Necessary Metacarpophalangeal Joints Range of Motion to Maintain Hand Function

<jats:sec><jats:title>Objective/Background</jats:title><jats:p> This study was conducted to ascertain the necessary flexion or extension range of motion (ROM) required for the finger metacarpophalangeal (MCP) joints to maintain hand function. </jats:p></jats:sec><jats:sec><jats:title>Methods</jats:title><jats:p> Twenty-one healthy adults were recruited for participation in this study. Each participant's right-hand function was evaluated using the Jebsen–-Taylor hand function test and the O'Connor finger dexterity test. Experiment 1 was conducted to assess the influence of the orthosis on hand function. The function of each participant's right hand was measured without an orthosis, with all the finger MCP joints limited to 90° of flexion and 45° of hyperextension. Experiment 2 was conducted to evaluate the impact of limited flexion and extension of all the MCP joints on hand function. The movements of all the finger MCP joints were limited to 70°, 60°, 50°, and 40° of flexion and 20°, 30°, 40°, and 50° of extension lag using orthoses. </jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p> No significant difference was found between a normal hand and a hand with either flexion of 90° or hyperextension of 45° in Experiment 1. In Experiment 2, no significant difference was found between a normal hand and a hand for which the flexion angle was 70°, with an extension lag of 30° or 20°. </jats:p></jats:sec><jats:sec><jats:title>Conclusion</jats:title><jats:p> The necessary ROMs of the MCP joints to maintain hand function are flexion ROM >70° with an extension ROM <30° of extension lag. </jats:p></jats:sec>