Reliability of isometric wrist extension torque using the LIDO WorkSET for late follow-up of postoperative wrist patients

The concurrent validity of a hand-held versus a stationary dynamometer in testing isometric shoulder strength

STUDY DESIGN

Clinical Measurement-Validity.

INTRODUCTION

Validity of the JTech PowerTrack II hand-held dynamometer (JTech; JTech Medical, Salt Lake City, UT) for measuring shoulder strength has yet to be established.

PURPOSE OF THE STUDY

To examine the concurrent validity of isometric strength scores obtained with the JTech PowerTrack II, and on a stationary dynamometer, the LIDO WorkSET (LIDO; LoredanBiomedical, West Sacramento, CA).

METHODS

Thirty-eight subjects performed three maximal efforts of shoulder flexion, abduction, and external rotation on a single occasion on the two dynamometers. Two testers were randomly assigned to administer the tests.

RESULTS

Pearson correlations between the scores on the two dynamometers (r.0.81) indicated a good concurrent validity. Correlations were similar when the results were subdivided by tester or gender.

CONCLUSIONS

This study suggests that either the JTech PowerTrack II or LIDOWorkSET provide comparable scores for shoulder strength. Although not interchangeable because of the differences in units of measurement, the relative conclusions about strength should be similar, regardless of which instrument is used.

LEVEL OF EVIDENCE

Not applicable.

Validity of self-report measures of pain and disability for persons who have undergone arthroplasty for osteoarthritis of the carpometacarpal joint of the hand

OBJECTIVE

To establish the validity of three self-report scales used to measure function following arthroplasty for osteoarthritis (OA) of the carpometacarpal joint.

METHOD

Persons with OA of the carpometacarpal joint (n=122) were assessed on one occasion 9-117 months following tendon interposition arthroplasty. They completed three self-report measures of hand/upper limb disability: the Australian/Canadian Osteoarthritis Hand Index (AUSCAN), the Patient-Rated Wrist Hand Evaluation (PRWHE), and the Disabilities of Arm, Shoulder and Hand (DASH). They also completed the Short Form 36 (SF-36) and performed tests of strength, range of motion (ROM), and dexterity. Factor analysis and correlations were used to determine the association among the scales and subscales considered to measure similar constructs (e.g., pain and physical disability). Correlations between the scales and measures of impairment were also conducted to examine construct validity of the disability measures. t-Tests evaluated the hypotheses that subjects with isolated hand OA would have lower scores than those with additional joint involvement.

RESULTS

All three scales or their subscales loaded on one factor. Convergent validity of the disability measures was demonstrated by high correlations between similar subscales (r>0.75), and divergent validity by a lack of correlation between the measures and self-report hand appearance. As expected, correlations between disability and strength, dexterity, or a global measure of ROM were higher than with ROM of individual joints. The AUSCAN and the DASH were better able to discriminate those with localized hand OA from those with involvement of other joints.

CONCLUSIONS

The AUSCAN, PRWHE, and DASH are valid assessments of pain and/or disability of hand OA, and provide information distinct from impairment measures.

Simulated work performance tasks in persons with neuropathic and myopathic weakness

OBJECTIVES

To determine the test-retest reliability of selected simulated work performance tasks in persons with neuropathic and myopathic weakness and control subjects, and the association between muscular performance during these work tasks and conventional isolated muscle group testing.

DESIGN

Measurement of three tasks performed on a work simulation device on two different days separated by 1 week. Associations between work task performance and previously reported strength measures in six muscle groups by hand-held dynamometry (HHD) were examined.

SETTING

Human performance laboratory of a university.

PARTICIPANTS

Convenience sample of ambulatory outpatients with hereditary motor and sensory neuropathy, type I (n = 9), myotonic muscular dystrophy (n = 10), and able-bodied controls (n = 11).

MAIN OUTCOME MEASURES

For work simulation, isokinetic peak torque and total work; and for HHD, maximal isometric torque.

RESULTS

Mean between-session differences for work simulation tasks ranged from -11% to +4% for peak torque and from -12% to +12% for total work; test sessions did not differ significantly for either patient or control groups. All groups had between-session intraclass correlation coefficients usually >.80, indicating good consistency. In general, correlations between peak torque during work simulation and HHD were strongest in the control group.

CONCLUSION

Persons with neuromuscular weakness reliably performed the simulated work tasks examined in this investigation. Work simulation tasks may be a useful tool to assess muscular performance in persons with neuromuscular weakness.