A nonvel computer-assisted navigation for intraoperative correction of femoral rotation deformity in diaphyseal fractures

Objective To evaluate the clinical effect of a novel computer-assisted navigation technique for intraoperative correction of femoral rotation deformity in diaphyseal fractures. Methods From November 2015 to November 2016, a navigation system (BrainLAB, Germany) was used in antegrade in-tramedullary nailing for 13 patients with femoral shaft fracture to intraoperatively restore the normal length and rotation of the fractured femur. They were 11 men and 2 women, with an average age of 38.2 years. The injury affected the left side in 5 cases and the right side in 8. According to the Winquist Classification, there were 6 cases of typeⅠ, 3 ones of type Ⅱ, 3 ones of type Ⅲ, and one of type Ⅳ. This navigation system allowed the surgeons to detect and set the femoral anteversion (FAV) and length of the injured leg at the desired angle and length of the healthy contralateral femur, precisely matching the contralateral limb and restoring the normal length and rotation of the fractured femur. All the patients underwent postoperative CT scan of bilateral femora for measurement of the lengths and rotations which were compared with the intraoperative values obtained with the navigation system. Results Additional operative time required for computerized navigation averaged 42.8 min (from 35 to 55 min). The mean length difference between the treated and untreated femora was 4.2 mm (from 2 to 9 mm). The FAVs obtained from intraoperative navigation and postoperative CT scan were 34.0°±8.4° and 33.5°±8.3° in the healthy side and 31.2°±8.5° and 32.8°±9.0° in the injured side, showing no significant differences either between the 2 sides or between intraoperation and postoperation (P >0.05). The mean rotational difference between the 2 extremities were 4.8°±1.6° for the navigation and 3.8°±1.9° for the CT scan, showing an insignificant difference (P >0.05). All the incisions healed well with no intraoperative or postoperative complications. Conclusions This novel navigation technique may serve as a reliable tool to accurately correct the rotational malalignment of femoral shaft fractures intraoperatively, but care should be taken in every step of the navigation procedure to reduce complications. Key words: Femoral fractures; Fracture fixation, intramedullary internal; Surgery, computer-assisted; Bone nails