Femoral Lengthening with Lengthening over a Nail has Fewer Complications than Intramedullary Skeletal Kinetic Distraction

Abstract

Background Lengthening over a nail and internal lengthening nails have been developed to minimize or eliminate patients' time wearing a frame during femur lengthening. However it is unclear whether either of these two approaches results in faster times to union or fewer complications over the other. Questions/purposes We asked which technique better achieved: (1) the lengthening goals, (2) the distraction rate control, (3) quality of the regenerate bone, (4) fewer complications, and (5) SF-36 and AAOS LLM scores also were compiled. The minimum followups for the ISKD and the lengthening over nail cohorts were 62 months (average, 76 months; range, 62-93 months) and 13 months (average, 27 months; range, 13-38 months), respectively. Results We observed no difference in achieving the lengthening goals between the two procedures. Distraction was not well controlled in the ISKD group; the distraction rates were 1.7 mm per day for the fast group (distraction rate greater than 1 mm/day) and 0.84 mm per day for the slow group (less than 1 mm/day). The lengthening over nail group had an average distraction rate of 0.88 mm per day. One of 20 of the patients who had lengthening over a nail had complications requiring additional unanticipated surgeries whereas six of 12 patients who had femoral lengthening in the ISKD group had such complications. Conclusions Based on our observations, we believe the lengthening over nail technique for femoral lengthening is associated with fewer complications than the ISKD. Level of Evidence Level III, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Current concepts of leg lengthening

“…Nail blockage also occurred in Albizzia series [16] and ISKD nails [51]. It is the main underlying cause of premature consolidation, which is about 12 % for ISKD [51,53,151], compared to below 5 % for all the other implants [16,50,53]. Runaway nails unintentionally lengthen more than 1.5 mm/day, a problem encountered in around 10 % of ISKDs [19,51,52,55]; one patient even underwent accidental 3 cm lengthening during manipulation under anaesthesia [51] and another expanded to 4 cm unintended length during the first 2 weeks [52].…”

“…About half of the difficulties are directly implant-related [55]. In a comparative study, the distraction control with ISKD was difficult and unexpected surgery more frequent (6/12 vs. 1/22), but the regenerate was better than in the LON group [53].…”

“…[48][49][50]. The composition of causes varies [12,[51][52][53][54][55]. Some series include bilateral lengthening for short stature, which is not the focus of this article [54].…”

“…Though callotasis and complex deformity correction is predominantly a paediatric orthopaedic field, the age of patients ranges from as young as 2 years up to 70 years (!). Patients treated with ring fixators and unilateral external fixators have an average age of around 12-16 years [48,49,65], whereas m'g [50,53,[59][60][61] or by solid nails [16, 46, 51-56, 60, 62, 63, 65] constitute young adults around the age of 18-25 years.…”

“…runaway nail), age [30 years, smoking, gain [4 cm, osteotomy at the same site of previous trauma or surgery and acute correction of associated deformities may be associated factors [19,53,63]. Partial or complete bony defects have been reported in up to 22 % for ISKD nails [19,51], mostly due to inadvertent higher distraction rates (1.5 vs 1.1 mm).…”