The Outcomes of Guided Growth System in Juvenile and Adolescent Patients With Blount Disease.

BACKGROUND

Guided growth offers a less invasive option for the treatment of Blount disease. Previous studies have found guided growth to be much less successful for individuals with more severe mechanical axis deviation (MAD). This study aims to assess the effectiveness and safety of guided growth systems for treating Blount disease in juvenile and adolescent patients with particular attention to patients presenting with severe deformities.

METHODS

Patients were included if greater than 4 years of age and had undergone guided growth from January 2005 to September 2023. Treatment success was defined as final correction to MAD zone -1, 0, or +1 using only guided growth. Failure was defined as individuals who did not achieve correction to the above zones or those requiring osteotomy. Odds ratios were calculated for failure in patients with initial presentation in MAD zones -3 and -4. To further analyze our results, we also compared the treatment success rate of the 4-screw construct versus 2-screw construct, both of which are used at our institution.

RESULTS

A total of 32 patients with 44 extremities were included in this study: 13 patients (41%) in the juvenile group, and 19 patients (59%) in the adolescent group. Overall, successful correction to MAD -1, 0, and +1 was 61%. Factors associated with failure were mean BMI 40.3 (±8.8) versus 33.5 (±9.3), ( P =0.034). The odds ratio of zone -3 and zone -4 deformity treatment failure were 1.64 (95% CI: 0.48-5.56) and 1.78 (95% CI: 0.51-6.17), respectively. The relative risk of 4-screw plate construct for treatment failure was 0.5 (95% CI: 0.21-1.19) while 2-screw plate construct carried a relative risk of 4.5 (95% CI: 0.579-35.6) for mechanical implant failure.

CONCLUSIONS

Our research demonstrates that moderate and severe varus deformity (zone -3 and -4) in children with Blount disease can be successfully treated by tension band plating, though the failure rate still remains high.

LEVEL OF EVIDENCE: Level III.