Abstract
BACKGROUND: Primary total knee arthroplasty (TKA) continues to grow exponentially, with a significant subset of patients requiring staged bilateral procedures. The optimal interval between staged procedures and effective strategies to minimize postoperative pain to enhance rehabilitation and mobility remain poorly understood. METHODS: 160 consecutive patients undergoing staged bilateral TKA between August 2017 and January-2021 was retrospectively reviewed. Patients with a history of chronic opioid dependency were excluded. Baseline demographics, primary outcome measures, including visual analog scale (VAS) pain scores, perioperative opioid utilization (MME/day), and surgical satisfaction were evaluated. All patients had a minimum follow-up of 1-year-postoperatively. All univariate and multivariate statistical analyses were performed with significance given by P < .05. RESULTS: The mean interval between staged TKA was 8-weeks (standard deviation, 4.9-weeks). Preoperative VAS pain scores were significantly higher for the initial TKA, confirming that the more symptomatic knee was addressed first. Despite this, VAS pain scores were significantly increased following second-side TKA at 6-months postoperatively (P = .001). Multivariate analysis identified weekly interval duration between staged procedures as the single-most predictive factor of increased pain following second-side TKA (β = -0.106; P < .01). Female patients were increasingly susceptible to elevated pain levels following second-side TKA (β = 0.372; P = .057). CONCLUSIONS: Postoperative pain increases after second-side TKA in staged-bilateral procedures, despite the more symptomatic side being addressed first. Our study identified weekly interval between staged procedures as the single-most predictive factor of pain, and female patients being predisposed to heightened pain following second-side TKA; implicating nociceptive pathways require weeks to normalize, necessitating gender-specific pain management and extended intervals.