Association between muscle strength, upper extremity fatigue resistance, work ability and upper extremity dysfunction in a sample of workers at a tertiary hospital.

BACKGROUND: Upper extremity musculoskeletal disorders negatively affect ability to perform activities of daily living, self-care and work. Therefore, outcome measurements that address muscle strength, fatigue resistance, functionality and work physical capacity must be defined to assess and plan specific actions to minimize them. OBJECTIVE: To investigate the association of upper extremity muscle strength with upper extremity fatigue resistance, work ability and upper extremity dysfunction in a sample of workers from a tertiary hospital. METHODS: Shoulder and elbow isokinetic strength were assessed by Biodex System 4™, isometric hand grip by JAMAR™, upper extremity fatigue resistance by Functional Impairment Test Hand and Neck/Shoulder/Arm (FIT-HaNSA), ability to work by the Work Ability Index and upper extremity dysfunction by the Quick-Disabilities of the Arm, Shoulder and Hand QuickDASH-Br questionnaire. The Nordic questionnaire and Numeric Pain Rating Scale (NPRS) were used for pain description. The associations were analysed by Spearman's correlation coefficient (rho) (p < 0.05). RESULTS: Twenty-seven participants: 59.2% women; mean age 46 years old; 70.3% obese/overweight; 62.9% active with predominantly dynamic muscle contraction work. Besides predominance of good to moderate work ability (81.4%) and comorbidities (37%), all participants had symptoms of the upper extremities for at least 12 months, with a predominance of low-intensity in the shoulder (55.5%). In addition, 88.8% reported pain in other segments. Muscle strength of abduction (rho = 0.49), adduction (rho = 0.40), internal rotation (rho = 0.44) and hand grip (rho = 0.68) presented moderate correlation with FIT-HaNSA. Hand grip (rho = - 0.52) showed moderate correlation with upper extremity dysfunction. CONCLUSIONS: The results of this preliminary study suggested the association of shoulder strength with fatigue resistance. Also, hand grip strength was associated with upper extremity dysfunction and fatigue resistance. No association was found with the Work Ability Index in this sample. So, it is suggested that hand grip and shoulder strength could be outcome measurements used for future interventions focused on upper extremity preventive exercises to improve strength and fatigue resistance of workers at risk for the development of musculoskeletal disorders. Other individual, psychosocial and organizational risk factors must also be considered as influences on upper extremity function.

Reliability, validity and responsiveness of Brazilian version of QuickDASH.

OBJECTIVE: To analyse the construct validity, test-retest reliability and responsiveness of the Brazilian version of Quick-DASH (QD-Br) in patients with upper limb disorders. METHOD: Participants completed the full Brazilian DASH, the QD-Br and the SF-12 Brazil questionnaires at the beginning of treatment, after 48-72h and the after 2-12 months. Construct validity was analysed by Pearson's correlation coefficient (r). To evaluate the test-retest reliability we used the Intraclass Correlation Coefficient (ICC) and the Cronbach's alpha coefficient to test the internal consistency. Responsiveness was analysed by Standardized Response Mean (SRM) and Effect Size (ES). The Minimal detectable change (MDC) score was based upon calculations of the standard error of measurement (SEM), confidence interval of 95%. RESULTS: The construct validity presented strong direct correlation with the total QD-Br score and the Brazilian DASH (r = 0.91), a moderate inverse correlation between the total QD-Br score and the physical component of the SF- 12 Brazil (r = -0.55) and weak inverse correlation between the QD-Br and the mental component of SF-12 Brazil (r = -0.49). The ICC test-retest showed good reliability of 0.81 (0.72-0.87). QD-BR presented high responsiveness, with ES of 1.06 and SRM of 0.94. The MDC was 17.27 points. CONCLUSION: These results provide evidence that the QD-Br was a valid, reliable and responsive instrument when utilized in patients with upper limb traumatic and no-traumatic disorders in the Brazilian population.

Construct validity of the Patient-Rated Wrist and Hand Evaluation questionnaire (PRWHE) for nerve repair in the hand.

BACKGROUND: Many tools have been described for outcome assessment after nerve repair. The Patient-Rated Wrist and Hand Evaluation (PRWHE) have been shown to be valid for several hand conditions. OBJECTIVES: To explore the construct validity of the PRWHE in comparison to cold intolerance, pain and dysfunction questionnaires; the Rosén score and its subcomponents; and threshold sensibility, dynamometry and dexterity tests for nerve repair of the hand. STUDY DESIGN: Clinical measurement. METHODS: Construct validity was analysed through Pearson's correlation coefficient in a convenience sample of 32 adult patients after long-term median and ulnar nerve repair. RESULTS: The PRWHE total score was highly to moderately associated with the Disability of Arm, Shoulder and Hand (r = 0.83), Cold Intolerance Symptom Severity (r = -0.60) and McGill's Pain (r = 0.58) questionnaires. In addition, it was correlated to motor (r = -0.55) and sensor subdomains (r = -0.56) of the Rosén score. Substantial to high associations were found for the motor, sensory impairment and dexterity test. CONCLUSIONS: The PRWHE was shown to be valid, based on construct validity, for patients with nerve repair of the hand.