The Effects of Total Knee Arthroplasty on Physical Functioning in the Older Population

Duke University, Durham, North Carolina 27708-0088, USA.
Arthritis & Rheumatology (Impact Factor: 7.76). 10/2008; 58(10):3166-71. DOI: 10.1002/art.23888
Source: PubMed


Clinical research provides convincing evidence that total knee arthroplasty (TKA) is safe and improves joint-specific outcomes. However, higher-level functioning associated with self care and independent living has not been studied. Furthermore, most previous studies of the effects of TKA relied on relatively small clinical samples. We undertook this study to estimate the effects of TKA on 3 levels of physical functioning in a national sample of older adults.
Data were obtained from the Medicare Current Beneficiary Survey from 1992 to 2003. Medicare claims data identified participants with osteoarthritis of the knee who received TKA (n=259) or no TKA (n=1,816). Propensity scores were used to match treatment and no-treatment groups according to demographic characteristics, comorbid conditions, and baseline functioning. Three levels of physical functioning were examined as outcomes of TKA. These levels were represented by items on the Nagi Disability Scale, the Instrumental Activities of Daily Living (IADL) Scale, and the Activities of Daily Living (ADL) Scale. These items were measured after TKA and at comparable intervals for the no-treatment group. Average treatment effects were calculated for relevant Nagi Disability Scale, IADL Scale, and ADL Scale tasks.
Between baseline and outcome assessments, TKA recipients improved on all 3 levels of physical functioning; the no-treatment group declined. Statistically significant average treatment effects for TKA were observed for one or more tasks for each measure of physical functioning.
TKA is associated with sizeable improvements in 3 levels of physical functioning among elderly Medicare beneficiaries.

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    • "While numerous studies have shown that individuals undergoing TKR on average experience an improvement in function [2] even compared with those who have OA but do not undergo TKR [10], we are unaware of any studies which have addressed whether the number of TKR’s in a group with OA are sufficient to affect the overall impact of disease on function limitation in all those with disease. Even if those with TKR have better function than those with knee OA without TKR, the difference is not necessarily a large one and may not be sufficient to have an effect on the population of persons with knee OA until a large percentage of persons with knee OA get replacements. "
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    ABSTRACT: Background To examine if different rates of total knee replacement (TKR) in two similar cohorts with symptomatic knee osteoarthritis (OA) were associated with different functional impact of disease. Methods Subjects from the Multicenter Osteoarthritis Study (MOST) and the Osteoarthritis Initiative (OAI), persons with or at high risk of OA, had knee radiographs, completed Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) surveys and had TKRs confirmed at each visit. At each visit, subjects were defined as having symptomatic OA (SxOA) if ≥ one knee had pain and radiographic OA or if they had a TKR. WOMAC function scores at each visit were compared by analysis of covariance adjusting for age, sex, body mass index, race, site, depression, comorbidity, painful leg joints and knees affected. Post-TKR function scores were imputed to estimate scores that would have been present without TKR. Results Subjects with SxOA (n > 750 in MOST and in OAI) had a mean age 66 to 67 years; most were women and were White. Subjects were followed 4–5 years. Among those with SxOA, more TKRs were done in MOST (35%) than OAI (19%). Adjusted mean WOMAC function (0–68, 68 = worst) improved from 26.9 to 21.9 in MOST and from 24.5 to 22.0 in OAI (difference between MOST and OAI in change in WOMAC function, p = .01). Estimates of function without TKRs showed function would not have changed in MOST (23.2 at baseline to 22.4). Conclusions Functional status of subjects with knee OA in MOST improved more than in OAI, probably because of higher rates of TKRs. The decline suggests that TKR diminishes the functional impact of OA in the community.
    BMC Musculoskeletal Disorders 05/2014; 15(1):145. DOI:10.1186/1471-2474-15-145 · 1.72 Impact Factor
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    • "In the US, over 500,000 total knee arthroplasty (TKA) surgeries are performed each year for severe knee osteoarthritis and that number is expected to increase sevenfold over the next two decades [1]. Most TKA recipients experience a successful reduction of their knee pain and an improvement in knee function [2] [3]. Unfortunately, not all TKA recipients experience substantial improvements in their levels of pain, functional status, nor overall health-related quality of life. "
    Dataset: 353149 (2)

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    • "Total Knee Arthroplasty (TKA) is a proven treatment for severe joint pain in osteoarthritis of the knee. This intervention is well established in the elderly with predictable and reproducible results [1] [2] [3] [4]. However, many orthopaedic surgeons are reluctant to perform TKA in younger patients due to the concern that high levels of activity may lead to increasing wear and aseptic loosening. "

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