Figure 6:

Final equilibrium positions for the 3 simulations involving the nominal “intrinsic-minus’ model, the 3 simulations involving moderate changes to joint laxity (50% nominal torque), and the 3 simulations involving moderate changes to PIP extensor moment arm (50% decrease in the radius of the kinematic constraint). Claw finger deformity was defined to be present when the final position included both hyperextension (extension beyond 0 degrees) of the MCP joint and concurrent flexion of the PIP joint greater than 20 degrees. In this figure, a red “+” indicates when either of these two conditions was present in a single simulation. Under these conditions, all impairment and excitation levels demonstrated hyperextension of the MCP joint. None of the nominal simulations and none of those that involved isolated changes to joint laxity or PIP extensor moment arm resulted in a claw finger deformity. Results for the 3 mild and 3 severe simulations for these two factors not shown, due to their similarity to the moderate results.