Aims and objectives
Genu valgum is one of the most common angular deformations of lower extremity in children. Correction of this pathology is a popular procedure in pediatric orthopedics.
There are many techniques used while treating this problem, moreover new methods are developed all the time. Since 2006, the 8-plate guided growth technique is the most advanced procedure of angular deformities treatment.
This method consists of implantation of extraperiosteal plate and two screws, which work like a tension band and thus correct the deformation angle of genu valgum. The device should be inserted at the periphery of the physis. Based on the severity of the deformation, different number of 8-plates needs to be implanted.
The purpose of this study was to investigate how the 8-plate technique influences the correction of genu valgum results in skeletally immature patients. The authors of the study wanted to compare radiological measurements made before, during and after the treatment in order to show the method’s efficacy.
Methods and materials
On the course of this prospective study cases of 14 patients (8 boys, 6 girls; age range: 2-15, mean age: 9 years old) were analysed. The patients underwent the 8-plate hemiepiphyseodesis. Lower extremities were examined on the frontal plane full-length standing radiographs of the legs pre-operatively, during the treatment and after the removal of the plates.
The basis for this research were compared values estimated from pre- and post-treatment images. Measured were: the mechanical axis deviation (MAD) and mechanical axis angle (MAA) on the frontal plane full-length standing radiographs of the legs. By MAD we assume the distance from the midpoint of the knee to the line connecting center of the hip and ankle joint. Whereas MAA describes the angle between two lines: first, from the midpoint of the femoral head to the center of the femoral intercondylar notch and, second, from the centres of tibial spines and ankle joint.
Results
Out of 14 implantations of 8-plates, in 9 case the plates were inserted on medial femur epicondyles and in 3 on medial tibia condyles. During two procedures implantations were performed in both femur and tibia medial compartments.
The study had revealed that in 10 cases the outcome of the correction of genu valgus was restoration of the regular values of MAD and MAA. The mean deformity correction results improved by 14 mm in case of MAD and by 5° for MAA. In 4 cases a significant improvement in reduction of the valgus was observed (mean improvement values for MAA: 8 mm, and for MAD: 7°).
Conclusion
Genu valgum is an extremely frequent angular deformity among children.
According to the literature, the 8-plate hemiepiphyseodesis technique is simple, non-invasive, yet effective. However, there are no significant accounts in regard to the radiological data.
Our study showed that it is possible to control the improvement of correction of angular deformity on the basis of measurements taken from full-length standing radiographs of the legs. Additionaly, the gathered data proves that the 8-plate hemiepiphyseodesis technique is very effective and noteworthy.