A varus deformity is an excessive inward angulation (medial, or towards the body's midline) of the distal segment of a bone or joint. The opposite of varus is called valgus.
The terms varus and valgus always refer to the direction that the distal segment of the joint points.
For example, a varus deformity at the knee results in a bowlegged posture with the distal part of the leg below the knee deviated inward in relation to the femur. Whereas in a valgus deformity of the knee, the distal part of the leg is deviated outward in relation to the femur, resulting in a knock-kneed posture.
Evolution of usage
The terms varus and valgus are both Latin, but confusingly, their Latin meanings conflict with their current usage. A varus deformity of the knee now describes bowed legs, but in the original Latin, varus meant "knock-kneed."[1][2] Similarly, while a valgus deformity of the knee now describes knocked knees, the original Latin meaning was "bow-legged."[3][4] This is because adjectival application of these words to other body parts in medicine has changed their definitions, so that they now refer to the angle of the distal segment (e.g., valgus impaction in a Garden I femoral neck fracture). Strictly, therefore, knock-knee is both a varus deformity of the hip joint (coxa vara) and a valgus deformity of the knee joint (genu valgum), but it now called simply a valgus knee.
However, when said of a bone rather than a joint, the terms describe the bone's distal segment. Thus, a varus deformity of the tibia (e.g., a mid-shaft tibial fracture with varus deformity) refers to the distal segment in a varus alignment compared to the proximal segment.[citation needed]
Examples
Hip:coxa vara (Latin coxa = hip) — the angle between the head and the shaft of the femur is reduced, resulting in a limp.[5]
Knee:genu varum (Latin genu = knee) — the tibia is turned inward in relation to the femur, resulting in a bowleg.
↑"Talipes equinovarus". Genetic and Rare Diseases Information Center (GARD). 2017. Archived from the original on 15 October 2017. Retrieved 15 October 2017.
