Changes in functional status among persons over age sixty-five undergoing total knee arthroplasty.
ABSTRACT This study assessed changes in physical functional status following receipt of total knee arthroplasty (TKA) for patients diagnosed with osteoarthritis (OA) of the knee in a national sample of persons aged 65+ in the United States relative to a sample of similar OA patients who did not receive TKA.
Data from the Health Retirement Survey (HRS) and linked Medicare claims from 1994 to 2006 were used to identify persons with diagnoses of OA of the lower leg who received a TKA (n = 516) and those who did not receive TKA (n = 1756). Predicted probabilities of receiving total knee arthroplasty from logit analysis were used for matching TKA and comparison groups on demographic, socioeconomic, and baseline functional status factors. Functional status measures were: mobility, gross motor function, large muscle, and limitations in activities of daily living (ADL). Average treatment effects of the treated (ATT), which compares changes in functional status between those who received TKA with similar individuals who did not receive TKA, were computed using propensity score matching.
Mobility (average treatment effect of the treated (ATT = 0.315; 95% CI: 0.118-0.512), gross motor function (ATT = 0.314; 95% CI: 0.156-0.472), and ADL limitations (ATT = 0.174; 95% CI: 0.055-0.293), improved among persons receiving TKA relative to the comparison group. Relative to the mean values of the physical function at baseline, mobility, gross motor function, and ADL limitations persons receiving TKA had better functional outcomes than the comparison group by 17.5, 39.3, and 46.9 percent, respectively.
TKA is effective in improving functional status in elderly persons.
- SourceAvailable from: Kris David Rogers[Show abstract] [Hide abstract]
ABSTRACT: The rate of total knee arthroplasty surgery (TKA) is rising in Australia despite varying impacts of TKA on physical function (PF) in population-based studies. There are potentially modifiable risk factors that could enhance PF after TKA, so we evaluated (1) the levels of PF in persons with TKA and the rest of the population, (2) potentially modifiable characteristics of those reporting poor PF after TKA. Nested case-control study. Population-based cohort study in New South Wales, Australia. Members of a large (n=267 151) cohort study recruited by a self-completed, mailed questionnaire from 2006 to 2008. After exclusions (for hip arthroplasty, partial TKA, missing important variables and mismatching TKA status between self-reported and hospital record data), this study included 205 148 participants. Primary outcome, Medical Outcomes Study Physical Function scale (MOS-PF). Secondary outcome, dispensings of analgesics or anti-inflammatory drugs. We found 2916 TKA participants and 202 232 participants with no TKA (confirmed across datasets). Persons with TKA had a lower MOS-PF (59.9, 95% CI 58.5 to 60.6) than those without TKA (83.8, 95% CI 83.7 to 83.9). In the matched analysis, the TKA group had a lower MOS-PF (59.9, 95% CI 59.9 to 62.4) than those without TKA (68.4, 95% CI 67.8 to 69.0). In persons with TKA, lower levels of MOS-PF were associated with low self-rated health, high psychological distress, comorbidity, greater age, recent treatment for osteoarthritis and use of paracetamol. Women had an MOS-PF that was 11.6 points (95% CI 9.5 to 13.8) lower than men. Several modifiable risk factors have been identified to influence PF in persons receiving TKA, with notable differences between sexes. The importance of these risk factors should be examined in incident TKA to test if early identification and intervention for individuals can improve outcomes.BMJ Open 07/2013; 3(7). · 2.06 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: This study used data for 1996-2010 from a U.S. longitudinal sample of elderly individuals from the Health and Retirement Study (HRS) merged with Medicare claims data to assess changes in several dimensions of physical functioning and general health up to 68 months following total knee arthroplasty (TKA) receipt. Using propensity score matching, we assessed outcomes at follow-up for Medicare beneficiaries receiving TKA and a comparable group of beneficiaries with the same osteoarthritis diagnoses (controls). Receipt of TKA was most often associated with improvements in physical functioning, especially in physical functioning measures most directly related to the knee. General health of TKA recipients only improved relative to controls on 1 of the 3 study general health measures. Improvements in physical functioning of TKA recipients persisted in this longer term analysis of outcome in a nationally representative population study.Journal of Aging and Health 07/2013; · 1.56 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: Quadriceps functional impairment accounts for a considerable amount of morbidity after knee replacement. Cruciate-retaining total knee arthroplasty (CR-TKA) may predispose to increased quadriceps demand. We compared bilateral relative quadriceps effort in seven patients with successful unilateral CR-TKA at least 2years after surgery. Dynamic electromyography (EMG) recorded quadriceps activity during walking recorded simultaneously with gait analysis using IDEEA. There was greater EMG activity for the operated knees, both in amplitude (43.08±26.47 vs. 16.02±5.38, P=.0355), and the area under the curve (7231.1±3869.8 vs. 2547.3±1007.9, P=.0267). The onset and duration of muscle activity were similar for both knees (P=.74). CR-TKA demonstrated threefold EMG activity and muscle effort during normal walking. The study suggested that quadriceps functional deficiency is associated with CR-TKA.The Journal of arthroplasty 12/2012; · 2.37 Impact Factor