Page 6 - RESULTS

Collectively, the patients in our series achieved a mean lengthening of 4.41 cm (0.5 to 6.5 cm) (Tables 3 and 4). Distraction was performed at a mean rate of 0.83 mm/d (0.5 to 1.11 mm/d), and healing was confirmed at a mean of 125.3 days (52 to 262 d). Complications that were encountered will be discussed within the subsets of patients.

When examined individually, the 23 patients who were treated for congenital limb leg discrepancy gained a mean length of 4.5 cm (0.5 to 6.5 cm), for a mean initial goal of 4.91 cm (1.5 to 6.5 cm). They had a preoperative measured/ calculated mean LLD of 6.27 cm (1.5 to 18.2 cm). The distraction rate in congenital LLD patients was 0.80 mm/d (0.5 to 1.07 mm/d), and the mean time for bony healing was 140.7 days (61 to 262 d). Three patients in this group developed deficient regenerate that required a bone grafting procedure that was performed at 230, 249, and 262 days postoperative from the initial surgery.

Five patients who undergoing lengthening of 6 segments did not reach their original goal. One patient was undergoing ipsilateral femoral and tibial lengthening when he developed subluxation at his knee postoperative day 41. This resolved with bracing and physical therapy after his lengthening stopped at both segments. Another patient requested to prematurely stop her femoral distraction to decrease the treatment time, in hope that she could enter the upcoming school year as full weight-bearing. One patient’s lengthening stopped 11mm short of the 6.5-cm goal due to what was thought to be premature consolidation. On removing the nail the internal mechanism was found to have failed.

One patient developed 3 complications starting with a postoperative osteotomy site seroma on postoperative day 27. This was resolved by, incision, drainage, and shortening of the distraction gap using the reverse function of the nail to shorten 18mm in the operating room (7 min/mm). As the seroma communicated through a fistula it is not clear if this was infected or just contaminated with skin flora. It was treated as a deep infection by 6 weeks of suppressive antibiotics. On postoperative day 40, the same patient sustained a spontaneous proximal intertrochanteric fracture around the implant that required open reduction and internal fixation with a plate. The nail was left in place and lengthening was continued. After 5 cm of lengthening there was only scant bone in the distraction gap and the lengthening was stopped. The distraction gap did not show bone healing and was therefore bone grafted with reamings from the opposite femur. The nail was exchanged for a nontelescopic locking nail by temporarily applying an external fixator in surgery to maintain the length. Length and alignment were maintained, and 3 months later she was found to have completely healed the defect and returned to activities without restriction.

The other deep infection occurred in a patient who accidentally fell asleep with a heating pad positioned over the distal tibial interlocking screws. This caused a second-degree burn and wound breakdown and infection on postoperative day 21. Despite, antibiotic treatment, she continued to drain. The lengthening was completed and on day 37, she was treated by applying an external fixator, removing the Precice and replacing it with an antibiotic-impregnated cement-coated nail. To maintain length an external fixator was applied first and then removed after locking the nail. She proceeded to heal the distraction gap, losing 5mm of the length gained. She shows no signs of infection. The cement-coated nail was removed on postoperative day 262.

One bilateral femur lengthening patient (who was born with a congenital femoral shortening that had a bad result from a previous shortening of the contralateral femur, required bilateral lengthening to restore the shortened femur to its original length and the congenital femur to match that length) required 2 separate returns to the OR for release of soft-tissue contractures on her congenital short side. She underwent release of the distal fascia lata on postoperative day 23 and then release of the upper fascia lata on day 54. Thereafter, she was able to complete the entirety of the lengthening uneventfully.

Another patient developed symptomatic trochanteric bursitis that required removal of the proximal interlock screws 6 months postoperatively. One patient with tibial hemimelia who had a very hypertrophied fibula and who had a tibia with a history of previous osteomyelitis from an external fixator lengthening has the Precice inserted retrograde into his hypertrophied fibula with the locking screws going across to the tibia. The proximal interlocking screws started to migrate through his osteoporotic bone late in the distraction phase. As he had a discrepancy >6.5 cm we used this opportunity to exchange his nail for a new Precice and continue to lengthen. We achieved a total of 7.5 cm of lengthening with these 2 nails. The bone healed uneventfully.