Comparative analysis of the effects of blade plate retention versus removal on paediatric bone remodelling following proximal femoral osteotomy.

INTRODUCTION

The decision to retain or remove blade plate implants after proximal femoral osteotomy (PFO) in paediatric patients remains contentious. While retention provides ongoing support, it increases stress shielding, potentially hindering bone remodelling and causing long-term complications. Conversely, early removal may restore normal mechanical loading and promote bone recovery. This study compares the effects of blade plate retention versus removal on bone density changes and implant risk of yield (RoY) over 36 months in a paediatric femur.

MATERIALS AND

METHODS

A personalised neuromusculoskeletal modelling and finite element analysis framework was developed using computed tomography scans and gait data. Using a strain energy-based remodelling analysis, the framework assessed changes in bone density and RoY for two clinical participants, comparing intact femurs with those retaining the implant for three years or having it removed after one year.

RESULTS

In both participants, implant retention diminished proximal femur remodelling. In P1, the average proximal bone density with implant increased by 0.11 g/cm3 over 36 months, compared to 0.38 g/cm3 in the intact model. In P2, the intact model's average proximal density increased by 0.27 g/cm3 versus 0.11 g/cm3 with the implant. Implant removal after 12 months reactivated remodelling, yielding final density changes of 0.14 g/cm3 (P1) and 0.21 g/cm3 (P2). The RoY decreased over time, stabilising at 71-75% for blade plates and 56-62% for screws.

DISCUSSION: These findings highlight the detrimental effects of prolonged retention due to stress shielding. Recovery in bone density after removal suggests that early removal may mitigate adverse effects and promote healthier bone adaptation, informing clinical decisions in paediatric PFO.