Postoperative Pain Mediates the Association Between Peripheral Nerve Blocks and Postoperative Sleep Following Lower Extremity Arthroplasty

Objectives: Despite substantial research showing the bidrectional relationship between sleep and pain, there remains a dearth of research examining the role of perioperative pain management interventions in mitigating postoperative sleep disturbances. This secondary analysis of a prospective observational multisite study examined the association between peripheral nerve block (PNB) use during total knee or total hip arthroplasty (TKA/THA) procedures and postoperative pain and sleep outcomes.

Materials and methods: Adult patients undergoing TKA or THA procedures were recruited from 2 tertiary care facilities. Average pain and sleep disturbance scores were collected preoperatively and at 1- and 2-week postoperatively. Participants were not randomized to receive PNB. Postoperative outcomes were compared based on receipt of PNB during surgery. Structural equation modeling path analysis was utilized to model multiple co-occurring relationships, including mediation pathways between perioperative pain management approaches, pain, and postoperative sleep outcomes.

Results: Of the 197 participants, 53% received PNB. Mediation analyses indicated that PNB was indirectly associated with 1-week sleep disturbance via its effects on 1-week pain intensity (β=-0.02, 95% confidence interval [CI] -0.04, -0.001, P=0.04). In addition, PNB was indirectly associated with 2-week sleep disturbance, via its effects on 1-week pain intensity and 1-week sleep disturbance (β=-0.04, 95% CI -0.07, -0.02, P=0.04). Lastly, PNB was indirectly associated with 2-week pain intensity via its effects on 1-week pain intensity (β=-0.10, 95% CI -0.19, -0.02, P=0.02).

Conclusions: Receipt of PNB during TKA or THA was found to be associated with improved 1-week postoperative pain intensity, which in turn was found to be associated with lower sleep disturbances at both 1- and 2-week postoperative time points. Multimodal opioid sparing pain management interventions, capable of improving postoperative sleep, are vital to improving recovery and rehabilitation following arthroplasty.