While there are many factors known to predict the outcomes of hip and knee arthroplasty procedures, there is a growing interest in predictors that take into consideration the social and psychological preparedness of patients prior to surgery. This study's aim was to determine whether patients' preoperative social support and pain catastrophizing characteristics are independently associated with the outcomes of postoperative length of stay or discharge disposition following primary total hip arthroplasty (THA) and total knee arthroplasty (TKA).
Data on a prospective sample of 189 THA and TKA adult patients using the pain catastrophizing scale and the medical outcomes study social support expectation score were analyzed. Demographic characteristics, such as age, gender, and race (Caucasian versus non-Caucasian), which served as covariates, were also collected. Bivariate associations between our outcome variables and covariates using Pearson's and Spearman's rank correlation coefficients and Mann Whitney U test for continuous variables (age, MOS-SSS) and Chi-squared tests for categorical variables (gender, race, ethnicity, procedure, catastrophizing) were employed. Statistical significance was set at p ≤ 0.05. Data are presented as median with range values, frequencies with percentages, or adjusted odds ratios (OR) and betas (β) with 95% confidence intervals (CI).
There were 73 (38.6%) patients categorized as catastrophizers. Median score for social support was 90.8 (range: 3.9 to 100). No statistically significant associations between pain catastrophizing or social support were observed for length of stay (β: 0.03, 95% CI: - 0.24-0.31, p = 0.81; β: - 0.002, 95% CI: - 0.010-- 0.006, p = 0.58) and discharge disposition (OR: 1.15, 95% CI: 0.51-2.55, p = 0.74; OR: 0.99, 95% CI: 0.97-1.01, p = 0.37). Significant associations with discharge to a rehabilitation facility included non-Caucasian (OR: 5.4, 95% CI: 2.4-11.8, p < 0.001) and longer length of stay (OR: 1.6, 95% CI: 1.01-2.4, p = 0.04). Female gender and non-Caucasian were associated with longer length of stay (β: 0.3, 95% CI: 0.03-0.6, p = 0.03; and β: 0.4, 95% CI: 0.1-0.6, p=0.008, respectively).
We did not find a significant association between pain catastrophizing behavior and level of social support with length of stay or discharge disposition.