolved after removal of the nail. In 17 patients the nail was removed at a mean of 26 months after its insertion. Locked intramedullary nails are useful in treating complications after distraction osteogenesis in skeletally mature patients. The risk of infection should be borne in mind

Aims

We analyzed the long-term outcomes of patients observed over ten years after resection en bloc and reconstruction with extracorporeal irradiated autografts

Objectives

The aim of this study was to analyze drain fluid, blood, and urine simultaneously to follow the long-term release of vancomycin from a biphasic ceramic carrier in major hip surgery. Our hypothesis was that there would be high local vancomycin concentrations during the first week with safe low systemic trough levels and a complete antibiotic release during the first month.