Journal of Bone & Joint Surgery - American Volume:
Letters to the editor
Corresponding author: Eric J. Wall, MD, Division of Pediatric Orthopaedic Surgery, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229-3039
E.J. Wall, V. Jain, V. Vora, C.T. Mehlman, and A.H. Crawford reply:
The malunion rate associated with titanium nails in our study was 23.2%; however, the overall malunion rate (for both titanium and stainless steel nails) was 15%. Ho et al. reported malunion rates ranging from 17% to 24%, depending on the duration of follow-up1.
Although the manufacturer of the titanium nail has suggested subsequent nail removal, they do not provide guidelines for the timing of the removal. In the literature, the times of nail removal have ranged from three months to one year2-4. Metaizeau et al. recommended routine removal between three and six months after insertion4,5. It has been our experience that waiting more than six months makes removal of elastic nails difficult.
We routinely remove the elastic nails when there is radiographic evidence of circumferential callus formation and an absence of the fracture line. In our study, the average times until nail removal were not significantly different between the stainless steel and titanium groups (130 and 147 days, respectively; p = 0.356). Furthermore, none of the patients who had malunion were found to have an increase in angulation when we compared their pre-extraction radiographs with those made at the time of final follow-up. Therefore, we disagree that early nail extraction was associated with higher malunion rates.
Early weight-bearing following the use of elastic nailing should be discouraged. Others have recommended waiting three to eight weeks before full weight-bearing is started1,3,4. Metaizeau recommended that partial weight-bearing be started at the beginning of the third week, with progression to full weight-bearing shortly thereafter5. We typically wait four weeks, and make sure that there is good callus formation at the fracture site, before allowing our patients to begin weight-bearing.
We did not specifically measure the time to union, which occurred rapidly in all but one patient. All fractures were completely united at the time of nail removal. We compared the variables of fracture pattern, age, weight, weight-nail ratio, nail-canal diameter ratio (with use of the 0.4 rule), and metal type in a multivariate analysis and found that only the nail material was significantly associated with malunion (p = 0.025); stainless steel was significantly superior to titanium.
These letters originally appeared, in slightly different form, on jbjs.org. They are still available on the web site in conjunction with the article to which they refer.
1. Ho CA, Skaggs DL, Tang CW, Kay RM. Use of flexible intramedullary nails in pediatric femur fractures. J Pediatr Orthop. 2006;26:497-504.
2. Flynn JM, Hresko T, Reynolds RA, Blasier RD, Davidson R, Kasser J. Titanium elastic nails for pediatric femur fractures: a multicenter study of early results with analysis of complications. J Pediatr Orthop. 2001;21:4-8.
3. Linhart WE, Roposch A. Elastic stable intramedullary nailing for unstable femoral fractures in children: preliminary results of a new method. J Trauma. 1999;47:372-8.
4. Ligier JN, Metaizeau JP, Prévot J, Lascombes P. Elastic stable intramedullary nailing of femoral shaft fractures in children. J Bone Joint Surg Br. 1988;70:74-7.
5. Metaizeau JP. Stable elastic intramedullary nailing for fractures of the femur in children. J Bone Joint Surg Br. 2004;86:954-7.