0
Scientific Articles   |    
Factors Predicting Complication Rates Following Total Knee Replacement
Nelson F. SooHoo, MD1; Jay R. Lieberman, MD1; Clifford Y. Ko, MD, MS, MSHS2; David S. Zingmond, MD, PhD3
1 Department of Orthopaedic Surgery, University of California at Los Angeles, 10945 Le Conte Avenue, PVUB #3355, Los Angeles, CA 90095. E-mail address for N.F. SooHoo: nsoohoo@mednet.ucla.edu
2 Department of Surgery, University of California at Los Angeles, School of Medicine, 10833 Le Conte Avenue, Room 72-215, Los Angeles, CA 90095
3 Department of Internal Medicine, University of California at Los Angeles, School of Medicine, 911 Broxton Plaza, Los Angeles, CA 90095
View Disclosures and Other Information
A commentary is available with the electronic versions of this article, on our web site (www.jbjs.org) and on our quarterly CD-ROM (call our subscription department, at 781-449-9780, to order the CD-ROM).
The authors did not receive grants or outside funding in support of their research for or preparation of this manuscript. They did not receive payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity. No commercial entity paid or directed, or agreed to pay or direct, any benefits to any research fund, foundation, educational institution, or other charitable or nonprofit organization with which the authors are affiliated or associated.
Investigation performed at the Department of Orthopaedic Surgery, University of California at Los Angeles, Los Angeles, California

The Journal of Bone and Joint Surgery, Incorporated
J Bone Joint Surg Am, 2006 Mar 01;88(3):480-485. doi: 10.2106/JBJS.E.00629
5 Recommendations (Recommend) | 3 Comments | Saved by 3 Users Save Case

Abstract

Background: The purpose of this investigation was to expand on previous studies by more fully examining the role of a variety of patient and hospital characteristics in determining adverse outcomes following total knee replacement.

Methods: With use of data from all hospital admissions in California from 1991 through 2001, multiple logistic regression was performed on the information regarding patients treated with total knee replacement. Rates of mortality and readmission due to infection and pulmonary embolism during the first ninety days after discharge were regressed against a variety of independent variables, including demographic factors (age, gender, race, ethnicity, and insurance type), burden of comorbid disease (Charlson comorbidity index), and provider variables (hospital size, teaching status, and surgical volume). A separate baseline probability analysis was then performed to compare the relative importance of all predictor variables.

Results: The sample size for this analysis was 222,684. A total of 1176 deaths (rate, 0.53%), 1586 infections (0.71%), and 914 pulmonary emboli (0.41%) occurred within the first ninety days after discharge. The average age of the patients at the time of surgery was sixty-nine years. Sixty-two percent of the patients were women, and 32% had a Charlson comorbidity index of >0. The significant predictors for complications (p < 0.05) included age, gender, race/ethnicity, Charlson comorbidity index, insurance type, and hospital volume. A baseline probability analysis was performed with the base case considered to be a white woman who was over the age of sixty-five years, had a Charlson comorbidity index of 0, had Medicare insurance, and was treated at a high-volume, non-teaching hospital. For a patient with the baseline case characteristics, the probability of death was 31/10,000, the probability of infection was 59/10,000, and the probability of pulmonary embolism was 41/10,000 in the first ninety days after discharge. Altering the base case by assuming that care was received at a low-volume hospital increased the expected mortality rate by a factor of 26%. Increasing the Charlson comorbidity index to 1 increased the mortality rate by 170%, whereas decreasing the age to younger than sixty-five years lowered the mortality rate by 73%. Hospital volume, comorbidity, and age had similar effects on the expected rates of readmission due to infection and pulmonary embolism.

Conclusions: The effects of age and the Charlson comorbidity index on the baseline probability of adverse outcomes following total knee replacement were shown to be similar to or greater than the effect of hospital volume. This study elucidates and compares the relative importance of the effects of several different factors on outcome. This information is important when considering the conclusions and implications of this type of policy-relevant outcomes research.

Level of Evidence: Prognostic Level II. See Instructions to Authors for a complete description of levels of evidence.

Figures in this Article
    Sign In to Your Personal ProfileSign In To Access Full Content
    Not a Subscriber?
    Get online access for 30 days for $35
    New to JBJS?
    Sign up for a full subscription to both the print and online editions
    Register for a FREE limited account to get full access to all CME activities, to comment on public articles, or to sign up for alerts.
    Register for a FREE limited account to get full access to all CME activities
    Have a subscription to the print edition?
    Current subscribers to The Journal of Bone & Joint Surgery in either the print or quarterly DVD formats receive free online access to JBJS.org.
    Forgot your password?
    Enter your username and email address. We'll send you a reminder to the email address on record.

     
    Forgot your username or need assistance? Please contact customer service at subs@jbjs.org. If your access is provided
    by your institution, please contact you librarian or administrator for username and password information. Institutional
    administrators, to reset your institution's master username or password, please contact subs@jbjs.org

    References

    Accreditation Statement
    These activities have been planned and implemented in accordance with the Essential Areas and policies of the Accreditation Council for Continuing Medical Education (ACCME) through the joint sponsorship of the American Academy of Orthopaedic Surgeons and The Journal of Bone and Joint Surgery, Inc. The American Academy of Orthopaedic Surgeons is accredited by the ACCME to provide continuing medical education for physicians.
    CME Activities Associated with This Article
    Submit a Comment
    Please read the other comments before you post yours. Contributors must reveal any conflict of interest.
    Comments are moderated and will appear on the site at the discretion of JBJS editorial staff.

    * = Required Field
    (if multiple authors, separate names by comma)
    Example: John Doe





    Related Content
    The Journal of Bone & Joint Surgery
    JBJS Case Connector
    Topic Collections
    Related Audio and Videos
    PubMed Articles
    Clinical Trials
    Readers of This Also Read...
    JBJS Jobs
    03/19/2014
    Virginia - VIRGINIA COMMONWEALTH UNIVERSITY MEDICAL CENTER
    01/22/2014
    Pennsylvania - Penn State Milton S. Hershey Medical Center
    04/16/2014
    Ohio - OhioHealth Research and Innovation Institute (OHRI)