, Volume 472, Issue 1, pp 86-97
Date: 30 Apr 2013

Impact of Socioeconomic Factors on Outcome of Total Knee Arthroplasty

Topic
Knee

Abstract

Background

Few data exist regarding the impact of socioeconomic factors on results of current TKA in young patients. Predictors of TKA outcomes have focused primarily on surgical technique, implant details, and individual patient clinical factors. The relative importance of these factors compared to patient socioeconomic status is not known.

Questions/purposes

We determined whether (1) socioeconomic factors, (2) demographic factors, or (3) implant factors were associated with satisfaction and functional outcomes after TKA in young patients.

Methods

We surveyed 661 patients (average age, 54 years; range, 18–60 years; 61% female) 1 to 4 years after undergoing modern primary TKA for noninflammatory arthritis at five orthopaedic centers. Data were collected by an independent third party with expertise in collecting healthcare data for state and federal agencies. We examined specific questions regarding satisfaction, pain, and function after TKA and socioeconomic (household income, education, employment) and demographic (sex, minority status) factors. Multivariable analysis was conducted to examine the relative importance of these factors for each outcome of interest.

Results

Patients reporting incomes of less than USD 25,000 were less likely to be satisfied with TKA outcomes and more likely to have functional limitations after TKA than patients with higher incomes; no other socioeconomic factors were associated with satisfaction. Women were less likely to be satisfied and more likely to have functional limitations than men, and minority patients were more likely to have functional limitations than nonminority patients. Implants were not associated with outcomes after surgery.

Conclusions

Socioeconomic factors, in particular low income, are more strongly associated with satisfaction and functional outcomes in young patients after TKA than demographic or implant factors. Future studies should be directed to determining the causes of this association, and studies of clinical results after TKA should consider stratifying patients by socioeconomic status.

Level of Evidence

Level III, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.

The institution of one or more of the authors has received funding from Biomet Inc (Warsaw, IN, USA) (RLB, AVL, KRB, WGH, RMN), EOS Imaging Inc (Cambridge, MA, USA) (RLB, RMN), Medical Compression Systems, Inc (West Hills, CA, USA) (RLB, RMN), NIH (Bethesda, MD, USA) (RLB, JP), Smith & Nephew, Inc (Memphis, TN, USA) (RLB, JP, CDV, RMN), Stryker Orthopaedics (Mahwah, NJ, USA) (RLB, AVL, JP, CDV, RMN), Wright Medical Technology, Inc (Arlington, TN, USA) (RLB, RMN), DePuy, a Johnson and Johnson company (Warsaw, IN, USA) (JP, WGH), 3 M (St Paul, MN, USA) (JP), Baxter Healthcare Corp (Deerfield, IL, USA) (JP), Musculoskeletal Transplant Foundation (Edison, NJ, USA) (JP), Zimmer Inc (Warsaw, IN, USA) (JP), and Inova Health Care Services (Falls Church, VA, USA) (WGH). The institutions of the authors have received funding from Stryker Orthopaedics in support of this study.
One of the authors certifies that he (RLB) has or may receive payments or benefits, during the study period, an amount of more than USD 1,000,001 from Smith & Nephew, Inc, and an amount of more than USD 1,000,001 from Stryker Orthopaedics.
One of the authors certifies that he (AVL) has or may receive payments or benefits, during the study period, an amount of more than USD 1,000,001 from Biomet Inc, and an amount of USD 10,000 to 100,000 from Innomed, Inc (Savannah, GA, USA).
One of the authors certifies that he (KRB) has or may receive payments or benefits, during the study period, an amount of more than USD 1,000,001 from Biomet Inc.
One of the authors certifies that he (JP) has or may receive payments or benefits, during the study period, an amount of USD 10,000 to 100,000 from Smith & Nephew, Inc, an amount of USD 10,000 to 100,000 from 3 M, an amount of USD 10,000 to 100,000 from Cadence Pharmaceuticals, Inc (San Diego, CA, USA), an amount of USD 10,000 to 100,000 from CeramTec (Laurens, SC, USA), an amount of USD 10,000 to 100,000 from Pfizer (New York, NY, USA), an amount of USD 10,000 to 100,000 from Salient Surgical (Minneapolis, MN, USA), an amount of USD 10,000 to 100,000 from TissueGene (Rockville, MD, USA), and an amount of USD 10,000 to 100,000 from Zimmer Inc.
One of the authors certifies that he (CDV) has or may receive payments or benefits, during the study period, an amount of USD 10,000 to 100,000 from Biomet Inc, an amount of USD 10,000 to 100,000 from Smith & Nephew, Inc, an amount of less than USD 10,000 from ConvaTec (Skillman, NJ, USA), and an amount of less than USD 10,000 from CD Diagnostics (Wynnewood, PA, USA).
One of the authors certifies that he (WGH) has or may receive payments or benefits, during the study period, an amount of USD 100,001 to 1,000,000 from DePuy, a Johnson and Johnson company, and an amount of USD 10,000 to 100,000 from Medtronic.
One of the authors certifies that he (RMN) has or may receive payments or benefits, during the study period, an amount of less than USD 10,000 from Smith & Nephew, Inc, an amount of less than USD 10,000 from Wright Medical Technology, Inc, an amount of less than USD 10,000 from Medtronic (Minneapolis, MN, USA), an amount of less than USD 10,000 from CardioMEMS (Atlanta, GA, USA), and an amount of less than USD 10,000 from Integra LifeSciences (Plainsboro, NJ, USA).
Each author certifies that his or her institution approved the human protocol for this investigation, that all investigations were conducted in conformity with ethical principles of research, and that informed consent for participation in the study was obtained.
All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research editors and board members are on file with the publication and can be viewed on request.
This work was performed at Washington University School of Medicine (St Louis, MO, USA), Joint Implant Surgeons, Inc (New Albany, OH, USA), Rothman Institute of Orthopedics at Thomas Jefferson University (Philadelphia, PA, USA), Midwest Orthopaedics at Rush (Chicago, IL, USA), and Anderson Orthopaedic Clinic (Arlington, VA, USA).