Does the Use of an Intra-Articular Local Anesthetic Injection During Total Hip Arthroplasty Reduce Patient Reported Pain Scores or Patient Opioid Consumption?

Background: During primary total hip arthroplasty (THA), some surgeons use an intra-articular injection (IAI) containing 200 mg ropivacaine to target postoperative pain. There is no clear consensus on the efficacy of an IAI alone. The purpose of this study is to evaluate the effect of a 200 mg ropivacaine IAI on pain scores, opioid consumption, and mobility for primary THA patients.

Methods: We retrospectively reviewed 571 patients who underwent primary THA at a single institution. Patients were grouped according to those who received a 200 mg ropivacaine IAI and those who did not. Primary outcome measures for this study included pain scores, morphine milligram equivalents (MMEs) dosed, distance of ambulation achieved, and time to ambulation.

Results: The intervention group reported higher average pain scores with activity than the control group (P = .024). The intervention group also required higher MMEs. When striated by hour, a statistically significant uptick in pain started at 16 hours (P = .0009) and persisted to 28 hours (P = .032) in patients receiving a 200 mg ropivacaine IAI. This correlated with an increase in MMEs seen at hour 24 through 32 (P = .003 to P = .012). Level of ambulation, time to ambulation, and distance ambulated did not differ between groups. An IAI of 200 mg ropivacaine also appeared to lead to higher pain scores and higher opioid doses in males.

Conclusion: The IAI does not appear to reduce postoperative pain scores or MMEs dosed for THA patients. More research is needed to look at the utilization and efficacy of intra-articular ropivacaine, especially focusing on functional outcomes and gender differences.