Do we need to do overcorrection in Blount's disease?

PURPOSE: In order to prevent recurrent deformity, overcorrection in Blount's disease has been a common practice by most paediatric orthopaedic surgeons. However, some patients have persistent valgus alignment resulting in awkward deformity. The femoro-tibial angle (FTA) was measured in this series of cases to determine the necessity of such practice.

METHOD: During 1998-2010, patients with Blount's disease stage 2 by Langenskiold, aged from 30 to 40 months who had failed from bracing and underwent valgus osteotomy were included. Seventeen legs had postoperative FTA 7-13° (group 1) and 48 legs had postoperative FTA more than 13° (group 2). ROC curve was used to determine the appropriate FTA that was suitable to prevent recurrence.

RESULTS

Four legs had recurrence (28.6%) in group 1 and six legs (12.5%) had recurrence in group 2. Chi-square test between two groups were not statistically significant in recurrence (p = 0.434). Age and BMI were not statistically significant between recurrent and non-recurrent groups. The ROC curve shows that overcorrection more than 15° did not show benefit to prevent the recurrence in Blount's stage 2.

CONCLUSION

Our study showed that the overcorrection group had non-statistically significant recurrence compared to the non-overcorrection group, and overcorrection more than valgus 15° has no benefit to prevent recurrence.