Arthritis of the Foot and Ankle
Arthritis is inflammation resulting from the degeneration of cartilage in a joint causing pain, swelling, and stiffness. Arthritis of the foot and ankle joints can occur due to fractures, dislocations, inflammatory diseases, or congenital deformities. The joints most commonly affected by arthritis are:
- The ankle joint (between the tibia, fibula and talus);
- The subtalar joint (the joint below the ankle joint, formed by the calcaneus and talus);
- The big toe joint (between the 1st metatarsal and 1st proximal phalanx);
- The midfoot (Lisfranc) joints, usually at the 1st, 2nd or 3rd tarso-metatarsal joints.
There are three major types of arthritis affecting the foot and ankle:
Post-traumatic arthritis is arthritis that develops following an injury. This condition may develop years after the trauma such as a fracture (broken bone), dislocation, or even severe sprains (ligament tears). Unlike the arthritis that mainly affects hips and knees, post-traumatic arthritis is the most common type of arthritis in the ankle.
Osteoarthritis, also called degenerative joint disease, most often occurs in older people. This disease affects cartilage, the tissue that cushions and protects the ends of the bones in a joint. With osteoarthritis, the cartilage starts to wear away over time. In end-stage arthritis, the cartilage can completely wear away, leaving nothing to protect the joint and resulting in bone-on-bone contact. Osteoarthritis also results in the formation of bone spurs (osteophytes) at the margins of the joint, as well as bone loss (cysts) and hardening of the bone (subchondral sclerosis).
Rheumatoid Arthritis: This is an auto-immune disease in which the body's immune system (the body's mechanism for fighting infection) attacks healthy joints and soft tissues, causing an inflammatory arthropathy. It can cause pain, stiffness, swelling, and loss of function in joints. Rheumatoid arthritis affects mostly joints of the hands and feet and tends to be symmetrical. This means the disease usually affects the same joints on both sides of the body (both feet) at the same time and with the same symptoms.
Other types of inflammatory arthritis include gout (commonly affecting the big toe), psoriatic arthritis, juvenile idiopathic arthritis, lupus and ankylosing spondylitis.
The major symptoms of foot and ankle arthritis include pain or tenderness, swelling, and stiffness in the joint with a limited range of motion.
Diagnosis of Arthritis
The diagnosis of foot and ankle arthritis is made with a medical history, physical examination and weight-bearing X-rays of the foot or ankle. Different types of arthritis have different appearances on x-rays. For example, osteoarthritis commonly causes joint space narrowing, subchondral sclerosis, subchondral cysts and osteophytes. Rheumatoid arthritis, in contrast, causes periarticular erosions and joint subluxations/dislocations.
In some cases, advanced imaging is required, such as a bone/SPECT scan, computed tomography (CT) scan or magnetic resonance imaging (MRI) scan. Ultrasound does not play a significant role in the diagnosis of foot arthritis, but can be a very useful tool for image-guided injections into joints.
Treatment of Foot and Ankle Arthritis
The first line of treatment should always be non-operative. This includes:
- Medications - painkillers (analgesics) and anti-inflammatories (NSAIDs)
- Orthotics, such as insoles with certain supports, pads or posts
- Shoe-wear modifications
- Weight loss
- Injections (local anaesthetic and corticosteroids)
Surgery may be necessary if your symptoms don’t improve with conservative treatments. Surgery performed for arthritis of the foot and ankle broadly falls into three categories: joint preserving surgery, joint replacement, and joint fusion.
Joint preserving operations aim to clean up, re-align, offload or promote repair of a partially arthritic joint. Examples include removing bony spurs around joints causing impingement and loss of movement; debridement and microfracture of areas of cartilage damage; or re-alignment of abnormal biomechanics with bone cuts.
Joint replacement, also known as arthroplasty, involves replacement of the damaged joint with an artificial implant. Total ankle joint replacement involves removal of the damaged surfaces of the tibia and talus, and replacement with metal implants on either side of the joint with a plastic liner in between them. Read more about ankle replacement here. Big toe arthritis (1st MTP joint) can be treated with either metal implants, or resurfaced with a synthetic cartilage implant. The goal of any joint replacement is to relieve pain and restore the normal function of the joint.
Joint fusion involves removing the damaged joint surfaces and positioning them together in order to get them to knit together. Screws and plates are often used in order to hold the joint in the ideal position until the bones unite (fuse). Fusing an arthritic joint eliminates pain by stopping movement of the damaged joint surfaces. Read more about ankle fusion, subtalar joint fusion, and great toe fusion.
Arthroscopic surgery is a procedure during which the internal structure of a joint is examined for diagnosis and treatment of problems inside the joint. In arthroscopic examination, a small incision is made in the skin through which very small instruments that have a small lens and lighting system (arthroscope) are passed. Arthroscopy magnifies and illuminates the structures of the joint with the light that is transmitted through fibre optics. It is attached to a television camera and the interior of the joint is seen on the television monitor. A variety of probes, forceps, knives, shavers, and other instruments can then be used to clean the joint area of foreign bodies, inflamed tissue, or bony outgrowths (spurs).
Some joint preserving procedures and joint fusions can be performed using arthroscopic techniques, which minimise the size of the cuts made in the skin, as well as limiting the amount of soft tissue dissection required.