Effects of two epiphyseal—stimulating procedures on local growth of long bones in rabbits

Objective:To study the effects of two epiphyseal stimulating procedures on local growth of long bone in rabbits.Methods:Osteotomy was performed in the metakphysis near the proximal tibial epiphyseal plate and hemicircumferential periosteal excision was made on the proximal tibial epiphysis.Tibia roentgenography,tetracycline labelling,histological method and electron microscopy were used.Results:The local stimulating effect following the hemicircumferential periosteal excision was more remarkable than the osteotomy.Conclusions:Periosteal excision is a better treatment for children‘s knee deformity.     

Can quantitative 99mTc-MDP bone scans be used to predict longitudinal growth of epiphyseal plate allografts after microvascular transplantation? An experimental study

Allograft and autograft microvascular proximal tibial epiphyseal plate transplants were performed in female New Zealand White (NZW) rabbits to quantify the growth rate and total growth potential of immunosuppressed and nonimmunosup-pressed rabbits. The purpose of this experiment is to examine whether the ^99mTc-MDP radionuclide uptake of the transplanted epiphyseal plate at 1 week postoperatively, done to assess anastomotic patency of the transplant, could also serve as a predictor of eventual longitudinal growth of the transplant or replant. All transplants and replants demonstrating positive ^99mTc-MDP uptake in the proximal tibial epiphyseal plate at 1 week showed continued longitudinal growth. The precise amount of ^99mTc-MDP uptake, however, did not correlate with the amount of growth at 3 and 5 weeks follow-up. © 1995 Wiley-Liss, Inc.     

Experimental tibial fractures in rabbits simulating proximal tibial metaphyseal fractures in children

The etiology of valgus deformity after a seemingly innocuous fracture of the proximal tibial metaphysis in children is unknown. The purpose of this work was to identify the etiology of this deformity using a rabbit model. Twenty-two eight-week-old rabbits were divided into two groups. In Group I, the medial periosteum was excised from the left proximal tibial metaphysis. A partial osteotomy was created 5 mm distal to the epiphyseal plate, involving the medial one-half of the tibial metaphysis. Two 0.7-mm Kirschner wires were placed as markers on each side of the osteotomy. In Group II, the identical procedure was performed from the lateral side. Standard roentgenograms were obtained postoperatively and weekly until death by sodium pentobarbital overdose at six weeks. The angular deformity, medial growth, and lateral growth were calculated from the markers on the roentgenograms. All tibias were decalcified and analyzed under light microscopy. In Group I, all 11 rabbits developed valgus deformity averaging 12.2 degrees; asymmetric growth was statistically significant. In Group II, ten of 11 rabbits developed varus deformity averaging 9.8 degrees; asymmetric growth was not statistically significant. Despite obvious asymmetric growth in both groups, light microscopy failed to reveal any asymmetry of the physis. Valgus and varus deformities are secondary to asymmetric growth, which is not demonstrable by light microscopy.     

两种骨骺刺激术影响长骨局部生长的实验研究

目的 比较截骨和骨膜切除两种常用骨骺刺激术对兔胫骨局部骨生长的影响。方法 将４０只兔分为胫骨上端骨骺远端２ｍｍ处截骨和上端骨骺线上下１ｍｍ以内骨膜切除两组，经大体骨标本测量。Ｘ线摄片，四环素荧光标记，组织学及电镜观察，进行比较研究，结果 骨膜切除术对骨骺生长的刺激作用大于截骨术。结论 骨膜切除术可作为治疗儿童膝关节畸形的良好方法。     

Transplantation of epiphyseal plate allografts between animals of different ages.

The purpose of the experiment was to study growth of epiphyseal plate allografts after transplantation into subjects of a different age, thus preparing for future transplantation of epiphyseal plate or extremity allografts in children. Microvascular transplantation of proximal tibial epiphyseal plate allografts was performed in skeletally immature New Zealand White female rabbits. The growth of 9-week-old epiphyseal plate allografts was examined in both 9-week-old and 17-week-old recipients, as was the growth of 17-week-old epiphyseal plate allografts in 17-week-old recipients. Immunosuppression was with cyclosporine (Cyclosporine A). Successful transplants were confirmed with 99mTc-MDP isotope scanning, and growth was evaluated with weekly standardized radiographs until death. Growth rate was found to depend on the age of the donor epiphyseal plate and was independent of the age of the recipient. This has clinical implications for the procurement of donor tissue in potential transplantation of epiphyseal plate allografts in children.     

Epiphyseal plate transplantation between sites of different growth potential

The purpose was to study epiphyseal plate growth after microvascular transplantation to sites of different growth potential. The hypothesis was that the growth potential of an epiphyseal plate transplant is a function of the donor irrespective of the recipient site to which it is transplanted. Immature rabbits were used in an experiment that transplanted microsurgically revascularized second metatarsal epiphyseal plates. There were three experimental groups in which transplants were made to (i) sites of the same growth potential (orthotopic), (ii) sites of higher growth potential (proximal tibia), and (iii) sites of lower growth potential (third metacarpal). Control groups were nonoperated animals, animals with an anteromedial proximal tibial osteotomy, and nonoperated contralateral limbs of all experimental animals. Postoperative graft viability was checked with fluorochrome labeling. Postoperative growth was measured from serial standardized radiographs. Follow-up was for either 5 or 8 weeks. Animals were then killed, and epiphyseal plate specimens removed for histomorphometric analysis. Results showed that the total growth of experimental second metatarsal transplants was not statistically different (p > 0.05) in any recipient site. It was noted, however, that transplanted epiphyseal plates in all experimental groups grew at lower rates than nonoperated controls.     

Growth plate reconstruction using chondrocyte allograft transplants

There is, as yet, no successful replacement for a completely damaged physis. In a test of the usefulness of allograft replacement of the plate, growth plate chondrocytes were transplanted to a defect in the proximal tibial growth plate. The defect remained after resection of a bony bridge that was created in rabbits. Seven of 10 rabbits at 3 weeks and six of 8 rabbits at 6 weeks after transplantation showed resumption of growth and prevented progression of the tibial deformity. Killed epiphyseal cells, on the other hand, were rapidly replaced by bone. It is not clear whether the transplanted live cells actually grew or served as a living, but inert filler.     

Preliminary observations on epiphyseal growth rate in congenital pseudarthrosis of tibia after free vascularized fibular graft

Observations were made on the growth rate of proximal and distal tibial epiphyseal growth plates in three children treated by free vascularized fibular grafts for congenital pseudarthrosis of the tibia. Postoperative measurements show that the distal tibial epiphysis can grow faster than the proximal epiphysis; the successful transfer of vascularized fibula may increase blood supply to the distal tibial epiphyseal plate, thus stimulating its growth.     

Differences of bone mass and bone structure in osteopenic rat models caused by spinal cord injury and ovariectomy

Summary Both spinal cord injury and ovariectomy can result in ostepenia in rats. SCI induces more deterioration of cortical geometric structure and trabecular microstructure in the proximal tibial metaphysis than OVX. The proximal tibial metaphysis microstructure significantly correlates with its biomechanical properties. Introduction The purpose of the present study was to compare the effects of spinal cord injury (SCI) and ovariectomy (OVX) on bone gain in young female rats. Methods Thirty young female Sprague-Dawley rats were randomized into three groups: age-matched intact control (CON), OVX and SCI. The tibiae were assessed for DXA and micro-CT analysis, biomechanical testing, the upper tibial epiphyseal plate height, and blood samples for biochemical analysis. Results SCI rats showed lower aBMD in the proximal tibiae as compared with OVX rats. Cortical geometric structural parameters of the tibial midshaft in SCI rats were significantly lower than OVX rats. SCI or OVX induced significant changes in all trabecular microstructural parameters in the proximal tibial metaphysis. The trabecular separation (Tb.Sp) and structure mode index (SMI) in SCI rats were significantly higher than in OVX rats. BV/TV explained 84% of the variation of ultimate load of the proximal tibial metaphysis. There was no difference of the upper tibial epiphyseal plate height between SCI and OVX rats. Serum NTX level in SCI rats was significantly higher than in OVX rats. Conclusions SCI induces more deterioration of cortical bone geometric structure and trabecular microstructure in the proximal tibial metaphysis than OVX.     

组织工程骺板软骨移植修复兔胫骨上骺板缺损

目的　探讨在体外以三维支架构建的组织工程骺板软骨修复胫骨上骺板缺损的效果 ,了解促进植入工程化软骨与受区骺板融合方法的效果。　方法　酶消化分离幼兔骺板软骨细胞并接种培养 ,收获第 1代软骨细胞 ,制成 2 .5× 10 7/ ml的细胞凝胶混悬液 ,接种于聚磷酸钙纤维 / L-聚乳酸 (CPPf/ PL L A)复合支架体外构建组织工程化软骨。采用幼兔右侧胫骨上骺板 4 0 %缺损模型 ,将日本大耳白兔 72只分为 4组 ,每组 18只 :A组缺损区植入同窝幼兔来源的工程化软骨 ,并以相同的细胞凝胶混悬液充填其间隙 ;B组充填复合有生物凝胶而无细胞的 CPPf/ PL L A支架材料 ;C组植入皮下脂肪 ;D组不做任何充填。分别于术后 2、4、6、8、12和 16周摄 X线片、大体及组织学观察。　结果　A组术后2周组织工程化软骨在骺板缺损区即衍生为典型的骺板组织结构 ,并与受区骺板组织很好融合 ;4周修复骺板组织 ,结构正常、胫骨无畸形 ;8周后骺板修复区出现早闭的组织学表现 ,胫骨出现短缩和内翻畸形 ;16周修复区骺板已闭合 ,胫骨畸形明显 ,生长功能恢复率为 4 3.6 %。B、C、D3组术后 2周胫骨即出现畸形 ;4周骺板缺损区均已骨性闭合 ,畸形明显 ;16周畸形严重。后三组间差异无统计学意义 ,骺板缺损区无骨生长。　结论　组织工程化的骺板软骨     

Development and validation of new model for microvascular transplantation of epiphyseal plate allografts with minimal adjoining epiphyseal and metaphyseal bone

A model for the free allograft microvascular transplantation of rabbit proximal tibial epiphyseal plate allografts was developed, validated, and tested in an in vivo animal model. Transplants contained the minimum amount of adjacent epiphyseal and metaphyseal bone compatible with preservation of the epiphyseal-plate vascular supply, as determined by corrosion casting. Perfusion to this graft was evaluated quantitatively using radioactive microspheres, and qualitatively using India-ink injection. Female New Zealand White rabbits at 12 weeks of age were utilized. Vascularized transplantation of epiphyseal plate allografts was performed either into a defect of matched size in the iliac crest or into a soft-tissue pocket without bone contact. Cyclosporine A immunosuppression (CSA) was administered daily for 6 weeks. Two control groups underwent identical surgical procedures, but had no postoperative immunosuppression. Epiphyseal plates both with and without bone contact, in rabbits immunosuppressed postoperatively with CSA, demonstrated longitudinal growth and preserved viability as determined by positive bromodeoxyuridine uptake. Control epiphyseal plates transferred without postoperative immunosuppression were uniformly nonviable. This new model has value as a basis for further studies into the clinical applicability of isolated epiphyseal-plate transplants.     

In vivo growth plate stimulation in various capacitively coupled electrical fields

The right proximal tibial growth plates of adolescent New Zealand white rabbits were stimulated with various capacitively coupled electrical fields. Capacitor plates attached to plastic jigs placed over the proximal tibiae were connected to function generators which supplied sine wave signals of 60 kHz frequency and various voltages (2.5, 5, 10, and 20 V peak-to-peak). At 0 h and at 48 h, each animal was labeled with intravenously injected oxytetracycline. For the next 48 h, each right proximal tibial growth plate was stimulated with one of the above electrical signals. At the end of the 48 h of stimulation, the animals were sacrificed, and the tibiae were excised; histological sections of the proximal growth plate in each tibia were made, and the distance the labels moved away from the bone-cartilage junction down into the metaphysis was measured under fluorescent microscopy. Results indicate that the rabbit growth plate can be consistently stimulated to statistically significant accelerated growth in a capacitively coupled electrical field. A dose-response effect was noted, with 5 V peak-to-peak exhibiting maximum growth acceleration. Thus, the application of the proper capacitively coupled electrical field significantly stimulated the rabbit growth plate at voltage and current levels that are safe for human use.     

缺血对腓骨近端骺板影响的实验研究

［摘要］ 目的 探讨腓骨近端骨骺缺血对骺板影响。方法 选择8周龄幼兔12只,随机分成3 组,分别对幼兔小腿按照带骨骺腓骨移植时腓骨头切取方法细心分离双侧腓骨近端及血管。通过阻断髂总血管方法对腓骨近端骨骺血供分别阻断0、1和1.5小时。术后每周复查X线,观察并记录各幼兔腓骨头骨骺闭合时间。用统计学方法对各组腓骨骨骺闭合时间进行统计学比较分析。结果 缺血0小时组骨骺闭合时间为8.25±0.71周,缺血1小时组骨骺闭合时间为8.13±0.99周,缺血1.5小时组骨骺闭合时间为8.13±0.99周。三组腓骨骨骺闭合时间无明显差异（P>0.05）。结论 在带骨骺腓骨移植过程中骨骺缺血时间控制在一定时间范围内,骨骺短期的缺血不会导致骨骺早闭。     

Epiphysenfraktur der proximalen Tibia

Proximal tibial epiphyseal injury is a rare finding in adolescents. We report the case of a 13-year-old boy with simultaneous epiphyseal fractures of both proximal tibiae to illustrate appropriate diagnosis and treatment of this condition. The injury occurred while performing a long jump: a Salter-Harris type II fracture of the right proximal tibia was sustained at take-off and a Salter-Harris type III avulsion fracture of the left tibial tuberosity upon landing. Closed reduction and internal fixation using K-wires were performed on the right side, whereas open reduction and internal fixation were done on the left side, using a lag screw and additional McLaughlin wiring.     

Selective soft tissue release preserves growth plate architecture during limb lengthening

Although distraction osteogenesis has proven successful in children, concerns remain regarding potential growth inhibition of the lengthened limb. Twenty-one 8-week-old New Zealand White rabbits underwent a unilateral 40% tibial lengthening with the contralateral tibia as control. The animals were divided into Achilles tendon release and non-release groups. Radiographs and histomorphometric analysis of the proximal tibial growth plate was performed 5 and 10 weeks after distraction. The corrected length of tibias without tenotomy was significantly shorter than the contralateral controls, whereas those with tenotomy were statistically equivalent to the contralateral control tibias. Histologically, the operated limbs without tenotomy showed a significant decrease in thickness and loss of cellular architecture of the proximal tibial growth plate compared with the tenotomy groups, which were of near-normal appearance. A concomitant tendo Achilles lengthening performed with 40% tibial lengthening preserves proximal tibial growth plate architecture in this model.     

Periosteal division and longitudinal growth in the tibia of the rat

Growth at the proximal tibial epiphyseal plate of the rat has been measured following three different growth-stimulating procedures. These were proximal periosteal release, distal periosteal release and full periosteal stripping of the diaphysis. A new radiographic method using a photographic technique has made it possible to take accurate measurements of the rate of long-bone growth in small experimental animals. From the results of this animal series we conclude that proximal tibial periosteal division is likely to be the most effective of the three procedures when used to correct leg-length discrepancy in the growing child.     

组织工程化软骨修复兔骺板损伤的实验研究

目的　探讨组织工程化软骨细胞 生物载体复合物修复兔骺板损伤的可行性。方法于 8周龄兔胫骨上端骺板缺损模型中 ,A、B、C三组分别植入组织工程化软骨、单纯外消旋聚乳酸(PDLLA)、空白对照 ,术后 4、8、16周时对双下肢行X线摄片、组织学检查。结果　 4、8、16周时双侧胫骨长度、胫骨角之差A组与B、C组相比 ,短缩与成角畸形轻 ,差异有统计学意义 (P <0 .0 1) ,组织学显示缺损区呈薄层骺软骨细胞样结构 ;B、C两组间差异无统计学意义 (P >0 .0 5 )。结论　骨髓间充质干细胞 (MSCs)可定向诱导分化为软骨细胞 ;组织工程化软骨细胞植入可减轻骺板损伤后肢体短缩与成角畸形。     

Valgus Deformity After Fracture of the Proximal Tibial Metaphysis in Childhood

When a childhood fracture of the proximal tibial metaphysis with valgus dislocation is not anatomically reduced, a valgus deformity comparable with the angulation seen on the accident X-ray develops within a few weeks.

The angulation of the proximal tibia shows neither exacerbation nor regression, but in a number of cases correction of the mechanical axis occurs in the distal epiphyseal plate.     

Mechanical overload of a single compartment induces early degenerative changes in the rabbit knee: a preliminary study

The purpose of this experiment was to determine whether mechanical overload of a single compartment of the knee in rabbits via proximal tibial osteotomy could produce early changes consistent with degenerative arthritis. Ten New Zealand white female rabbits were allocated into two groups. Group 1 (five animals) underwent a right 20 degrees valgus proximal tibial osteotomy to overload the lateral compartment of the knee. Group 2 (five animals) underwent a tibial osteotomy without malalignment (sham controls). The osteotomies were stabilized with a mini AO/ASIF plate and screws, allowing early mobilization. The left leg in each animal was left intact and served as a control. Animals were sacrificed after 3 months. Histological grading of the cartilage was performed according to Mankin et al. The mean histological gradings for the right minus the left knee were the same for the lateral and medial compartments in the 0 degrees sham osteotomy group. However, the mean histological grading of the "overloaded" lateral compartment was 2.4 times greater than the medial compartment in the 20 degrees valgus osteotomy group. These findings suggest that histological evidence of degenerative changes can be surgically induced in the rabbit knee by creating a biomechanical overload of one compartment.     

Mechanical Overload of a Single Compartment Induces Early Degenerative Changes in the Rabbit Knee: A Preliminary Study

The purpose of this experiment was to determine whether mechanical overload of a single compartment of the knee in rabbits via proximal tibial osteotomy could produce early changes consistent with degenerative arthritis. Ten New Zealand white female rabbits were allocated into two groups. Group 1 (five animals) underwent a right 20° valgus proximal tibial osteotomy to overload the lateral compartment of the knee. Group 2 (five animals) underwent a tibial osteotomy without malalignment (sham controls). The osteotomies were stabilized with a mini AO/ASIF plate and screws, allowing early mobilization. The left leg in each animal was left intact and served as a control. Animals were sacrificed after 3 months. Histological grading of the cartilage was performed according to Mankin et al. The mean histological gradings for the right minus the left knee were the same for the lateral and medial compartments in the 0° sham osteotomy group. However, the mean histological grading of the “overloaded” lateral compartment was 2.4 times greater than the medial compartment in the 20° valgus osteotomy group. These findings suggest that histological evidence of degenerative changes can be surgically induced in the rabbit knee by creating a biomechanical overload of one compartment