Neurotrophins are proteins that regulate neuronal survival, axonal growth, synaptic plasticity and neurotransmission. They are members of the neurotrophic factors family and include factors such as the nerve growth factor (NGF), the brain derived neurotrophic factor (BDNF), the neurotrophin-3 (NT-3), and the neurotrophin-4/5 (NT-4/5). These molecules bind to two types of receptors: i) tyrosine kinase receptors (TrkA, TrkB, TrkC) and ii) a common neurotrophin receptor (p75NTR). The two receptor types can either suppress or enhance each other's actions. Neurotrophins have a multifunctional role both in the central and peripheral nervous system. They have been suggested as axonal guidance molecules during the growth and regeneration of nerves. It has also been proven that they stimulate axonal growth by mediating the polymerization and accumulation of F-actin in growth cones and axon shafts. Neurotrophins, as other neurotrophic factors, have been shown that they reduce neuronal injury by exposure to excitotoxins, glucose deprivation, or ischemia. Furthermore, the nerve regeneration promoting effect of these growth factors is well documented for many different models of central or peripheral nervous system injury. Several studies have shown that exogenous administration of these factors has protective properties for injured neurons and stimulates axonal regeneration. Based on these properties, these molecules may be used as therapeutic agents for treating degenerative diseases and traumatic injuries of both the central and peripheral nervous system.

Bone marrow edema syndrome (BMES) refers to transient clinical conditions with unknown pathogenic mechanism, such as transient osteoporosis of the hip (TOH), regional migratory osteoporosis (RMO), and reflex sympathetic dystrophy (RSD). BMES is primarily characterized by bone marrow edema (BME) pattern. The disease mainly affects the hip, the knee, and the ankle of middle-aged males. Many hypotheses have been proposed to explain the pathogenesis of the disease. Unfortunately, the etiology of BMES remains obscure. The hallmark that separates BMES from other conditions presented with BME pattern is its self-limited nature. Laboratory tests usually do not contribute to the diagnosis. Histological examination of the lesion is unnecessary. Plain radiographs may reveal regional osseous demineralization. Magnetic resonance imaging is mainly used for the early diagnosis and monitoring the progression of the disease. Early differentiation from other aggressive conditions with long-term sequelae is essential in order to avoid unnecessary treatment. Clinical entities, such as TOH, RMO, and RSD are spontaneously resolving, and surgical treatment is not needed. On the other hand, early differential diagnosis and surgical treatment in case of osteonecrosis is of crucial importance.

Massive bony defects of the lower extremity are usually the result of high-energy trauma, tumor resection, or severe sepsis. Vascularized fibular grafts are useful in the reconstruction of large skeletal defects, especially in cases of scarred and avascular recipient sites, or in patients with combined bone and soft-tissue defects. Microvascular free fibula transfer is considered the most suitable autograft for reconstruction of the middle tibia because of its long cylindrical straight shape, mechanical strength, predictable vascular pedicle, and hypertrophy potential. The ability to fold the free fibula into two segments or to combine it with massive allografts is a useful technique for reconstruction of massive bone defects of the femur or proximal tibia. It can also be transferred with skin, fascia, or muscle as a composite flap. Proximal epiphyseal fibula transfer has the potential for longitudinal growth and can be used in the hip joint remodeling procedures. Complications can be minimized by careful preoperative planning of the procedure, meticulous intraoperative microsurgical techniques, and strict postoperative rehabilitation protocols. This literature review highlights the different surgical techniques, indications, results, factors influencing the outcome, and major complications of free vascularized fibular graft for management of skeletal or composite defects of the lower limb.

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For the past 45 years, the advent of microsurgery has led to replantation of almost every amputated part such as distal phalanx, finger tip, etc. Replantation of digits and hand can restore not only circulation, but also function and cosmetic of the amputated part. The goals of replantation are to restore circulation and regain sufficient function and sensation of the amputated part. Strict selection criteria are necessary to optimize the functional result. The management of this type of injuries includes meticulous preoperative management, microsurgical experience and continuous postoperative care. Among various factors influencing the outcome, the most important are the type and the level of injury, ischemia time, history of diabetes, age, sex, and smoking history. During the replantation procedure, bone stabilization, tendon repair, arterial anastomoses, venous anastomoses, nerve coaptation, and skin coverage should be performed. All structures should be repaired primarily, unless a large nerve gap or a flexor tendon avulsion injury is present. Adequate postoperative evaluation is mandatory to avoid early or late complications. To improve functional results, many replantation patients may need further reconstructive surgery.

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Although acute vascular injury is a common complication in children with severely displaced supracondylar humeral fractures, the management of patients with a pink pulseless hand still remains controversial. Between 1994 and 2006, 66 children with displaced supracondylar fractures of the humerus were treated. Five patients had an absence of the radial pulse with an otherwise well perfused hand. In one patient, radial pulse returned after closed reduction of the fracture. In four patients, open reduction and vascular exploration was required. Three patients had brachial artery occlusion because of thrombus formation. Thrombectomy was performed, which led to the restoration of a palpable radial pulse. In one patient with open fracture, brachial artery contusion and spasm were found, and treated by removal of adventitia. Surgical exploration for the restoration of brachial artery patency should be performed, even in the presence of viable pink hand after an attempt at closed reduction.Résumé Au cours d'une fracture supra condylienne du coude déplacée, les complications vasculaires sont relativement fréquentes. Le traitement, lui aussi, est largement controversé, notamment lorsqu'il existe une absence de pouls radial après la fracture. Entre 1994 et 2006, 66 enfants présentant une fracture supra condylienne du coude ont été traités. 5 présentaient une complication vasculaire avec absence de pouls radial. Chez un des patients, le pouls radial est réapparu après réduction à foyer fermé. Chez les 4 autres patients, il a été nécessaire de faire une réduction sanglante avec exploration vasculaire. 3 des patients avaient une occlusion de l'artère humérale. La thrombectomie a été réalisée avec restauration du pouls radial. Sur un patient, il s'agissait d'une contusion de l'artère brachiale avec spasme et une réapparition du pouls après endar térectomie. L'exploration vasculaire chirurgicale doit être réalisée même si la main se recolore après une réduction à foyer fermé.