RESUMEN
The authors present a methodology to measure the frontal plane angular and linear displacement and the transverse plane angular displacement of subtalar joint movement. This method is combined with a modification of the Kirby method for determining the transverse plane projection of the subtalar joint axis onto the plantar foot. A mathematical model is then used to construct the subtalar joint axis into a three-dimensional linear equation. Data are obtained from an in vivo series of 62 feet that indicates that within acceptable clinical errors of measurement the subtalar joint is a ginglymus type of joint that moves around a single fixed axis. Results also indicate that the subtalar joint axis is more superior and lateral to the neutral foot than any previous studies on cadaver feet have shown. Finally, the authors show that once the subtalar joint axis can be accurately located, the torque on the joint axis produced by ground reactive forces and muscular forces can be computed.
Asunto(s)
Antropometría/métodos , Rango del Movimiento Articular , Articulación Talocalcánea/fisiología , Adolescente , Adulto , Fenómenos Biomecánicos , Estudios de Evaluación como Asunto , Humanos , Modelos Lineales , Pronación , Valores de Referencia , Rotación , Articulación Talocalcánea/anatomía & histología , SupinaciónRESUMEN
The primary aim of this study was to determine the predictive value of the bone mineral density of the calcaneus for fracture of the metatarsals. The authors report a strong positive correlation between the bone mineral density of the calcaneus and the four-point bending strength of each of the five metatarsals (r2 = 0.76, 0.64, 0.70, 0.68, and 0.78 for metatarsals 1 through 5, respectively). In addition, the relative strengths of the metatarsals and the correlation with their in vivo loads during gait as previously reported in the literature are discussed.
Asunto(s)
Densidad Ósea , Calcáneo/diagnóstico por imagen , Huesos Metatarsianos/diagnóstico por imagen , Absorciometría de Fotón , Adulto , Anciano , Anciano de 80 o más Años , Fenómenos Biomecánicos , Cadáver , Calcáneo/fisiopatología , Femenino , Humanos , Masculino , Huesos Metatarsianos/fisiopatología , Persona de Mediana Edad , Cintigrafía , Sensibilidad y Especificidad , Estrés MecánicoRESUMEN
The authors describe a previously unreported anatomical structure in the calcaneocuboid joint of the foot and discuss the clinical significance. Fibroadipose synovial folds or labra are present in different locations throughout the calcaneocuboid joint of the foot. They appear to be wedge-shaped infections attached to the joint capsule in areas of incongruent joint spaces. Their surface is covered with synovial cells with a highly vascular loose connective tissue sublayer. Nerve fibers were seen in association with the joint capsule, but not within the V-shaped labrum. The clinical significance of the presence of the labrum is discussed, but their function is uncertain. These structures can project up to half the joint distance and have the possibility of producing impingement syndromes, or even tears. Since they are covered with two to three layers of synoviocytes, they also have the ability to produce a synovitis. The labrum can be identified using MRI, and once their presence is known arthroscopic repair of these structures is theoretically possible.