Ali H. Alnahdi

Gait after unilateral total knee arthroplasty: Frontal plane analysis

After unilateral total knee arthroplasty (TKA), osteoarthritis (OA) in the non‐operated knee often progresses. The altered gait mechanics exhibited by patients after TKA increase the loading on the non‐operated knee and predispose it to disease progression. Therefore, our objective was to examine the potentially detrimental changes in frontal plane kinetics and kinematics during walking in patients who underwent unilateral TKA. Thirty‐one subjects 6 months after TKA, 24 subjects 1 year after unilateral TKA, and 20 control subjects were recruited. All subjects underwent 3D gait analysis. In the TKA groups, the non‐operated knee had a higher adduction angle and higher dynamic loading, knee adduction moment and impulse, compared to the operated knee. This increased loading may be an underlying reason for OA progression in the non‐operated knee. Measures of loading in the control knee did not differ from that of the non‐operated knee in the TKA group, but the TKA group walked with shorter step length. While the non‐operated knee loading was not different from controls, there may be greater risk of cumulative loading in the non‐operated knee of the TKA group given the shorter step length.

Muscle Impairments in Patients With Knee Osteoarthritis

Context: Muscle impairments associated with knee osteoarthritis (OA) are the primary underlying cause of functional limitations. Understanding the extent of muscle impairments, its relationship with physical function and disease progression, and the evidence behind exercise therapy that targets muscle impairments is crucial. Evidence Acquisition: An electronic search for relevant articles using MEDLINE and CINHAL databases up to September 2011 was performed. In addition to the electronic search, retrieved articles were searched manually for relevant studies. Results: Quadriceps, hamstrings, and hip muscles are significantly impaired in subjects with knee OA compared with age-matched controls. Muscle strength, especially quadriceps, is a major determinant of both performance-based and self-reported physical function. Whether stronger quadriceps is protective against knee OA onset and progression is not clear. Exercise therapy, including global and targeted resistance training, is effective in reducing pain and improving function in subjects with knee OA. Conclusions: Subjects with knee OA have significant muscle impairments. These muscle impairments affect physical function and should be targeted in therapy. Further research is needed to explore the relationship between quadriceps strength and knee OA initiation and progression and to determine the optimal exercise prescription that augments outcomes in this patient population.

Hip Abductor Strength Reliability and Association With Physical Function After Unilateral Total Knee Arthroplasty: A Cross-Sectional Study

Background Because people with total knee arthroplasty (TKA) have persistent functional limitations and disability, identifying modifiable risk factors for persistent disability is warranted. Before surgery, people have pervasive lower extremity muscle weakness. The fact that hip abductor muscle strength is often not targeted in postoperative rehabilitation may contribute to functional limitations. Objective Study objectives were: (1) to examine the reliability of handheld dynamometry (HHD) for measuring hip abductor strength and (2) to determine whether hip abductor strength contributes to physical function beyond the contribution of quadriceps muscle strength. Design This was a cross-sectional study. Methods Two-hundred ten participants underwent quadriceps and hip abductor muscle strength testing and measurement of physical function (performance-based and self-reported outcomes). Correlation and regression equations were built to determine the relationships of strength, pain, and functional ability. A subset of 16 participants underwent hip abductor strength testing at 2 sessions to determine the reliability of the measure. Results Measuring hip abductor strength with HHD yielded excellent relative reliability, with an intraclass correlation coefficient (ICC [2,3]) of .95 and a 95% confidence interval of .86 to .98, but moderate absolute reliability, with a minimal detectable change (with 95% confidence) of 47.6 N and a 95% confidence interval of 35.5 to 76.5. Hip abductor strength made a significant additional contribution to performance-based measures of physical function after anthropometric covariates and quadriceps muscle strength were accounted for. Hip abductor strength did not show bivariate correlations with patient-reported measures of physical function and did not contribute to patient-reported physical function after covariates and quadriceps muscle strength were accounted for. Limitations A cause-and-effect relationship between hip abductor strength and physical function could not be established. Conclusions In people with unilateral TKA, HHD testing of hip abductor strength is reliable. Hip abductor strength contributes to performance-based but not patient-reported measures of physical function in people with unilateral TKA.

Cross-cultural adaptation, validity and reliability of the Arabic version of the Lower Extremity Functional Scale.

Abstract Purpose: The aim was to translate and cross-culturally adapt the Lower Extremity Functional Scale (LEFS) into Arabic language and to examine its measurement properties in patients with musculoskeletal disorders of the lower extremity. Methods: Standard forward and backward translation followed by expert committee review, then preliminary testing was carried out to produce the final Arabic version of LEFS (LEFS-Ar). The test–retest reliability, measurement error, internal consistency and construct validity of the LEFS-Ar were examined in patients with musculoskeletal disorders of the lower extremity (N = 116). Results: The LEFS-Ar had excellent test–retest reliability (ICC2,1 = 0.96). LEFS-Ar standard error of measurement was 3.5 points while the minimal detectable change MDC95 was 9.8 points. LEFS-Ar showed excellent internal consistency with Cronbach’s alpha of 0.95. Parallel analysis and factor analysis showed that LEFS-Ar measures one underlying factor with all items loading heavily on this single factor. LEFS-Ar showed significant positive correlation with patient’s global assessment of function (r = 0.59) and that patients recovering from surgery reported lower LEFS-Ar score compared to patients with no surgery further supporting the construct validity of the LEFS-Ar. Conclusion: LEFS-Ar has excellent internal consistency, test–retest reliability with relatively small measurement error and is a valid measure of activity limitation due to lower extremity musculoskeletal disorders. All these measurement properties of the LEFS-Ar suggest the clinical usefulness of this measure. Implications for Rehabilitation The Arabic Lower Extremity Functional Scale (LEFS-Ar) is a reliable and valid measure of activity limitation due to lower extremity musculoskeletal disorders with relatively small measurement error. LEFS-Ar can be used in daily clinical practice and for research purposes to quantify activity limitation in Arabic-speaking individuals with lower extremity musculoskeletal disorders.

Reference values for the Y Balance Test and the lower extremity functional scale in young healthy adults.

[Purpose] This study aimed to establish gender-specific reference values for the Y Balance Test (YBT) and the Arabic version of the Lower Extremity Functional Scale (LEFS-Ar) in healthy young adults in Saudi Arabia, and to examine gender differences in the YBT and LEFS-Ar values. [Subjects and Methods] Healthy young adults (31 females, 30 males) completed the YBT and LEFS-Ar in 1 test session. Descriptive statistical analysis (mean, standard deviation, 95% confidence interval) was used to compute the YBT and LEFS-Ar reference values. Independent t-tests were used to examine gender differences in the YBT and LEFS-Ar values. [Results] Gender-specific reference values were obtained for the right, left, dominant, and non-dominant leg as well as for the average performance of both the legs. males showed greater YBT normalized reach distances than females did in the anterior, posteromedial, and posterolateral directions; furthermore, males showed higher YBT composite scores than females did. However, the LEFS-Ar values did not differ between males and females. [Conclusion] Gender-specific reference values were obtained for the YBT and LEFS-Ar in healthy young adults in Saudi Arabia. males performed better than females did in the YBT. However, no gender differences were noted in LEFS-Ar.

Rasch validation of the Arabic version of the lower extremity functional scale

Abstract Purpose: The purpose of this study was to examine the internal construct validity of the Arabic version of the Lower Extremity Functional Scale (20-item Arabic LEFS) using Rasch analysis. Methods: Patients (n = 170) with lower extremity musculoskeletal dysfunction were recruited. Rasch analysis of 20-item Arabic LEFS was performed. Once the initial Rasch analysis indicated that the 20-item Arabic LEFS did not fit the Rasch model, follow-up analyses were conducted to improve the fit of the scale to the Rasch measurement model. These modifications included removing misfitting individuals, changing item scoring structure, removing misfitting items, addressing bias caused by response dependency between items and differential item functioning (DIF). Results: Initial analysis indicated deviation of the 20-item Arabic LEFS from the Rasch model. Disordered thresholds in eight items and response dependency between six items were detected with the scale as a whole did not meet the requirement of unidimensionality. Refinements led to a 15-item Arabic LEFS that demonstrated excellent internal consistency (person separation index [PSI] = 0.92) and satisfied all the requirement of the Rasch model. Conclusion: Rasch analysis did not support the 20-item Arabic LEFS as a unidimensional measure of lower extremity function. The refined 15-item Arabic LEFS met all the requirement of the Rasch model and hence is a valid objective measure of lower extremity function. The Rasch-validated 15-item Arabic LEFS needs to be further tested in an independent sample to confirm its fit to the Rasch measurement model. Implications for Rehabilitation The validity of the 20-item Arabic Lower Extremity Functional Scale to measure lower extremity function is not supported. The 15-item Arabic version of the LEFS is a valid measure of lower extremity function and can be used to quantify lower extremity function in patients with lower extremity musculoskeletal disorders.

Cross-Cultural Adaptation and Validation of the Back Beliefs Questionnaire to the Arabic Language.

Study Design. Translation, cross-cultural adaptation, and psychometric testing. Objective. To translate the Back Beliefs Questionnaire (BBQ) into Arabic and investigate its psychometric properties in an Arabic-speaking sample of individuals with low back pain (LBP). Summary of Background Data. Back pain beliefs are associated with pain chronicity and disability in people with LBP. The BBQ is a recognized and frequently used tool for measuring these beliefs. To date the BBQ has not been translated into Arabic. Methods. The English version of the BBQ was translated and culturally adapted into Arabic (BBQ-Ar) according to published guidelines. The BBQ-Ar was then tested in a sample of 115 Arabic-speaking individuals with LBP. Reliability was evaluated through internal consistency (Cronbach &agr;) and test-retest reliability (intraclass correlation coefficient), the latter in a subgroup of 25. Construct validity was assessed using exploratory factor analysis and by examining the correlation between the BBQ-Ar, the Oswestry Disability Index and a Numerical Pain Rating Scale. Results. Internal consistency of the BBQ-Ar was good (Cronbach &agr; = 0.77). Test-retest reliability was good (intraclass correlation coefficient [2,1] = 0.88). Exploratory factor analysis revealed a three-factor structure, explaining 46% of total variance, with the first factor alone explaining 24%. Eight of the nine scoring items were loaded on the first factor thus forming a unidimensional scale. A significant negative correlation was found between Oswestry Disability Index and BBQ-Ar scores (r = −0.307; P < 0.01), whereas no significant correlation was found between BBQ-Ar and Pain Rating Scale scores. No floor or celling effects were observed. Conclusion. The BBQ-Ar is a valid and reliable tool that can be used to assess back pain beliefs in Arabic-speaking individuals. Level of Evidence: N/A

Validation of an Arabic version of Fatigue Severity Scale

Objectives: To develop and test the psychometric properties of an Arabic version of Fatigue Severity Scale (FSS-Ar) that can be used to measure fatigue in Arabic patients with disorders where fatigue is a major symptom. Methods: Forward and backward translations of FSS were undertaken to develop an Arabic version. The validity and reliability of the FSS-Ar was then tested on 28 patients with systemic lupus erythematosus (SLE), 24 patients with multiple sclerosis (MS), and 31 healthy subjects. Exploratory factor analysis and hypothesis testing methods were used to examine construct validity. The correlation between FSS-Ar and the vitality domain of the RAND 36-Item Health was examined to test construct validity. The study was conducted at the King Khalid University Hospital, Riyadh, Kingdom of Saudi Arabia between February and June 2012. Results: Using a score of ≥4.05 to define fatigue, 39 of 52 (75%) participants were fatigued compared with 10 out of 31 (32%) healthy participants. The correlation between the FSS-Ar and the vitality domain of the RAND-36 was acceptable (r = -0.46). Factor analysis showed that items of the FSS-Ar measured one underlying construct, namely, fatigue. Test-retest reliability and internal consistency of the FSS-Ar was acceptable (intraclass correlation coefficient model 2,1 = 0.80; Cronbach’s alpha = 0.84). Conclusion: The Arabic version of the FSS demonstrated acceptable psychometric properties and was able to differentiate between patients with SLE or MS, and healthy subjects.

Cross-cultural adaptation and validation of the Saudi Arabic version of the Knee Injury and Osteoarthritis Outcome Score (KOOS)

The Knee Injury Osteoarthritis Outcome Score (KOOS) is a widely used joint-specific measure employed to evaluate pain, symptoms, activities of daily living, recreational activities, and quality of life in patients with knee osteoarthritis (OA). Although the original KOOS has been translated into many languages, a Saudi Arabic version is not available. This study aimed to culturally adapt and evaluate the psychometric properties of the Saudi Arabic version of the KOOS in patients with knee OA. The original KOOS was translated and adapted into Saudi Arabic version over six stages according to the guidelines suggested by Beaton and recommended by the American Association of Orthopedic Surgeons Outcome Committee. Patients diagnosed with knee OA (n = 136) were recruited to examine the psychometric properties, such as internal consistency that was tested using Cronbach’s alpha, test–retest reliability that was analyzed using the intra-class correlation coefficient (ICC2,1), and construct validity that examined by testing the correlations between the new version subscales, Form 36 Health Survey subscales, and the Visual Analog Scale, Spearman’s correlation coefficient (rs) was used to measure the correlations. A total of 122 (89.7%) of the 136 participants with knee OA completed the second re-test of new Saudi Arabic version. Excellent internal consistency (Cronbach’s alpha = 0.87–0.92) was detected in the subscales of the adapted version, as well as excellent test–retest reliability (ICC2,1 = 0.92–0.94). The pattern of correlation between the subscales of the Saudi Arabic version of the KOOS, SF-36 domains and the Visual Analog Scale for pain supported the construct validity of the adapted version. The Saudi Arabic version of the KOOS was well accepted and exhibited excellent reliability, internal consistency, and construct validity in Saudi patients with knee OA.