Is my son done growing becase his wrist growth plates are closed?

[TheodoreDavis]

My 15yo son broke his arm a few months ago. The doctor treating him noted that the growth plates in his wrist are closed and that he was close to done growing (another inch or so).  This distressed us because he only 5'5" . I am 5'8" and my wife is 5'5".  I always assumed he would be about as tall as I am at least.  We took him to an endo who did blood work and x-rayed his wrist.  Blood work is fine but the growth plates in the wrist are indeed fused.  I have read that apart from the shoulders the bones in the hips and spine are the last to finish growing.  My son and I have the same inseam measurement so I'm assuming that our legs are about the same length which seems to indicate the 3in difference in our height is in our torsos.  He does appear short in the torso if you look at him.  Is it possible that he will grow another 2-3inches?