ABSTRACT
PURPOSE: Traditional teaching for fixation of paediatric femur fractures recommends 80% nail diameter/medullary canal diameter ratio (ND/MCD) for successful maintenance of reduction. Prior studies have investigated this with stainless steel Enders nails. Our aim was to assess the impact of ND/MCD on maintenance of reduction and malunion rates in paediatric femur fractures treated with flexible intramedullary nails (FINs). METHODS: Retrospective data was collected on all paediatric patients treated with FINs for diaphyseal femur fractures at a single tertiary care institution over a ten-year period. Patients with co-morbidities affecting bone quality were excluded. Patients were subdivided into groups based on ND/MCD. RESULTS: A total of 66 patients met inclusion criteria. Mean ND/MCD was 76.3% (32.9% to 98.8%, SD 14.3). In all, 50% (n = 33/66) of patients had > 80% ND/MCD, and only 13.6% (n = 9/66) of patients had less than 60% ND/MCD. When controlling for fracture stability, ND/MCD had no correlation with mean shortening (p = 0.07) There was no correlation between ND/MCD and angulation in the sagittal (p = 0.96) or coronal plane (p = 0.20). Three patients fit malunion criteria. ND/MCD for these patients were 40%, 67% and 79%. CONCLUSION: There was no correlation between ND/MCD and shortening or malangulation. The majority of patients in this series with less than 80% fill with FIN healed within acceptable parameters. LEVEL OF EVIDENCE: III.
ABSTRACT
PURPOSE: Traditionally, flexible intramedullary nails (FINs) are not to be used to fix femur fractures in patients > 50 kg (110 lbs). However, studies have not examined the efficacy of this technique in overweight and obese patients who may be under this 'weight cutoff'. The purpose of this study was to assess how patient body mass index (BMI) impacts the treatment of paediatric femur fractures managed with FINs. METHODS: Retrospective data was collected on all paediatric patients treated with FINs for diaphyseal femur fractures at a single tertiary care institution over a ten-year period. BMI was calculated and categorised according to the Centre for Disease Control BMI Calculator for Children and Teens. Patients with comorbidities affecting bone quality were excluded. RESULTS: A total of 54 patients met inclusion criteria. In all, 14 patients were underweight, 20 were within a normal weight range, and 20 were overweight/obese. There was no correlation between BMI and mean shortening (underweight: 7.1 mm, normal weight: 5.2 mm, overweight/obese: 7.2 mm; p = 0.55). There was no correlation between BMI and mean anterior/posterior angulation (underweight: 3.1°, normal weight: 3.8°, overweight/obese: 3.3°; p = 0.93). There was no correlation between BMI and varus/valgus angulation (underweight: -0.86°, normal weight: -0.5°, overweight/obese: -1.25°; p = 0.89). Three cases fit malunion criteria. One of these patients fell into the 'underweight' category and two patients fell into the 'normal weight' category. CONCLUSION: We found no association between BMI and malunion in FIN fixation of femoral diaphyseal fractures in children. All cases of malunion were seen in underweight or normal weight patients.
