gms | German Medical Science

Objectives: Angular long bone deformities and leg length discrepancies are important non-traumatic conditions in children being referred to pediatric orthopedists. Latest developments are tension-band-like implants. So far, only small studies from single-center settings have been published. Aim of our study was to assess outcomes of the Eight Plate in “real life use” with a large and diverse population to reliably quantify implant- and growth-plate related adverse events (AEs).

Methods: We conducted a retrospective international multicenter study in seven centers in Switzerland, Germany, India and the United Kingdom. Patients were treated according to the local standard of care. Data on indication, deformity and AEs were collected from the charts of 126 patients at baseline, implant removal and follow-up. Patients were included if they had undergone Eight Plate implantation and removal between October 2007 and October 2012. Follow up took place at a minimum of six months after implant removal. Correction was rated as maintained when the remaining varus or valgus deformity (VVD) was less than 5° and the remaining leg length difference (LLD) was less than 10 mm. Analysis was conducted by means of descriptive statistics.

Results and Conclusion: Most patients (75%) were treated for VVD, 18% for LLD and 7% for a combination of both. The reason for deformity was idiopathic in most children (72%), whilst in 19% a disease or syndrome had led to the deformity. In 6% a previous trauma and in 2% a previous infection was the cause. Full correction was achieved in 66% of VVD and in 59% of LLD patients. In combined VVD and LLD cases, alignment and length correction were achieved in 67% and 78% respectively. Correction was maintained over time in 85%; cause for loss of correction was mainly rebound. Twenty-one patients (19%) underwent 25 additional surgeries between implantation and removal of the Eight Plate, which were mainly (56%) staged implantations or removals; 32% were due to newly emerging indications and 12% were screw-related. Twenty patients (18%) experienced 43 adverse events. The most common AEs were screw-related. Screw bending, loosening, breakage or migration through the growth plate occurred in 5%, 2%, 1% and 2% of patients respectively. Second common AEs were premature epiphyseal closures in 5% of patients. Screw- and growth-plate related AEs typically occurred in a clustered manner.

Our study is the first, which presents outcomes of the Eight Plate from a diverse clinical setting and a broad range of indications and shows that the AE rate of the Eight Plate is acceptable. Considering the type of the most common AEs ant their clustered occurrence, we believe that the majority of AEs could have been avoided through tighter monitoring.