Hallux rigidus is not a bunion, but still affects the same joint as bunions – the first metatarsophalangeal joint. Like the bunion (hallux valgus), the term hallux refers to the big toe, so hallux rigidus is a rigid big toe. This means that there is no motion or next to no motion in that joint. When there is very limited motion it is often accompanied by osteoarthritis, though there can be some confusion about this.
The problem is often caused by osteoarthritis and there may be history of an old injury to the joint.
The consequences of a hallux rigidus is that it alters the way you walk. The big toe joint is so crucial for normal function, as it has to bend so the body can move forward over the foot. If the big toe joint does not move, then that movement has to be achieved by movement at other joints, which may or may not be able to take it. If they can’t then this can cause problems in those other joints.
The conservative treatment for hallux limitus is pain management initially, the use of physical therapy and the use of stiffer shoes or a rocker sole shoe to stop the joint from moving as much. Often the conservative treatments are not that satisfactory (just look at all the questions in forums about it!). Surgical options range from a fusion of the joint to help with the pain; to the removal of any bony blocks that is causing a limitation in the motion; to a type of joint replacement with a spacer in the joint.