Seat Broken problems of the 1999 Ford Windstar

While stopped at red light, our Ford Windstar was rear-ended by a Ford focus estimated to be going 50-60mph. Both of us in the front seats suffered severe calf muscle injuries. We believe these were caused by the manual seat adjustment bar that runs the full width of the seat. We were both wearing seatbelts. An additional note: the driver's seatback broke on impact. Is there any history of leg trauma caused by seat hardware in rear-end collisions?.