Older Age as a Prognostic Factor of Attenuated Pain Recovery After Shoulder Arthroscopy

Background: Shoulder pain and surgery are common among older adults. However, the extent to which older age affects recovery after shoulder surgery is not well understood. Objective: To assess influence of older age on postoperative recovery factors 3 and 6 months after shoulder arthroscopy. Design: Prospective cohort study. Setting: University-affiliated outpatient orthopedic surgical center. Patients: A convenience sample of 139 persons between 20 and 79 years of age who experienced shoulder pain, had musculoskeletal dysfunction based on imaging and physician assessment, and were scheduled for an arthroscopic shoulder procedure. Main Outcome Measures: Postoperative outcomes were compared among younger, middle-aged, and older adults before surgery and at 3 and 6 months after surgery using analysis of variance modeling. Movement-evoked pain and an experimental laboratory correlate of pain processing were assessed at each time point. The influence of older age on 3- and 6-month pain outcomes were determined via multivariate regression analyses after accounting for preoperative, intraoperative, and postoperative prognostic factors. Results: Older adults had higher movement-evoked pain intensity (F_2,108 = 5.18, P = .007) and experimental pain response (F_2,111 = 7.24, P = .001) at 3 months compared with young and middle-aged adults. After controlling for key prognostic factors, older age remained a positive predictor of 3-month movement-evoked pain (R² = 0.05; standardized [St.] β = 0.263, P = .031) and experimental pain response (R² = 0.07; St. β = 0.295, P = .014). Further, older age remained a positive predictor of movement-evoked pain at 6 months (R² = 0.04; St. β = 0.231, P = .004), despite no age group differences in outcome. Older age was found to be the strongest predictor of 3- and 6-month movement-evoked pain. Conclusion: Older adults may experience more pain related to movement, as well as endogenous pain excitation, in the first few months after shoulder arthroscopy. Future age-related research should consider use of movement-evoked pain intensity and experimental pain response as pain outcomes, as well as the utility of such measures in clinical care.