Radiographic Parameters Associated with Insertional Achilles Tendinopathy

Insertional Achilles tendinopathy (IAT) is a common cause of posterior heel pain, and calcaneal morphology and hindfoot alignment may contribute to its development.

To compare ankle and hindfoot alignment parameters between patients with IAT and healthy controls, evaluate their relationship with tendon thickness, and identify independent radiographic predictors.

Retrospective case-control study; Level of Evidence, Level III.

Overall, 313 individuals (116 IAT, 197 controls) were included. Weight-bearing radiographs and magnetic resonance imaging (MRI) were used to measure ankle and hindfoot parameters, including the Fowler-Philip angle, posterior tuberosity inclination angle (PTIA), Chauveaux angle, bump height, and Achilles tendon thickness. Group comparisons, Spearman correlation, and multivariate logistic regression were performed (p < 0.05).

The Fowler-Philip angle, PTIA, Chauveaux angle, bump height, X/Y ratio, and Achilles and Achilles-plantar fascia angles were significantly higher in the IAT group; the calcaneal pitch angle and arch height ratio were lower (p = 0.040 and 0.030). Tendon thickness was increased in the IAT group (p < 0.001) and correlated positively with the Fowler-Philip angle (ρ = 0.61) and PTIA (ρ = 0.58), and negatively with the calcaneal pitch angle and arch height ratio. Independent predictors were the Fowler-Philip angle (odds ratio [OR] 1.26; p < 0.001), PTIA (OR 1.15; p = 0.014), bump height (OR 1.21; p = 0.005), and tendon thickness (OR 1.23; p = 0.002).

The Fowler-Philip angle, PTIA, bump height, and increased tendon thickness were independently associated with IAT and may enhance radiographic diagnosis and structural characterization.

Level III, Retrospective Comparative Study.