Limb Axis Disorder During Leg Length Discrepancy Treatment with Temporary Epiphysiodesis Using Eight-Plate Implants

Background: A common problem in pediatric orthopedics is leg length discrepancy (LLD). In adulthood, this may result in overload and degenerative changes in the lumbar spine, hip, and knee joints of the longer limb, and the fixed equinus position of the foot of the shorter limb. Surgical treatment using temporary epiphysiodesis with eight-plate implants is a minimally invasive, safe, and patient-tolerated procedure in LLD. However, publications mainly describe the effects of treatment in the form of achieved equalization and there is little information about the occurrence of secondary deformations. Our study aimed to determine the effect of temporary growth plate blocking on the final axis after treatment. Methods: The study was based on an analysis of radiographs recorded from 2010 to 2019 and an assessment of parameters such as MAD (mechanical axis deviation), mMPTA (mechanical medial proximal tibial angle), and M/at (mechanical axis of the tibia). Results: Twenty-four girls and thirty-six boys treated with eight-plate implants were included in the investigation. The duration of the treatment was 18 months (group I), 30 months (group II), and 42 months (group III). Our study revealed that the most significant differences were observed in the MAD parameter. MAD changed in a statistically significant manner across all investigated groups, for both girls and boys, regardless of the treatment duration. Conclusions: The treatment of LLD with epiphysiodesis using eight-plate implants influences both the anatomical axis of the bones and the mechanical axis of the limb.