Genu valgum or "knocked knees" are part of the coronal plane deformities of the lower extremity. The majority of patients are asymptomatic and have no functional limitations. This condition can be preceded by flat feet and occasional medial foot and knee pain. Children start developing physiologic genu valgum starting by age 2, and it becomes most prominent between ages 3 to 4. After that, it typically decreases to a stable, slightly valgus position by age 7 years. In the adolescent age group, minimal, if any, change in this alignment is expected. Intermalleolar distance has been used to assess the degree of genu valgum. It is the distance between the medial malleoli in a standing patient with touching medial femoral condyles. Intermalleolar distances greater than 8 cm is considered pathologic. Rarely, in cases where valgus alignment continues to increase, it can be associated with an out-toed gait, lateral subluxation of the patella, and rubbing of the knees together as the child ambulates.
膝外翻或“X形腿”是下肢冠状面畸形的一部分。大多数患者无症状，没有功能限制。这种情况可能先出现扁平足以及偶尔的足内侧和膝盖疼痛。儿童从2岁开始出现生理性膝外翻，在3至4岁时最为明显。之后，到7岁时通常会减少到稳定的轻度外翻位置。在青少年年龄组中，预计这种对线变化极小（如果有变化的话）。踝间距已被用于评估膝外翻程度。它是站立位且双侧股骨内侧髁相触的患者双侧内踝之间的距离。踝间距大于8厘米被认为是病理性的。极少数情况下，若外翻对线持续增加，可能会伴有外八字步态、髌骨外侧半脱位以及儿童行走时膝盖相互摩擦。
