Prevalence of central sensitivity syndromes in patients with hip osteoarthritis before total hip arthroplasty
The number (prevalence) of patients with CSSs is shown in Table 1. Migraine or tension headaches; neck injury, including whiplash; depression; temporomandibular joint disorder; irritable bowel syndrome; anxiety or panic attacks; and FM were present in 8.0%, 7.4%, 5.7%, 5.1%, 1.7%, 1.1%, and 1.1% of patients, respectively. Additionally, 0.6% of patients had a history of restless leg syndrome, multiple chemical sensitivities, and chronic fatigue syndrome. Furthermore, 18.3%, 4.6%, 1.1%, and 0.6% of patients were diagnosed with 1–4 CSSs, respectively. After excluding patients with FM, 41 patients with one or more CSSs and 132 patients without CSSs were analyzed (Fig. 1). Demographic and clinical factors of patients with and without CSSs are shown in Table 2. The proportion of women was higher among patients with CSSs than among those without CSSs (P = 0.010). The CSI score was higher in patients with CSSs than in patients without CSSs (P < 0.001). There were no significant differences in other factors between the two groups.
Correlations between the pre-operative central sensitization inventory score and post-operative clinical outcomes in patients with and without central sensitivity syndromes
Table 3 indicates the correlations between the pre-operative CSI score and post-operative JHEQ and VAS pain scores in patients with and without CSSs. The CSI score correlated negatively with the pain, function, mental, and total scores on JHEQ in patients without CSSs (pain, ρ = − 0.291, P < 0.001; function, ρ = − 0.209, P = 0.016; mental, ρ = − 0.334, P < 0.001; total, ρ = − 0.305, P < 0.001). In contrast, there were no significant correlations between the CSI score and all clinical outcomes in patients with CSSs.
Changes in visual analog scale pain score before and after total hip arthroplasty in patients with and without central sensitivity syndromes
Figure 2 shows the VAS pain scores at 1 month pre-operatively and at 3 and 6 months post-operatively in patients with and without CSSs. At baseline (1 month pre-operatively), VAS pain scores did not significantly differ between the two groups (P = 0.456, Cohen’s d = 0.100). However, VAS pain scores were significantly higher at 3 and 6 months post-operatively in patients with CSSs than in those without CSSs (3 months, P < 0.001, Cohen’s d = 0.788; 6 months, P < 0.001, Cohen’s d = 0.556).
VAS pain scores at 1 month before, and 3 and 6 months after total hip arthroplasty in patients with and without CSSs. ‡P < 0.001. VAS visual analog scale, CSS central sensitivity syndrome, Pre 1 month before surgery, 3m 3 months after surgery, 6m 6 months after surgery.
Differences in Japanese Orthopedic Association Hip Disease Evaluation Questionnaire scores after total hip arthroplasty in patients with and without central sensitivity syndromes
Figure 3 indicates differences in JHEQ scores at 6 months after THA between the two groups. VAS satisfaction on JHEQ was lower in patients with CSSs than in those without CSSs (P < 0.001, Cohen’s d = 0.538). Pain, mental, and total scores on JHEQ were also lower in patients with CSSs than in those without CSSs (pain, P = 0.011, Cohen’s d = 0.400; mental, P = 0.032, Cohen’s d = 0.343; total, P = 0.026, Cohen’s d = 0.393). The functional score did not significantly differ between the two groups (P = 0.174, Cohen’s d = 0.271).
JHEQ scores at 6 months after total hip arthroplasty in patients with and without CSSs. (A) VAS satisfaction on JHEQ. (B) Pain, function, mental, and total scores on JHEQ. *P < 0.05 and ‡P < 0.001. VAS visual analog scale, CSS central sensitivity syndrome, JHEQ Japanese Orthopedic Association Hip-Disease Evaluation Questionnaire.
Differences in Japanese Orthopedic Association Hip Disease Evaluation Questionnaire scores after total hip arthroplast according to the number of central sensitivity syndromes
Table 4 shows the influence of the number of CSSs diagnoses (one or ≥ 2) on JHEQ scores after THA in patients with HOA. Both one and ≥ 2 CSS diagnoses impacted VAS satisfaction on JHEQ (one CSS, β = − 0.181, P = 0.019; ≥ 2 CSSs, β = − 0.175, P = 0.023). Furthermore, the presence of ≥ 2 CSSs was the only factor that significantly impacted the pain score on JHEQ (one CSS, β = − 0.093, P = 0.233; ≥ 2 CSSs, β = − 0.175, P = 0.027). Borderline significance (0.05 < P < 0.18) was found between one CSS and mental score, both one and ≥ 2 CSS diagnoses and total scores (mental score, one CSS, β = − 0.110, P = 0.163, ≥ 2 CSSs, β = − 0.073, P = 0.356; total score, one CSS, β = − 0.105, P = 0.177, ≥ 2 CSSs, β = − 0.122, P = 0.142).