A joint support device for limiting the range of motion of a joint disposed between proximal and distal sections of a limb, said joint defining an axis of rotation, said joint support device comprising: a proximal cuff, adapted to fit closely about said proximal section of said limb, and be secured thereto; a distal cuff, adapted to fit closely about said distal section of said limb, and be secured thereto; said proximal and distal cuffs (302, 306) each being secured to respective proximal and distal side plates (310, 312) on both medial and lateral sides thereof, said proximal and distal side plates (310, 312) comprising cooperating bores for receiving medial and lateral pivot axles, such that said proximal and distal side plates (310, 312) can be assembled to one another, thereby defining an axis of rotation of said joint support device substantially aligned with the axis of rotation of said joint; a first stop member fixed to one of said proximal and distal side plates (310, 312) on at least one of said medial and lateral sides, and a second stop member releasably secured to the other of said proximal and distal side plates (310, 312) on said at least one of said medial and lateral sides, said first and second stop members (326, 328) being located so as to contact one another upon extension of said joint, so as to limit the range of motion of the joint; wherein the second stop member releasably secured to the other of said proximal and distal side plates (310, 312) can be released therefrom, rotated in order to adjust the range of motion of the joint to be permitted, and resecured thereto; and characterized in that said second stop member is releasably secured to the other of said proximal and distal side plates (310, 312) by a first mechanism operable by a user without tools to release and resecure the second stop member from the other of said proximal and distal side plates (310, 312), and by a second mechanism that requires the user to apply force to remove the second stop member from the other of said proximal and distal side plates (310, 312). a proximal cuff, adapted to fit closely about said proximal section of said limb, and be secured thereto; a distal cuff, adapted to fit closely about said distal section of said limb, and be secured thereto; said proximal and distal cuffs (302, 306) each being secured to respective proximal and distal side plates (310, 312) on both medial and lateral sides thereof, said proximal and distal side plates (310, 312) comprising cooperating bores for receiving medial and lateral pivot axles, such that said proximal and distal side plates (310, 312) can be assembled to one another, thereby defining an axis of rotation of said joint support device substantially aligned with the axis of rotation of said joint; a first stop member fixed to one of said proximal and distal side plates (310, 312) on at least one of said medial and lateral sides, and a second stop member releasably secured to the other of said proximal and distal side plates (310, 312) on said at least one of said medial and lateral sides, said first and second stop members (326, 328) being located so as to contact one another upon extension of said joint, so as to limit the range of motion of the joint; wherein the second stop member releasably secured to the other of said proximal and distal side plates (310, 312) can be released therefrom, rotated in order to adjust the range of motion of the joint to be permitted, and resecured thereto; and characterized in that said second stop member is releasably secured to the other of said proximal and distal side plates (310, 312) by a first mechanism operable by a user without tools to release and resecure the second stop member from the other of said proximal and distal side plates (310, 312), and by a second mechanism that requires the user to apply force to remove the second stop member from the other of said proximal and distal side plates (310, 312).