PURPOSE: We investigated if there was any change of the growth plate after recovery of bone length by distraction osteogenesis in the shortened long bone. MATERIALS AND METHODS: Three groups of 15 immature rabbits underwent shortening osteotomy of their right tibia by 20, 30, 40%, with minimal injury to the surrounding soft tissue, and distraction osteogenesis was performed to recover the original length. Radiographic, histomorphometric, and immunohistochemical studies were done to evaluate the activity of the growth plate. RESULTS: No significant difference was found between the lengths of both tibiae when the rabbits became mature. Three groups also showed no difference in the activity of the growth plate regardless of the amount of lengthening. CONCLUSION: These results suggest that distraction osteogenesis to recover the original length of bone does not disturb the physeal growth activity if the soft tissue envelope remains intact.
Growth Plate* ; Osteogenesis, Distraction* ; Osteotomy ; Rabbits ; Tibia*

We investigated the effect of tibial lengthening by means of callotasis on enchondral growth of the tibia, Ninety-nine 5-week-old immature rabbits were separated into five groups according to the percentage of lengthening : GroupI(10% lengthening), Group II (20% lengthening), Group III (30% lengthening), Group IV (40% lengthening), Group V (sham operation without lengthening). Osteotomy of the tibia and fibula was made at the proximal metaphysiodiaphyseal junction. Distraction was started at the rate of 0.25mm twice a day from the third postoperative day to simulate the currently accepted callotasis. In Group I, II, and V, there two were no statistically significant differences in the growth rates between the left operated and the right normal tibiae. In contrast, the ratios of left over right tibial length decreased significantly in Group III (4.8%), and Group IV (8.6%) at the completion of lengthening(p < 0.0001), and remained decreased until near skeletal maturity. Histomorphometric study revealed that, in Group III and IV, there were statistically significant decreases in the ratios of the thickness of left over night tibiae at both proximal and distal growth plate(p < 0.0001). Immunohistochemical study also revealed that, in Group III and Group IV, the ratios of left over right bromodeoxyuridine(BrdUrd) labeling percentage decreased significantly (p < 0.0001). In summary, when the tiba was lengthened 30% or more, retardation of enchondral growth was evident, which persisted from the time of completion of lengthening to near skeletal maturity. It is postulated that unphysiologically increased pressure on the growth plate due to excessive bone lengthening may be closely related with the inhibition of enchondral growth.
Bone Lengthening ; Fibula ; Growth Plate ; Osteogenesis, Distraction ; Osteotomy ; Rabbits ; Tibia

The disease Blount called tibia vara in 1937, is characterized by a failure of growth localized to the postero-medial part of the upper tibial metaphysis and epiphysis. The growth of the epiphyseal cartilage as well as that of the metaphysis and the epiphysis is disturbed, with consequent angulation of the tibia at the upper epiphysis which may, in untreated cases, produce bizarre deformities. Blount described two different types of tibia vara, an infantile type and an adolescent type. Presenting case is an adolescent type. He is 11 year old boy. The deformed tibia is corrected by osteotomy.
Adolescent ; Congenital Abnormalities ; Epiphyses ; Growth Plate ; Humans ; Male ; Osteotomy ; Tibia

Tibia valga has been described as a consequence of non-displaced fractures of the proximal metaphysis of the tibia in children. There has been considerable speculation about the cause of this deformity. Four cases of estabilished valgus deformity following injury to the proximal tibia metaphysis in children are presented. In one case of them, it was showed that an infolding of a portion of the periosteum of the tibiain medial opening of this fracture. It was treated by surgical clearence of the infolding periosteum and varus osteotomy with slight over-correction and partial fibulectomy. The recurrence of valgus deformity was absent during post operative one year. In another case, roentgenogram showed an asymmetrical growth arrest line of the pmximal tibia. The presence of asymmetrical growth arrest lines in the pmximal metaphysis of the tibia demonstrates that the valgus deformity in this patient was caused by overgrowth of the medial portion of the proximal tibial epiphyseal plate. In the remainder, we observed the deformity developed without any specific cause.
Child ; Congenital Abnormalities ; Growth Plate ; Humans ; Osteotomy ; Periosteum ; Recurrence ; Tibia

Bone Marrow ; Insulin-Like Growth Factor I ; Osseointegration ; Osteoblasts ; Tibia ; Titanium ; Transforming Growth Factor beta

We performed a procedure to transplant cultured growth plate chondrocyte embedded in type I collagen gel into the defects of the proximal tibial physis in a 6-week-old rabbit. Twenty eight New Zealand White rabbits were used and were divided into 4 groups, of which the medial half of the proximal epiphyseal plate of the right tibia were excised. In group I, the defects were left without collagen gel implantations served as a control. In group II, chondrocytes were embedded in collagen gel were inserted into defect, In group III, chondrocytes cultured with TGF-beta1 in collagen gel, and in group IV chondrocytes cultured with TGFbeta1 in collagen gel three weeks after excision of the growth plate. After transplantations of growth plate chondrocytes, we assessed the varus angulation and the length of tibia, and histological characteristics at 2, 4, 6, 8, and 12 weeks. Bone-bridge formation, growth artiest, and varus deformity between the tibial epiphysis and metaphysis were prevented or minimized in group III and IV. The transplanted chondrocyte retained its normal morphology in a columnar arrangement in group II, III and IV. These results indicate that it is possible to reduce varus angulation and growth arrest in epiphyseal plate defect of immature rabbits by using cultured chondrocytes embedded in type I collagen gel including TGF-beta1.
Chondrocytes* ; Collagen ; Collagen Type I ; Congenital Abnormalities ; Epiphyses ; Growth Plate* ; Rabbits ; Tibia ; Transforming Growth Factor beta1 ; Transplantation

Approximately 15% of all fractures in children involve the physis. Although the majority heal without impairment of the growth mechanism, epiphyseal growth plate fracture-seperation can lead to shortening and angulation. The physiologic events in epiphyseal growth fracture seperation that lead to growth disorders relate to 1) destruction of the epiphyseal circulation and 2) communication between the epiphyseal circulation with its osteoprogenitor cells, thus forming a bony bridge. Although the classic procedure of osreotomy, epitphysiodesis, leg shortening and leg lengthening have not lost their importance in the treatment of the sequeales of partial closure of an epiphyseal plate, the possibility of regaining growth in the affected region should be considered before other measures are taken. Simple excision of the bone bridge is ineffective, since the large cancellous surface thus produced will allow for rapid reformation of the bridge. Thus, a material has to be interposed into the defect created by removal of such a bridge in order to prevent its reformation. Langenskiold first demonstrated that a bone bridge could be effectively resected and its reformation prevented by utilizing fat as an interposition material. Other investigators have used a variety of different interposition materials to prevent bone bridge recurrence following operative removal including cartilage, Silastic, Methymethacrylate, bone wax, muscle flap, Gelfoam as well as fat. Thus it is the purpose of this study to analysis and comparing shortening and angulation by resection of a bone bridge and its replacement with different interposition materials. For this study, a total of 32 rabbits with an initial weight of about 600 to 800 gm was used. Control group comprised 4 rabbits and after appmpriate preparation, the medial condyle of the pmximal tibia was exposed surgically. One plug of bone was removed at the level of the epiphyseal plate using a small curet to a depth of 5 mm. and in the other groups, we made a defect with the same curet and filled it with an interposition material directly. The following experimental groups were created. Group 1 (N-4) Control group: no interposition material Group 2 (N-4) Gelfoam interposition material Group 3 (N-4) Bone was interposition material Group 4 (N-4) Muscle flap interposition material Group 5 (N-4) Fat interposition material Group 6 (N-4) Bone cement interposition material Group 7 (N-4) Silastic interposition material Postoperatively the anirnals were sacrificed 15wks following operation. As sacrifice, tibia including fibular is removed, examined grossly and radiographed. Tibia length and angular deformity were determined by measurement of radiographs. Specimens stained with H-E stain were observed during 15 wks after operation. Through these examination, following results were obtained. l. In control group, coronal histological sections of each curetted proxirnal tibial growth plate revealed osseous bridging as early as 3 wks, and this bridging was found consistently in all control groups for the duration of the study. 2. The groups using gel foam, muscle flap and bone wax as interposition material were found effective for the prevention of the formation of epiphyseometaphyseal bone bridge to some extent. 3. The groups using Silastic or bone cement diminished both the angular deformity and growth retradation to a highly significant degree. Although the use of fat did reduce somewhat the amount of shortening and angular deformity when used as an interposition material, it was not effective as Silastic or bone cement. 4. Coronal histological section of the traumatized, margin of the growth plate, with an interposition material revealed thin fibrous layer and lose columnar orientation, foam rounded clone-like structures and randomness to growth. The injured portion of the cartilage may originate from the regeneration of the adjacent part of the growth plate. From these morphological and radiological results, it is suggested that Silastic or bone cement is better interposition material in the elimination of trahsphyseal closure after physeal damage.
Cartilage ; Child ; Congenital Abnormalities ; Gelatin Sponge, Absorbable ; Growth Disorders ; Growth Plate ; Humans ; Leg ; Rabbits ; Recurrence ; Regeneration ; Research Personnel ; Tibia

PURPOSE: This preliminary rabbit study was conducted to evaluate the effect of recombinant human transforming growth factor-beta2 (rhTGF-beta2)/poly lactic-co-glycolic acid (PLGA) coating on osseointegration of the titanium (Ti) implant. MATERIALS AND METHODS: Eight Ti implants were anodized with 300 voltages for three minutes. Four of those were coated with rhTGF-beta2/PLGA by an electrospray method as the experimental group. The implants were placed into tibiae of four New Zealand rabbits, two implants per a tibia, one implant per each group. After 3 and 6 weeks, every two rabbits were sacrificed and micro-computed tomography (microCT) was taken for histomorphometric analysis. RESULTS: In scanning electron microscope (SEM) image, the surface of rhTGF-beta2/PLGA coated Ti implant showed well distributed particles. Although statistically insignificant, microCT analysis showed that experimental group has higher bone volume / total volume (BV/TV) and trabecular thickness (Tb.Th) values relatively. Cross sectional view also showed more newly formed bone in the experimental group. CONCLUSION: In the limitation of this study, rhTGF-beta2/PLGA particles coating on the Ti implant show the possibility of more favorable quantity of newly formed bone after implant installation.
Humans ; Osseointegration* ; Rabbits ; Tibia ; Titanium* ; Transforming Growth Factor beta2 ; X-Ray Microtomography*

A corticocancellous core was removed from both femurs and tibias in 5 skeletally immature pigs. The cavity was treated with 5%, 25% phenol cautery, cryosurgery, and normal saline irrigation (control). The animals were sacrified after 7days. The extent of the bone necrosis was assessed by gross examination, simple radiography, MRI evaluation and histological examination with tissue mapping. After cryosurgery, the extent of necrosis was most profound in the depth of 2.0-9.0mm beyond the cavity wall. The effect of 25%-phenol was next to cryosurgery, with a depth of 1.0-3.0mm of necrosis. 5%-phenol made necrosis with the depth of 1.0-2.5mm. Very mild degree of necrosis with the width of 0.5-1.0mm was found along the cavity wall even in control group. On MRI, signal change was well visualized on T2 weighted coronal section and it was quite coincided with the extent of bone necrosis proved by histological tissue mapping to all cases. When the epiphyseal plate was open or very close to the cavity, curettage itself, 5%- and 25%-phenol cautery and cryosurgery all produced mild ischemic necrosis along the provisional calcification zone of physeal plate. These findings suggest that cryosurgery made more profound necrosis beyond cavity than phenol cautery and MRI is very sensitive and specific to find osteonecrosis along the cavity wall after phenol cautery or cryosurgery. When epiphyseal plate is open or very close to the cavity, phenol cautery, or cryosurgery, or even curettage itself could produce an ischemic necrosis to the physeal plate itself.
Animals ; Cautery* ; Cryosurgery* ; Curettage ; Femur* ; Growth Plate ; Magnetic Resonance Imaging ; Necrosis* ; Osteonecrosis ; Phenol* ; Radiography ; Swine ; Tibia*

BACKGROUND: Osteoporosis of transplanted/grafted bone is well known in the immediate post bone transplantation/bone grafting period. In limb transplantation, the growth plates in the transplanted limbs retain their longitudinal growth properties. However, there is a paucity of reports on what happens to the bone and the growth potential of the growth plate when limb transplantation between a juvenile donor and an adult recipient is performed. MATERIALS AND METHODS: Ten juvenile to juvenile hind limb transplants and five juvenile to adult hind limb transplants were performed in male syngeneic Lewis rats. Osteoporosis in the isochronograft as well as the heterochronograft limbs was measured by 3D micro-CT. In addition, the increase in tibial length, after transplantation was measured and compared with the increase in the tibial length of the opposite non-operated limbs. RESULTS: The 3D CT parameters indicate a significantly inferior bone quality in the heterochronografts compared with the isochronografts. After transplantation, the increase in the tibial length of the isochronografts was similar the increase in length of the opposite juvenile non operated tibiae and the heterochronograft tibias. CONCLUSION: Age is a significant factor that affects the bone quality, resulting in post transplant osteoporosis in heterochronografts compared with isochronografts. However, the growth plate after transplantation remains unaffected by the difference in age and continues to grow at its own inherent rate in adult recipients as it does in the juvenile recipients.
Adult ; Animals* ; Extremities* ; Growth Plate* ; Humans ; Male* ; Osteoporosis ; Rats* ; Tibia ; Tissue Donors ; Transplantation ; Transplants