[Bone scintigraphy in evaluation of bone vascularisation at wrist and hand]. / La scintigraphie osseuse dans l'évaluation de la vascularisation osseuse au niveau de la main et du poignet.

Diphosphonate bone scintigraphy is used since the 1970s for studying bone pathology; it is increasingly common because of increased physical activity of the population. The disphosphonate uptake in bone requires the preservation of bone vascularity and reflects osteoblastic activity; it allows studying the viability of bone. Using data from the literature and our experience, we tried to take stock of its main uses in routine emphasizing the study of vascular and describe its use in fractures of the scaphoid and in the study of vascularised bone transfers. If the value of scintigraphy is well known, the use made by means of pinhole collimator and the market entry of new and more sensitive detectors with better resolution could allow the side of the imaging anatomy of improving the study of the vascularisation of small bone transfers which are increasingly used, particularly at wrist and hand.

[Osseous vascular anatomy in the hand and wrist]. / Anatomie vasculaire osseuse à la main et au poignet.

The design and the realization of vascularized osseous grafts at the hand and the wrist require a precise knowledge of the general and regional anatomy. This article gives first a progress report on current knowledge about the general organization of arterial and venous vascularization, of the long bones (number and localization of the nutrient foramina, communication between the epiphyseo-metaphyseal and diaphyseal networks) and of the short bones, in the adult and the child, before the closing of the growth plate. The general organization of arterial vascularization of the hand and the wrist is pointed out, with the current nomenclature and the contribution of the recent publications, in particular in these, which relate to the distal extremity of the radius. The vascularization of each bone (radius and ulna, carpal bones, metacarpals and phalanges) is then described; making way, the anatomical bases of each vascularized bone graft, which can be harvested there, are described. The last technical projections are included, in particular the realization of the reverse flow vascularized bone grafts harvested from the metacarpals. This article still gives a progress report on the osseous vascularization of the short bones, in particular of those which are exposed the most to the osteonecrosis (scaphoid, lunatum). It has the ambition to light the reader and to prepare him (her) with the reading of the following chapters.

[The role of imaging in the assessment of vascularity at hand and wrist]. / Apport de l'imagerie dans le diagnostic de la vascularisation osseuse à la main et au poignet.

The viability of the bone is compromised in two main situations at the wrist: Kienböck's disease and scaphoid nonunion with avascular necrosis. Plain radiography and CT allow an accurate anatomical approach of morphological changes associated with avascular necrosis of the lunate and the scaphoid fracture with complications. CT is readily available to detect nondisplaced fractures. However, early forms of necrosis can be misdiagnosed and evaluation of bone vitality is impossible. MRI is the best imaging modality to detect avascular necrosis and the intravenous injection of gadolinium improves the specificity of diagnosis of necrosis. The lack of enhancement of the proximal fragment of the scaphoid leads the surgeon to use a vascular graft in the treatment of nonunion. The technique has its limitations. The bone necrosis is histologically complex and contrast enhancement does not mean necessarily viability. However, MRI is still the most powerful imaging modality in the assessment of the bone marrow.

Vascularized bone grafts for upper limb reconstruction: defects at the distal radius, wrist, and hand.

Vascularized bone grafts have been successfully applied for the reconstruction of bone defects at the forearm, distal radius, carpus, and hand. Vascularized bone grafts are most commonly used in revision cases in which other approaches have failed. Vascularized bone grafts can be obtained from a variety of donor sites, including the fibula, the iliac crest, the distal radius (corticocancellous segments and vascularized periosteum), the metacarpals and metatarsals, and the medial femoral condyle (corticoperiosteal flaps). Their vascularity is preserved as either pedicled autografts or free flaps to carry the optimum biological potential to enhance union. The grafts can also be transferred as composite tissue flaps to reconstruct compound tissue defects. Selection of the most appropriate donor flap site is multifactorial. Considerations include size matching between donor and defect, the structural characteristics of the graft, the mechanical demands of the defect, proximity to the donor area, the need for an anastomosis, the duration of the procedure, and the donor site morbidity. This article focuses on defects of the distal radius, the wrist, and the hand.