Long-Term Functional Outcomes and Prognostic Factors After Corrective Valgus Osteotomy for Infantile Blount's Disease.

BACKGROUND: Long-term functional outcomes following corrective valgus osteotomy for infantile Blount's disease (IBD) remain insufficiently characterized, particularly using patient-reported outcome measures (PROMs). METHODS: This retrospective cohort study with prospective long-term follow-up included patients with IBD who underwent corrective valgus osteotomy between 2002 and 2019 and had a minimum follow-up of 5 years. Functional outcomes were assessed using the Pediatric International Knee Documentation Committee (Pedi-IKDC), with the Patient Acceptable Symptom State (PASS) threshold used to define satisfactory outcomes. Health-related quality of life was evaluated using Pediatric Quality of Life Inventory 4.0 (PedsQL). Univariable and multivariable logistic regression analyses were performed to identify prognostic factors. RESULTS: Thirty-four patients (59 limbs) were evaluated at a mean follow-up of 13.1 ± 4.8 years (range, 5.8-22.6). The mean Pedi-IKDC score was 86.1 ± 17.1, with 81.4% achieving PASS. The mean PedsQL score was 84.3 ± 17.1, with 70.6% achieving PASS. Recurrence occurred in 27.1% of limbs and 23.7% required reoperation. Patients failing PASS had higher body mass index (BMI) and greater preoperative deformity. In multivariable analysis, preoperative femorotibial angle (FTA) varus ≥23° independently predicted unsatisfactory outcomes (odds ratio 0.03, p = 0.013), while BMI >33 kg/m2 showed a nonsignificant trend. CONCLUSIONS: In the subset of patients available for long-term follow-up, corrective valgus osteotomy was associated with favorable functional outcomes in most patients. Greater preoperative varus deformity (FTA ≥23°) independently predicted unsatisfactory functional outcomes. LEVEL OF EVIDENCE: Level III. See Instructions for Authors for a complete description of levels of evidence.