Asymmetry correction equations for hand volume, grip and pinch strengths in healthy working people.

Assessments of oedema and decrease in hand strength are useful for patients with a hand lesion. This study examined the asymmetry of the arms and determined the estimates of the unknown prior to lesion values for hand volume, grip strengths assessed with a Jamar dynamometer (GS[J]) and a Collins dynamometer (GS[C]), and pinch strength with a Jamar pinch gauge (PS) in 100 healthy working people. Hand volume, GS(J), GS(C) and PS of the dominant hand were respectively 3.6 +/- 4.1%, 6.6 +/- 9.2%, 11.7 +/- 11.2%, and 8.0 +/- 13.2% higher than those of the non-dominant hand (p < 0.001). Very good estimates were obtained with the values of the contralateral arm for all the indices studied. The correlation coefficient equalled 0.95 for hand volume, 0.91 for GS(J), 0.83 for GS(C), and 0.72 for PS. These estimates allow us to evaluate the evolution of oedema and hand strengths in patients with hand injury, especially to determine whether they could return to work as they are mostly manual workers with demanding jobs.