Abstract:PurposeTo compare patient characteristics, operative time, estimated blood loss (EBL), postoperative length of hospital stay (LOS) and complications after insertion and removal of submuscular plates (SMPs) versus flexible nails (FNs) for paediatric diaphyseal femur fractures.MethodsWe reviewed records of 58 children (mean age, 7.7 years SD 2.0) with diaphyseal femur fractures who underwent treatment with SMPs (n = 30) or FNs (n = 28) from 2005 to 2017 (mean follow-up, 22 months SD 28). Patients with pathological fractures or musculoskeletal comorbidities were excluded. Alpha = 0.05.ResultsInsertion of FNs was associated with shorter operative time (ß = –24 mins) and less EBL (ß = –38 mL) (both, p < 0.001) compared with insertion of SMPs, after adjusting for fracture type and time from beginning of study period. Removal of FNs was also associated with shorter operative time (ß = –15 min) compared with removal of SMPs (p < 0.001). EBL during removal was similar between groups (p = 0.080). The FN group had a shorter LOS after insertion (ß = –0.2 d) compared with the SMP group (p = 0.032). Four patients treated with SMPs and three treated with FNs developed surgical site infections. Two patients treated with SMPs and seven treated with FNs experienced implant irritation that resolved with removal. No other complications occurred.ConclusionCompared with SMPs, FNs were associated with shorter operative time (for insertion and removal), less EBL (for insertion) and shorter post-insertion LOS in patients with diaphyseal femur fractures.Level of Evidence:III