**3.3. Effect of intervention**

*Primary outcome:* After the intervention in both, the experimental (US) and the control (ESWT), groups reduce of pain severity on VAS were identified. Pain severity decreased in the right knee, as well as in the left knee by the mean of 3 cm (±1) in the US group, whereas the ESWT group decreased in the right knee by the mean of 4 cm (±2), and in the left knee by the mean of 5 cm (±2). The significant between-group differences on the VAS score in the right knee and the left one were found. The ESWT group had lower score of pain severity on the VAS in the right and the left knees, by the mean of 2 cm (95% CI 1–3, p < 0.001, Cohen d = 0.63), and (95% CI 1–3, p < 0.000, Cohen d = 1.26), respectively. The effect size for pain on VAS was medium in the right knee and large in the left one, as presented in **Table 1**.

*Secondary outcome:* Regarding secondary outcomes, after the intervention in both, the experimental (US) and the control (ESWT), groups improvement of perceived health on WOMAC were identified. The domain "pain" (P) improved by the mean of 4 points (±2), the domain "stiffness" (ST) improved by the mean of 2 points (±2), the domain "physical function" (PF) improved by the mean of 17 points (±10), and the total score on WOMAC improved by the mean of 22 points (±11) in the US group. The ESWT group improved domain P by the mean of 10 points (±4), improved domain ST by the mean of 5 points (±1), improved domain PF by the mean of 29 points (±17), and improved the total score on WOMAC by the mean of 43 points (±20). The significant between-group differences were found. The ESWT group had better scores on the WOMAC for the domain P, by the mean of 6 points (95% CI 3–9, p < 0.000, Cohen d = 1.90), for domain ST, by the mean of 3 points (95% CI 2–5, p = 0.002, Cohen d = 1.90), for domain PF, by the mean of 12 points (95% CI 1–22, p = 0.001, Cohen d = 0.86). Consequently, a significant between-group difference on WOMAC was identified for total score of perceived health, with the mean of 20 points (95% CI 7 to 33, p = 0.002, Cohen d = 1.30) in favor for the

**Figure 1.** Recruitment and flow of participants through the trial.

Effect of Nonpharmacological Therapies on Pain and Health Perception in Patients with Knee Osteoarthritis http://dx.doi.org/10.5772/66477 269


**Table 1.** Characteristics of the participants.

ESWT group. The effect size was large for perceived health on WOMAC, as presented in **Table 1**.

All of the outcomes show that greater reduce of pain severity leads to the better perceived health, which promotes generally better quality of life in the participants from the ESWT group than in the participants from the US group, as presented in **Tables 2** and **3**.
