Around every joint in the body is what is called a joint capsule. This capsule is what holds the bones each side of the joint together and keep the fluid in the joint that lubricates it in place. Areas of that joint capsule tend to be thicker and stronger. These thicker and stronger parts are the ligaments that give stability to the joint. In the joints at the base of the toes in the foot, the metatarsophalangeal joints, the thickened bottom part of that joint capsule is normally referred to as the plantar plate. This needs to be thicker and stronger since we place a lot of force through it whenever running and walking and it has to be able to resist it. Sometimes that force may be so high it will strain that plantar plate or ligament and it can become damaged. When this happens, the technical term is plantar plate dysfunction and in some cases it can go on to a tiny tear in the plate, so will get referred to as a plantar plate dysfunction.
Usually the signs and symptoms for this are pain under the joint when walking or on deep touch or pressure, with the pain being more established toward the front side of the joint. It frequently only impacts one joint but occasionally several can be affected. The toe might be moderatly raised as the plantar plate is can not hold the toe down because of the injury to its strength from the strain or tear. Generally the diagnosis is pretty obvious, but if not an ultrasound assessment can often be carried out to confirm it. The treatment usually consists of strapping the toe to keep it in a plantarflexed position so the plantar plate is under less load to give it a chance to recover. A metatarsal pad can also be used in the shoe to keep weightbearing from the damaged region. If these kinds of measures don't help, then a surgical repair of the plantar plate tear may be needed.