Review Question - QID 5807

This patient has infantile tibia vara that has persisted beyond age 3. His treatment should include an osteotomy of the proximal tibia.

Infantile tibia vara that is Langenskold I or II and in a patient less than age 3 is typically treated with observation and anti-varus bracing. Evidence in the literature suggests that performing an osteotomy by age 4 decreases the risk of recurrence, and thus a deformity that has persisted beyond 3 years of age should undergo osteotomy before the age of 4 years. The osteotomy should overcorrect into valgus as well as some lateral translation and external rotation of the distal fragment.

Levine et al. present their work trying to distinguish physiologic bowing from true infantile Blount disease. They compared tibiofemoral angles and found no significant differences between the physiologic and pathologic groups. However, when comparing metaphyseal-diaphyseal (MD) angles they did find a statistically significant difference between the two groups. Their data suggest that a MD angle 11° or greater suggests true infantile Blount disease.

Birch presents a review on Blount disease. He notes that proximal tibial osteotomy is the treatment of choice for children who have a progressive deformity or exceed criteria for bracing (Langenskold III or greater, or older than age 3 years).

Figure A is a standing AP radiograph of bilateral legs showing bilateral Langenskold II infantile tibia vara. Illustration A demonstrates how to measure a MD angle. Illustration B is a postoperative radiograph following a valgus producing osteotomy for infantile tibia vara.

Incorrect answers:
Answer 1: This patient is over age 3 and thus continued observation is not recommended.
Answer 2: The radiograph seen in Figure A is consistent with infantile tibia vara and does not have features of an underlying metabolic disorder such as rickets.
Answer 3: A brace may have been appropriate prior to age 3, but for this age is not the treatment of choice.
Answer 4: Infantile tibia vara is a deformity about the proximal tibial physis and thus the osteotomy should be done in the tibia, not the femur.