Does Weber Classification Predict Patient Reported Outcomes using PROMIS Scores?
Authors: Hadley Steven M. , Peabody John J. , Westvold Sarah , Bergman Rachel , Chang Shaun , Patel Milap , Kadakia Anish R. 
Published: December 2024

Category:

Ankle; Trauma

Introduction/Purpose:

It remains unclear whether ankle fracture pattern as described by the Weber classification—a reproducible method describing the level of fracture with respect to the distal tibiofibular syndesmosis—impacts outcomes. Patient Reported Outcome Measurement Information System (PROMIS) is a validated measure of outcomes after foot and ankle surgery. To our knowledge, no study has compared PROMIS scores between Weber subtypes. Our study thus examines whether Weber fracture subtype impacts surgical outcomes as measured by PROMIS scores. We hypothesize that both Weber B and Weber C fracture patterns will not have a significant difference in PROMIS scores when anatomically reduced during operative repair. This study is the largest evaluating PROMIS scores of Weber fracture subtypes.

Methods:

All 782 patients who underwent surgical repair of an ankle fracture at Northwestern between January 1, 2016 and December 31, 2021 were retrospectively reviewed. Two foot and ankle fellowship trained orthopedic surgeons independently reviewed all radiographs and stratified them by Weber fracture subtype, fixation technique, and reduction quality at final follow-up. Patients with multiple injuries at time of presentation, pilon variants, and who identified as a part of vulnerable populations were excluded. Of the 703 patients included, 218 completed a post-operative PROMIS physical function (PF) and pain interference (PI) computerized adaptive test. Subsequently, only the 200 closed Weber B and Weber C fractures were included for final analysis. The Mann-Whitney U test was used to compare differences in PROMIS scores. The Kruskal-Wallis test was used when comparisons were between three or more groups.

Results:

No significant difference existed between Weber B and Weber C fractures anatomically reduced intraoperatively in terms of mean PF (52.19 ± 9.84 vs. 53.59 ± 9.46, p=0.52) and PI (48.30 ± 8.74 vs. 46.77 ± 7.86, p=0.33). Analysis of those with anatomic reduction at minimum one-year follow-up found no significant difference between Weber B’s and Weber C’s with regard to mean PF (51.46 ± 9.97 vs. 53.67 ± 9.51, p=0.32) and PI (47.76 ± 9.15 vs. 47.68 ± 7.75, p=0.67). Compared to lower BMIs, BMIs of 30 or greater had significantly worse mean PF (p=0.02) and PI (p=0.01). Compared to males, females had worse mean PF (49.88 ± 7.99 vs. 57.92 ± 10.78, p< 0.001) and PI (49.10 ± 8.56 vs. 45.54 ± 8.03, p< 0.01).

Conclusion:

Weber classification remains a reliable method for categorizing fracture subtypes. We can conclude that anatomic reduction and fixation can return patients with both Weber C and Weber B fractures back to population mean functional outcomes. Although Weber C fractures with known syndesmotic injury result in larger soft tissue trauma, anatomic surgical reduction and fixation can achieve equivalent outcomes to patients with lower energy Weber B fractures. BMI, sex, and age affect functional outcomes following operative repair and may help surgeons guide patient expectations during recovery.