The Journal of Bone and Joint Surgery reports on research looking at 20 children with longitudinal radial deficiency.  The children exhibited reduced grip strength and active range of motion although children performed functional activities fairly well.  There was a large variation in poor strength and activity abilities but range of motion displayed a linear relationship with activity performance.

Reference:  Buffart, Laurien M., Roebroeck, Marij E., Janssen, Wim G.M., Hoekstra, Anneke, Selles, Ruud W., Hovius, Steven E.R., Stam, Henk J.  Hand Function and Activity Performance of Children with Longitudinal Radial Deficiency  J Bone Joint Surg Am 2008 90: 2408-2415