Page 9 - The Outcome Question Continued

In a second parallel study by the senior author, Paley et al40 studied 10 patients who underwent bilateral cosmetic tibial lengthening with the ISKD between 2001 and 2006. The preoperative height was 153 cm (range, 142 to 165 cm) [60.2 inches (range, 55.9 to 65 inches)]. The average amount of length obtained was 6.8 cm (range, 5 to 8 cm). The postoperative height was 160 cm (range, 150 to 170 cm) [63 inches (range, 59 to 66.9 inches)]. An average of 1 complication per limb was observed (range, 0 to 2 complications/limb). Nonunion occurred in 12 (60%) of 20 limbs. All nonunions were in patients who underwent >6 cm of lengthening. Nonunion was treated with exchange nailing (4 limbs), exchange nailing with allograft/autograft (5 limbs), and exchange nailing with autograft (3 limbs). Other complications included nerve injury in 1 limb that required nerve decompression, stress fracture in 1 limb after rod removal, and premature consolidation in 1 limb, which required shortening of the contralateral side. Despite the very high number of major complications in the ISKD tibial lengthening group, the preoperative and postoperative Enneking scores were not significantly different, indicating that aggressive treatment of complications can prevent permanent harmful sequelae of lengthening.

In a second parallel study by the senior author, Paley et al40 studied 10 patients who underwent bilateral cosmetic tibial lengthening with the ISKD between 2001 and 2006. The preoperative height was 153 cm (range, 142 to 165 cm) [60.2 inches (range, 55.9 to 65 inches)]. The average amount of length obtained was 6.8 cm (range, 5 to 8 cm). The postoperative height was 160 cm (range, 150 to 170 cm) [63 inches (range, 59 to 66.9 inches)]. An average of 1 complication per limb was observed (range, 0 to 2 complications/limb). Nonunion occurred in 12 (60%) of 20 limbs. All nonunions were in patients who underwent >6 cm of lengthening. Nonunion was treated with exchange nailing (4 limbs), exchange nailing with allograft/autograft (5 limbs), and exchange nailing with autograft (3 limbs). Other complications included nerve injury in 1 limb that required nerve decompression, stress fracture in 1 limb after rod removal, and premature consolidation in 1 limb, which required shortening of the contralateral side. Despite the very high number of major complications in the ISKD tibial lengthening group, the preoperative and postoperative Enneking scores were not significantly different, indicating that aggressive treatment of complications can prevent permanent harmful sequelae of lengthening.

Intramedullary telescopic nails have tried to revolutionize how we accomplish distraction osteogenesis and circumvent the traditional complications seen with external fixation.41,42 Initial devices have made progress in the field and identified design weakness and new complications. Issues in the past include: intramedullary infections, distraction mechanism failure, nail breakage, unreliable rate control with too rapid distraction (so called runaway nail), nonunions, and painful distraction mechanisms. 8,12,13,16,43,44 Previous mechanisms required rotation through the osteotomy, which can be painful and unpredictable and often require general anesthetic to accomplish distraction. 43,45,46 In comparison, patient feedback regarding the ERC device and the PRECICE mechanism has been excellent, both for rate control and for evoking little or no pain. In contrast to our experience, Schiedel et al47 reported 43% (10/23) rate of required reprogramming of ERC for failure to achieve desired lengths according to the machine. This was not our experience and could be explained by inexperience and user error. Our patients are coached on how to use the device and have medical staff available daily if they require assistance.

The issue of rate control is important because it is a key principle to achieve distraction osteogenesis. Slow rates will predispose to premature consolidation requiring reosteotomy surgery. Distracting too fast can predispose to contractures, nerve injury, and joint subluxation. Rates over 1.5 mm/d have been shown to lead to poor regenerate formation, which may go on to nonunion.46,48 Our experience with the P2 has shown excellent reliability of the distraction mechanism. The P1, as was previously reported by one of the authors, had some failures to distract due to breakage of the mechanism.16 We experienced no cases that distracted more than the prescribed amount. We also had no cases of nonunion, unlike reports from other series.10,16,46,48 One previous study, looking particularly at reliability the PRECICE distraction mechanism, found P1 distraction accuracy to be 96%.49.