Sagittal alignment measurements in operatively treated distal femur fractures [Poster #P483] Conference Poster uri icon

abstract

  • INTRODUCTION: Open reduction and internal fixation (ORIF) is presently the treatment of choice for distal femur fractures. However, with the increasing popularity of less invasive stabilization methods, there is an increasing need for reliable radiographic methods for assessing adequate reduction, particularly in the sagittal plane. METHODS: This is a retrospective study of 67 adult patients without prior knee arthroplasty and with distal femur fractures treated with internal fixation. Research staff attempted each of seven previously validated measurements utilizing radiographic landmarks. Measurements were attempted on the most adequate postoperative lateral image of the distal femur. Measurement comprised the angle subtended by the anterior femoral cortical line and a line between two of six different radiographic landmarks. The Blumensaat Line-Shaft Angle (BLSA) was also recorded. The average measurement for each available data point was recorded in degrees, as was the success of obtaining each measurement point. Demographic data were also collected. Intra-observer reliability was calculated. RESULTS: In only seven of 67 patients (10.4%) were all seven measurements obtainable. The average number of obtainable data points (out of seven) was 4.59. Two landmarks (AD and BD) were measurable in 95.5% and 92.5% of patients, respectively. Both measurements involved the proximal rim of the femoral condylar articular surface. Intraobserver reliability was calculated for these two variables, both of which were statistically significant and moderate to strong in correlation, respectively: AD: R = 0.53254 (P = 0.01891); BD: R = 0.73039 (P = 0.00087) DISCUSSION AND CONCLUSION: Historically, reliable imaging of distal femur fractures to determine proper reduction has been difficult to obtain. One recent study has attempted to describe intraoperative landmarks for assessing sagittal plane alignment of distal femur fractures. However, to our knowledge, no attempt at reproducible measurement of sagittal plane distal femoral anatomy after operative fixation has been performed. Despite the possibility of distal femoral implants obscuring radiographic measurements of sagittal plane alignment, two angular measurements were obtainable in over 90% of included patients. This data suggests that the proximal rim of the femoral condylar articular surface is the most easily identifiable of five different radiographic landmarks in patients treated with distal femoral internal fixation. These two most reliable measurements may be used to guide intraoperative decision making with the use of standard image intensification.

publication date

  • 2016