Reindeer bone extract can heal the critical-size rat femur defect.

Bone extract from reindeer induces new ectopic bone formation (BF) in muscle pouches, but its feasibility in experimental bone lesions has not been evaluated. We investigated the effects of implants, containing 2, 5, 15, 20 or 50 mg of reindeer bone extract in a collagen carrier, on the healing of 8-mm femur defects in 78 rats. We used 30 µg of recombinant human bone morphogenetic protein-2 (rhBMP-2) in a collagen carrier, collagen and untreated defects as controls. Bone healing was evaluated with radiographs, peripheral quantitative computed tomography (pQCT), biomechanics and histology. In comparison with empty defects, the groups receiving bone extracts showed more BF at three weeks and had better bone union (BU), larger mean cross-sectional bone area at the defect site in groups receiving higher doses of extract, showed greater torsional stiffness of the bones and higher maximum breaking load of bones at six weeks. In comparison to all other groups, in the rhBMP-2 group, BF and BU were best at the three- and six-week follow-up, bone area was largest and mechanical test results were best. Although rhBMP-2 is superior for new bone regeneration, native reindeer bone extract is also effective in the six-week follow-up period.

Bioglass as a carrier for reindeer bone protein extract in the healing of rat femur defect.

Bioactive glasses have been developed as scaffolds for bone tissue engineering but combination with reindeer bone protein extract has not been evaluated. We investigated the effects of bone protein extract implants (5-40 mg dosages) with bioglass (BG) carrier on the healing of rat femur defects. Bioglass implants and untreated defects served as controls. All doses of extract increased bone formation compared with the control groups, and bone union was enhanced with doses of 10 mg or more. In comparison with untreated defect, mean cross-sectional bone area at the defect site was greater when implants with BG + 15 mg of extract or bioglass alone were used, bone density at the defect site was higher in all bioglass groups with and without bone extract, and the BG + 15 mg extract dosage marginally increased bone torsional stiffness in mechanical testing. Bioglass performed well as a carrier candidate for reindeer bone protein extract.

Treatment of congenital pseudarthrosis of the tibia with native bovine BMP: a case report.

Bone morphogenetic proteins (BMP) have been shown to induce bone formation and union in long bone defects and nonunions. We report a case of congenital pseudarthrosis of the tibia treated with a composite implant consisting of a biocoral frame, collagen carrier, and native bovine BMP extract. A six-year-old boy had persisting congenital proximal tibial pseudarthrosis despite six prior operations. At surgery, the sclerotic surfaces of both fragments were excised, fixation was performed using Ilizarov's device, and the composite implant and an autograft were applied to the nonunion site. Three months after the operation, radiographs showed union, and at four months, the Ilizarov device was removed. Two years later, the proximal pseudarthrosis remained clinically and radiologically united. It is concluded that BMP may contribute to the healing of congenital tibial pseudarthrosis of the tibia.

Intraosseous schwannoma of the middle phalanx.

Intraosseous schwannoma is an extremely rare, benign neoplasm. Only a few cases involving the bones of the hand have been reported, and none of these cases has involved middle phalanx. We present a case of intraosseous schwannoma of the middle phalanx of the right ring finger.

Effect of porosity on the osteointegration and bone ingrowth of a weight-bearing nickel-titanium bone graft substitute.

Porous nickel-titanium (NiTi) alloy is a promising new material for a bone graft substitute with good strength properties and an elastic modulus closer to that of bone than any other metallic material. The purpose of this study was to evaluate the effect of porosity on the osteointegration of NiTi implants in rat bone. The porosities (average void volume) and the mean pore size (MPS) were 66.1% and 259+/-30 microm (group 1, n=14), 59.2% and 272+/-17 microm (group 2, n=4) and 46.6% and 505+/-136 microm (group 3, n=15), respectively. The implants were implanted in the distal femoral metaphysis of the rats for 30 weeks. The proportional bone-implant contact was best in group 1 (51%) without a significant difference compared to group 3 (39%). Group 2 had lower contact values (29%) than group 1 (p=0.038). Fibrotic tissue within the porous implant was found more often in group 1 than in group 3 (p=0.021), in which 12 samples out of 15 showed no signs of fibrosis. In conclusion, porosity of 66.1% (MPS 259+/-30 microm) showed best bone contact (51%) of the porosities tested here. However, the porosity of 46.6% (MPS 505+/-136 microm) with bone contact of 39% was not significantly inferior in this respect and showed lower incidence of fibrosis within the porous implant.

Bone modeling controlled by a nickel-titanium shape memory alloy intramedullary nail.

Nitinol (NiTi) shape memory metal alloy makes it possible to prepare functional implants that apply a continuous bending force to the bone. The purpose of this study was to find out if bone modeling can be controlled with a functional intramedullary NiTi nail. Pre-shaped intramedullary NiTi nails (length 26 mm, thickness 1.0-1.4 mm) with a curvature radius of 25-37 mm were implanted in the cooled martensite form in the medullary cavity of the right femur in eight rats, where they restored their austenite form, causing a bending force. After 12 weeks, the operated femurs were compared with their non-operated contralateral counterpairs. Anteroposterior radiographs demonstrated significant bowing, as indicated by the angle between the distal articular surface and the long axis of the femur (p = 0.003). Significant retardation of longitudinal growth and thickening of operated femurs were also seen. Quantitative densitometry showed a significant increase in the average cross-sectional cortical area (p = 0.001) and cortical thickness (p = 0.002), which were most obvious in the mid-diaphyseal area. Cortical bone mineral density increased in the proximal part of the bone and decreased in the distal part. Polarized light microscopy of the histological samples revealed that the new bone induced by the functional intramedullary nail was mainly woven bone. In conclusion, this study showed that bone modeling can be controlled with a functional intramedullary nail made of nickel-titanium shape memory alloy.

Biocompatibility and strength properties of nitinol shape memory alloy suture in rabbit tendon.

Nitinol (NiTi) is a promising new tendon suture material with good strength, easy handling and good super-elastic properties. NiTi sutures were implanted for biocompatibility testing into the right medial gastrocnemius tendon in 15 rabbits for 2, 6 and 12 weeks. Additional sutures were implanted in subcutaneous tissue for strength measurements in order to determine the effect of implantation on strength properties of NiTi suture material. Braided polyester sutures (Ethibond) of approximately the same diameter were used as control. Encapsulating membrane formation around the sutures was minimal in the case of both materials. The breaking load of NiTi was significantly greater compared to braided polyester. Implantation did not affect the strength properties of either material.

Successful treatment of scaphoid fractures and nonunions using bioabsorbable screws: report of six cases.

PURPOSE: A variety of implants have been used for the fixation of scaphoid fractures, but we have found no reports on bioabsorbable screws used for this purpose. We report 6 cases of scaphoid fractures treated with bioabsorbable screws. METHODS: Six patients with scaphoid waist region fractures (3) and nonunions (3) treated using bioabsorbable self-reinforced poly-L-lactide screws. Interposition of a bone graft from the iliac crest was used in 4 cases. Immobilization in a short arm-thumb spica cast was applied after surgery for an average of 8 weeks. RESULTS: Solid union was achieved in 5 cases. Using the Mayo modified Green-O'Brien wrist score, we graded the results as excellent in 1 case, good in 4 cases, and poor in the single case of nonunion. CONCLUSIONS: These results suggest that bioabsorbable self-reinforced poly-L-lactide screws might offer an alternative in the fixation of scaphoid fractures and nonunions in the future, provided that cannulated screws of appropriate size will be available.

Composite implant of native bovine bone morphogenetic protein (BMP), collagen carrier and biocoral in the treatment of resistant ulnar nonunions: report of five preliminary cases.

INTRODUCTION: Bone morphogenetic protein (BMP) has been shown to induce bone formation and union in long bone defects and nonunions. There are, however, no previous reports of BMP being used for ulnar nonunions. We report on five cases of resistant ulnar nonunions treated with a composite implant consisting of a biocoral frame, collagen carrier, and bovine BMP. MATERIALS AND METHODS: Four diaphyseal and one olecranon ulnar nonunions were treated using BMP/coral implant combined with internal fixation. Additional autografting was used in three cases. All of the cases were challenging in their own ways: Three of the patients had been operated on earlier for their nonunion without success, one had a 40 mm bone loss, and one had a 9-month-old untreated olecranon fracture. After excision of the sclerotic surfaces of the nonunion, the gap was filled with autograft and a composite implant containing BMP. Fixation was done with a compression plate in the diaphyseal nonunions and with a tension band in the olecranon nonunion. RESULTS: Solid union was achieved in all five cases. No infections or other adverse effects were encountered. CONCLUSION: These preliminary results suggest that BMP-containing implants might be a feasible alternative or superior to autografting in the treatment of resistant ulnar nonunions.