Prophylactic Intramedullary Rodding After Femoral Lengthening in Patients With Achondroplasia and Hypochondroplasia.

BACKGROUND

Femoral fracture after femoral lengthening in patients with achondroplasia and hypochondroplasia is a frequent complication, occurring in up to 30%. The purpose of this study is to demonstrate the effectiveness of prophylactic intramedullary rodding in preventing this complication.

METHODS

Multicenter retrospective study involving 86 femoral lengthening procedures in 43 patients with achondroplasia or hypochondroplasia. Forty-two femora (21 patients) were prophylactically managed with intramedullary Rush rodding after external fixation removal (11 females and 10 males, mean age 14.6 years) compared with 44 femora (22 patients) without prophylactic intramedullary rodding (13 females and 9 males, mean age 15.2 years). The mean amount of lengthening in the rodding group was 13.3 cm (52.6%) with an External Fixation Index of 25.8 days/cm; in patients without rodding was 14.3 cm (61.5%) and 24.5 days/cm, respectively.

RESULTS

Seven cases (15.9%) without rodding developed fractures. Four of them required surgical correction due to displacement or shortening. Only 1 patient (2.4%) had fracture of the femur after prophylactic rodding, and surgery was not required. The incidence of femur fracture was significantly lower in the prophylactic rodding group compared with the nonrodding group (2.4% vs. 15.9%, respectively; P =0.034). There were no cases of infection or avascular necrosis.

CONCLUSIONS

Prophylactic intramedullary rodding is a safe and effective method for preventing femoral fractures after femoral lengthening in patients with achondroplasia or hypochondroplasia.

LEVEL OF EVIDENCE: Level III-a retrospective comparative study.