Background: Multiple authors have sought to determine what patient characteristics influence outcomes after total knee arthroplasty (TKA). The impact of gender on outcomes after TKA remains controversial. Previous studies had less than 5 years of follow-up after TKA. The aim of this evaluation was to determine what differences in pain, function, and quality of life (QoL) exist between female and male patients 5 years after primary TKA.

Methods: A prospective, multicenter cohort of 11,602 unilateral primary TKA patients (7,284 females and 4,318 males) was prospectively evaluated. All patients were enrolled in the Function and Outcomes Research for Comparative Effectiveness in Total Joint Replacement. Demographic data, musculoskeletal and medical comorbid conditions, and patient-reported outcome measures, including the Knee Injury and Osteoarthritis Outcome (KOOS) and Short-Form (36-item) Health Survey mental component score (MCS) and physical component score (PCS) were collected preoperatively and at 5 years after TKA. Descriptive statistics were generated, and stratified by gender, and differences in pain, function, and QoL between female and male patients were evaluated. Multivariate regression models with a 95% confidence interval (CI) were used to assess the role of patient gender as a predictive factor for KOOS pain and function in daily living (ADL) scores reported 5 years after primary TKA, while adjusting for other variables.

Results: Prior to surgery, female patients reported worse pain (KOOS pain 46 versus 52), function (KOOS ADL 53 versus 59), and QoL (KOOS QoL 26 versus 29) than male patients. The differences in preoperative scores ranged from 2.70 (KOOS QoL) to 6.12 (KOOS ADL). At 5 years after TKA, female patients reported slightly worse pain (87 versus 89), function (85 versus 87), and QoL (74 versus 75) when compared to male patients. The differences in the mean 5-year postoperative KOOS scores (range, 0.99 to 2.73), although statistically significant (P < .001), were clinically negligible. Female patients achieved greater improvement in pain (41 versus 37), function (32 versus 29), and QoL (48 versus 46) scores in comparison to male patients. Female patients also reported lower preoperative PCS global function (33 versus 35) scores, 5-year postoperative PCS scores (45 versus 46), and MCS global mental function scores (52 versus 54). Similarly, the differences in the 5-year postoperative Short-Form (36-item) Health Survey MCS and PCS scores were clinically negligible. Multivariate regression analysis showed that female gender was not independently predictive for either pain (β = -1.08; 95% CI [-1.25 to 1.03] [P = .85]) or function (β = 0.64; 95% CI [-0.51 to 1.79] [P = .28]) 5 years after surgery.

Conclusions: There are no clinically significant gender differences in pain, function, or QoL 5 years after TKA. Female patients typically have worse symptoms prior to surgery, improve more than male patients, and end up with pain, function, and QoL scores clinically equal to male patients. These data can enhance the shared decision-making process between female patients and surgeons and assist in setting appropriate patient expectations prior to TKA.