BACKGROUND: Fear-avoidance variables are present in patients with musculoskeletal pain conditions, such as chronic low back pain (CLBP) and Achilles tendinopathy (AT) and can lead to reduced function and recovery. It is unknown how these variables relate in populations with different etiologies but similar pain provocation mechanisms.

OBJECTIVE: To compare kinesiophobia, pain catastrophizing, and disability between these two groups.

METHODS: Patients with CLBP and those with AT were included. Tampa Scale of Kinesiophobia (TSK-17) and Pain Catastrophizing Scale (PCS-13) were evaluated in both groups. The CLBP group completed the Oswestry Disability Index (ODI) and the AT group completed the PROMIS-29 questionnaire. Gait speed was calculated for each group. Disability outcomes were normalized between groups.

RESULTS: 119 patients in the CLBP group (64 female, 46 ± 8 years) and 83 patients in the AT group (42 female, 48 ± 12 years) were included. Both groups (CLBP, AT) presented with high prevalence of kinesiophobia (67%, 55%) but the CLBP group presented with higher prevalence of pain catastrophizing (22%, 2%). The CLBP group demonstrated higher levels of disability via normalized ODI (MD= 12.4, 95% CI: 9.2, 15.5) but the AT group demonstrated slower gait speed (MD= 0.1 m/s, 95% CI: 0.0, 0.2).

CONCLUSION: Similarly high prevalence of kinesiophobia was found in patients with CLBP and patients with AT. While the CLBP group reported greater prevalence of catastrophizing thoughts and greater disability, the AT group had slower gait speed. Overall, these findings demonstrate that CLBP and AT have similarities that may allow clinicians to learn from one to inform treatment of the other.

CLINICAL TRIAL REGISTRATION NUMBERS: NCT03523325, ISRCTN17115599.