The osteogenic effects of swimming, jumping, and vibration on the protection of bone quality from disuse bone loss.

We assessed and compared the effects of swimming, jumping, and vibration therapies on the prevention of bone loss because of unloading. Eighty Wistar rats were randomly divided into eight groups: S, permanent hind limb-suspended rats; CON, control rats; S + Swim, unloading interrupted by swimming exercise; S + C(Swim), suspension interrupted by regular weight-bearing with the same duration as in the S + Swim protocol; S + Jump, unloading interrupted by jumping exercise; S + C(Jump), suspension interrupted for regular weight-bearing as in the S + Jump group; S + Vibr, unloading interrupted by vibration; and S + C(Vibr), suspension with interruptions for regular weight-bearing with the same protocol as that used for the S + Vibr rats. At the end of the experiment, the bone mineral density, bone strength, histomorphometric parameters, and serum levels of the bone markers were analyzed. The hind limb-suspended rats exhibited bone quality loss. In contrast, the trained rats showed a significant increase in bone mass, bone strength, bone formation, and serum levels of bone markers compared with the respective controls. Although we did not find a significant difference among the three physical exercises, the osteogenic effect of vibration was slightly lower than that of swimming and jumping. Thus, all physical exercises were efficient in preventing bone loss because of unloading and preserving bone quality.

Bovine bone screws: metrology and effects of chemical processing and ethylene oxide sterilization on bone surface and mechanical properties.

We assess the effects of chemical processing, ethylene oxide sterilization, and threading on bone surface and mechanical properties of bovine undecalcified bone screws. In addition, we evaluate the possibility of manufacturing bone screws with predefined dimensions. Scanning electronic microscopic images show that chemical processing and ethylene oxide treatment causes collagen fiber amalgamation on the bone surface. Processed screws hold higher ultimate loads under bending and torsion than the in natura bone group, with no change in pull-out strength between groups. Threading significantly reduces deformation and bone strength under torsion. Metrological data demonstrate the possibility of manufacturing bone screws with standardized dimensions.

Morphological comparison of different protocols of skeletal muscle remobilization in rats after hindlimb suspension.

The aim of this study was to evaluate and compare the efficacy of different remobilization protocols in different skeletal muscles considering the changes induced by hindlimb suspension of the tail. Thirty-six female Wistar rats were divided into six groups: control I, control II, suspended, suspended free, suspended trained on a declined treadmill and suspended trained on a flat treadmill. Fragments of soleus and tibialis anterior (TA) muscle were frozen and processed by different histochemical methods. The suspended soleus showed a significant increase in the proportional number of intermediate/hybrid fibers and a decrease in the number of type I fibers. Some of these changes proved to be reversible after remobilization. The three remobilization programs led to the recovery of both the proportional number of fibers and their size. The TA muscle presented a significant increase in the number and size of type I fibers and a cell size reduction of type IIB fibers, which were recovered after training on a declined treadmill and free movement. Especially regarding the soleus, the present findings indicate that, among the protocols, training on a declined treadmill was found to induce changes of a more regenerative nature, seemingly indicating a better tissue restructuring after the suspension procedure.

The quality of Achilles tendon repair five to eight years after percutaneous tenotomy in the treatment of clubfoot: clinical and ultrasonographic findings.

AIMS: Our aim was to describe the mid-term appearances of the repair process of the Achilles tendon after tenotomy in children with a clubfoot treated using the Ponseti method. PATIENTS AND METHODS: A total of 15 children (ten boys, five girls) with idiopathic clubfoot were evaluated at a mean of 6.8 years (5.4 to 8.1) after complete percutaneous division of the Achilles tendon. The contour and subjective thickness of the tendon were recorded, and superficial defects and its strength were assessed clinically. The echogenicity, texture, thickness, peritendinous irregularities and potential for deformation of the tendon were evaluated by ultrasonography. RESULTS: The appearance of the Achilles tendon was slightly abnormal, with more thickening and less conspicuous contours than a normal tendon. Its strength was grossly normal, with no insufficiency of the triceps surae. Ultrasonographic findings revealed a mild fusiform thickening in 12 children (80%). The tissue at the site of the repair had a slightly hypoechoic, fibrillar quality with hyperechoic striation and the anterior contour was irregular and blurred. There was a focal narrowing within the healing tissue in two children. CONCLUSION: This mid-term evaluation of the ability of the Achilles tendon to repair after division suggests a combination of intrinsic and extrinsic mechanisms. There were minor abnormalities which did not appear to affect function. Cite this article: Bone Joint J 2017;99-B:139-44.

High-impact exercise in rats prior to and during suspension can prevent bone loss.

High-impact exercise has been considered an important method for treating bone loss in osteopenic experimental models. In this study, we investigated the effects of osteopenia caused by inactivity in femora and tibiae of rats subjected to jump training using the rat tail suspension model. Eight-week-old female Wistar rats were divided into five groups (n=10 each group): jump training for 2 weeks before suspension and training during 3 weeks of suspension; jump training for 2 weeks before suspension; jump training only during suspension; suspension without any training; and a control group. The exercise protocol consisted of 20 jumps/day, 5 days/week, with a jump height of 40 cm. The bone mineral density of the femora and tibiae was measured by double energy X-ray absorptiometry and the same bones were evaluated by mechanical tests. Bone microarchitecture was evaluated by scanning electron microscopy. One-way ANOVA was used to compare groups. Significance was determined as P<0.05. Regarding bone mineral density, mechanical properties and bone microarchitecture, the beneficial effects were greater in the bones of animals subjected to pre-suspension training and subsequently to training during suspension, compared with the bones of animals subjected to pre-suspension training or to training during suspension. Our results indicate that a period of high impact exercise prior to tail suspension in rats can prevent the installation of osteopenia if there is also training during the tail suspension.

Osteoid osteomas with chromosome alterations involving 22q.

Cytogenetic analysis was performed in two osteoid osteomas. In both, the modal chromosome number was 46. One of the cases presented a del(22)(q13.1) as the sole clonal chromosome alteration. The other had clonal monosomies of chromosomes 3, 6, 9, 17, 19, and 21, as well as a +del(22)(q13.1) was detected as a non-clonal chromosome alteration. There is only one osteoid osteoma reported so far showing clonal karyotypic alterations. The cytogenetic behavior of osteoid osteomas described here was different from that of the osteoid osteoma of the literature. Numerical alterations of chromosomes 3, 6, 9, 17, 19, 21 and 22 have been described in several neoplasias including bone tumors. The breakpoint of chromosome 22 involves a region where important genes for the regulation of the cell cycle have been mapped.

Experimental physeal fracture-separations treated with rigid internal fixation.

Salter-Harris Type-III and Type-IV epiphyseal injuries were created in the distal aspect of the femur in growing rabbits, and the healing process was analyzed both in the absence of any treatment and after treatment with anatomical reduction and fixation with compression with use of a cortical screw. A sham operation was performed on the left knee, to create a control group. Untreated Type-III injuries led to an angular deformity of the femur that became more severe with time. In the group that had an untreated Type-IV injury, a step-off developed on the articular surface and increased with time. Early vascular anastomoses between the epiphysis and the metaphysis preceded the formation of osseous bridges in these lesions. The healing process in the animals that were treated with anatomical reduction and rigid internal fixation occurred without the formation of osseous callus, and no marked abnormalities were discernible in the physis.

Fuhrmann syndrome: two Brazilian cases.

We describe two unrelated boys with bilateral fibula aplasia, poly- and oligodactyly, and bowed tibiae in two non-consanguineous Brazilian families. These cases are similar to those reported by Fuhrman et al. [(1980). Skeletal Dysplasias. New York: Alan R. Liss Inc. pp. 519-524].

Pamidronate for the treatment of osteoporosis secondary to chronic cholestatic liver disease in Wistar rats.

Osteoporosis is a major complication of chronic cholestatic liver disease (CCLD). We evaluated the efficacy of using disodium pamidronate (1.0 mg/kg body weight) for the prevention (Pr) or treatment (Tr) of cholestasis-induced osteoporosis in male Wistar rats: sham-operated (Sham = 12); bile duct-ligated (Bi = 15); bile duct-ligated animals previously treated with pamidronate before and 1 month after surgery (Pr = 9); bile duct-ligated animals treated with pamidronate 1 month after surgery (Tr = 9). Rats were sacrificed 8 weeks after surgery. Immunohistochemical expression of IGF-I and GH receptor was determined in the proximal growth plate cartilage of the left tibia. Histomorphometric analysis was performed in the right tibia and the right femur was used for biomechanical analysis. Bone material volume over tissue volume (BV/TV) was significantly affected by CCLD (Sham = 18.1 ± 3.2 vs Bi = 10.6 ± 2.2%) and pamidronate successfully increased bone volume. However, pamidronate administered in a preventive regimen presented no additional benefit on bone volume compared to secondary treatment (BV/TV: Pr = 39.4 ± 12.0; Tr = 41.2 ± 12.7%). Moreover, the force on the momentum of fracture was significantly reduced in Pr rats (Sham = 116.6 ± 23.0; Bi = 94.6 ± 33.8; Pr = 82.9 ± 22.8; Tr = 92.5 ± 29.5 N; P < 0.05, Sham vs Pr). Thus, CCLD had a significant impact on bone histomorphometric parameters and pamidronate was highly effective in increasing bone mass in CCLD; however, preventive therapy with pamidronate has no advantage regarding bone fragility.

High-impact exercise in rats prior to and during suspension can prevent bone loss

High-impact exercise has been considered an important method for treating bone loss in osteopenic experimental models. In this study, we investigated the effects of osteopenia caused by inactivity in femora and tibiae of rats subjected to jump training using the rat tail suspension model. Eight-week-old female Wistar rats were divided into five groups (n=10 each group): jump training for 2 weeks before suspension and training during 3 weeks of suspension; jump training for 2 weeks before suspension; jump training only during suspension; suspension without any training; and a control group. The exercise protocol consisted of 20 jumps/day, 5 days/week, with a jump height of 40 cm. The bone mineral density of the femora and tibiae was measured by double energy X-ray absorptiometry and the same bones were evaluated by mechanical tests. Bone microarchitecture was evaluated by scanning electron microscopy. One-way ANOVA was used to compare groups. Significance was determined as P<0.05. Regarding bone mineral density, mechanical properties and bone microarchitecture, the beneficial effects were greater in the bones of animals subjected to pre-suspension training and subsequently to training during suspension, compared with the bones of animals subjected to pre-suspension training or to training during suspension. Our results indicate that a period of high impact exercise prior to tail suspension in rats can prevent the installation of osteopenia if there is also training during the tail suspension.

Biomechanics and structural adaptations of the rat femur after hindlimb suspension and treadmill running.

We microscopically and mechanically evaluated the femurs of rats subjected to hindlimb unloading (tail suspension) followed by treadmill training. Female Wistar rats were randomly divided into five groups containing 12-14 rats: control I (118 days old), control II (139 days old), suspended (tail suspension for 28 days), suspended-released (released for 21 days after 28 days of suspension), and suspended-trained (trained for 21 days after 28 days of suspension). We measured bone resistance by bending-compression mechanical tests of the entire proximal half of the femur and three-point bending tests of diaphyseal cortical bone. We determined bone microstructure by tetracycline labeling of trabecular and cortical bone. We found that tail suspension weakened bone (ultimate load = 86.3 +/- 13.5 N, tenacity modulus = 0.027 +/- 0.011 MPa.m vs ultimate load = 101.5 +/- 10.5 N, tenacity modulus = 0.019 +/- 0.006 MPa.m in control I animals). The tenacity modulus for suspended and released animals was 0.023 +/- 0.010 MPa.m vs 0.046 +/- 0.018 MPa.m for trained animals and 0.035 +/- 0.010 MPa.m for control animals. These data indicate that normal activity and training resulted in recovered bone resistance, but suspended-released rats presented femoral head flattening and earlier closure of the growth plate. Microscopically, we found that suspension inhibited new bone subperiosteal and endosteal formation. The bone disuse atrophy secondary to hypoactivity in rats can be reversed by an early regime of exercising, which is more advantageous than ordinary cage activities alone.

Effect of treadmill exercise on lumbar vertebrae in ovariectomized rats: anthropometrical and mechanical analyses.

The purpose of this study was to examine the preventive effect of exercise on lumbar vertebrae in ovariectomized rats. Three-month-old female Wistar rats were divided into 3 groups: control group (A, n = 10); non-exercised ovariectomized group (B, n = 7) and exercised ovariectomized group (C, n = 7). The rats from group C were subjected to treadmill exercise (15 m/minute in the initial six weeks and 19 m/minute in the next six weeks, 1 hour/day, 4 days/week) for 12 weeks. At death, the fourth lumbar vertebrae were removed and an anthropometrical analysis by a paquimeter and a mechanical compression test by a universal test machine were performed. After 12 weeks, the ovariectomy decreased the superior-inferior vertebral height and the maximal braking load in group B compared to group A, while the exercise increased the vertebral mass in group C compared to both groups A and B (rho< 0.01) and the stiffness compared to group B. We concluded the physical activity has an important role to prevent the osteopenia in lumbar vertebrae.

Pamidronate for the treatment of osteoporosis secondary to chronic cholestatic liver disease in Wistar rats

Osteoporosis is a major complication of chronic cholestatic liver disease (CCLD). We evaluated the efficacy of using disodium pamidronate (1.0 mg/kg body weight) for the prevention (Pr) or treatment (Tr) of cholestasis-induced osteoporosis in male Wistar rats: sham-operated (Sham = 12); bile duct-ligated (Bi = 15); bile duct-ligated animals previously treated with pamidronate before and 1 month after surgery (Pr = 9); bile duct-ligated animals treated with pamidronate 1 month after surgery (Tr = 9). Rats were sacrificed 8 weeks after surgery. Immunohistochemical expression of IGF-I and GH receptor was determined in the proximal growth plate cartilage of the left tibia. Histomorphometric analysis was performed in the right tibia and the right femur was used for biomechanical analysis. Bone material volume over tissue volume (BV/TV) was significantly affected by CCLD (Sham = 18.1 ± 3.2 vs Bi = 10.6 ± 2.2%) and pamidronate successfully increased bone volume. However, pamidronate administered in a preventive regimen presented no additional benefit on bone volume compared to secondary treatment (BV/TV: Pr = 39.4 ± 12.0; Tr = 41.2 ± 12.7%). Moreover, the force on the momentum of fracture was significantly reduced in Pr rats (Sham = 116.6 ± 23.0; Bi = 94.6 ± 33.8; Pr = 82.9 ± 22.8; Tr = 92.5 ± 29.5 N; P < 0.05, Sham vs Pr). Thus, CCLD had a significant impact on bone histomorphometric parameters and pamidronate was highly effective in increasing bone mass in CCLD; however, preventive therapy with pamidronate has no advantage regarding bone fragility.

Idiopathic genu valgum treated by epiphyseodesis in adolescence.

Twenty-three patients (13 boys and 10 girls) with the adolescent type of genu valgum were treated by temporary medial epiphyseodesis of both distal femurs with Blount staples (46 knees); 5 also underwent stapling of the proximal tibia. Evaluation before the operation and during the follow up was based on growth charts, photographs and measurement of the intermalleolar distance. The indication for operation was increasing genu valgum with 10 cm or more of intermalleolar separation; the median distance before operation was 13 cm for boys and 12 cm for girls. The staples were removed after a median time of 11 months. At skeletal maturity the median intermalleolar separation was 3 cm for boys and 2 cm for girls. The median frontal angle before operation was 14 degrees for boys and 6 degrees at follow up, the corresponding figures for girls being 14 degrees and 4 degrees. In 2 cases the deformity recurred because the staples were removed too early. In another case a bony bridge formed after the staple was removed and a varus deformity developed; the bridge was resected and the knees became valgus again, but 1 cm of shortening remained on one side. There were no other complications.

Nonunion using a canine model.

The investigation involved a search for a model of atrophic nonunion. Fifty-two mature, adult, mongrel dogs were used to study the repair after creating a 0.5-cm bone defect in the mid-diaphysis of the radius. In addition, a 2-cm wide strip of periosteum was circumferentially resected from each osteotomy extremity. No immobilization was used thereafter. The reparative process was assessed by X-rays, histology, vascular injection, and scintigraphy. The dogs we distributed into three groups according to the time of follow-up (1, 3, and 6 months). Two kinds of repair were recognized after 3 months and were well-established after 6 months: disturbed healing with much callus (54%) and disturbed healing with absent or scanty callus (46%). In the first instance, the periosteum had regenerated and produced the external callus. The bone ends were capped with fibrocartilage; the vascularization around the defect was increased and displayed a well-defined vascular picture. In the healing pattern with absent external callus (atrophic nonunion), the bone defect was enlarged and filled with fibrous tissue, but there was no deficient vascularization in and around the osteotomy. Radioactivity counting showed an increased uptake around the osteotomy site in both types of repair, which persisted over time but was higher in the 1-month group. It was concluded that the present model yields a consistent pattern of a disturbed reparative process that mimics human cases of atrophic or hypertrophic nonunion. The differences between the two kinds of repair seemed to be related to the periosteal capacity of regeneration.

Footprint analysis during the growth period.

Static footprints were obtained from 672 healthy white subjects ranging in age from newborn to 15 years. The length of the footprint was measured and the medial longitudinal arch was evaluated. The findings showed that the feet grew most rapidly up to 3 years of age. From age 3 onward, the feet maintained an almost constant growth rate, which was the same for both sexes until age 12 years, when girls' feet stopped growing, but boys' feet exhibited further growth. From birth up to 2 years of age, there was a higher incidence of flat feet. Rapid progression of plantar arch development was observed between 2 and 6 years of age.

Biomechanics and structural adaptations of the rat femur after hindlimb suspension and treadmill running

We microscopically and mechanically evaluated the femurs of rats subjected to hindlimb unloading (tail suspension) followed by treadmill training. Female Wistar rats were randomly divided into five groups containing 12-14 rats: control I (118 days old), control II (139 days old), suspended (tail suspension for 28 days), suspended-released (released for 21 days after 28 days of suspension), and suspended-trained (trained for 21 days after 28 days of suspension). We measured bone resistance by bending-compression mechanical tests of the entire proximal half of the femur and three-point bending tests of diaphyseal cortical bone. We determined bone microstructure by tetracycline labeling of trabecular and cortical bone. We found that tail suspension weakened bone (ultimate load = 86.3 ± 13.5 N, tenacity modulus = 0.027 ± 0.011 MPa·m vs ultimate load = 101.5 ± 10.5 N, tenacity modulus = 0.019 ± 0.006 MPa·m in control I animals). The tenacity modulus for suspended and released animals was 0.023 ± 0.010 MPa·m vs 0.046 ± 0.018 MPa·m for trained animals and 0.035 ± 0.010 MPa·m for control animals. These data indicate that normal activity and training resulted in recovered bone resistance, but suspended-released rats presented femoral head flattening and earlier closure of the growth plate. Microscopically, we found that suspension inhibited new bone subperiosteal and endosteal formation. The bone disuse atrophy secondary to hypoactivity in rats can be reversed by an early regime of exercising, which is more advantageous than ordinary cage activities alone.

Traumatic separation of epiphyses. An experimental study in rats.

Four types of physeal fracture-separations, defined by the Salter-Harris classification, were created experimentally in the proximal physis of the right tibia of immature rats. The four types are: Type I, pure epiphyseal separation; Type II, separation of the epiphysis with a metaphyseal fracture; Type III, partial epiphyseal separation with a vertical fracture of the epiphysis; and Type IV, vertical epiphyseal and metaphyseal fractures. A sham operation performed on the left tibia served as the control. The animals were killed at various intervals up to 25 days after the operation. The findings were assessed by roentgenographic, histologic, and vessel injection methods. For Types I and II morphometric analyses were also performed. The influence of various types of lesions on the growth rate and the healing process was documented. For Types I and II lesions there was a transitory growth arrest and an increased thickening of the zone of hypertrophic cells. The alterations regressed after Day 15, and by day 25, a nearly normal plate was seen. For Type III lesions an angular deformity of the tibia occurred that increased with time. For Type IV lesions, a step-off developed on the articular surface that became more severe with time. Early vascular anastomoses between the epiphysis and the metaphysis led to the formation of bone bridges in Type III and Type IV lesions.

Mechanical testing of the tension band wire fixation in the proximal femur.

The mechanical stability of proximal femoral osteotomies fixed by the tension band wire technique was studied in flexion-compression and torsion tests. The fixation consisted in crossing the section with two Kirschner wires and with a wire cerclage applied to the tension surface. The study was conducted in three steps. First, cyclinders of wood were cut either transversely or at 30 degrees of inclination in relation to the long axis of the specimen, and fixed with two Kirschner wires and a wire cerclage. We concluded that the inclination of the plane of section significantly increased the stability of fixation. No significant difference was observed when oblique sections were made in the reverse orientation. Second, 30 degrees subtrochanteric varus osteotomies were performed in dog femurs, so that the section plane was transverse in one group and oblique in another, after closing the osteotomy. In both groups the fixation was achieved by two Kirschner wires that crossed the osteotomy and a wire cerclage placed on the lateral cortex (tension surface). We concluded that inclination of the osteotomy plane increased the stability of osteosynthesis in bone specimens, as already seen with the wood pieces. Third, the stability of tension band wire fixation was compared with that provided by the AO/ASIF paediatric angled plate. Varus osteotomies (30 degrees) were created at the subtrochanteric level of paired dog femurs. On one side, the femur was fixed with Kirschner wires and a wire cerclage as described previously. For the other femur, the osteotomy was fixed with the angled plate. We found that both types of fixation presented the same stability in flexion-compression tests. However, under torsion the tension band wire fixation was 30%-50% less stable than the plate fixation.

Experimental nonunion in dogs.

A consistently reproducible nonunion was produced in mongrel dogs by resecting 3 mm of bone and 1 cm of periosteum at the diaphyseal-metaphyseal junction in the radius. Bone wax was used to seal the cut surfaces. No external or internal immobilization was necessary. The animals were sacrificed at various intervals up to one year after the operation. In one subgroup the events were assessed by radiologic and histologic techniques, and in another the limb was examined by microvascular and bone scintigraphic methods. Nonunion of the hypertrophic type occurred in 85% of cases and of the oligotrophic type in 15% of cases. Pseudarthrosis (with persistent mobility, neocapsule, synovial-like fluid, and well-differentiated cartilaginous tissue capping the bone ends) was established by the 28th week.