Arthritis of the big toe joint is common, and can be particularly disabling. Options to manage this condition non-surgically are few, given the express need for the big toe joint to attempt bending during the walking cycle. This article discusses the cause of this painful arthritis, as well as surgical treatment options to relieve pain.
The big toe joint consists of the first metatarsal bone forming the 'ball' of the joint, and the initial bone of the big toe (the first proximal phalanx) forming the 'socket'. It has an important role in how the body moves when walking, and limitation of its motion forces other joints and muscles to function abnormally to take up the slack. Arthritis of this joint, or cartilage wear, occurs when there is abnormal pressure or positioning of the joint bones. This results in grinding down of the smooth cartilage that covers the bone surface at the joint, allowing for smooth motion. As this cartilage erodes, the bone underneath begins to become exposed, and parts of the joint surface start to see bone rubbing during joint motion.
In addition to this, thickened spurs of bone can develop along the margins of the joint, further hampering motion. When bone grinds on bone and when spurs limit joint motion, pain usually results. This condition will gradually worsen, leading to destruction of much of the joint surface. In severe cases, the bones will even partially fuse together. The structural cause of arthritis can be due to many factors. Natural bone structure can contribute to this, such as seen in people with longer or shorter first metatarsals, as well as first metatarsals that are angled too steeply in elevation or declination with respect to the ground surface. Bunions and other rotational deformities of the big toe joint can also contribute to cartilage wear and tear. Fractures, crushes, sprains, and other injuries to the joint can also result in arthritis after awhile. Finally, certain body-wide joint-affecting diseases will cause joint erosion as well, such as seen with rheumatoid arthritis and psoriasis.
Non-surgical treatment is limited, consisting of measures to limit the painful motion of the joint and decrease the resulting inflammation. Stiff soled shoes and specialized custom foot inserts can be used to limit the painful motion. Anti-inflammatory medications and steroid injections can reduce the inflammation, although this is not nearly as effective as it is in larger joints like the knee. However, the unique structure of the big toe joint generally necessitates surgical treatment in many cases of arthritis. Surgical treatment is divided into procedures that destroy the joint and procedures that maintain the joint (in the case of mild arthritis). When joint destruction is severe or significant, the joint destruction technique is chosen as the cartilage of the joint will have to be replaced or removed entirely in order for the pain to be resolved.
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 can replace the ball of the joint, the socket, or both. 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 surgeon is not advising their use, 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. It differs from painful arthritis that is partially fused in that there are still areas of motion in those cases that produce pain. 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. Eventually the body adapts to this, although some minor strain can occur to the joint in the middle of the big toe, or the complex of joints in the middle of the foot. If the arthritis is only mild, the surgeon may elect to preserve the joint. In this technique, the surgeon simply 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.
Regardless of the selected procedure, repair of the big toe joint is generally successful, with good long term results. Complications, including infections and implant or hardware failure, do occur. However, they are uncommon and most patients are restored to pain-free or significantly reduced pain-limited walking within a month or two following the surgery. Nearly all podiatrists (and a small number of specially trained orthopedic surgeons) perform these procedures. If one is suffering from big toe joint arthritis, a visit to their foot and ankle specialist can lead to relief and restoration of activity.
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