Intramedullary elastic nails have become a widely used option for pediatric diaphyseal femur fracture treatment, particularly in patients 6 to 12 years. Typically they have been most successfully utilized in length stable fracture patterns such as transverse or short oblique fractures in patients less than 100 lbs. While the relatively low risk of complications and quick return to mobility reported in studies in the 1990s and 2000s have made elastic nails appealing to both surgeons and patients, patients treated with elastic nails often undergo another surgery for hardware removal, and more recent reports have revealed several technical challenges and complications that may serve to limit the use of intramedullary nails in certain populations.
Anastasopoulos et al. recently analyzed 36 patients aged 7 to 13.5 years [26
]. At mean follow-up of 25.5 months, successful fracture union was observed in all patients. Follow-up reports indicated return to a full range of motion for all patients with the exception of one who experienced a 10° extension lag. However, radiographic review revealed 44% of the children had a malalignment at the fracture site and 50% had a leg length discrepancy, though these patients did not present with clinical misalignment or report pain or inconvenience. In another cohort of 70 patients aged 4 to 15 years, Sagan et al. found malunion—defined as greater than a 15° of angulation on the lateral radiograph or 10° angulation on the anteroposterior radiograph—in 16 patients, mostly older children [22
•]. They additionally found that weight was a significant predictor of anterior bow formation, with mean weight in patients treated with elastic nailing who experienced anterior bowing greater than 15° was 46.5 kg
13.5, whereas the mean weight of those who did not experience bowing was 36.8 kg
•]. Additionally, the authors revealed that 47% of their patients experienced torsional malalignment following elastic nail treatment. Previous biomechanical data also cautions against the use of elastic nails in heavier patients. Li et al. [27
] evaluated 4-point bending load to failure following fracture fixation in a cadaveric model. The authors noted that weight greater than 40–45 kgs provides a load at which permanent sagittal and coronal deformation of the nail can occur [27
]. Salem et al. [21
] reported similarly high rates of torsional differences
15° in 50% of 68 children who underwent elastic nailing of femur fractures. This group included 31 patients with external torsion but only four cases of clinical out-toeing.
Conversely, Garner et al. found that compared to a weight matched cohort that underwent rigid locking nail treatment, heavier patients (defined as those weighing 47–85 kgs) who underwent elastic nail treatment had less blood loss, a shortened time in the operating room, fewer complications, and were observed to have no increased risk of malunion or leg length discrepancy [28
•]. Despite these intra-operative benefits, six of the 15 patients in the elastic nail treated cohort still experienced a complication.
Altay et al. investigated the effect of the use of an open versus a closed reduction technique during TEN [23
]. Of 87 children, 42 were treated with a mini-open technique by which a 2–3 cm lateral incision is made at the point of fracture to achieve reduction, while 45 were treated with a closed technique where fluoroscopic control is used to insert the nail. Duration of surgery and intraoperative fluoroscopy time were significantly higher in the closed reduction group, while similar union and complication rates for both procedures were seen at an average of almost 2 years follow-up.
Jencikova-Celerin et al. recently reported on outcomes following use of a flexible interlocking nailing system, which incorporates a nail less rigid than an external fixator but more rigid than an elastic nail, as well as an interlocking screw [29
]. Of the 58 patients who received the interlocking fixation, only 19% experienced complications compared to the 30.4% of the 70 patients in the study treated with other fixation methods. The authors found that patients who weighed under 45.5 kg who were treated with standard elastic nails had 8.1 times the complication rate of those treated with the interlocking nails; however, the patients treated with interlocking nails were 1.7 times more likely to develop trochanteric heterotopic ossification than those treated with other fixation procedures. While technical modifications of traditional intramedullary nailing such as these may improve results, other types of fixation have also begun to be used for this middle age group.