Risk factors for reoperations following guided growth around the knee

Guided growth using tension band plates is a common treatment for genu varum and valgum deformities in children. Reoperation is a significant adverse event in surgical treatments. This study aims to identify the causes and risk factors for reoperations following guided growth around the knee.

This retrospective study reviewed children who underwent guided growth for genu varum and valgum deformities between 2012 and 2019. Reoperation was defined as revision surgeries for deformities at the same knee, excluding procedures for implant removal. Potential risk factors including age, sex, body mass index, surgical location, underlying etiology, and knee deformities were compared between cases with and without reoperation using the t-test and chi-square test. Risk factors were determined by logistic regression.

A total of 91 patients who underwent guided growth on 142 knees were included, with a mean age of 10.9 years at the time of surgery. Reoperations were performed in 36 patients (39.5 %). These included reoperations for recurrence of deformity in 26 knees, slow response in 13 knees, overcorrection in 5 knees, recurvatum of the tibial plateau in 1 knee, and infection in 1 knee. Logistic regression revealed younger age (Odds ratio [OR] 0.6 per older by 1 year, 95 % confidence interval [CI] 0.5-0.8) and non-idiopathic etiologies (OR 3.5, 95 % CI 1.0-11.8) as risk factors. Receiver operating characteristic curve determined age 10.1 years as a cutoff point that had sensitivity 73 % and specificity 91 % in predicting reoperation.

The reoperation rate can exceed 50 % in patients with specific etiologies such as rickets, Blount's disease, physeal injuries, and osteochondroma. Timely guided growth is essential for patients with progressive deformities, and retaining the epiphyseal screw and plate for potential recurrence is recommended. In cases of asymptomatic idiopathic knee deformities, delaying guided growth until after age 10 may be considered to reduce the risk of reoperation.