Association of posterior calcaneal enthesophytes with ultrasonographic Achilles tendon abnormalities: A comparative radiographic and ultrasonographic study

Abstract

Achilles tendinopathy may be accompanied by tendon thickening and fibrillar pattern abnormalities on ultrasonography. Posterior calcaneal enthesophytes are frequently identified on lateral ankle radiographs, but their relationship with Achilles tendon abnormalities remains unclear. The aim of this study was to assess the associations of posterior calcaneal enthesophyte presence and length with ultrasonographic findings of the Achilles tendon. A hospital-based cross-sectional study included 46 patients with heel or posterior ankle pain, with 54 ankles used as the unit of analysis. Enthesophyte presence and length were assessed using lateral ankle radiography, whereas Achilles tendon thickness and fibrillar pattern abnormalities were evaluated using ultrasonography. Associations were analyzed using Fisher’s exact test, and continuous measurements were compared using the Mann–Whitney U test. Posterior calcaneal enthesophytes were identified in 40.7% of ankles. Tendon thickening and fibrillar pattern abnormalities were observed in 1.9% and 9.3% of ankles, respectively. Enthesophyte presence was not significantly associated with tendon thickening (p=0.407), and tendon thickness did not differ significantly between ankles with and without enthesophytes (p=0.063). Fibrillar pattern abnormalities were observed in 22.7% of ankles with enthesophytes and in none of the ankles without enthesophytes (p=0.008). An enthesophyte length ≥0.85 mm was associated with fibrillar pattern abnormalities (p=0.005) but not tendon thickening (p=0.370). Median enthesophyte length was greater in ankles with fibrillar abnormalities than in those without abnormalities (2.50 mm vs 0.00 mm; p=0.005). This study highlights that posterior calcaneal enthesophytes were associated with fibrillar pattern abnormalities but not tendon thickening. Since ultrasonographic abnormalities were uncommon and clinical outcomes were not assessed, these preliminary cross-sectional associations require confirmation in larger prospective studies.