In my case they have. The fastest one to do so was one that I kept wrapped for some weeks after an injury that left part of my left thumb tip looking like hamburger meat. In fact by the time it had healed the matrix was about five millimeters longer than it was before the injury. (That time I also patched the nail damage using a fiber mat and nail polish until it grew out completely. Now I'd use an UV gel instead of polish.)
If the deformity is bad enough to warrant surgical correction, you could also ask a doctor experienced with finger injuries to extend the matrix. That would involve a distal skin excision, but from the photographs I've seen the results can be quite impressive.
