Intraoperative Evaluation of the Anatomic Lateral Distal Femoral Angle and Its Variation due to Positioning

The effect of coronal plane angulation on patient reported outcome measures of operatively treated distal femur fractures: A multi-center prospective evaluation

OBJECTIVES

The goal of this trial was to determine whether coronal plane angulation affects functional and clinical outcomes after the fixation of distal femur fractures.

DESIGN

Multicenter, randomized controlled trial SETTING: 20 academic trauma centers PATIENTS/PARTICIPANTS: 156 patients with distal femur fractures were enrolled. 123 patients were followed 12 months. There was clinical outcome data available for 105 patients at 3 months, 95 patients at 6 months and 81 patients at one year.

INTERVENTION

Lateral locked plating or retrograde intramedullary nailing MAIN OUTCOME MEASUREMENTS: Radiographic alignment, functional scoring including SMFA, Bother Index, and EQ-5D. Clinical scoring of walking ability, need for ambulatory support and ability to manage stairs.

RESULTS

At 3 months, there was no difference between groups (varus, neutral or valgus) with respect to any of the clinical functional outcome scores measured. At 6 months, compared to those with neutral alignment, patients with varus angulation had a worse Stair Climbing score (4.33 vs. 2.91, p = 0.05). At 12 months, the average patient with neutral or valgus alignment needed less ambulatory support than the average patient in varus. Walking distance ability was no different between the groups at any time point. With respect to the validated patient-based outcome scores, we found no statistical difference in in the SMFA, Bother, or EQ-5D between patients with valgus or varus mal-alignment and those with neutral alignment at any time point (p > 0.05). Regardless of coronal angulation, the SMFA trended towards lower (improved) scores over time, while EQ-5D scores for patients with varus angulation did not improve over time.

CONCLUSIONS

Valgus angulation and neutral angulation may be better tolerated in terms of clinical outcomes like stair climbing and need for ambulatory support than varus angulation, though patient reported outcome measures like the SMFA, Bother Index and EQ-5D show no statistical significance. Most patients with distal femur fractures tend to improve during the first year after injury but many remain significantly affected at 12 months post injury.

Limb position affects intraoperative assessment of condylar width

PURPOSE

We sought to define how changes in position and rotation of fluoroscopic imaging may affect the assessment of condylar widening intraoperatively.

METHODS

Thirty-three patients with tibial plateau fractures were prospectively identified and included in this study. Fluoroscopic images of the uninjured tibial plateau were obtained in (1) full extension and (2) slight flexion on foam ramp. Beginning with a plateau view, additional views of the tibial plateau were then obtained by rotating the fluoroscope around the knee in 5 degree increments up to 15 degrees in both internal and external rotation. Measurements of distal femoral condylar width (DFW), distal femoral articular width (FAW), proximal tibial articular width (TAW) and lateral plateau width (LPW) were performed.

RESULTS

LPW was decreased in flexion compared to extension at all degrees of rotation (p = 0.04-0.00001). There was a trend toward increasing LPW with increasing degrees of internal rotation which reached significance at 15˚ of internal rotation when the knee was flexed. On ANOVA, there was a significant difference of LPW with increasing degree of internal rotation when the knee was in flexion (p = 0.008), but not in extension. There were no differences in DFW, FAW, TAW and DFW/TAW at any point though LPW was decreased in flexion at all degrees of rotation. The FAW/TAW ratio was increased in flexion at all degrees of rotation.

DISCUSSION

The knee in flexion will underestimate the measurement of condylar width compared to the knee in full extension, by ~ 2 mm. Rotation of the knee, in comparison, did not have a significant effect on condylar width assessment.

LEVEL OF EVIDENCE

Diagnostic II.

Symmetry and reliability of the anterior distal tibial angle and plafond radius of curvature

INTRODUCTION

Using the radiographs of uninjured extremities as a template for reduction of articular fractures may be beneficial. While there is a significant amount of radiographic data about the relationship of bony landmarks in the hip and knee, there is minimal data investigating the symmetry of lateral measurements in ankles side to side. The aim of this study was to determine if radiographic anatomic differences were evident when comparing bilateral lateral radiographs of uninjured patient ankles.

PATIENTS AND METHODS

A retrospective review of patients with bilateral lateral ankle radiographs for mid- or fore-foot related complaints was performed. Patient demographics and radiographic measurements relating to the anterior distal tibial angle (ADTA) and plafond radius of curvature (ROC) were collected. Paired student's t-test was used to determine similarities.

RESULTS

478 patient radiographs were evaluated and 215 met inclusion criteria. The average ADTA was 84.0° (76°-92°, σ=3.03°) and plafond ROC was 20.4 mm (11.3-37.1 mm, σ=4.01 mm). There was no significant difference between left and right ankles in ADTA (p = 0.08) and ROC (p = 0.06). Females had a significantly smaller ROC and larger ADTA (p<0.001,p = 0.03). Inter-observer and intra-observer reliability were excellent for the ADTA (>0.9) and good for the ROC (>0.75).

CONCLUSION

This study demonstrates that the ADTA and plafond ROC measurements are reliable and symmetrical in patients. Furthermore, females are more like to have a flatter ADTA (closer to 90°) and a smaller ROC of their plafond. These findings confirm that the lateral radiograph of the uninjured ankle may be used as a template for reduction when treating articular injuries of the distal tibia.