A Predictive Score for Infantile Blount Disease Recurrence After Tibial Osteotomy.

INTRODUCTION AND OBJECTIVE: Several predictive factors for infantile Blount disease recurrence after tibial osteotomy were discovered. This study aimed to examine and utilize various predictors to develop a prediction score for infantile Blount disease recurrence after tibial osteotomy.

METHODS: We conducted a retrospective cohort study of infantile Blount disease patients who underwent tibial osteotomy between January 1998 and December 2020. Potential predictors, including clinical and radiographic parameters, were examined for their association with the disease recurrence after receiving tibial osteotomy. A predictive score was subsequently developed based on those potential predictors through multivariable logistic regression modeling.

RESULTS: A total of 101 extremities diagnosed with infantile Blount disease from 58 patients who underwent tibial osteotomy were included. Of those, 15 extremities (14.9%) recurred. Univariable logistic regression analysis identified age older than 42 months [odds ratio (OR)=4.28; P=0.026], Langenskiöld classification stage III (OR=9.70; P <0.001), LaMont classification type C (OR=15.44; P <0.001), preoperative femorotibial angle <-14 degrees (OR=4.21, P=0.021), preoperative metaphyseal-diaphyseal angle >16 degrees (OR=8.61, P=0.006), preoperative medial metaphyseal slope angle >70 degrees (OR=7.56, P=0.001), and preoperative medial metaphyseal beak angle >128.5 degrees (OR=13.46, P=0.001) as potential predictors of infantile Blount disease recurrence after tibial osteotomy. A predictive score comprised of age younger than 42 months, LaMont classification type C, and medial metaphyseal beak angle >128 degrees demonstrated an excellent predictive performance (area under the receiver operating characteristic curve =0.87), good calibration, and high internal validity.

CONCLUSIONS: Our developed predictive score accurately predicted infantile Blount disease recurrence after tibial osteotomy. The results from our developed prediction tool allow physicians to inform prognosis, increase awareness during the follow-up period, and consider additional interventions to prevent disease recurrence.

LEVEL OF EVIDENCE: Level II.