The Evaluation Of The Chinese Version Of The Short Musculoskeletal Function Assessment (SMFA) Based On Classical Test Theory And Item Response Theory

Study BackgroundMusculoskeletal injuries are a series of damage in the bone and joint and muscular system, with pain and limited mobility as the main clinical manifestations, which involving the neck, shoulders, arms, upper limb, lower limbs, back, waist and other parts of the body. Musculoskeletal injuries are a major public health problem because they are one of the main determinants of disability, work absenteeism, and rising health care costs, which can have profound effects on the quality of life (QOL) of the patient.In clinical practices and clinical researches, there were often need to evaluate the patients of musculoskeletal injuries. The assessments of functional outcomes are generally divided into two categories:doctor-reported outcomes (DROMs) and patient-reported outcomes (PROMs). The characteristics of patient-reported outcomes were allowing patients to express their symptoms and dysfunctions by themselves. It has been recognized as important guides of treatment decision and the effective indexes of clinical intervention measures. PROMs often use scales or questionnaires, divided into the universal (general) scales and specific-disease scales. Some scholars liked to divid into the overall-health scales and anatomic site function scales. The general scales or overall-health scales can be used for all of the patients and normal peoples, but sometimes missed important contents of disease without evaluation.Specific-disease scales or anatomic site function scale aim to some kind of diseases or a certain type of peoples, which response better to the special changes on the health status. The drawback is that cannot be compared among different groups or research.In clinical studies and in clinical practice, functional limitations and quality of life for the patients often need to evaluate,which due to musculoskeletal injuries, as well as the effects of conservative or surgical treatments. There were more than 300 kinds of rating scales of outcomes in orthopedic literatures, and many different rating scales can be selected at the same site of injuries. But, there was lack of uniform standards to choose the rating scales in the using. The universal scales or general health scales were not enough sensitive to functional changes with musculoskeletal injuries. It was very important to choose a reliable scales to get more informations in the busy clinical works, which maintaining the function of tmusculoskeletal injuries, quality of daily life, and mental states.The Short Musculoskeletal Function Assessment (SMFA) questionnaire is one of the most commonly used scales recommended by the American academy of orthopedic surgeons that has been internationally used for more than 14 years for extensive assessment of the functional status and quality of life (QOL) of patients with a broad range of musculoskeletal disorders encountered in clinical practice. The SMFA was suit to a variety of limb musculoskeletal injuries and disorders treatment and health assessment, which assess to both multiple injuries in the same patient and different patients with different injuries, can also compare functional improvements in different surgical patients.Thus far, the SMFA has been translated, cross-culturally adapted and validated into several languages. However, a Chinese version of the SFMA has not been created as yet.To use the SMFA in China, it was to translate the SMFA questionnaire into Chinese, adapt it to cultural specificities, and evaluate the psychometric properties of the Chinese version of the SMFA. The process of translation and adaptation into Chinese followed the guidelines recommended by the American Association of Orthopedic Surgeons (AAOS) and the guidelines for cross-cultural adaptation of health-related quality of life measures.There were two kinds of measurement theories, the classical test theory(CTT) and the item response theory(IRT). CTT was used and circulated most widely in currently testing of academic, depicts quiz random error by using reliability, validity and other indicators. But CTT cannot further elaborate item properties detailed. IRT is emerging in recent years in psychometric theory, which analysis and evaluate the items in the microscopic levels using latent trait and characteristic curve to build mematical model project.The applicability and application evaluation in clinical scales, more choice of classical test theory, item response theory was less used, combined with the above two kinds of measurement theory has not been reported. The aim of this study was to translate the original English version of SMFA questionnaire into Chinese, adapt it to Chinese cultural specificities, analysis the Chinese version of the SMFA comprehensive from the micro and macro levels based on classical test theory and item response theory, providing methodological reference for the promotion and application of modern measurement theory in the study of assessment scales.Part one Translation and cross-cultural adaptation of the Chinese version of SMFAObject:The current study was to translate the original English version of SMFA questionnaire into Chinese, adapt it to Chinese cultural specificities, and provide a convenient and effective tool for the evaluation of musculoskeletal injury patients.Methods:The process of translation into Chinese followed the guidelines recommended by the American Association of Orthopedic Surgeons (AAOS) and the guidelines for cross-cultural adaptation of health-related quality of life measures. Take "forward translation-integrated and coordinated-reverse translation team evaluation-pre-survey" approach, on the English original version of SMFA was translation and cross-cultural adaptation.Results:1.93.4% of respondents to the Chinese version of SMFA to fully understand, the scales recovery were 100%,96.67% completion rate, the average fill time of 16.67 minutes. These results suggest that the scale has good acceptability.Conclusion:After localization and cross-cultural adaptation, we got a Chinese version of SMFA. The acceptability of the Chinese version of SMFA was good through preliminary investigation.Prat two Evaluation of the Chinese version of SMFA based on the classical measurement theoryObject:The aim of this part was to evaluate the applicability and psychometric properties of the Chinese version of the SMFA in patients with skeletal muscle injury, based on the classical measurement theory.Methods:A total of 339 patients with skeletal muscle injury were enrolled in this study. The measurement tools consisted of a demographic information questionnaire, two QOL/health status scales (Chinese versions):SMFA, Health Survey Short Form (SF-36), and a region-specific questionnaire (Chinese versions) including the disabilities of the arm, shoulder, and hand questionnaire (DASH), the hip disability and osteoarthritis outcome score (HOOS), the knee injury and osteoarthritis outcome score (KOOS) and the foot function index (FFI), depending on the region of the injury. Based on the classical measurement, the Chinese version of the SMFA was evaluated the psychometric properties as expressed by its feasibility, internal consistency, reliability, convergence, and construct validity.Results:1. SMFA was divided into two and a half scale, and then calculates the split-half reliability of the scale. A total split-half reliability of Chinese version of SMFA was 0.975, the dysfunction index was 0.917, and the bother index was 0.922 degree. The split-half reliability of the daily activities categories, emotional status categories, arm/hand function categories, and mobility categories as follows:0.892,0.759,0.846, 0.824.2. The Cronbach’s a was 0.954 for the dysfunction index, and 0.935 for the bother index. For the four categories, the Cronbach’s a ranged from 0.776 to 0.928.3. The results showed moderate to good correlations between the mobility category, dysfunction index and the bother index and the three subscales (PF, RP, and BP) of the SF-36, and Spearman rank correlation coefficients were greater than the absolute value of 0.6, the correlation of 0.001 level. In 84 patients with upper limb injury, moderate to good correlations were found between the subscales of the SMFA and the DASH, Spearman rank correlation coefficient from 0.56 to 0.75, the correlation of 0.001 levels. In the patients with hip and knee injuries, the convergent validity was demonstrated through moderate to good correlations between the SMFA category daily activities and two subscales and the ADL subscale of HOOS and KOOS, Spearman rank correlation coefficient between the absolute value of 0.65 to 0.738,0.001 level correlations. Only 62 patients were injured in the foot or ankle. The SMFA categories and subscales indices correlated more closely with the limitations of the FFI than foot pain and difficulty with activities, Spearman rank correlation coefficients were greater than 0.7, the correlation at 0.001 level.4. The factor structure of the Chinese version of SMFA was evaluated using principal component method. The Kaiser-Meyer-Olkin value was 0.953, Bartlett test of sphericity was significant (p<0.01), exploratory factor analysis of the SMFA identified a six-factor structure which accounted for 66.852% of the total SMFA variance.5. The known-groups comparison showed that the dysfunction index and the bother index of the SMFA discriminated well between patients, which above 60 years scored higher than the other groups (P<0.01); females were higher than males (P<0.01); lower limb injuries higher than upper limb disorders (P<0.01); conservative treatment higher than operation group (P<0.01).Conclusion:1. The Chinese version of SMFA was found to be satisfactory and had good reliability; as well as between the SF-36 questionnaires with four specific regions have good correlation; its factor structure for the complete classification of six factor structures was similar with the original SMFA. The Chinese version of SMFA can successfully identify with different levels of functional limitation.2. Based on the above evaluation results, the Chinese version of the SMFA questionnaire is a reliable and valid instrument to measure the quality of life and functional status of musculoskeletal injuries in the upper or lower extremities.Prat three Evaluation of the Chinese version of SMFA based on Item Response TheoryObject:To study each item of the six dimensions in the Chinese version of SMFA from micro-level based on the item response theory, and explores the cross-cultural adaptation of the clinical assessment scales in the application and possible problems with modern measurement theory.Methods:Use the same data with second part; test the one-dimensional of each dimension in the Chinese version of SMFA with factor analysis of SPSS. The item of six dimensions was respectively analysis with GRM model of MULTILOG7.03, estimate the discrimination and response threshold using maximum likelihood algorithm, drawn characteristic curve, information curve, and the total test information curve.Results:1. Based on the item response theory, the various dimensions of the Chinese version of SMFA were estimate the discrimination and response threshold, finding good ability to distinguish the different qualities of the patient’s with musculoskeletal injuries.2. Item response theory can be applied to cross-cultural adaptation of the clinical assessment scale, and provide microscopic, detailed information which does not reflect by the CTT.3. Discriminations of each item in emotional state dimension were from 0.70 to 4.25, only the item of 31 discrimination>2, the item of 29 discrimination<1. The fourth response threshold of item 7 was exceeded the range of-3 to 3, and the other items were in the range of-3 to 3. Difficulty factor of each items were increasing state, no reverse threshold. The shapes of Item Characteristic Curve basically achieve the desired effect. Only the Information curves of the items 31,34 were flat, covering a smaller area. The information of total information curve> 5 in-1 to 3.4. Discriminations of each item in arm and hand function dimension were from 1.00 to 4.97, the items 2,11,18 discrimination<2. In addition to item 18, the response threshold of other items were from-3 to 3 range. The shape of ICC in this dimension was right shape. The IICs in item 5,10,16,17 were flat, smaller coverage area. The dimensions of total information curve in this> 5 in-0 to 3.5. Discriminations of each item in mobility dimension were from 1.00 to 5.14, the items 4,8,12,13 discrimination between 1 and 2. Except for the item 26, the response thresholds of other items were from-3 to 3 ranges. The shape of ICC in this dimension was right. The IICs in item 4,8,13 were flat, smaller coverage area. Except for them, all Information curves of other items were higher peak, and their curves covering a larger area. The dimensions of total information curve> 5 in-1 to 2.6. Discriminations of each item in bother index were from 1.00 to 4.97, the items 39,42,45 discrimination over 2. The first response threshold was exceeded the theoretical range in the item 42. The response thresholds of other items were from-3 to 3 ranges. The shape of ICC in this dimension was right. The IICs in item 36, 38,40,44,45 were flat, smaller coverage area. The dimensions of total information curve> 5 in-1 to 3.Conclusion:1. Based on the item response theory, the various dimensions of the Chinese version of SMFA were estimate the discrimination and response threshold, finding good ability to distinguish the different qualities of the patient’s with musculoskeletal injuries.2. The discriminations of part of the items were too high and found reversed thresholds,need to increase the sample size in the future research, and then consider whether to further express the content of these items be adjusted or revised.