Page 5 - PATIENTS AND METHODOLOGY

Data were obtained retrospectively from a consecutive series of 48 patients who underwent placement of 65 Precice implants between December 1, 2011 and December 4, 2012 (Figs. 5–8) (Tables 1 and 2). All patients have completed the distraction and consolidation phases resulting in one of 2 endpoints, either successful healing or nonunion that required a bone grafting procedure. Institutional Review Board approval was obtained for this study.

To be considered eligible for treatment, patients needed to possess a limb leg discrepancy of at least 1.5 cm, or desire to undergo a cosmetic lengthening. Patients were offered internal lengthening with the Precice as long as the diameter of the canal and length of the bone in question was large enough to safely accommodate the implant, there was no evidence of active infection, and there were no associated deformities that precluded its use. They also needed to be capable of undergoing daily physical therapy and lengthening throughout the duration of the distraction at our institution. Initially, all patients were required by the FDA to undergo distraction by a physician. However, as of October 2012, the FDA cleared home use of the mobile ERC unit, allowing patients to perform their distraction at home.

Forty-one patients had 54 nails inserted into the femur. Of these, 36 femoral nails were inserted in skeletally mature patients using a piriformis entry. Twelve nails were inserted via trochanteric entry in skeletally immature patients or femurs with deformities that precluded a piriformis entry (eg, coxa valga). Six femoral nails were inserted in a retrograde manner.

Seven patients underwent tibial lengthenings, accounting for 8 nails. Six were inserted in standard antegrade manner, and 2 were placed retrograde in patients with undergoing simultaneous hind-foot fusions. One patient underwent unilateral humeral lengthening with a nail inserted in a standard antegrade manner. Another patient with tibial hemimelia and a hypertrophic fibula underwent lengthening of his fibula that required 2 implants inserted retrograde in a staged manner to achieve the desired length. The majority of patients were treated with 12.5mm diameter nails (40) that were 230mm in length (44).

The mean age of the patients in this series is 25.6 years (10.3 to 58.4 y) with a median of 20.0 years. Twenty-three patients whose mean age was 18.5 years (10.3 to 43.7 y) were treated for congenital limb leg discrepancy. Their mean preoperative goal was 4.91 cm (1.5 to 6.5 cm), whereas the preoperative mean limb length discrepancy (LLD) was 6.27 cm (1.5 to 8.2 cm). Four patients with a mean age of 17.8 years (13 to 27 y) were treated for developmental limb leg discrepancies and had a preoperative mean goal of 3.68 cm (1.5 to 6.5 cm). Six patients were treated for posttraumatic limb length discrepancies. Their mean preoperative goal was 3.48 cm (1.7 to 5.0 cm) and their mean age was 49.0 years (30 to 58 y). In addition to this, 15 patients underwent cosmetic lengthening. Their mean age was 29.7 years (15 to 48 y), baseline height was 166.2 cm (150 to 177 cm), and the preoperative goal of lengthening was 5.64 cm (3.0 to 6.5 cm).

All surgical procedures were performed using the same preoperative planning and intraoperative surgical techniques described above. The osteotomy level was selected based on a calculation using the physical specifications of the implant while taking into account the desired overall lengthening. A level was determined that would ensure adequate bony support for both the proximal and distal nail segments throughout the lengthening process. Multiple drill holes were then placed at the planned osteotomy level to allow for venting and dispersion of reamings at the osteotomy site to assist in bone healing. This was followed by reaming of the canal to 2mm larger than the chosen diameter of the implant. The nail was always distracted between 1.0 and 2.0mm intraoperatively, until functionality of the nail and completion of the osteotomy could be confirmed on fluoroscopic imaging. Patients were discharged from the hospital according to our established protocol generally by postoperative day 3. Lengthening began in our office on postoperative day 5 at an initial distraction rate of 1.0 mm/d for noncongenital LLD femurs and 0.75 mm/d for tibias, as well as, femurs of congenital LLD patients. This rate was further adjusted throughout the distraction phase based upon quality of regenerate formation, as well as, findings on clinical examination. Patients also began daily physical therapy at our institution beginning on postoperative day 5. Radiographs were obtained 14 days postopearatively and subsequently thereafter at 2-week intervals until the distraction was completed. Once the patient entered the consolidation phase, radiographs were obtained at monthly intervals until healing was confirmed and the patient was advanced to full weight-bearing.