Guided growth surgery for angular deformity of the knee: one centres experience.

Background: Angular deformity in the lower extremity can result in pain, gait disturbance, cosmetic deformity and joint degeneration. Up until the introduction of guided growth, which has since become the widely accepted treatment for frontal plane angular angular deformity around the knee in skeletally immature patients, treatment consisted of staples, corrective osteotomy or an angular epiphysiodesis. Guided growth modulation uses the tension band principle with the goal of treatment being to normalise the lower limb mechanical axis resulting in lower morbidity than previous treatments. In order to assess the success of this procedure we reviewed our results in an attempt to identify patients who may not benefit from this elegant procedure.

Methods: We performed a retrospective review of prospectively collected surgical records and diagnostic imaging in our paediatric tertiary national referral centre to identify all patients who had guided growth surgery for coronal plane angular deformity of the knee from 2007 to 2023. We noted the patient demographics, diagnosis, peri-operative experience and outcome. All patients were followed until skeletal maturity, until their hardware was removed or at least 2 years.

Results: Two hundred thirty-six patients were assessed for eligibility. Of the 282 treated knees which met the criteria for final assessment 55 (19.5%) were unsuccessful. Complications were few but included infection and metal-work prominence. Procedures that were less likely to be successfully included growth disturbances following trauma (18.8% failure) or infection (40%), tumour (66.6%), mucopolysaccharidoses type I (15.7%), spondyloepiphyseal dysplasia (25%) or Blount's disease (60%). Idiopathic angular deformity showed an 89.5% success rate with guided growth.

Conclusion: In our hands, guided growth had an 80.5% success rate when all diagnoses were considered. We continue to advocate the use of guided growth as a successful treatment option for skeletally immature patients with limb deformity however caution should be employed when considering its use in certain patient groups.

Level of evidence: Level III, retrospective cohort study.