Treatment of Infantile Blount Disease with Double Osteotomy: Medial Hemielevation and Lateral Closing Wedge Single Stage with the Use of a Polyetheretherketone Cage: Case Series.

BACKGROUND: This study aimed to evaluate the effectiveness of polyetheretherketone (PEEK) cage grafting in achieving union at the medial tibial plateau hemielevation site, using intraoperative knee arthrography to assess the accuracy of correction. Advanced infantile Blount disease (Langenskiöld stages V and VI) poses considerable surgical challenges owing to its complex multiplanar deformities and elevated risk of recurrence. Several surgical strategies, including staged and single-stage corrections, have been described. This case series presents the outcomes of a single-stage approach that simultaneously addresses joint-level and proximal tibial deformities, combined with lateral epiphysiodesis to mitigate the risk of recurrence. METHODS: Between 2015 and 2020, 13 patients (6 males, 7 females; aged 8-12 years) with stage V or VI infantile Blount disease underwent double osteotomy consisting of medial hemielevation and lateral closing wedge correction. Medial tibial plateau realignment was guided intraoperatively by arthrography, and the resulting gap was filled with a lumbar PEEK cage. A fibular osteotomy was performed in all patients. Fixation was achieved using a 4.5-mm T-plate that crossed the epiphyseal plate to facilitate lateral growth arrest. One patient had a history of prior surgical intervention. RESULTS: The mean Pediatric Outcomes Data Collection Instrument score improved significantly from 47.9% preoperatively to 83.1% postoperatively (p < 0.001). All patients achieved a full range of knee motion without residual instability or varus thrust. Radiographic evaluation demonstrated correction of the mean tibiofemoral angle from 30° varus to 6° valgus, the medial proximal tibial angle from 60.0° to 87.1°, and the depressed medial plateau angle from 24.8° to 2.9° (all p < 0.001). No recurrence of deformity was observed, and the final limb-length discrepancy was < 1 cm in all patients. CONCLUSIONS: Single-stage double osteotomy with PEEK cage interposition, guided by intraoperative knee arthrography and stabilized with a lateral T-plate, provides effective correction of advanced tibial deformities in infantile Blount disease. This technique restores articular congruency, achieves mechanical alignment, and reduces the risk of recurrence.