The aim of this study was to assess the reliability of a technique to measure the strength of the intrinsic hand muscles. Intraclass Correlation Coefficients showed an excellent level of reliability for the comparison of muscle strength between groups of patients. However, for the results of individual patients, the calculated Standard Error of Measurements (10-16%) and the Smallest Detectable Differences for intraobserver (31-36%) and interobserver (37-52%) values indicate that only relatively large changes in strength can be confidently detected with this technique. The results of the present study were compared with those of four previous grip strength studies.

No abstract

The excursion of the flexor digitorum profundus tendon during active flexion of the third finger was measured with colour Doppler imaging in 10 healthy volunteers. Repeated measurements were made by one observer in three sessions to assess the test-retest reliability. An analysis of variance (ANOVA) was done to find out the multiple sources of measurement error. The intraclass correlation coefficient was 0.81. For single measurements, the standard error of measurement was not more than 0.17 cm. The smallest detectable difference between two consecutive measurements was 0.48 cm. The test-retest reliability of colour Doppler measurements of excursion of the flexor digitorum profundus III tendon (FDP III) in healthy subjects is good. With series of 25 flexion movements, colour Doppler imaging is applicable in the assessment of tendon excursions in patients.

The present study demonstrated large and significant differences among the different rehabilitation protocols and experimental models in terms of absolute and relative tendon displacement. More importantly, the present study clearly demonstrated the influence of the position of the adjacent fingers on the flexor tendon displacement of the finger that is mobilized.

When testing for an extensor tendon central slip lesion at the proximal interphalangeal (PIP) joint, it is proposed that the affected finger should be compared with the non-injured finger of the other hand. In this modified Elson's test, the injured finger is flexed at about 90° in the PIP joint and pushed against the dorsal side of the midphalanx of the same finger of the non-injured hand. Once in this position, the patient is asked to extend the distal interphalangeal (DIP) joints. The finger with a central slip lesion will be able to extend the distal phalanx more than the non-injured distal phalanx. The difference between the extension at the DIP joint of the injured and noninjured hand is easily observed. Asymmetrical position of the two distal phalanges in an effort to extend the distal phalanges suggests that the central slip is not in continuity. If the two fingers remain in a symmetrical position when trying to extend the distal phalanges, a central slip lesion is highly unlikely.