Femoral Deformity in Tibia Vara and Its Response to Growth Modulation

Janet L. Walker, David M. Dueber, Allison C. Scott, Lindsay P. Stephenson, Joel A. Lerman, Sarah B. Nossov, Corinna C. Franklin, Kenneth P. Powell, David E. Westberry, Jeffery D. Ackman

Research output: Contribution to journalArticlepeer-review

Abstract

Background: While tibia vara is a disorder of the proximal tibial physis, femoral deformity frequently contributes to the overall limb malalignment. Our purpose was to determine how femoral varus deformity in tibia vara responds to growth modulation, with/without lateral tension band plating (LTBP) to the femur. Methods: One-hundred twenty-seven limbs undergoing LTBP for tibia vara were reviewed. All had tibial LTBP and 35 limbs also had femoral LTBP for varus. Radiographs were measured for correction of the mechanical lateral distal femoral angle (mLDFA) and mechanical axis deviation (MAD). Preoperative-femoral varus was defined with an age-adjusted guide: mLDFA >95 degrees for 2 to below 4 years and mLDFA >90 degrees for 4 to 18 years. The 35 limbs having femoral LTBP were compared with 50 limbs with femoral varus and no femoral LTBP. In addition, 42 limbs that did not have preoperative-femoral varus were followed. Patients with early-onset (below 7 y) tibia vara were compared with those with late-onset (≥8 y). Outcome success was based on published age-adjusted mLDFA and MAD norms. Results: Following femoral LTBP, the mean mLDFA decreased from 98.0 to 87.1 degrees. All femurs had some improvement, with 28/35 femurs (80%) achieving complete correction. One limb, with late follow-up, overcorrected, requiring reverse (medial) femoral tension band plating. For the 50 limbs with femoral varus and only tibial LTBP, 16/22 limbs (73%) with early-onset and 11/28 limbs (39%) with late-onset completely corrected their femoral deformities. If the limb had preoperative-femoral varus, femoral LTBP statistically correlated with successful mLDFA correction and improvement of MAD, only in the late-onset group. Forty-two limbs, without preoperative-femoral varus, had no change in their mean mLDFA of 87 degrees. However, 4 femurs (10%) ended with posttreatment varus. Conclusions: Femoral LTBP is effective in correcting femoral varus deformity in the tibia vara. For femoral varus associated with late-onset tibia vara, femoral LTBP should be considered. Those that had femoral LTBP had statistically more successful femoral and overall limb varus correction. However, in early-onset tibia vara, with associated femoral varus, observation is warranted because 73% of femurs are corrected without femoral intervention. This study was underpowered to show additional improvement with femoral LTBP in the early-onset group. Even limbs with normal femoral alignment, should be observed closely for the development of femoral varus, during tibial LTBP treatment for tibia vara. Level of Evidence: Level III.

Original languageEnglish
Pages (from-to)303-310
Number of pages8
JournalJournal of Pediatric Orthopaedics
Volume43
Issue number5
DOIs
StatePublished - May 1 2023

Bibliographical note

Publisher Copyright:
© 2023 Lippincott Williams and Wilkins. All rights reserved.

Keywords

  • Blount disease
  • children
  • guided growth
  • knee
  • lower limb deformity

ASJC Scopus subject areas

  • Pediatrics, Perinatology, and Child Health
  • Orthopedics and Sports Medicine

Fingerprint

Dive into the research topics of 'Femoral Deformity in Tibia Vara and Its Response to Growth Modulation'. Together they form a unique fingerprint.

Cite this