Effect of Obesity on Clinical and Radiographic Outcomes Following Reconstruction of Stage II Adult Acquired Flatfoot Deformity

Background: Obesity is a known risk factor for the development of adult acquired flatfoot deformity (AAFD), but obesity's effects on outcomes following AAFD reconstruction are unknown. We hypothesized that obesity would negatively impact outcomes following joint-preserving stage II AAFD reconstruction.

Methods: This retrospective study compared the outcomes of normal-weight (18.5 kg/m(2) ≤ BMI < 25 kg/m(2)), overweight (25 kg/m(2) ≤ BMI < 30 kg/m(2)), and obese (BMI ≥ 30 kg/m(2)) patients after AAFD reconstruction. Clinical outcome measures included the Foot and Ankle Outcome Score (FAOS), Short-Form 12 (SF-12), and Numeric Rating Scale of Pain (NRS Pain) administered preoperatively and at least 1 year postoperatively. Anteroposterior and lateral radiographs were taken preoperatively and at least 6 months postoperatively. Pre- to postoperative changes in outcome measures were assessed within BMI classes. Preoperative, postoperative, and pre- to postoperative changes in outcomes were compared among BMI classes. There were 41 normal-weight patients, 39 overweight patients, and 44 obese patients with a mean age of 56 years, FAOS follow-up of 2.9 years, and radiographic follow-up of 2.1 years. Demographics and reconstructive procedures were comparable among the 3 BMI classes.

Results: All outcomes significantly increased pre- to postoperatively in the 3 groups with the exception of the FAOS Symptoms subscale for normal-weight patients (P = .340) and SF-12 Mental Component score for all 3 BMI classes (P > .999). Preoperatively, obese patients had more symptoms than normal-weight patients, scoring 12 points lower on the FAOS Symptoms subscore (P = .008). Obese patients also scored 11 points lower preoperatively on the SF-12 Overall score (P = .028) and had 31% greater pain than normal-weight patients (P = .003). There were no differences among the 3 BMI classes in any postoperative outcomes assessed.

Conclusion: Although obese patients had significantly worse symptoms, overall health, and NRS pain scores preoperatively, the short-term clinical and radiographic outcomes of stage II AAFD reconstruction were similar for normal-weight, overweight, and obese patients. We suggest that joint-preserving reconstruction remains a viable alternative to fusion of the triple joint complex for the treatment of overweight and obese stage II AAFD patients.

Level of evidence: Level III, retrospective cohort study.