Two-thousand patients completed the survey with valid data from 1,948 patients: 454 (23%) for neck/back, 767 (39%) for hip/knee, 378 (20%) for shoulder/elbow, and 349 (18%) for foot/ankle. Significant differences were observed in sex, education, and overweight/obese proportions across the cohorts (Table ). The greatest proportion of women was found among the foot/ankle group, low educational attainment among the neck/back cohort, and greatest proportion of overweight/obese among the hip/knee cohort. Income differences were marginally non-significant across cohorts, with the proportion of low household income greatest among the shoulder/elbow cohort. Significant age differences were observed across cohorts, with the highest mean age (55.5 years) among the hip/knee. The difference between the oldest (hip/knee) and youngest cohorts (foot/ankle and neck/back) was 6 years, and age ranges were similar across the groups.
Sample demographic and health characteristics, overall and by surgical cohort, including tests of differences across cohorts
Significant differences across the cohorts were found across all health domain scores (Table ). Lower mean scores (i.e. worse scores) were found among the neck/back group for bodily pain, among the hips/knees for physical functioning, and among the neck/back for mental and general health.
From combined analyses (Table ), adjusted for demographic factors, comorbidity and BMI, neck/back patients had worse health domain scores, except for physical functioning, compared to hip/knee patients. Compared to the hip/knee group, foot/ankle patients had better health domain scores, except for general health. The elbow/shoulder group had similar health domain scores to the hip/knee group, except for physical functioning where better scores were observed in the elbow/shoulder group.
Path regression results; cohorts considered together*
Increasing age was associated with worse bodily pain and physical functioning scores, and better mental health scores. Women had worse scores for bodily pain and physical functioning but no sex differences were observed for other health domains. Consistently, a lower level of household income and educational attainment was associated with worse health domain scores. Compared to Whites, Blacks had significantly worse general health scores, and South Asians worse physical functioning and general health scores. Across cohorts, increasing comorbidity was associated with worse health domain scores. Finally, obesity was associated with worse scores for all health domains, except mental health.
From stratified analyses, a number of differential effects on the health domain scores were noted across the cohorts. Results are presented in Tables , , , for each of the four health domains, respectively.
Cohort-stratified path regression results; outcome: bodily pain score*
Cohort-stratified path regression results; outcome: physical functioning score*
Cohort-stratified path regression results; outcome: mental health score*
Cohort-stratified path regression results; outcome: general health score*
For bodily pain (Table ): Increasing age was generally associated with worse scores. While female sex was associated with worse scores, generally, the effects were much larger within elbow/shoulder and hip/knee group, where scores were 4–5 points lower for women, as compared to the foot/ankle group where the difference in scores between men and women was less than 0.5 points. Low income was associated with worse scores, and this effect was most notable for the foot/ankle group, where scores were 11 points lower for the low income group as compared to those with high income. Compared to Whites, Asians tended towards better scores across the cohorts. However, this was much more so among the elbow/shoulder group, where Asians had average scores 16 points higher than Whites. Being overweight or obese was generally associated with worse bodily pain scores. The negative effects of being obese were most pronounced for the foot/ankle group, with average scores 13 points lower for obese vs. normal BMI, compared to 4–7 points lower among the other groups.
For physical functioning (Table ): Women had lower scores in three of the cohorts, (approximately 6–7 points lower for elbow/shoulder and hip/knee, and 4 points lower for neck/back), but this relationship was not seen in the foot/ankle cohort, in which mean scores were approximately 5 points higher among women. The negative effects of low income on physical functioning scores also varied across groups, with scores on average 10–14 points lower for the foot/ankle and elbow/shoulder group, compared to 1–5 points lower for the neck/back and hip/knee groups. Though not statistically significant, individuals of South Asian ethnicity generally had worse physical functioning scores compared to Whites. Again, obesity was associated with worse scores across the groups. However, these negative effects varied from 5 points lower among the elbow/shoulder group, to more than 14 points lower among the foot/ankle group, as compared to normal BMI.
For mental health (Table ): Increasing age was associated with better mental health scores across the cohorts, while low income status was associated with worse scores. Compared to Whites, Asians trended towards better mental health scores. Blacks, however, had worse scores across three of the groups (15 points lower among the foot/ankle cohort), and better scores, nearly 7 points higher on average, within the hip/knee group. Significant effects for overweight and obese status were not found across the groups for mental health scores.
Finally, for general health (Table ): Low income status and lower educational attainment were generally associated with worse scores across the groups. Compared to Whites, Asians trended towards worse scores within the hip/knee and neck/back cohorts, and Blacks towards worse scores within the three groups not including hip/knee, averaging nearly 14 points lower among foot/ankle compared to 6–8 points lower within elbow/shoulder and neck/back groups. South Asians scored on average 10–11 points lower within the elbow/shoulder and neck/back group, while showing no effects within foot/ankle and hip/knee groups. As was the case for each of the other health domain outcomes, higher comorbidity counts were associated with worse scores across all groups. Finally, obesity was associated with worse scores, but more so among the foot/ankle group, where scores were on average 13 points lower, compared to 3–6 points lower among the other cohorts.