Patients Perceive Subtalar Osteoarthritis to Be as Severe as Ankle Osteoarthritis: A Prospective Cohort Study

Research Type: Level 2 - Prospective comparative study, Meta-analysis of Level 2 studies or Level 1 studies with inconsistent results Introduction/Purpose: The literature has demonstrated that ankle osteoarthritis (OA) is at least as disabling as end-stage hip and knee arthritis, and comparable to that of congestive heart failure and end-stage chronic kidney disease. To date, there is no evidence analyzing the extent of disability caused by hindfoot osteoarthritis or how its severity is perceived by patients compared with ankle osteoarthritis. Methods: Patients were recruited from the same hospital between 2003 and 2023. Hindfoot and ankle osteoarthritis patients were respectively recruited from a prospective randomized controlled trial and a retrospective cohort study involving individuals who required a subtalar fusion or an ankle replacement. The inclusion criteria were patients over 18 years or older who agreed to participate in these studies. The exclusion criteria included patients without a recorded AOS score in the preoperative evaluation or those with a history of prior fusions or replacements in the hindfoot or ankle. For the hindfoot group, concomitant ankle osteoarthritis was also excluded. Patient characteristics (age, diabetes history, BMI, and smoking history) were compared between groups. The AOS score was compared using the Mann-Whitney test, and a robust linear regression was performed to adjust for potential confounders and analyze for interactions. Results: In 234 individuals (178 with ankle OA vs. 56 with hindfoot OA) statistically significant differences were observed in the baseline characteristics age (median ankle OA: 67.05 ± 11.36 versus hindfoot OA: 59 ± 13.2, p-value 0.01), smoking (ankle OA: 6.18% versus hindfoot OA: 50%, p-value 0.01), and BMI (median ankle OA: 27.4 ± 5 versus hindfoot OA: 29.5 ± 6.5, p-value 0.04). There were no significant univariate associations between these variables and the AOS score. There was no difference in the AOS score by OA location (median ankle OA: 59.88, IQR 46.33–72.62 versus hindfoot OA: 57.56, IQR 46.77–69.67; p-value 0.81). Robust linear regression showed no association of OA location, age, and smoking status with the AOS score. However, a significant positive association emerged for BMI. Conclusion: This study revealed that hindfoot osteoarthritis causes a level of discomfort and disability comparable to that of ankle osteoarthritis, as assessed by the AOS score. In addition, higher BMI was independently associated with greater discomfort and disability, underscoring the importance of weight management in patients with lower-limb osteoarthritis, regardless of its location.