Correction of multiplanar deformities around the knee with monolateral external fixator

Introduction
duction Angular deformities around the knee are common during childhood and most cases are a variation in the normal growth pattern. Uncorrected deformities change the biomechanics by disturbing stress distribution on the knee joint weight-bearing surface. Monolateral external fixator with osteotomy has shown better results being simple, and offers accurate correction, a low complication rate, the ability to correct valgus, varus, and rotational deformities, with early mobilization of the patient.


Patient and methods
A multicenter study case series prospective study was conducted from January 2020 to January 2021. A total of 30 patients with coronal plane deformities were included in the study. Of them, 15 patients (all cases were unilateral, 9 left limbs and 6 right limbs) presented with genu valgum with an age range between 10 and 16 years, and mean age was 10.5 years. Eight patients presented with genu varum only and six cases presented with genu varum and internal tibial torsion (all cases were unilateral, seven right limbs and eight left limbs) with an age range between 10 and 16 years and a mean of was 12.4 years.


Results
There is a statistically significant decrease of tibiofemoral angle (TFA) and mechanical axis deviation (MAD) after surgical correction of genu valgum among the included children with P value=0.001, and there is a statistically significant increase of lateral distal femoral angle (LDFA) after surgical correction of genu valgum with P value=0.001. There is a statistically significant increase of TFA, medial proximal tibial angle (MPTA), and MAD after surgical correction of genu varum among the included children with P value=0.001.


Conclusion
Correction of multiplanar deformities around knee using monolateral external fixator has good results in genu valgus with the improvement of LDFA and TFA, and with the improvement of MPTA and TFA in genu varum and with correction of MAD in both of the deformity after surgical correction, with rotation correction using the ability of direction of Schanz placement.