Activity Levels, Physical Activity Participation After TKA
Activity Levels, Physical Activity Participation After TKA
This study included 369 patients with TKA, and we performed a retrospective analysis of prospectively collected data. The inclusion criteria were: a diagnosis of osteoarthritis, TKA with follow-up care and the TKA was performed from 1 to 3 years before the survey. In total, 567 patients were included as candidates and were mailed the postal questionnaire. Of these patients, 369 (65%) returned the completed questionnaire or responded to a telephone survey (35 patients; 6%) at a mean of 2 years (range, 1 to 3 years) after surgery (Figure 1). There were 339 (92%) female patients and 30 (8%) male patients. The mean age was 68.8 years (range, 50–83 years). The mean preoperative height and weight were 153.3 cm (range; 140–179 cm) and 64.5 kg (range, 42–92 kg), respectively. The mean body mass index (BMI) was 27.4 kg/m (range, 19.3–39.1 kg/m). The bilateral procedure was performed in 251 (68%) patients and the unilateral procedure in 118 (32%) patients.
(Enlarge Image)
Figure 1.
Flowchart detailing inclusion and exclusion criteria of patients. In total, 567 patients were included as candidates and were mailed the postal questionnaire. Of these patients, 369 (65%) returned the completed questionnaire or responded to a telephone survey (35 patients; 6%) at a mean of 2 years (range, 1 to 3 years) after surgery.
The questionnaire consisted of these three parts (Additional file 1 http://www.biomedcentral.com/1471-2474/15/240/additional); Part I collected socio-demographic data, Part II evaluated the physical activities of patients before and after TKA, and Part III assessed patient satisfaction with overall surgical outcome and with their physical activity level. Part I included 4 questions that asked about place of residence (urban vs. rural), residence with family members, socioeconomic class (low, middle, high) and education level (no formal education, elementary school, middle school, high school, university or graduate school). Part II contained 5 questions about their regular physical activities before and after surgery, the types of physical activities in which the patient participated before and after surgery, and the preoperative and postoperative University of California at Los Angeles (UCLA) activity scale. They were asked about participation in the following 12 physical activities: hiking, swimming, cycling, walking, running, gymnastics, table tennis, badminton, gate ball, golf, stretching and other activities. The aforementioned activities were based on the 1999 Knee Society Survey of activity after TKA and adapted to the Korean cultural background. Patients were also asked to list other activities in an open-ended question. We used the UCLA activity scale to assess patient activity level because it is a validated method for examining routine activity levels in a clinical series. Furthermore, the UCLA activity scale provides the best reliability and has no floor effects. Part III included 2 questions that evaluated patient satisfaction with the overall surgical outcome and with their physical activity level after surgery using a visual analog scale (VAS). The satisfaction scales ranged from 0 (indicating complete dissatisfaction) to 10 (indicating complete satisfaction). The reporting of the study follows the "Strengthening the Reporting of Observational studies in Epidemiology" (Additional file 2 http://www.biomedcentral.com/1471-2474/15/240/additional). All participants gave their informed consent to participate in the study, and this study was approved by the ethics committee of Seoul National University of Bundang Hospital.
An independent investigator (YGK) prospectively collected demographic characteristics and clinical data, which included height, weight, BMI, pain scores and function scores of the knee, using preprinted forms. Degrees of pain were measured using the pain subscale of the American Knee Society Score (AKS) and the pain subscale of the Western Ontario and McMaster University Osteoarthritis Index (WOMAC). Functional status was measured using the function subscales of the AKS and WOMAC and SF-36 questionnaire. Clinical evaluations were performed preoperatively and postoperatively at 6 months, 1 year and annually thereafter.
Statistical analysis was performed using SPSS for Windows (version 18.0; SPSS Inc., Chicago, IL), and P values of <0.05 were considered statistically significant. To describe the changes in the physical activity profiles following TKA, we compared the preoperative and postoperative UCLA activity score, the number of physical activities per person, the proportion of patients with regular physical activities and the types of physical activities, based on the questionnaire completed 1–3 years after TKA. The UCLA activity scores were summarized as means and ranges, and the statistical significance of the difference between the preoperative and the postoperative means was determined using the paired t test. We arbitrarily set the clinically meaningful difference at a difference greater than 1 point in the mean UCLA score because there were no previous studies suggesting a meaningful difference. In addition, the UCLA activity scores were categorized into low (≤3), moderate (4–6), and high (≥7) activity levels, and the preoperative and postoperative distributions these categories were compared using the McNemar's test.
To determine whether patient socio-demographic factors and postoperative functional outcomes were associated with postoperative physical activity levels, subgroup comparisons and partial correlation analyses were performed. Socio-demographic data were dichotomized as follows: place of residence, urban vs. rural; living with family members, yes vs. no; education level, elementary school or lower vs. middle school or higher; and self-perceived income level, middle class or higher vs. low class. The mean UCLA score of the two groups, defined by the dichotomized socio-demographic factors, was compared using analysis of covariance (ANCOVA). The ANCOVA test was selected to adjust for the potential confounding effects of age, preoperative BMI and preoperative UCLA activity score, which were reported as factors that influence postoperative sports activities. The effects of postoperative functional outcomes on physical activity levels were assessed using partial correlation analyses. The raw scores of the pain and functional scores of the WOMAC index, were transformed into a 0–100-point scale, with higher scores representing better outcomes. Age, preoperative BMI and UCLA activity scores were entered as covariates in the partial correlation analyses.
To determine whether regular participation in physical activity postoperatively was associated with patient satisfaction with replaced knees, the level of patient satisfaction of patients with and without regular physical activities was compared. The significance of differences in satisfaction VAS scores was determined using the ANCOVA test. To adjust for the potential confounding effects of potentially influential factors, the patient age, postoperative UCLA activity score, AKS function, WOMAC function, and the SF-36 PCS and MCS were entered as covariates in the ANCOVA test. We arbitrarily set the clinically meaningful difference at a difference greater than 1 point in VAS satisfaction score because no previous study has defined a clinically meaningful difference for the VAS satisfaction score.
Methods
This study included 369 patients with TKA, and we performed a retrospective analysis of prospectively collected data. The inclusion criteria were: a diagnosis of osteoarthritis, TKA with follow-up care and the TKA was performed from 1 to 3 years before the survey. In total, 567 patients were included as candidates and were mailed the postal questionnaire. Of these patients, 369 (65%) returned the completed questionnaire or responded to a telephone survey (35 patients; 6%) at a mean of 2 years (range, 1 to 3 years) after surgery (Figure 1). There were 339 (92%) female patients and 30 (8%) male patients. The mean age was 68.8 years (range, 50–83 years). The mean preoperative height and weight were 153.3 cm (range; 140–179 cm) and 64.5 kg (range, 42–92 kg), respectively. The mean body mass index (BMI) was 27.4 kg/m (range, 19.3–39.1 kg/m). The bilateral procedure was performed in 251 (68%) patients and the unilateral procedure in 118 (32%) patients.
(Enlarge Image)
Figure 1.
Flowchart detailing inclusion and exclusion criteria of patients. In total, 567 patients were included as candidates and were mailed the postal questionnaire. Of these patients, 369 (65%) returned the completed questionnaire or responded to a telephone survey (35 patients; 6%) at a mean of 2 years (range, 1 to 3 years) after surgery.
The questionnaire consisted of these three parts (Additional file 1 http://www.biomedcentral.com/1471-2474/15/240/additional); Part I collected socio-demographic data, Part II evaluated the physical activities of patients before and after TKA, and Part III assessed patient satisfaction with overall surgical outcome and with their physical activity level. Part I included 4 questions that asked about place of residence (urban vs. rural), residence with family members, socioeconomic class (low, middle, high) and education level (no formal education, elementary school, middle school, high school, university or graduate school). Part II contained 5 questions about their regular physical activities before and after surgery, the types of physical activities in which the patient participated before and after surgery, and the preoperative and postoperative University of California at Los Angeles (UCLA) activity scale. They were asked about participation in the following 12 physical activities: hiking, swimming, cycling, walking, running, gymnastics, table tennis, badminton, gate ball, golf, stretching and other activities. The aforementioned activities were based on the 1999 Knee Society Survey of activity after TKA and adapted to the Korean cultural background. Patients were also asked to list other activities in an open-ended question. We used the UCLA activity scale to assess patient activity level because it is a validated method for examining routine activity levels in a clinical series. Furthermore, the UCLA activity scale provides the best reliability and has no floor effects. Part III included 2 questions that evaluated patient satisfaction with the overall surgical outcome and with their physical activity level after surgery using a visual analog scale (VAS). The satisfaction scales ranged from 0 (indicating complete dissatisfaction) to 10 (indicating complete satisfaction). The reporting of the study follows the "Strengthening the Reporting of Observational studies in Epidemiology" (Additional file 2 http://www.biomedcentral.com/1471-2474/15/240/additional). All participants gave their informed consent to participate in the study, and this study was approved by the ethics committee of Seoul National University of Bundang Hospital.
An independent investigator (YGK) prospectively collected demographic characteristics and clinical data, which included height, weight, BMI, pain scores and function scores of the knee, using preprinted forms. Degrees of pain were measured using the pain subscale of the American Knee Society Score (AKS) and the pain subscale of the Western Ontario and McMaster University Osteoarthritis Index (WOMAC). Functional status was measured using the function subscales of the AKS and WOMAC and SF-36 questionnaire. Clinical evaluations were performed preoperatively and postoperatively at 6 months, 1 year and annually thereafter.
Statistical analysis was performed using SPSS for Windows (version 18.0; SPSS Inc., Chicago, IL), and P values of <0.05 were considered statistically significant. To describe the changes in the physical activity profiles following TKA, we compared the preoperative and postoperative UCLA activity score, the number of physical activities per person, the proportion of patients with regular physical activities and the types of physical activities, based on the questionnaire completed 1–3 years after TKA. The UCLA activity scores were summarized as means and ranges, and the statistical significance of the difference between the preoperative and the postoperative means was determined using the paired t test. We arbitrarily set the clinically meaningful difference at a difference greater than 1 point in the mean UCLA score because there were no previous studies suggesting a meaningful difference. In addition, the UCLA activity scores were categorized into low (≤3), moderate (4–6), and high (≥7) activity levels, and the preoperative and postoperative distributions these categories were compared using the McNemar's test.
To determine whether patient socio-demographic factors and postoperative functional outcomes were associated with postoperative physical activity levels, subgroup comparisons and partial correlation analyses were performed. Socio-demographic data were dichotomized as follows: place of residence, urban vs. rural; living with family members, yes vs. no; education level, elementary school or lower vs. middle school or higher; and self-perceived income level, middle class or higher vs. low class. The mean UCLA score of the two groups, defined by the dichotomized socio-demographic factors, was compared using analysis of covariance (ANCOVA). The ANCOVA test was selected to adjust for the potential confounding effects of age, preoperative BMI and preoperative UCLA activity score, which were reported as factors that influence postoperative sports activities. The effects of postoperative functional outcomes on physical activity levels were assessed using partial correlation analyses. The raw scores of the pain and functional scores of the WOMAC index, were transformed into a 0–100-point scale, with higher scores representing better outcomes. Age, preoperative BMI and UCLA activity scores were entered as covariates in the partial correlation analyses.
To determine whether regular participation in physical activity postoperatively was associated with patient satisfaction with replaced knees, the level of patient satisfaction of patients with and without regular physical activities was compared. The significance of differences in satisfaction VAS scores was determined using the ANCOVA test. To adjust for the potential confounding effects of potentially influential factors, the patient age, postoperative UCLA activity score, AKS function, WOMAC function, and the SF-36 PCS and MCS were entered as covariates in the ANCOVA test. We arbitrarily set the clinically meaningful difference at a difference greater than 1 point in VAS satisfaction score because no previous study has defined a clinically meaningful difference for the VAS satisfaction score.
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