Growth diagrams for individual finger strength in children measured with the RIHM

Abstract

Background: Although grip and pinch strength provide a more global measure of a large number of digits and muscles, measuring strength of individual fingers or the thumb can provide additional and more detailed information regarding hand strength.

Questions/purposes: We developed growth diagrams for individual finger strength in children.

Patients and methods: We measured thumb palmar abduction, thumb opposition, and thumb flexion in the metacarpophalangeal joint, and abduction of the index and little fingers in 101 children (4-12 years old) using a myometer. We recorded hand dominance, gender, height, and weight. All measurements were performed in a randomized order by the same researcher. We developed statistical models for drawing growth diagrams using estimated percentiles for each strength measurement. Separate models for dominant and nondominant hands of boys and girls were developed, in addition to a combined model.

Results: Because there was no difference in strength between boys and girls and between dominant and nondominant hands, both hands and genders were combined in one growth diagram for each measurement. The normative data were presented in a table format and in growth diagrams for each myometer measurement.

Conclusions: These diagrams can be used for pediatric patients such as patients with congenital malformations or neuromuscular disorders who receive interventions or therapy aimed at function of the hand, fingers, or thumb. The growth diagrams facilitate distinguishing between the effects of growth and intervention on strength development.

Fig. 1

The different RIHM measurements performed according to the official instructions are shown. (Published with permission of Elsevier and adapted from Molenaar HM, Selles RW, Schreuders TA, Hovius SE, Stam HJ. Reliability of hand strength measurements using the Rotterdam Intrinsic Hand Myometer in children. J Hand Surg Am. 2008;33:1796-1801.).

Fig. 2

A graph shows thumb palmar abduction strength plotted against age. The percentiles 2.5%, 16%, 50%, 84%, and 97.5% are shown.

Fig. 3

A graph shows thumb opposition strength plotted against age. The percentiles 2.5%, 16%, 50%, 84%, and 97.5% are shown.

Fig. 4

A graph shows thumb (metacarpal phalangeal joint) flexion strength plotted against age. The percentiles 2.5%, 16%, 50%, 84%, and 97.5% are shown.

Fig. 5

A graph shows index finger abduction strength plotted against age. The percentiles 2.5%, 16%, 50%, 84%, and 97.5% are shown.

Fig. 6

A graph shows little finger abduction strength plotted against age. The percentiles 2.5%, 16%, 50%, 84%, and 97.5% are shown.