Factors Predicting Frequency and Severity of Postoperative Pain After Arthroscopic Rotator Cuff Repair Surgery

Abstract

Background: Postoperative pain after arthroscopic rotator cuff repair (RCR) is difficult to predict and manage. The experience of pain is thought to be influenced by a range of different factors. Determining which patient factors contribute to the pain may help us to better understand and manage it. Purpose: To evaluate the preoperative patient characteristics that may be predictive of, and correlated with, postoperative pain after arthroscopic RCR. Study Design: Cohort study; Level of evidence, 3. Methods: The study evaluated 2172 patients who underwent an arthroscopic RCR between February 2004 and December 2015. Pain frequency and severity were measured preoperatively and at 6 weeks after surgery using a modified L’Insalata questionnaire with Likert scales. This 6-week time point was chosen as previous studies have shown patients rank this time point as high in terms of pain after RCR. Logistic regression analysis was conducted to examine the relationship between postoperative pain scores and preoperative pain scores, age, sex, tear size, strength, level of sporting and work activity, and work-related injury status. Results: The severity of preoperative pain at night ( r = 0.33; P < .001), preoperative pain at rest ( r = 0.32; P < .001), and frequency of extreme pain ( r = 0.31; P < .001) were the strongest independent associations with the frequency of pain at 6 weeks postoperatively. Other associations with postoperative pain frequency included reduced liftoff strength ( r = −0.21; P < .001), work-related injury status ( P < .001), younger age ( P = .001), and female sex ( P = .04). Tear size was inversely related with pain severity ( R2 = 0.85). The severity of preoperative pain had the strongest independent association with the severity of postoperative pain at 6 weeks after surgery ( r = 0.35; P < .001). Other associations with postoperative pain severity included increased patient-ranked preoperative stiffness ( P < .001), a poorer impression of one’s shoulder ( P < .001), reduced level of sporting activity ( P < .001), and work-related injury status ( P < .001). Conclusion: Multiple risk factors have been identified for postoperative pain after RCR, the strongest of which is preoperative pain. However, of note, the magnitude of the correlations between preoperative severity and frequency of pain and postoperative severity and frequency of pain were found to be weak to moderate ( r = 0.30-0.35). This suggests that while preoperative pain and its severity are associated with postoperative pain, other factors are likely involved in predicting pain. Smaller tear size, younger age, female sex, and work-related injuries were also associated with postoperative pain at 6 weeks after surgery.