SLR - August 2018 - Gerald Merritt
Reference: Chan, J., Greenfield, S., Soukup, D., Do, H., Deland, J. and Ellis, S. (2015). Contribution of Lateral Column Lengthening to Correction of Forefoot Abduction in Stage IIB Adult Acquired Flatfoot Deformity Reconstruction. Foot & Ankle International, 36(12), pp.1400-1411. (Chan et al., 2015)
Scientific Literature Review
Reviewed By: Gerald Merritt, DPM
Residency Program: Westside Regional Medical Center – Plantation, FL
Podiatric Relevance: Lateral column lengthening (LCL) is an important aspect to adult acquired flatfoot reconstruction. Many different techniques have been discussed in podiatric and orthopedic literature. Many authors have suggested using a graft length of 8mm to 12mm. However, there have not been any clinical studies to date that quantify how the lateral column lengthening size affects correction. This study demonstrates that the lateral incongruency angle is a reliable and easy method to assess the correction in forefoot abduction.
Methods: This retrospective comparative study overviewed 41 patients who underwent an Evans-type LCL for stage II flatfoot reconstruction. Pre-operative and post-operative anteroposterior radiographs were taken and were reviewed to determine the correction in forefoot abduction as measured by the talonavicular coverage, talonavicular uncoverage percent, talus-first metatarsal angle and lateral incongruency angle. The lateral incongruency angle was defined as the angle between a line connecting the lateral aspect of the talar and navicular surfaces and a line connecting the lateral aspect of the talar neck and talar articulation surface. Fourteen other variables were also evaluated for association in forefoot abduction.
Results: Of the 41 patients that were evaluated only two variables effected the lateral incongruency angle. These variables were weight and the amount of lateral column lengthening. However further analysis revealed that the lateral column lengthening was the only predictor in change to the lateral incongruency angle. It was found that in normal patients that the lateral incongruency angle was approximately 6 degrees. Utilizing the linear equation it was found that every millimeter of lateral column lengthening there was a 6.8 degree change in lateral incongruency angle.
Conclusion: The authors conclude that the lateral incongruency angle can serve as a very valuable preoperative measurement to help surgeons correct forefoot abduction.