Guided growth vs. Tibial osteotomy at early stage of Blount disease in squelletically immature patients

Background: There are no comparative study between guided growth and tibial osteotomy in early stage of Blount disease (BD) to our knowledge. The aim of this work was to compare the results of patients treated by these two techniques. Method: This was a retrospective, descriptive, and analytical study over a period of 5 years in including 17 children (24 Knees) with an early stage of infantile BD in two centers. Patient were classified in two groups: group 1(treated by guided growth), group 2 (treated by Tibial Osteotomy). Preoperative alignment analysis using the tibial femoral angle (HKA) and the proximal medial tibial mechanical angle (mMPTA) were compared with three measurements taken postoperatively in each of the groups. The mean variations of the angles were compared between the two groups. Results: Socio-demographic characteristics were similar for the two groups. Median age at surgery was 6.5 +/- 2.5 [3-9 years] in group 1 and 6.8 +/- 2.9 years [3-9 years]. At a follow-up of 24 +/- 3.5 months, the limb alignment was significantly corrected (1,03 degrees/month) in group 1 (median HKA 144 degrees-171 degrees; p = 0,001; median MMPTA 78 degrees-87 degrees, p = 0,018), and in group 2 we observed at a follow-up of 23 +/- 15 months a progressive loss (0,52 degrees/month) of the correction obtained immediately postoperatively (median HKA 160 degrees-176 degrees(immediate post operative) to 165,5 degrees; p = 0,31; median MMPTA = 78 degrees-86 degrees (immediate post operative) to 80,5 degrees; p = 0,37). There was a statistically significant difference between the mean variation in HKA between the two groups (group 1 = 22,5; group 2 = 4,5, p = 0.00), as well as for MMPTA; (group 1 = 7; group 2 = 2,5, p = 0,023). The rate of correction was 78% in group 1 with no rebound at a median follow-up after removal of the material of 10 +/- 2.4 months. Within group 2, the rate of correction was 10% with a recurrence rate of 60%. Conclusion: Guided growth appears to be the best treatment for early stage of BD in squelletically immature patients.