Prevalence and Predictors of Symptom Resolution and Functional Restoration in the Index Knee Following Knee Arthroplasty: A Longitudinal Study

Publication date: Available online 9 January 2018
Source:Archives of Physical Medicine and Rehabilitation
Author(s): Daniel L. Riddle
ObjectivesTo determine the prevalence of a one- to two-year postsurgical pain-free state and pain plus symptom-free state as well as function restoration following knee arthroplasty (KA). A second purpose was to identify predictors of these outcomes.DesignAn inception cohort from the Osteoarthritis Initiative (OAI) dataset, a nine-year NIH funded cohort study of persons with or at high risk for knee osteoarthritis was studied.SettingSubjects were recruited from the communities of four sites in the Midwest, Eastern and Southeastern United States.ParticipantsConsecutive persons from the OAI who underwent KA over the first 8 years of study were included. The average age of the sample was 67.95 (sd = 8.5) years and 61.4% were female. Postoperative data were collected, on average, 558 days (SD = 114) following surgery.Main Outcome MeasuresA composite pain score included the Western Ontario McMaster Universities' Osteoarthritis Index (WOMAC) Pain scale and two generic pain rating scales. Composite pain plus other symptoms scores included the three pain scales, a stiffness scale and, in addition, the Knee injury and Osteoarthritis Outcome Score (KOOS) Symptoms scale. The WOMAC Function scale was used to quantify functional status. Prevalence estimates and predictors of a pain-free state, symptom-free state and a fully functioning state were determined.ResultsA sample of 383 persons with KA was studied and of these, 34.1% (95%CI = 29.3%, 39.2%) had a composite score of 0 for pain. A total of 14.1% (95%CI = 10.8%, 18.1%) had a composite score of 0 indicating a symptom-free state, while 29.0% (95% CI = 24.4%, 34.0%) achieved a score of 0 for WOMAC Function.ConclusionThe prevalence of complete pain relief was 34%, complete pain and symptom relief was 14%, and complete functional restoration was 29% following KA. Persons who are older and persons with lower (better) WOMAC pain scores were more likely to be pain-free following surgery. These data collected from a community-based sample have the potential to inform clinicians screening patients for KA consultation in a shared decision-making discussion to better align expectations with likely outcome.



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