According to a cross-sectional, observational study published in Rheumatology International, patients with PsA who self-reported Achilles tendon (AT) involvement experienced persistent pain, contributing to severe functional impairment and lower PsA-related QOL.

From January 2020 to February 2022, Aimie Patience, PhD, and colleagues recruited 33 adults with PsA, with and without current unilateral/bilateral self-reported AT pain. Investigators divided participants into three equal groups: patients with PsA with AT pain (PsA+AT), patients with PsA without AT pain, and age and gender-matched healthy controls. Age, BMI, and gender did not vary significantly between the groups.

The team employed a comprehensive approach to evaluate the AT, including clinical and ultrasound examination, performance-based evaluations (bilateral heel raise test and 10-minute walk), and patient-reported outcome measures such as the Victorian Institute of Sport-Assessment-Achilles (VISA-A).

The group with AT pain had a meaningfully longer disease duration than the group with no AT pain (P=0.019). Within the AT pain group, the duration of AT symptoms varied. Notably, three participants experienced symptoms 2 to 6 years before their PsA diagnosis.

There were significant group variances regarding the presence of AT involvement on Leeds Enthesitis Index (P=0.001), self-reported current AT pain (P<0.001), self-reported AT morning stiffness (P<0.001), pain on the passive dorsiflexion of the ankle (P=0.011), and pain on the resisted plantarflexion of the ankle (P=0.003). Researchers also noted that the heel raise repetition rate was significantly different between PsA groups (P=0.005) and between both PsA groups and healthy controls (P=0.008).

“There were significant differences in the structure and function of the AT between groups which could be clinically relevant when assessing and managing AT pain in people with PsA, although the presence of these features in the general population also needs to be considered,” Dr. Patience and colleagues said.

Of note, a clinical examination only detected two of seven cases with ultrasound ‘active’ enthesitis. This finding was in line with previous evidence that suggests “a poor correlation between clinical assessment for AT enthesitis (palpatory tenderness) and ultrasound findings.”

“AT pathology can often extend beyond the enthesis in PsA. Therefore, identification of the origin of pain using ultrasound as a supporting tool (ie, structural, inflammatory, or mid-portion pathology) could help guide more targeted therapy,” the researchers concluded. “The results of this study add to a body of literature suggesting AT pathology in PsA cannot be fully assessed by clinical examination alone.”