Regional vs. General Anesthesia for Total Knee and Hip Replacement: An Analysis of Postoperative Pain Perception from the International PAIN OUT Registry.

BACKGROUND: Total hip and knee replacements are common surgeries, and an optimal pain treatment is essential for early rehabilitation. Since data from randomized controlled trials on the use of regional anesthesia in joint replacements of the lower extremities are conflicting, we analyzed the international PAIN OUT registry for comparison of regional anesthesia vs. general anesthesia regarding pain and morphine consumption on the first postoperative day.

METHODS: International Classification of Diseases-9 (ICD-9) codes were used to identify 2,346 cases of knee arthroplasty and 2,315 cases of hip arthroplasty between 2010 and 2016 from the PAIN OUT registry. Those were grouped according to anesthesia provided (general, regional, and a combination of both). On the first day after surgery, pain levels and opioid consumption were compared. Adjusted odds ratios (ORs [and 95% confidence intervals (CIs)]) were calculated with logistic regression, and propensity matching was used as a sensitivity analysis.

RESULTS: After adjustment for confounders, regional anesthesia was associated with reduced opioid consumption (OR 0.20 [95% CI 0.13 to 0.30], P < 0.001) and less pain (OR 0.53 [95% CI 0.36 to 0.78], P = 0.001) than was general anesthesia in knee surgery. In hip surgery, regional anesthesia was only associated with reduced opioid consumption (OR 0.17 [95% CI 0.11 to 0.26], P < 0.001), whereas pain was comparable (OR 1.23 [95% CI 0.94 to 1.61], P = 0.1). Results from a propensity-matched sensitivity analysis were similar.

CONCLUSION: In total knee arthroplasty, regional anesthesia was associated with less pain and lower opioid consumption. In total hip arthroplasty, regional anesthesia was associated with lower opioid consumption, but not with reduced pain levels.