Big toe joint arthritis is the most common form of arthritis seen in the foot. The big toe joint is very important to the overall function of the foot during walking. When that joint is arthritic, walking becomes painful, and even limited. This in turn leads to difficulty in walking, and ultimately in one's ability to stay active. Early treatment can be of benefit, especially in avoiding the development of more serious forms of the arthritis.
The cause behind arthritis of the big toe joint can be varied. Usually it is related to joint tissue destruction due to mechanical causes. The joint itself is the joining of one of the toe bones with the long 1st metatarsal bone in the foot. Each adjoining end of these bones is covered in a slick material called cartilage, which allows the bones to gently slide on each other. When arthritis forms, the smooth cartilage is worn down, and the bones begin to grind on themselves. This causes pain and inflammation. The factors that contribute to this wearing of the cartilage often start in the womb. The position of the 1st metatarsal often determines the stress the joint endures over a lifetime. Factors that contribute to the eventual development of big toe joint arthritis are excessive length or shortness of the 1st metatarsal compared with the 2nd metatarsal next to it, and excessive elevation of the bone compared to the ground level. Excessive mobility due to flat feet can also contribute to the joint damage, as well as the presence of a bunion deformity. Arthritis can also develop as a result of fracture or joint surface injury from some type of trauma. The traumatic event could include a heavy weight dropping on the joint, or kicking and stubbing the toe with a lot of force. Over time, the injury will lead to destruction of the joint cartilage, especially if a fracture went through the joint surface.
Treatment of big toe joint arthritis involves either protection of the joint from further damage or fixing the damage itself. Big toe joint arthritis is somewhat different from large joint arthritis, such as the knee, in that it does not respond as well to conservative measures like joint injections and anti-inflammatory medications. These measures may help temporarily, however the unique nature of the big toe joint, and the force and mass of the body weight it carries, tends to allow a quick decline back into pain and inflammation. The use of structural support seems to help decrease the forces of the body on the joint and improve the inflammation in milder to moderate cases. This support includes stiff soled shoes to reduce the 'bendability' of the joint, as well as the use of prescription custom shoe inserts with a stiff extension under the big toe joint to further limit joint motion. Over time this will lessen the wearing of the great toe joint surface, but will not fix the damage already done. Surgical treatment is needed in many cases of big toe joint arthritis. Surgical treatment is divided into procedures that destroy the joint and procedures that maintain the joint (in the case of mild arthritis). Severe arthritis requires that the joint be destroyed or remodeled completely to relieve the pain. This is done by either using an implant or fusing the bones together. The choice of whether to use an artificial implant or fuse the joint surgically is up to the health of the patient and the preference of the surgeon. Joint implants have been in use for fifty years, and are made of metal or silicone gel. Various designs have been used over the years. There are advantages and disadvantages to each design, and certain conditions like diabetes with nerve disease, poor circulation, and obesity limit their use. Their lifespan is much longer than hip or knee implants, which have to be replaced after a certain number of years. The motion restored by these implants is rarely equal to the motion of the joint before the onset of arthritis, but in generally is significant enough to relieve all motion pain and limitation. When these fail, or if the arthritis is so severe the joint is nearly fused already, a joint fusion is the preferred method of relieving joint pain. This procedure fuses the bones across the joint, resulting in no motion at all. By removing all motion, the joint is no longer painful, leading to a stiff lever upon which the foot rolls off during the walking cycle. Mild cases of arthritis call for procedures that preserve the joint. In these techniques, the surgeon usually removes any bone spur limiting motion, and drills holes in the eroded areas of cartilage. The drilling promotes growth of a tissue called fibrocartilage, which is a rough form of cartilage that is not as functional as regular joint cartilage, but is better than the bare bone below. It is usually necessary to address the underlying structural problem if this procedure is selected, as leaving the reason behind the arthritis alone will simply result in further arthritic change years down the road. These additional procedures could include procedures to elevate, lower, shorten, or shift over the first metatarsal back to a proper position based on the underlying structural problem. Often a bunion is corrected if present. Follow-up with long term orthotics foot supports is usually needed, along with periodic monitoring.