Changes in young rat radius following excision of the perichondrial ring

Summary The distal growth plate of the radius was exposed in young rats and the perichondrial ring and fibrous covers were removed at the exposed surface. In addition, a small portion of either the adjacent epiphysis or of the adjacent metaphysis was removed also. In the following days, important alterations in bone structure were observed at the level of the removed perichondrial ring. The most relevant changes were an enlargement of the growth plate at the exposed surface that grew in an abnormal direction, proliferation of bone trabecules at the level of the excised perichondrial ring, and bending of the bone. No regeneration of the perichondrial ring occurred. These changes support both the role of the perichondrial ring in the mechanical constraint of the growth plate, and the induction of bone formation by the hypertrophic cartilage at the level of the absent perichondrial ring.     

An Osteochondroma Limiting Flexion of the Proximal Interphalangeal Joint in Hereditary Multiple Exostosis: a Case Report

We describe a patient in which an osteochondroma, which resulted from hereditary multiple exostoses, limited flexion of the proximal interphalangeal (PIP) joint at birth. The tumor grew over the original distal head of the proximal phalanx, and the early appearance of a second ossification center on the base of the middle phalanx was observed. The mass was removed surgically when the patient was 17 months old. There was an improvement in the range of motion at a follow-up evaluation 3 years later. The tumor shape and the growth of the affected PIP joint are examined in detail.     

Osteochondroma of the coronoid process of the mandible

A case of osteochondroma of the coronoid process with histological confirmation is presented. CT scan was used for diagnosis and resection was by the intraoral approach.     

Regeneration of growth plate cartilage induced in the neonatal rat hindlimb by reamputation

Following primary hindlimb amputations dividing the lower femur or the central tibiofibula, the neonatal rat innately regenerates the distal growth plate(s) with a frequency of about 20-30%. One or two reamputation procedures were performed in an effort to increase the frequency of physeal regeneration, noting that such procedures, and related forms of tissue stimulation, have been repeatedly shown to induce regenerative growth at limb amputation sites of some amphibians that display little innate regenerative capacity. The present reamputation sequences divided the skeletal stump through the cartilaginous mass arising at its distal end. Following first reamputation an approximate three fold increase in the frequency of growth plate cartilage regeneration was observed at transfemoral and transtibiofibular sites. Only after second reamputation, however, did tibiofibular physeal cartilage regeneration equal in frequency that observed after first reamputation through the lower femur. Ectopic growth plate cell architecture was identified in cartilaginous extensions arising from the side of the distal femoral shaft, and also within the regrown secondary cartilage body, which unites the lower tibia and fibula in the shank of the rat. Moreover, among 3 of 11 femoral amputees that had sustained reamputations, regrowth of the distal femoral condylar mass and profile were achieved to varying degrees. It is concluded that a regimen of reamputation, known to induce regenerative growth in the amphibian limb, also induces skeletal regneration in the mammalian limb, and lead to the appearance of ectopic growth plate cell architecture at adjacent sites.     

Osteochondroma of the scapula: a case report

Osteochondroma is one of the most common benign tumors of the axial skeleton. Location of a solitary exostosis in the scapula is relatively rare. We report the case of an osteochondroma of the scapula in a 13-year-old boy. Because of the atypical location with nonspecific shoulder pain, the diagnosis is often made late. CT is necessary to determine the correct position of the osteochondroma. Despite the young age of the patient, surgical excision of the exostosis was performed, because of an arising thoracic pressure pain. The outcome was good, the patient noticed disappearance of previous painful symptoms, and a normal profile of the scapula was gained.     

Metaphyseal pattern: Uniqueness of this structure in growing bones originating from cartilaginous anlage. A microradiographic study

Summary Microradiographic examination of metaphyses in long and short tubular growing bones allowed detection of a repetitive, clearly defined pattern of three adjacent zones; the latter are successively formed by the mineralization of cartilaginous longitudinal intercolumnar septa and by the subsequent apposition of other mineralized tissues concurrently with resorption. Consequently, each zone of the metaphysis includes mineralized tissues of various compositions and ages, identifiable by their different mineralization densities. Microradiography of pieces of the growing skeleton in several animal species shows that the same organization is not only present in long and short tubular bones but also in many other such as the pelvis and scapula, cuboid bones like the calcaneum and talus, and cartilaginous bones at the base of the skull. This suggests that there is no difference between the osteogenesis pattern of these bones and tubular ones. The problem of identifying the factors generating such metaphyseal organization is raised.     

关节－干骺端软骨细胞移植修复兔桡骨缺损

目的研究组织工程软骨移植于成年兔桡骨缺损后的生长、分化与转归特点,以及引导性骨再生和骨缺损的修复机制。方法取自一日龄新生兔关节－干骺端复合物的软骨细胞在几丁质纤维网中增殖21d后装入硅胶管内,套接在成年兔桡骨干1cm的缺损处（实验组12只）;对照组10只在缺损处套接空硅胶管,2只仅填入裸几丁质纤维。术后4周两组各处死3只动物取材,其余在术后16周取材。结果实验组术后4周3只动物的工程软骨组织在骨缺损内形成软骨样组织,术后16周9只动物中有2只动物的缺损愈合。对照组术后4周已开始骨愈合,术后16周9只动物的骨缺损全部愈合。结论新生兔关节－干骺端复合物的软骨细胞在成年兔桡骨缺损区（套管内）未肥大钙化,未再现软骨内化骨过程。缺损内的工程软骨可能因占据空间、阻碍成骨成分进入而中断了骨缺损修复过程。引导性骨再生的机制可能是人工膜管加强了骨膜的天然引导作用而促进了骨愈合。     

Osteochondroma of the proximal phalanx of toe presenting as widening of third web space- a rare case report

Osteochondromas are the most common benign bone tumors, which usually affect the metaphyseal region of long bones. Foot is an unusual location for these tumors with phalanges being a much rare site. Only a few case reports have been made of phalangeal osteochondromas. A patient with proximal phalangeal osteochondroma of third toe, presenting clinically as widening of the third web space, is described. A simple extraperiosteal excision of the tumor was done which resolved his forefoot deformity. At five years followup the patient had no recurrence or symptoms.     

Osteochondroma of the Hyoid Bone: A Previously Unrecognized Location and Review of the Literature

Osteochondroma is a benign cartilaginous neoplasm and the most common benign tumor of bone. Osteochondromas occur primarily in the axial skeleton with a predilection for the distal femur, and relatively few cases occur in the head and neck region. The majority of cases of osteochondromas in the head and neck region affect the mandibular condyle, with fewer cases reported in the skull base and the neck. To our knowledge, there is no reported case of osteochondroma of the hyoid bone documented in the English literature. We thus report the first case of a hyoid bone osteochondroma, presenting as an asymptomatic mass in a young woman.     

Three-dimensional finite element analysis of the pediatric lumbar spine. Part I: pathomechanism of apophyseal bony ring fracture

The purpose of this study was to (1) develop a three-dimensional, nonlinear pediatric lumbar spine finite element model (FEM), and (2) identify the mechanical reasons for the posterior apophyseal bony ring fracture in the pediatric patients. The pediatric spine FE model was created from an experimentally validated three-dimensional adult lumbar spine FEM. The size of the FEM was reduced to 96% taking into account of the ratio of the sitting height of an average 14-years-old children to that of an adult. The pediatric spine was created with anatomically specific features like the growth plate and the apophyseal bony ring. For the stress analyses, a 10-N m moment was applied in all the six directions of motion for the lumbar spine. A preload of 351 N was applied which corresponds to the mean body weight of the 14-years-old group. The stresses at the apophyseal bony ring, growth plate and endplate were calculated. The results indicate that the structures surrounding the growth plate including apophyseal bony ring and osseous endplate were highly stressed, as compared to other structures. Furthermore, posterior structures in extension were in compression whereas in flexion they were in tension, with magnitude of stresses higher in extension than in flexion. Over time, the higher compression stresses along with tension stresses in flexion may contribute to the apophyseal ring fracture (fatigue phenomena).Part II of this article can be found at .     

Osteochondroma in the lumbar spinal canal causing sciatic pain: report of two cases

 A search of the English-language medical literature found only two cases in which expansion of an osteochondroma into the lumbar spinal canal caused sciatica. We report another two cases of spinal nerve root compression by solitary lumbar spinal canal osteochondromas: in a 56-year-old man and a 55-year-old woman with no history of hereditary multiple exostoses. Osteochondromas compressing the spinal nerve root were seen at the inferior articular processes of the lumbar vertebrae by computed tomography (CT), three-dimensional reconstruction of CT scans, myelography, and magnetic resonance imaging. The symptoms disappeared after surgical removal of the lesions. Histopathologic examination confirmed the diagnosis of benign osteochondroma. Received: June 4, 2002 / Accepted: September 1, 2002 Offprint requests to: S. Ohtori     

Rapamycin retards growth and causes marked alterations in the growth plate of young rats

Rapamycin is a potent immunosuppressant with antitumoral properties widely used in the field of renal transplantation. To test the hypothesis that the antiproliferative and antiangiogenic activity of rapamycin interferes with the normal structure and function of growth plate and impairs longitudinal growth, 4-week-old male rats (n = 10/group) receiving 2 mg/kg per day of intraperitoneal rapamycin (RAPA) or vehicle (C) for 14 days were compared. Rapamycin markedly decreased bone longitudinal growth rate (94 ± 3 vs. 182 ± 3 μm/day), body weight gain (60.2 ± 1.4 vs. 113.6 ± 1.9 g), food intake (227.8 ± 2.6 vs. 287.5 ± 3.4 g), and food efficiency (0.26 ± 0.00 vs. 0.40 ± 0.01 g/g). Signs of altered cartilage formation such as reduced chondrocyte proliferation (bromodeoxiuridine-labeled cells 32.9 ± 1.4 vs. 45.2 ± 1.1%), disturbed maturation and hypertrophy (height of terminal chondrocytes 26 ± 0 vs. 29 ± 0 μm), and decreased cartilage resorption (18.7 ± 0.5 vs. 31.0 ± 0.8 tartrate-resistant phosphatase alkaline reactive cells per 100 terminal chondrocytes), together with morphological evidence of altered vascular invasion, were seen in the growth plate of RAPA animals. This study indicates that rapamycin can severely impair body growth in fast-growing rats and distort growth-plate structure and dynamics. These undesirable effects must be kept in mind when rapamycin is administered to children.     

Time-related changes in the ultrastructure of osteoclasts after injection of parathyroid hormone in young rats

Summary The effects of parathyroid hormone (PTH) on the size of the osteoclasts, nuclei, ruffled borders, and clear zones in long bones of thyroparathyroidectomized (TPTX) rats were quantitated as a function of time. These data were compared with the number of osteoclasts in the bone and with plasma calcium levels. A significant increase in the average size of the ruffled borders was demonstrated 30 min after injection of 50 U of purified bovine PTH, and of the clear zones 30–90 min after PTH. This was followed at 90 min by an increase in the average size of the cells. The sizes of ruffled borders and clear zones dropped sharply to control levels after 6 h, whereas the size of the cells remained elevated up to 12 h and returned to control values at 24 h. Plasma calcium levels were increased, but not significantly, between 30 min and 6 h. An increase in the number of osteoclasts was significant after 12 h. Removal of the parathyroid glands did not diminish the normal activity of osteoclasts. In animals with intact glands injection of 50 U of PTH did not cause a significant change in cell size or resorbing apparatus. It is concluded that PTH acts to rapidly stimulate the bone resorptive activity of osteoclasts and to cause a delayed increase in their number.     

Ultrastructure of the rat epiphyseal growth plate following chronic ethanol ingestion

Summary We have previously demonstrated that ethanol has a direct toxic effect on the rat skeleton characterized by decreased trabecular bone volume. In the present study, we examined the ultrastructure of the distal radial epiphyseal growth plates in these same animals. Eight weeks of ethanol administration to 12 male rats results in serum alcohol levels of 140 mg/dl but did not alter the width or light microscopic appearance of the radial growth plate. Quantitative electron microscopy failed to demonstrate morphologic evidence of toxicity in the skeletal cells. We conclude that although ethanol appears to have a direct effect on rat bone characterized by enhanced resorption, toxicity is not attended by ultrastructural changes in the skeletal cells.     

Benign Parosteal Osteochondromatous Proliferation of the Hand Originally Diagnosed as Osteochondroma: A Report of Two Cases and Review

Bizarre parosteal osteochondromatous proliferation (BPOP) is a rare cartilaginous neoplasm that often presents in the long bones of the hands and feet. BPOP is a benign but locally aggressive fibro-osseous mass that has striking clinical, radiographic, and histologic similarities with osteochondroma. Differentiating between the two lesions is important as BPOP often requires more extensive surgical resection and has a higher recurrence rate compared to osteochondroma. This report presents two cases of BPOP where initial clinical diagnosis of osteochondroma was made even after appropriate imaging and histologic samples were evaluated. This report reviews clinical, radiographic, and histologic characteristics that can differentiate between the two lesions.     

Fractures of the distal tibia: minimally invasive plate osteosynthesis

Unstable fractures of the distal tibia that are not suitable for intramedullary nailing are commonly treated by open reduction and internal fixation and/or external fixation, or treated non-operatively. Treatment of these injuries using minimally invasive plate osteosynthesis (MIPO) techniques may minimise soft tissue injury and damage to the vascular integrity of the fracture fragments. We report the results of 20 patients treated by MIPO for closed fractures of the distal tibia. Their mean age was 38.3 years (range: 17-71 years). Fractures were classified according to the AO system, and intra-articular extensions according to Rüedi and Allg?wer. The mean time to full weight-bearing was 12 weeks (range: 8-20 weeks) and to union was 23 weeks (range: 18-29 weeks), without need for further surgery. There was one malunion, no deep infections and no failures of fixation. MIPO is an effective treatment for closed, unstable fractures of the distal tibia, avoiding the complications associated with more traditional methods of internal fixation and/or external fixation.     

大鼠胫骨生长板软骨细胞的分离与培养鉴定

目的 探讨高效生长板软骨细胞分离方法 和体外培养条件.方法 采用二步酶消化法对6只SD大鼠胫骨生长板的软骨细胞进行分离,采用含炭吸附过的胎牛血清培养基培养,按5×105个/瓶的密度接种细胞并对软骨细胞进行形态学观察和鉴定,描绘原代软骨细胞在无激素培养基中的生长曲线.结果 软骨细胞贴壁较慢,12 h后开始附壁,第8天时90%融合,互相连接成"铺路石"样结构.原代软骨细胞胞质Ⅱ型胶原免疫着色强阳性,传代后染色减弱.结论 本研究所采用的方法 能高效快速获得原代软骨细胞,原代软骨细胞最接近体内生理状态,最适合进行实验研究.     

应用商环行小儿改良包皮环切术800例治疗体会

【摘要】〓目的〓探讨应用商环行改良包皮环切术的临床效果。方法〓应用商环行改良性包皮环切术,用3把血管钳提起包皮口,将商环内环倾斜塞入龟头与包皮内板之间,再将商环外环套于包皮外板外并卡紧,对800例患儿行包皮环切术,分析其手术时间、出血量、脱环时间、术后并发症、术后外观满意情况。结果〓手术时间为4.65±1.25 min,平均出血量<3 mL,术后并发症主要为感染0.50%(4/800)、包皮明显水肿3.12%(25/800)、伤口裂开0.25%(2/800)、伤口出血0.25%(2/800),脱环时间14±5 d,术后再粘连2.25%(18/800),外观满意率达99.38%(795/800),98.13%(785/800)的家长觉得治疗费用合理。结论〓应用商环行小儿改良包皮环切术,手术时间短、出血量少、术后并发症少、外观满意率高,是治疗小儿包茎、包皮过长的良好方法,具有优势。