Session I - Femur Fractures

Fluoroscopic Control of the Rotational Malalignment in Femoral Nailing

Kyu-Hyun Yang, MD, Dae-Yong Han, MD

Yonsei University College of Medicine, Yongdong Severance Hospital, Seoul,Korea

Introduction: Closed interlocking nailing is a treatment of choicein femoral shaft fractures. Its high union rate and low incidence of majorcomplications expands its indication to the fractures in the metaphysisas well. However, incidence of torsional deformity after intramedullarynailing is relatively high ranging 14 - 19%. Torsional deformity exceeding15° or more may cause pain in the knee and an awkward gait. Only fewstudies were performed to scrutinize the causes of this deformity in theinterlocking nailing, even if the efforts should be made to minimize therotational deformity to less than 15°.

Purpose: Malrotation of the femur following interlocking nailingcontinues to be a problem. We performed the prospective studies to evaluate[1] the accuracy of the fluoroscopic measurement (F) of the femoral anteversion(AV), [2] the change of the AVs during the nailing procedure, [3] the causesof torsional deformity, [4] the technique for correction of the torsionalmalalignment.

Material & Method: Study 1: AVs of sixteen normal and twentynailed femora (two patients sustained bilateral femoral shaft fractures)were measured by F and CT scan. In measuring AV of the femur, posteriormargins of the both femoral condyles were used for one reference line andthe angle of the femoral neck was used as the second reference line. AVsof twenty-three fractured femora were traced during the operation by F tocheck the changes of AVs. All nailings were performed in supine positionunder skeletal traction.

Result: 1: The average AV of the sixteen normal femora was 12.6°and 11.8° in CT scan and F, respectively. The difference between thesetwo methods was 2.4° in average. The average AV of twenty nailed femorawas 15.9° and 14.4° in CT scan and F, respectively. The differencebetween these two methods was 5.5° in average. Perioperative changesof the AV in twenty-three nailed femora were 7.0° in average. 0°- 5°: 11 cases, 6° - 10°: 8 cases, 11° - 25°: 4 cases.Perioperative changes of more than 10° happened in the fractures whichshowed moderate to severe flexion deformities of the proximal fragmentsin the preoperative traction [ X 2 -test, p<0.005 ]. Three out of twentypatients showed the AV difference of l5° or more between both femoraafter the nailing.

Material & Method, Study 2: When the preoperative AV was lessthan 0° or more than 15°, we adjusted the rotational alignment toget the postoperative AVs between 10° - 15° by rotating distal fragmentsinternally or externally. We compared these estimated AVs to postoperativelychecked AVs to see if rotation of the distal fragments worked appropriatelyto correct the rotational malalignment.

Result 2: Fifteen preoperatively measured AVs were out of rangementioned above. Mean correction angle was 11.2°. Average of the differencebetween the estimated and final postoperative AVs was 2.3°. There wasno preoperative flexion deformity of the proximal fragments in this group.No patient had the AV difference of more than 10°.

Discussion: Torsional deformity increases morbidity of the patientsdue to pain in the knee joint and unplanned second operation to fix it.Braten et al. [1993] concluded that torsional deformities were usually establishedduring the operation. However, there was no answer to the questions suchas when this deformity occurs and how to prevent it. Our study clearly demonstratedthe cause of this deformity by tracing AV during the nailing procedure.Excessive positional change of the proximal fragments during the reductionprocess caused the change of the rotational alignment which was measuredpreoperatively. Rotation of the distal fragments can effectively correctthe preoperatively measured rotational malalignment.

Conclusion: AV did not change a lot during the nailing procedureunless there was an excessive flexion deformity of the proximal fragment.If preoperatively measured AV is out of normal range, torsional malalignmentcan be corrected effectively by rotation of the distal fragment.