Upon admission to the hospital for surgery to replace large joints (knee or hip joints) and diagnosis with osteoarthritis of the knee or hip joint (M15.0, M16, M17), patients with comorbidities underwent 20-minute psychological counseling (PC) session. During PC the levels of depression (F32.0, F32.1 or F32.9) and anxiety (F41.0, F41.1, F41.3, F41.8 or F41.9) were assessed using the STAI and HADS questionnaires. In the experimental group, patients with identified increased levels of depression or anxiety underwent a session of rational-emotional-behavioral therapy, which aimed to modify incorrect thinking patterns. The level of anxiety and depression was reassessed after the surgery.

Upon admission to the hospital for surgery to replace large joints (knee or hip joints) and diagnosis with osteoarthritis of the knee or hip joint (M15.0, M16, M17), patients with comorbidities underwent 20-minute PC. During PC, their levels of depression (F32.0, F32.1 or F32.9) and anxiety (F41.0, F41.1, F41.3, F41.8 or F41.9) were assessed using the STAI and HADS questionnaires. In the first control group, patients with identified increased levels of depression or anxiety did not receive REBT therapy. The level of anxiety and depression was reassessed after the surgery.

Upon admission to the hospital for surgery to replace large joints (knee or hip joints) and diagnosis with osteoarthritis of the knee or hip joint (M15.0, M16, M17), patients without comorbidities underwent 20-minute PC session. During PC the levels of depression (F32.0, F32.1 or F32.9) and anxiety (F41.0, F41.1, F41.3, F41.8 or F41.9) were assessed using the the STAI and HADS questionnaires. In the second control group, patients with identified increased levels of depression or anxiety underwent a session of rational-emotional-behavioral therapy, which aimed to modify incorrect thinking patterns. The level of anxiety and depression was reassessed after the surgery.

During REBT in patients with osteoarthritis and concomitant diseases with diagnosed depression or anxiety before arthroplasty the patients learn how to manage their irrational or unhealthy emotions, thoughts, and behaviors.

Each subscale uses a 4-point Likert scale with a range from 1 ("not at all" for S- or "almost never" for T-Anxiety) to 4 ("very much so" for S- and "almost always" for T-Anxiety). Reverse scoring is used for anxiety-absent items (e.g., "I feel calm" or "I am happy"), and therefore, a higher score indicates more severe anxiety with a potential range from 20 to 80 for each subscale. According to the developer scores of 20-39, 40-59, and 60-80 indicate low, moderate, and high anxiety, respectively. Normative values are available in the manual.

The HADS is a self-report rating scale of 14 items on a 4-point Likert scale (range 0-3). with a range from 0 ("not at all") to 3 ("most of the time"). Reverse scoring is used for items with positive wording (e.g., "I still enjoy the things I used to enjoy"). The total score is the sum of the 14 items, and for each subscale the score is the sum of the respective seven items (ranging from 0-21). A score of 8-10 should be classified as a mild disorder, 11-15 as a moderate disorder, and 16 or more as a severe disorder.