Patient demographic information
Patient demographics and clinical assessments are summarised in Table 1. The mean age was 63.9±11.6 years, and there were 15 men and 85 women. All patients had hip OA, categorised as advanced and terminal stage (Tönnis grade 2–3) on preoperative plain radiography. The mean duration of hip pain was 4.2±4.4 years. The mean VAS score was 3.2±2.7 for pain at rest and 6.1±2.5 for pain on activity. The mean HHS was 47.4±13.0. The mean CSI score was 19.5±11.3. The classification of CS severity level according to the scoring in CSI Part A is shown in Table 2. Seventy-nine patients were classified as subclinical (score: 0–29), 16 were classified as mild (score: 30–39), 3 were classified as moderate (score: 40–49), 2 were classified as severe (score: 50–59), and none were classified as extreme (score: 60–100). Five percent of the patients had a score of 40 or more points. Prevalence rates of CSS diagnoses according to CSI Part B are shown in Table 3.
Table 1. Patients’ demographics and clinical assessments (N=100)
|
Mean±SD or N = %
|
Sex, N
|
Male:15, Female:85
|
Age (years)
|
63.9±11.6
|
Tönnis grade, N
|
0:0 1:0 2:23 3:77
|
Duration of hip pain (years)
|
4.2±4.4
|
VAS pain at rest
|
3.2±2.7
|
VAS pain on activity
|
6.1±2.5
|
HHS
|
47.4±13.0
|
CSI score
|
19.5±11.3
|
Note: All data are reported as mean± standard deviation ratings, unless otherwise indicated.
Abbreviations: SD: standard deviation; VAS: Visual Analogue Scale; HHS: Harris Hip Score; CSI: Central Sensitization Inventory
Table 2. The classification of CS severity level according to the CSI score
CSI score
|
N = %
|
Subclinical (0-29)
|
79
|
Mild (30-39)
|
16
|
Moderate (40-49)
|
3
|
Sever (50-59)
|
2
|
Extreme (60-100)
|
0
|
40 or above
|
5
|
Note: The percentage of patients by central sensitization severity levels and patients with a score of 40 points or higher in Central Sensitization Inventory Part B.
Abbreviations: CS: Central Sensitization; CSI: Central Sensitization Inventory
Table 3. The prevalence rates of patients with a history of CSSs
CSS Diagnoses
|
N = %
|
Restless leg syndrome
|
0
|
Chronic fatigue syndrome
|
0
|
Fibromyalgia
|
0
|
Temporomandibular joint disorder
|
3
|
Migraine or tension headaches
|
3
|
Irritable bowel syndrome
|
3
|
Multiple chemical sensitivities
|
1
|
Neck injury including whiplash
|
4
|
Anxiety or panic attacks
|
1
|
Depression
|
5
|
Number of patients with at least one CSS
|
15
|
Note: The prevalence of patients with a history of each central sensitization syndrome (CSS) and at least one CSS in Central Sensitization Inventory Part B.
Abbreviations: CSSs: Central Sensitization Syndromes
Relationship between radiographic hip OA severity and the CSI score
The CSI score did not differ significantly between patients with Tönnis grades 2 and 3 (P=0.063) in Table 4. There were also no significant differences in other factors, including patient demographics and clinical scores.
Table 4. Comparison between hip OA severities and patients’ demographics and clinical assessments
|
Tönnis grade 2
(N=23)
|
Tönnis grade 3
(N=77)
|
P-value
|
Male/Female, N
|
6/17
|
9/69
|
0.090
|
Age (years)
|
63.7±12.4
|
64.0±11.4
|
0.446
|
Duration of hip pain (years)
|
3.0±2.5
|
4.9±5.7
|
0.310
|
VAS pain at rest
|
2.9±2.7
|
3.2±2.8
|
0.717
|
VAS pain on activity
|
6.0±2.8
|
6.1±2.4
|
1.000
|
HHS
|
48.7±14.1
|
47.1±12.7
|
0.306
|
CSI score
|
15.3±8.2
|
20.8±11.8
|
0.063
|
Note: All data are reported as mean± standard deviation, unless otherwise indicated. Continuous variables were calculated using the Mann-Whitney U test and categorical variables were calculated using the chi-square test. P values <0.05 were considered to indicate statistical significance.
Abbreviations: VAS: visual analogue scale; CSI: Central Sensitization Inventory; HHS: Harris Hip Score
Correlation between characteristics of hip OA patients and CSI score
The CSI score significantly correlated with VAS pain at rest (r = 0.348, P<0.001) in all patients with hip OA (Figure 2). Other factors, including age, duration of hip pain, VAS pain on activity, and HHS, were not significantly associated with the CSI score.
The CSI score in hip OA patients with and without CSSs
Fifteen percent of the patients were diagnosed with one or more CSSs. The CSI score was significantly higher in patients with one or more CSSs (30.00±12.50) than in patients without a CSS diagnosis (17.70±10.00; P<0.001) (Table 5). There were no significant differences in other factors, including patient demographics and clinical scores.
Table 5. Comparison between patients with and without CSSs in patients’ demographics and clinical assessments
|
with CSSs
(N=15)
|
without CSSs
(N=85)
|
P-value
|
Male/Female, N
|
1/14
|
14/71
|
0.327
|
Age (years)
|
59.1±13.1
|
64.8±11.2
|
0.189
|
Duration of hip pain (years)
|
4.1±3.0
|
4.5±5.5
|
0.522
|
VAS pain at rest
|
4.2±3.2
|
3.0±2.6
|
0.120
|
VAS pain on activity
|
6.5±2.8
|
6.0±2.4
|
0.440
|
HHS
|
45.3±10.1
|
47.8±13.3
|
0.364
|
CSI score
|
30.0±12.5
|
17.7±10.0
|
< .001
|
Note: All data are reported as mean± standard deviation, unless otherwise indicated. Continuous variables were calculated using the Mann-Whitney U test and categorical variables were calculated using the chi-square test. Statistically significant P-value (<0.05) is in bold.
Abbreviations: CSSs: Central Sensitization Syndromes; VAS: visual analogue scale; CSI: Central Sensitization Inventory; HHS: Harris Hip Score