Functional and radiographic consideration of lower limb malalignment in children and adolescents with idiopathic genu valgum

Abstract

Three-dimensional gait analysis is capable of assessing dynamic load characteristics and the resulting compensatory effects of lower limb malalignment, which are generally not reflected in static imaging. This study determined differences in gait parameters in the frontal and transverse plane between patients and controls in order to identify compensatory mechanisms, and to correlate radiographic measurements and gait parameters in a consecutive series of children with idiopathic genu valgum. Thirty-three patients (mean age 12.3 years) were retrospectively reviewed and compared to a healthy control group. Children with genu valgum demonstrated significantly decreased internal knee valgus moments, shifting into varus moments. Furthermore, significantly different transverse plane gait patterns (decreased external knee rotation, increased external hip rotation) were observed. These patterns showed a relevant influence on the frontal knee moments, with knee rotation and foot progression angle showing the highest predictive value for changes and possible compensation of frontal knee moments. The correlation between commonly used radiographic measurements (i.e., mechanical axis deviation) and findings of the gait analysis was only low. Besides showing decreased internal knee valgus moments, our results suggest that considerable compensatory gait mechanisms may be present in children with idiopathic genu valgum to reduce joint loading. ß

Rotational gait patterns in children and adolescents following tension band plating of idiopathic genua valga

“…Increasing internal rotation of the foot and knee was directly associated with larger, more positive, and more normal knee moments. 7 The same gait pattern, previously beneficial for knee loading in the non-corrected, pathologic situation prior to TBP, resulted in pathologically increased knee valgus moments despite straight limbs after correction. Hence, the medial compartment may be overloaded, which in turn could be detrimental for the chondral joint surface.…”

“…7 In addition to demographic data, the following radiographic parameters were measured on the both the pre-and postoperative radiographs in a standardized manner using digital software (TraumaCad®; Brainlab, Inc., USA): (1) mechanical axis deviation (MAD), (2) This article is protected by copyright. All rights reserved 5 mechanical lateral distal femoral angle (mLDFA), (3) mechanical medial proximal tibial angle (mMPTA), (4) mechanical lateral distal tibial angle (mLDTA; normal range 86-92°), (5) joint line congruency angle (JLCA; normal range 0-2°), and mechanical tibiofemoral angle (mTFA; normal range 1.3  1.3° varus alignment).…”

“…Radiographic Assessment and Gait Analysis AP full-length standing radiographs were obtained on the same day as the gait analysis, as previously described. 7 In addition to demographic data, the following radiographic parameters were measured on the both the pre-and postoperative radiographs in a standardized manner using digital software (TraumaCad 1 ; Brainlab, Inc., Westchester, IL): (i) mechanical axis deviation (MAD); (ii) mechanical lateral distal femoral angle (mLDFA); (iii) mechanical medial proximal tibial angle (mMPTA); (iv) mechanical lateral distal tibial angle (mLDTA; normal range 86-92˚); (v) joint line congruency angle (JLCA; normal range 0-2˚), and mechanical tibiofemoral angle (mTFA; normal range 1.3 AE 1.3˚varus alignment). 9 As described in our previous study, we used a 12-camera system (VICON MOTION SYSTEM 1 , Oxford Metrics, UK; camera resolution 4 megapixels, capturing frequency 150 Hz) in combination with three strain-gauge force plates (Advanced Mechanical Technology Inc., Watertown, MA) to trace spherical markers.…”

“…6 We previously investigated pre-operative gait patterns in children and adolescents with idiopathic genua valga. 7 This previous study included a cohort of 33 patients, the majority of which exhibited considerable gait deviations with regards to both frontal and transverse planes. 7 Specifically, these children demon-strated significantly decreased (and thus worsened) internal knee valgus moments, and alterations in transverse plane gait patterns, such as decreased external knee rotation and increased external hip rotation.…”

“…7 This previous study included a cohort of 33 patients, the majority of which exhibited considerable gait deviations with regards to both frontal and transverse planes. 7 Specifically, these children demon-strated significantly decreased (and thus worsened) internal knee valgus moments, and alterations in transverse plane gait patterns, such as decreased external knee rotation and increased external hip rotation. Interestingly, moments at the knee were more positive (normal) in cases where internal rotation of the knee and foot was present.…”