The forefoot consists of the five toes and their connecting long bones, the metatarsals. Each toe (phalanx) is made up of small bones called phalanges. The phalanges of all five toes are connected to the metatarsals by metatarsophalangeal (MTP) joints at the ball of the foot. During efficient walking and running, the forefoot bears half the body’s weight and balances pressure on the ball of the foot, and the big toe joint (first MTP joint) should take on the majority of the push off force for forward movement.
The big toe, or hallux, has two phalanges and two joints (interphalangeal joints); it also has two tiny round sesamoid bones that enable it to move up and down. On an x-ray of the foot, the sesamoids appear as a pair of distinctive oval dots near the first metatarsal head. The sesamoid bones are embedded in the flexor hallucis brevis tendon, one of several important tendons that exert pressure from the big toe against the ground and help initiate the act of walking. The sesamoids help disperse some of the impact when the foot strikes the ground, and contribute to the fulcrum that provides the flexor tendons a mechanical advantage as they pull the big toe down against the ground during walking and running.
When walkers and runners develop lower extremity injuries, the big toe should be assessed in conjunction with the other more commonly assessed joints in the kinetic chain (knee, ankle, hip). Normal range of motion (dorsiflexion at the 1st MTP joint) is 60-70 degrees and is necessary for efficient push off. Two common dysfunctions of the big toe are hallux rigidus/limitus and sesamoiditis which may develop and limit the great toe mobility and its important function.
By definition, hallux rigidus/limitus is a ‘stiff toe’ which can be caused by degenerative changes in the joint including narrowing joint space and bone spur formation. Sesamoiditis is simply inflammation at the sesamoid bones, which is usually caused by repetitive, excessive chronic pressure and tension on the forefoot. Damage to the sesamoid bone (stress fractures) can also contribute to sesamoiditis which results in quite a bit of pain, swelling, and ambulatory dysfunction.
Treatment for these conditions is usually noninvasive. Minor cases require a strict period of rest and the use of a modified shoe or a shoe pad with a cutout to reduce pressure on the affected area. Metatarsal pads and/or taping to immobilize the joint as much as possible will facilitate healing. Anti-inflammatory drugs can be used to reduce swelling, and physical therapy is the key to restoring normal joint motion and biomechanical function of the foot and lower leg.
Corticosteroid injections may help reduce pain in cases of hallux rigidus and sesamoiditis, but ultimately the structure and function of the joint should be properly assessed and treated by a physical therapist. Manual joint mobilization techniques and flexor tendon strengthening exercises are used to promote the proper mobility and stability of the first MTP joint. Assessment of footwear and ground surface should also be part of the rehab process, and patients sometimes need to consult with a podiatrist for orthotics.
Addressing all of these factors is essential for return to pain free push off through the great toe when returning to walking or running for exercise after injury. Neuromuscular training if often necessary to balance the body weight in the forefoot and ensure proper push off through the big toe. This can be surprisingly difficult for some patients who may need to change a long-standing gait pattern, but it can certainly be trained and result in performance improvements. The big toe may seem like a small insignificant joint to some when we look at the body as a whole, but its structure and function is very important when dealing with any type of lower extremity injury.