Alargamiento óseo tibial mediante fijación externa. Estudio comparativo entre la técnica tradicional y la asistida por clavo intramedular / Tibial bone lengthening via external fixation: Comparative study of the traditional technique and a technique with intramedullary nail assistance

Objetivo. Comparar resultados y complicaciones al realizar elongaciones óseas con dos métodos diferentes: fijación externa aislada versus fijación externa sobre clavo intramedular. Material y método. Estudio comparativo retrospectivo de 30 casos de elongación tibial divididos en dos grupos simétricos. Los casos se emparejaron en función de una serie de variables para maximizar la homogeneidad entre los grupos. Las variables utilizadas para la comparación fueron el tiempo de fijación externa, el índice de fijación externa, el índice de consolidación, los resultados clínicos, las dificultades y el rango de movilidad articular. Resultados. El tiempo medio de fijación externa fue de 2,08 meses en el grupo alargado sobre clavo, frente a los 5,85 del grupo estándar (p<0,0001). La media del índice de fijación externa fue de 0,42 meses por centímetro en el grupo de clavo frente a los 1,15 del grupo sin clavo (p<0,0001). No hubo diferencias significativas en el índice de consolidación (1,23 meses por centímetro frente a 1,15) ni en cuanto a los resultados clínicos. Se aprecian diferencias en la tasa de complicaciones (1,2 por paciente frente a 2,6) en favor de la técnica con clavo. No hay diferencias en el rango de movilidad articular del tobillo. Discusión y conclusiones. La elongación sobre clavo intramedular es más efectiva que la fijación externa aislada para alargamientos tibiales en cuanto al tiempo de fijación externa, índice de fijación externa y tasa de complicaciones. No se han demostrado sus ventajas en cuanto a índice de consolidación y movilidad articular (AU)

Objective. To compare outcomes and complications when performing bone lengthening with two different techniques: isolated external fixation versus external fixation combined with intramedullary nail. Material and method. Comparative retrospective study of thirty cases of tibial lengthening divided in two symmetrical groups. Cases were matched based on several variables to maximise homogeneity between the groups. Variables used for comparison were external fixation time, external fixation index, rate of consolidation, clinical outcomes, complications and range of joint motion. Results. Mean external fixation time was 2.08 months in the group lengthened with nail while the standard group showed 5.85 months (P<.0001). Mean external fixation index was 0.42 months per centimetre in the nail group compared with 1.15 in the group without nail (P<.0001). There were no significant differences in the rate of consolidation (1.23 months per centimetre against 1.15) or in terms of clinical outcomes. We found differences in the rate of complications (1.2 per patient to 2.6) in favour of the technique with nail. There were no differences in the range of motion of ankle joint. Discussion and conclusions. Lengthening over an intramedullary nail is more effective than using external fixation alone for tibial lengthening with regard to time of external fixation, index of external fixation and complication rate. We found no advantages in terms of consolidation and joint mobility (AU)

Systemic treatment with telmisartan improves femur fracture healing in mice.

Recent clinical studies indicated that angiotensin receptor blockers (ARBs) would decrease the risk of bone fractures in the elderly populations. There is little known about the role of the ARBs in the process of fracture healing. The purpose of the present study was to verify the hypothesis that systemic treatment with telmisartan has the ability to promote fracture healing. In this study, femur fractures were produced in 96 mature male BALB/c mice. Animals were treated with the ARBs telmisartan or vehicle. Fracture healing was analysed after 2, 5 and 10 weeks postoperatively using X-ray, biomechanical testing, histomorphometry, immunohistochemistry and micro-computed tomography (micro-CT). Radiological analysis showed the diameter of the callus in the telmisartan treated animals was significantly increased when compared with that of vehicle treated controls after two weeks of fracture healing. The radiologically observed promotion of callus formation was confirmed by histomorphometric analyses, which revealed a significantly increased amount of bone formation when compared with vehicle-treated controls. Biomechanical testing further showed a significantly greater peak torque at failure, and a higher torsional stiffness in telmisartan-treated animals compared with controls. There was an increased fraction of PCNA-positive cells and VEGF-positive cells in telmisartan-treated group compared with vehicle-treated controls. From the three-dimensional reconstruction of the bony callus, telmisartan-treated group significantly increased the values of BV/TV by 21.7% and CsAr by 26.0% compared to the vehicle-treated controls at 5 weeks post-fracture. In summary, we demonstrate in the current study that telmisartan could promote fracture healing in a mice model via increasing mechanical strength and improving microstructure. The most mechanism is probably by an increase of cell proliferation and neovascularization associated with a decreased VEGF expression in hypertrophic chondrocytes.

Distracción osteogénica vertical de injerto microvascularizado de peroné para reconstrucción mandibular y optimización de la rehabilitación implantológica / Vertical distraction osteogenesis of microvascularised fibular grafts for mandibular reconstruction and optimisation of rehabilitation implantology

Introducción: En la actualidad, se considera que el injerto microvascularizado de peroné es la mejor opción de tratamiento para las reconstrucciones mandibulares de defectos óseos mayores de 6 cm. No obstante, debido a su limitada altura, presenta una importante desventaja en cuanto a la rehabilitación protésica, particularmente en aquellos casos de resecciones mandibulares parciales con una hemimandíbula contralateral dentada. Material y métodos: Presentamos un caso clínico de mixoma mandibular tratado mediante resección quirúrgica y reconstrucción mandibular primaria mediante injerto microvascularizado de peroné, al que se sometió a distracción osteogénica vertical para optimizar la posterior rehabilitación implantológica. Resultados: La discrepancia de altura se solucionó completamente y se colocaron tres implantes osteointegrados en el área distraída, lo cual permitió una rehabilitación protésica muy satisfactoria, tanto estética como funcionalmente. Conclusiones: La distracción osteogénica vertical de peroné constituye una excelente opción terapéutica para igualar la altura del peroné a la del reborde alveolar de la hemimandíbula dentada contralateral, tras la reconstrucción de defectos mandibulares extensos, de cara a una posterior rehabilitación implantológica, lo que permite llevar a cabo ésta con resultados, tanto funcionales como estéticos, muy satisfactorios. Además, no presenta los inconvenientes de otras técnicas empleadas en estos pacientes, como el peroné en doble barra (mayor dificultad técnica y mayor riesgo de trombosis en el pedículo) y el empleo de injertos “onlay” (morbilidad añadida en la zona de toma del injerto)(AU)

Introduction: Free vascularized fibular flap is considered the treatment of choice in mandibular reconstruction for extensive bone defects. But, when the reconstruction involves a dentate mandible, the fibula has the limit as it doesn’t offer sufficient bone height to restore the alveolar arch up to the occlusal plane. Therefore, the deficiency in bone height makes implant placement impractical. Materials and methods: We report a case of vertical distraction osteogenesis of a free vascularized fibula flap used to reconstruct a hemimandible after resection of an odontogenic myxoma. The distraction device was applied intraorally. Distraction of 0.5 mm per day was performed followed by 3 months of consolidation period. Results: The vertical discrepancy between the fibula and the native hemimandible was corrected. The increase of vertical bone height was stable and enabled placement of dental implants without any complications. Conclusions: We believe that vertical distraction osteogenesis of free vascularized flaps is a reliable technique that optimizes implant positioning for ideal prosthetic rehabilitation, after mandibular reconstruction following tumour surgery(AU)

Instability prolongs the chondral phase during bone healing in sheep.

In this sheep study, we investigated the influence of fixation stability on the temporal and spatial distribution of tissues in the fracture callus. As the initial mechanical conditions have been cited as being especially important for the healing outcome, it was hypothesized that differences in the path of healing would be seen as early as the initial phase of healing. Sixty-four sheep underwent a mid-shaft tibial osteotomy that was treated with either a rigid or a semi-rigid external fixator. Animals were sacrificed at 2, 3, 6 and 9 weeks postoperatively and the fracture calluses were analyzed using radiological, biomechanical and histological techniques. Statistical comparison between the groups was performed using the Mann-Whitney U test for unpaired non-parametric data. In the callus of the tibia treated with semi-rigid fixation, remnants of the fracture haematoma remained present for longer, although new periosteal bone formation during early healing was similar in both groups. The mechanical competence of the healing callus at 6 weeks was inferior compared to tibiae treated with rigid fixation. Semi-rigid fixation resulted in a larger cartilage component of the callus, which persisted longer. Remodeling processes were initiated earlier in the rigid group, while new bone formation continued throughout the entire investigated period in the semi-rigid group. In this study, evidence is provided that less rigid fixation increased the time required for healing. The process of intramembranous ossification appeared during the initial stages of healing to be independent of mechanical stability. However, the delay in healing was related to a prolonged chondral phase.

Alveolar distraction: analysis of 10 cases.

OBJECTIVE: The purpose of this study was to evaluate intraoperative and postoperative complications of alveolar distraction and outcome. STUDY DESIGN: Ten patients with alveolar ridge deficiencies were treated with alveolar distraction osteogenesis by means of intraosseous distractors (Lead system, Stryker Leibenger, Kalamazoo, Mich). The deficiencies were caused by atrophy after periodontal disease or atrophy after tooth extraction (n = 6), benign tumor resection (n = 2), trauma (n = l), or oligodontia in a case of ectodermal dysplasia (n = l). The location of the defects was the anterior mandible (7), posterior mandible (1), and anterior maxilla (2). The mean follow-up was 1.8 years, with a range of 10 months to 3 years. RESULTS: The mean alveolar distraction achieved in 10 cases was 8.7 mm (5-15 mm). The intraoperative and postoperative problems encountered were lingual (n = 3) and palatal (n = 2) displacement of the distracted segment, fracture of the distracted segment in a very thin alveolar bone (n = 1), and intraoperative bleeding (n = 1). CONCLUSION: Overall complication rate was 70%. However, most of the complications were minor and eliminated easily. Implant success rate was 85%.