ABCs of Pain: A Functional Scale Measuring Perioperative Pain in Total Hip Arthroplasty Patients

Abstract

Introduction: Functional pain assessments are critical in total hip arthroplasty. This pilot study investigated a novel functional pain scale-the Activity-Based Checks of Pain (ABCs)-and its correlations with the 0 to 10 numeric rating scale (NRS) and outpatient milligram of morphine equivalents (MMEs) prescribed and needed in the first 2 weeks after total hip arthroplasty.

Methods: ABCs and NRS were collected at the baseline, inpatient, and 2-week follow-up. Primary outcome metrics were needed for pain medication at the time of pain scale completion, MMEs prescribed at discharge, and MMEs taken. Individual ABC functions and composite score were analyzed using Spearman rho and Mann-Whitney U tests.

Results: ABC and NRS scores were greatest preoperatively (n = 39). At each stage, the ABCs correlated with the NRS (ρ = 0.450, P < 0.01; ρ = 0.402, P < 0.05; and ρ = 0.563, P < 0.01). ABC or NRS scores did not correlate with MMEs prescribed. Last in-house NRS correlated with MMEs taken postoperatively (r = 0.571, P < 0.01). Specific ABCs functions-"sitting up" (ρ = 0.418, P < 0.01), "walking in room" (ρ = 0.353, P < 0.05), and "walking outside room" (ρ = 0.362, P < 0.05)-on the day of discharge correlated with MMEs taken.

Conclusion: ABCs scale correlates with NRS. Neither scale correlated with MMEs prescribed at discharge, suggesting pain is undervalued in analgesic planning. Clinicians should assess pain with functions found to correlate with MMEs taken-"sitting up," "walking in room," and "walking outside room."