Biopsychosocial Influences on Shoulder Pain: Analyzing the Temporal Ordering of Postoperative Recovery

Shoulder surgery is a primary intervention for shoulder pain, yet many individuals experience persistent postoperative pain. Previously, we found individuals categorized as having a high-risk phenotype (comprised of COMT variation and pain catastrophizing) had approximately double the chance of not reaching a 12-month pain recovery criterion. As a means to better understand the development of persistent postoperative shoulder pain, this study advanced our previous work by examining temporal ordering of postoperative shoulder recovery based on potential mediating factors, and expansion of outcomes to include movement-evoked pain and shoulder active range of motion. Before surgery, individuals were categorized as either high-risk (high pain catastrophizing, COMT-genotype linked to low enzyme activity [n = 41]) or low-risk (low pain catastrophizing, COMT-genotype linked to normal enzyme activity [n = 107]). We then compared potential mediating variables at 3, 6, and 12 months postoperatively 1) endogenous pain modulation defined by a conditioned pain modulation paradigm; and 2) and emotion factors such as anxiety, fear of movement, and depressive symptoms. At 3 months, the high-risk subgroup had higher fear and movement-evoked pain, and causal mediation analysis confirmed the direct effect of risk subgroup on 12-month movement evoked pain. However, baseline to 12-month change in depressive symptoms were found to mediate 53% of the total effect of risk subgroup on 12-month movement-evoked pain. This study introduces potential temporal components and relationships to the development of persistent postoperative shoulder pain, which future studies will confirm and assess for potential therapeutic targets. PERSPECTIVE: This study expands upon postoperative shoulder recovery measures to include movement-evoked pain and depressive symptoms, and provides preliminary indication of temporal ordering to postoperative shoulder recovery for a preidentified high-risk subgroup. Future studies will distinguish temporal components of shoulder surgery that may optimize treatment targets of postoperative recovery.