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External Fixation (external + fixation)
Selected AbstractsA case of nevus comedonicus syndrome associated with neurologic and skeletal abnormalitiesINTERNATIONAL JOURNAL OF DERMATOLOGY, Issue 10 2001Young-Joon Seo MD A 12-year-old male was referred to us with recurrent pus discharge from tender nodules on the right axilla dating from the neonatal period. The nodules were black, characterized by scarring with dilated follicular openings and there were black papules filled with comedo-like keratin plugs in both axillae. Physical examination revealed a bowing deformity of the right third finger and retardation in language ability. The patient was referred to the Departments of Neurology and Orthopedics in Chungnam National University Hospital, Korea. Histologic examination of one of the black comedo-like lesions showed a bulbous and dilated infundibulum that contained laminated keratin, indicating a diagnosis of nevus comedonicus. A CT scan of the brain revealed dysgenesis of the corpus callosum. The IQ (intelligence quotient) score of the patient, measured by the Korean Wechsler Intelligence Scale for Children-Revised, was 94. The only difficulty noted for ordinary life was learning language. A radiograph of the right hand revealed hyperextension and an ulnar drift deformity of the right middle finger. Corrective osteotomy with external fixation and an iliac bone autograft were performed. Intermittent neurologic follow-up visits were ordered for the noted language deficit. At present the patient only exhibits difficulty in calculation. Oral antibiotics were administered to the skin lesions on occasion for secondary infections and inflammation of the cysts and comedones. Extraction of the comedones was performed as needed. [source] A biomechanical and histological analysis of standard versus hydroxyapatite-coated pins for external fixationJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 2 2008Antonio Moroni Abstract This sheep study was designed to make a comparative evaluation of two external fixation pin types each with and without hydroxyapatite (HA) coating. The two pins had different taper, pitch, and self drilling capabilities. Twenty Orthofix standard, self-tapping pins (group A), 20 Orthofix HA-coated, self-tapping pins (group B), 20 X-caliber, self-drilling, self-tapping pins (group C), and 20 X-caliber HA-coated, self-drilling, self-tapping pins (group D) were selected. Four pins were implanted in the right femurs of 20 adult sheep that were euthanized at 6 weeks. Mean pin insertion torque was 2745 ± 822 Nmm in group A, 2726 ± 784 Nmm in group B, 2818 ± 552 Nmm in group C, and 2657 ± 732 Nmm in group D (ns). Mean pin extraction torque was 1567 ± 541 Nmm in group A, 2524 ± 838 Nmm in group B, 1650 ± 650 Nmm in group C, and 2517 ± 726 Nmm in group D. HA-coated pins (group B and D) had a significantly greater mean pin extraction torque compared to similar uncoated pins (group A and C) (p < 0.0005). Histological analysis showed good osteointegration of the two coated pin types. This study shows that HA-coating is more important for optimal pin fixation than the particular combination of design parameters used in each pin type. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008 [source] A new animal model for bone atrophic nonunion: Fixation by external fixatorJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 12 2008Katharina Kaspar Abstract A new small animal model of bone atrophic nonunion was established for investigating the process of bone regeneration by performing cauterization of the periosteum, removal of the local bone marrow, and stabilization with external fixation. The model allows the creation of an atrophic nonunion without the need for a critical size defect. Furthermore, it provides reproducible, well-defined mechanical conditions and minimized physical interference of the implant with the biological processes in the healing zone. Eighty adult Sprague-Dawley rats received an osteotomy of the left femur, stabilized with an external fixator. In half of the animals, the periosteum proximal and distal to the osteotomy was destroyed by cauterization and the adjacent bone marrow was removed (nonunion group). At 2 and 8 weeks after surgery, radiological, biomechanical, histological, and histomorphometrical analyses showed a typical physiological healing in the control group, while the nonunion group was characterized by resorption of the bone ends with some callus formation distant to the osteotomy. At both time points, the callus was composed of significantly less bone and significantly more connective tissue (p,<,0.001). In addition, the torsional strength of the osteotomized femur was significantly less in the nonunion group than in the control group, which was comparable to that of the intact femur (p,<,0.001). In conclusion, the present model allows the induction of an atrophic nonunion without the need of a critical size defect. It is reproducible, provides standardized biomechanical conditions, and allows minimized interaction of the implant with the healing zone. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res [source] Effects of delayed stabilization on fracture healingJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 12 2007Theodore Miclau Abstract Previous studies have revealed that delayed internal fixation can stimulate fracture callus formation and decrease the rate of nonunion. However, the effect of delayed stabilization on stem cell differentiation is unknown. To address this, we created fractures in mouse tibiae and applied external fixation immediately, at 24, 48, 72, or 96 h after injury. Fracture healing was analyzed at 10 days by histological methods for callus, bone, and cartilage formation, and the mechanical properties of the calluses were assessed at 14 days postinjury by tension testing. The results demonstrate that delaying stabilization for 24,96 h does not significantly affect the volume of the callus tissue (TV) and the new bone (BV) that formed by 10 days, or the mechanical properties of the calluses at 14 days, compared to immediate stabilization. However, delaying stabilization for 24,96 h induces 10,40× more cartilage in the fracture calluses compared with fractures stabilized immediately. These findings suggest that delaying stabilization during the early phase of fracture healing may not significantly stimulate bone repair, but may alter the mode of bone repair by directing formation of more cartilage. Fractures that are not rigidly stabilized form a significantly larger amount of callus tissue and cartilage by 10 days postinjury than fractures stabilized at 24,96 h, indicating that mechanical instability influences chondrocytes beyond the first 96 h of fracture healing. © 2007 Orthopaedic Research Society. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 25:1552,1558, 2007 [source] Induction of a neoarthrosis by precisely controlled motion in an experimental mid-femoral defectJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 3 2002Dennis M. Cullinane Bone regeneration during fracture healing has been demonstrated repeatedly, yet the regeneration of articular cartilage and joints has not yet been achieved. It has been recognized however that the mechanical environment during fracture healing can be correlated to the contributions of either the endochondral or intramembranous processes of bone formation, and to resultant tissue architecture. Using this information, the goal of this study was to test the hypothesis that induced motion can directly regulate osteogenic and chondrogenic tissue formation in a rat mid-femoral bone defect and thereby influence the anatomical result. Sixteen male Sprague Dawley rats (400 ± 20 g) underwent production of a mid-diaphyseal, non-critical sized 3.0 mm segmental femoral defect with rigid external fixation using a custom designed four pin fixator. One group of eight animals represented the controls and underwent surgery and constant rigid fixation. In the treatment group the custom external fixator was used to introduce daily interfragmentary bending strain in the eight treatment animals (12°s angular excursion), with a hypothetical symmetrical bending load centered within the gap. The eight animals in the treatment group received motion at 1.0 Hz, for 10 min a day, with a 3 days on, one day off loading protocol for the first two weeks, and 2 days on, one day off for the remaining three weeks. Data collection included histological and immunohistological identification of tissue types, and mean collagen fiber angles and angular conformity between individual fibers in superficial, intermediate, and deep zones within the cartilage. These parameters were compared between the treatment group, rat knee articular cartilage, and the control group as a structural outcome assessment. After 35 days the control animals demonstrated varying degrees of osseous union of the defect with some animals showing partial union. In every individual within the mechanical treatment group the defect completely failed to unite. Bony arcades developed in the experimental group, capping the termini of the bone segments on both sides of the defect in four out of six animals completing the study. These new structures were typically covered with cartilage, as identified by specific histological staining for Type II collagen and proteoglycans. The distribution of collagen within analogous superficial, intermediate, and deep zones of the newly formed cartilage tissue demonstrated preferred fiber angles consistent with those seen in articular cartilage. Although not resulting in complete joint development, these neoarthroses show that the induced motion selectively controlled the formation of cartilage and bone during fracture repair, and that it can be specifically directed. They further demonstrate that the spatial organization of molecular components within the newly formed tissue, at both microanatomical and gross levels, are influenced by their local mechanical environment, confirming previous theoretical models. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved. [source] Vascularized free fibular bone graft in the management of congenital tibial pseudarthrosisMICROSURGERY, Issue 5 2009Anastasios V. Korompilias M.D. Congenital pseudarthrosis of the tibia (CPT) remains one of the most challenging problems confronting the orthopaedic surgeon. The operative results are frequently less than successful; many cases require several surgical procedures, and a significant number of them ending in amputation. The purpose of this study was to access the surgical results, complications, secondary procedures, and long-term results of free vascularized fibular graft (FVFG) in the treatment of congenital pseudarthrosis of the tibia. Between 1992 and 2007, nine patients with CPT were treated consecutively at our clinic with free fibula transfer. There were six females and three males. The mean age at the time of operation was 6.5 years (range, 1,12 years). Stability, after reconstruction with FVFG, was maintained with internal fixation in five patients, unilateral frame external fixation in three patients, and intramedullary pin in one patient. Average postoperative follow-up time was 9 years (range, 2,15 years). In seven patients, both ends of the graft healed primarily within 3.7 months (range, 1.5,6 months). In one patient, the distal end of the graft did not unit. This patient required three subsequent operations to achieve union. Stress fracture occurred in the middle of the grafted fibula in one patient, who underwent four additional operations before union, was achieved. Despite the relatively high-complication rate, FVFG remains a valid method for the treatment of CPT. However, even achieving union of pseudarthrosis is not enough for the resolution of the disease. This is only half of the problem; the other half is to maintain union. Long-term follow-up beyond skeletal maturity, if possible, is necessary to evaluate surgical results. © 2009 Wiley-Liss, Inc. Microsurgery, 2009. [source] Conception of a navigation system controlling diaphyseal fracture reduction treated with external fixationTHE INTERNATIONAL JOURNAL OF MEDICAL ROBOTICS AND COMPUTER ASSISTED SURGERY, Issue 1 2009T. Leloup Abstract Background The reduction of long bone fractures treated with external fixation is usually performed with fluoroscopic images, which include several disadvantages: 2D information, distortions, and irradiation to the patient and the surgical team. This article presents a new navigation technique to control the reduction of such fractures while minimizing the irradiation. Methods Optically tracked markers are fixed to pins inserted into the bone fragments. These last are modelled using two initial calibrated radiographs. The models can be improved with several types of anatomical data and are displayed in real time. Results This navigation system was tested on dry bones and an anatomical specimen leg. Conclusions This new technique allows the visualization of the fracture in real time and from any viewpoint during the reduction. Irradiation is minimized using only two X-ray images. Copyright © 2009 John Wiley & Sons, Ltd. [source] | ||||||||||