Ogden J A
Skeletal Radiol. 1984;11(4):246-57. doi: 10.1007/BF00351348.
The patella initially ossifies at between three and five years, commencing as multiple foci that rapidly coalesce. As the patellar ossification center enlarges the expanding margins may be irregular and associated with accessory ossification centers. These are most common superolaterally and may lead to the development of a bipartite patella. The bipartite patella has cartilaginous continuity despite the appearance of osseous discontinuity. The patella expands to all cartilaginous contours during late adolescence when the epiphyseal ossification centers around the knee are also in the final stages of maturation. The only cartilage not replaced is that occupying the superior two-thirds of the articular surface (the lower one-third is covered by the fat pad). The subchondral plate does not assume the actual articular contours until the late stages of osseous maturation (after ten to twelve years). Accordingly, typical measurements such as medial and lateral angulation cannot be accurately done prior to the final stages of patellar ossification expansion and maturation. The tibial tuberosity begins ossification at between seven and nine years as a distal focus. This progressively enlarges proximally and anteriorly, while the main tibial ossification center concomitantly expands downward into the tuberosity. A section of epiphyseal cartilage usually remains between these two ossification centers until close to physeal maturity. The anterior chondro-osseous region at the site of patellar tendon attachment is a biomechanically susceptible region that may be acutely or chronically traumatized to create an Osgood-Schlatter lesion. The physis associated with the tibial tuberosity is histologically modified in a proximal to distal gradation of columnar adaptation to specific biomechanical demands in this region. Closure of the tuberosity physis occurs in a proximal to distal direction.
髌骨最初在3至5岁时开始骨化，起初为多个骨化中心，这些中心会迅速融合。随着髌骨骨化中心的扩大，其边缘可能不规则，并伴有附属骨化中心。这些附属骨化中心最常见于髌骨的外上侧，可能导致二分髌骨的形成。尽管二分髌骨在影像学上表现为骨质连续性中断，但实际上其软骨是连续的。在青春期后期，当膝关节周围的骨骺骨化中心也处于成熟的最后阶段时，髌骨会扩展至所有软骨轮廓。唯一未被骨替代的软骨占据关节面的上三分之二（下三分之一被脂肪垫覆盖）。直到骨成熟后期（10至12岁后），软骨下骨板才呈现出实际的关节轮廓。因此，在髌骨骨化扩展和成熟的最后阶段之前，无法准确进行诸如内外侧角度等典型测量。胫骨结节在7至9岁时开始骨化，最初为远端的一个骨化中心。该骨化中心逐渐向近端和前方扩大，而胫骨的主要骨化中心则同时向下扩展至结节。在这两个骨化中心之间通常会保留一段骨骺软骨，直至接近骨骺成熟。髌腱附着部位的前软骨骨区域是一个生物力学上易受影响的区域，可能会受到急性或慢性创伤，从而导致胫骨结节骨软骨炎。与胫骨结节相关的骨骺在组织学上会根据该区域特定的生物力学需求，从近端到远端逐渐发生柱状适应性改变。结节骨骺的闭合是从近端向远端进行的。
