In orthopedics, a varus deformity is a term for the inward angulation 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, in a varus deformity of the knee, the distal part of the leg below the knee is deviated inward, resulting in a bowlegged appearance. Conversely, a valgus deformity at the knee results in a knock-kneed appearance, with the distal part of the leg deviated outward.
The terminology is made confusing by the etymology of these words.
In Latin, varus actually means "knock-kneed" and valgus means "bowlegged," the opposite of what was described in the preceding section! This is because the Latin words were used in describing the relationship of the bones at the hip joint rather than at the knee.
In a knock-kneed person, the femur is deviated inward in relation to the hip, so the term varus is correctly applied for the hip, as it refers to the distal segment being angled inward.
But in the same knock-kneed person, the opposite situation is found at the knee, with the distal segment now being deviated outward, so the term valgus is used for the knee.
It is correct for a knock-kneed deformity to be called both a varus deformity at the hip/femur and a valgus deformity at the knee/tibia, although the common terminology is to refer to it as genu valgus.
If this is confusing, just remember that "varus = inward" and "valgus = outer" and always refers to the direction that the distal part of the joint points.
When the terminology specifies a bone rather than a joint, the bone is taken to be the distal segment of a joint. Thus, a varus deformity of the tibia refers to the femur/tibia joint (the knee) and not the ankle joint.
Examples
Hip:coxa varus (from Latin cox = hip) — the shaft of the femur is bent inward in respect to the neck of the femur, causing knock-knee.
Knee:genu varus (from Latin genu = knee) — the tibia is turned inward in relation to the femur, resulting in a bowlegged deformity.
Ankle:talipes varus (from Latin talus = ankle and pes = foot) — inward turning of the heel, resulting in clubfoot with the person walking on the outer part of the foot.
Toe:hallux varus (Latin hallux = big toe) — inward deviation of the big toe away from the second toe.
Deformities in the coronal plane are well compensated for by the subtalar joint, and deformities in the sagittal plane are compensated for by the ankle joint.
For the correction of a varusdeformity of the tibia or a varus tibiotalar joint, we prefer a medial opening wedge osteotomy and we use an anteromedial and a small lateral approach (for the fibular osteotomy).
In cases where the deformity is minimal and the opening wedge is not anticipated to affect the mechanical axis, a greenstick cut of the tibia is made in anticipation of the possibility that a fibular osteotomy may not need to be performed.
In orthopedics, a varusdeformity is a term for the inward angulation of the distal segment of a bone or joint.
It is correct for a knock-kneed deformity to be called both a varusdeformity at the hip/femur and a valgusdeformity at the knee/tibia, although the common terminology is to refer to it as genu valgus.
Hip: coxa varus (from Latin cox = hip) — the shaft of the femuris bent inward in respect to the neck of the femur, causing knock-knee.
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