Short-term comparison of the use of static and expandable intramedullary rods in the lower limbs of children with osteogenesis imperfecta
Keywords:osteogenesis imperfecta, intramedullary rod, Rush rod, Fassier-Duval rod, fracture
Background: Children with osteogenesis imperfecta suffer from frequent fractures and deformities due to skeletal fragility. Stabilisation of fractures, correction of deformity and intramedullary rodding result in decreased pain and improved function. Modern expandable intramedullary rods aim to provide lasting stability during growth, without an increase in complications. The aim of our study was to determine and compare the outcome of static Rush rods and expandable Fassier-Duval rods in terms of complications and reoperation rate.
Methods: We reviewed the records of a cohort of 17 children (seven female) with osteogenesis imperfecta (11 Sillence type III, six Sillence type IV) who were treated with intramedullary rods in the lower limb between 2011 and 2017. They had 64 rodding (38 femoral and 26 tibial) procedures (26 Rush rods and 38 Fassier-Duval rods). These were a primary procedure in 46, and a revision procedure after previous Rush rodding in 18 cases.
Results: The overall complication rate was 66% (n=42). There was a higher complication rate in the Rush rod group (81%, n=21) when compared to the Fassier-Duval group (55%, n=21)(p=0.035). The most frequent complication in the Rush rod group was distal deformity as the rod is outgrown (69%, n=18). The most frequent complication in the Fassier-Duval rod group was intramedullary migration due to a failure to expand (45%, n=17). Factors that were associated with increased risk of complications included younger age (p=0.031), type of rod (p=0.035), and deformity as an indication for surgery (77% complications, p=0.033). At a mean follow-up of 3.1 years, the reoperation rate in the Rush rod group was 58% (n=15). Comparatively, at a mean of 3.7 years follow-up, there were no reoperations in the Fassier-Duval group.
Conclusions: Despite the numerous innovations, the surgical management of lower limb deformities and fractures in children with osteogenesis imperfecta remains challenging with a relatively high complication rate. The use of Fassier-Duval rods may result in a lower reoperation rate when compared to Rush rods, in the short term.
Level of evidence: Level 4