One of the most unique features of the human body is the opposable thumb. Our thumbs have a wide range of motion that allows us to grasp and manipulate large and small objects in our hands with dexterity and strength. This mobility makes the thumb a valuable tool, but it is also what causes the thumb joint to be prone to the wear and tear of osteoarthritis (OA). By some estimates, 60% of hand use depends on the thumb. Because this digit is responsible for so many daily tasks, any pain or loss of mobility in the thumb has a significant impact on daily living. Fortunately, there are many things you can do to manage thumb OA and keep doing your daily activities. With joint-protection techniques, strategies for managing pain, and stretching and strengthening exercises for thumb arthritis, you can preserve hand function. First, let’s take a look at the thumb joint and how it is affected by OA.
When osteoarthritis affects the thumb (CMC joint)
The base of the thumb is one of the most common sites of OA in the hand. The carpometacarpal (CMC) joint is where the metacarpal bone of the thumb meets a bone called the trapezium in the wrist. The trapezium forms a shallow “saddle” into which the metacarpal bone nestles, and the ends of both bones are covered with cartilage, a slippery, cushioning material that allows for smooth, pain-free movement of the joint. The metacarpal bone and the trapezium are connected by bands of soft tissue called ligaments, which support the joint and keep it stable.
OA develops when the cartilage in a joint breaks down and wears away. The CMC joint may be more vulnerable to OA than other hand joints because it withstands significant forces during daily activities. When we pinch something using our thumb, the force at the tip of the thumb becomes magnified 12 times as it is transferred to the CMC joint. So if you are turning a key in a tight lock, for example, that pinching movement may place 10 pounds of force on the thumb tip but 120 pounds of force at the CMC joint. Such forces are quite stressful to a vulnerable joint that lacks stability. If the tip or middle joint of the thumb is unstable because ligaments are loose, even more pinching force transmits to the basal joint. Over time, these stresses may lead to wear and tear on the cartilage. A prior sprain or fracture can also make a thumb joint more vulnerable to OA.
If you have OA of the thumb, you may have pain when opening jars or bottles or turning a key. A diagnosis is based in part on symptoms of pain and tenderness at the base of the thumb. A doctor may verify the diagnosis with an x-ray that shows cartilage loss in the joint.
OA of the CMC joint is more common in women than in men, and it is especially common in women over 40. X-ray studies show that after age 75, 40% of women and 25% of men have thumb OA. Yet not everyone with such x-ray findings has symptoms that lead them to seek treatment; for reasons not well understood, the severity of pain doesn’t always correlate with cartilage loss shown on x-rays.
In early stages of thumb OA, a physician may observe inflammation around the joint and the breakdown of cartilage, which may begin in one area of the cartilage surface and eventually progress to the whole surface area. Osteophytes, or bone spurs, may develop as the OA advances, and the thumb may contract into the palm, making it harder to open the hand. The best treatment in the early stages is a conservative approach that can include joint protection, pain-management strategies, exercises, and medicines. After a physician makes the diagnosis, a hand therapist or occupational therapist may be able to help guide you through an appropriate treatment program. If conservative treatments don’t work for you, other options include injections and surgery. Here’s a look at each of the options.
Strategies for CMC joint protection
An ounce of prevention is worth a lot when it comes to reducing thumb pain. Changing the way you use your thumbs is an important strategy because it reduces the stresses on the CMC joint and prevents further injury. Start by identifying the activities that cause pain, and then look at ways to change how you perform those activities. Here are some tips for protecting your thumb joint during common tasks:
- When lifting a heavy plate or tray, place your palms underneath it rather than grasping the sides.
- Don’t pinch books with your thumbs. Hold the book with one palm flat underneath the book’s spine and the other palm on top to balance the book. Alternatively, place both palms underneath to support the book or put the book on a table and place a palm on top to keep the pages open.
- Enlarge the handles of knives and other tools with foam cylindrical tubing. Larger handles are easier to grasp.
- When cutting with a knife, hold the knife in both hands for strength and leverage, and use a rocking motion if possible. Or try using a pizza cutter.
- When stirring, don’t pinch the spoon with your thumb. Instead, hold it in your palm with your fingers wrapped around the handle. This will help to transfer the stress to larger joints and muscles.
- Grasp a toothbrush or hairbrush with your fingers. Place your thumb alongside your fingers — don’t press it against the brush.
- Lubricate locks that are difficult to turn with a key, or have a locksmith modify them.
- Attach keys to a key holder, a tool with a long handle that acts as a lever. A key holder lets you turn keys with your palm rather than your thumb.
- Use a nonslip rubber or silicone mat when opening jars and bottles. You can place a second mat on the table under a jar to secure it as you loosen the lid. Put a nonslip mat under pans or bowls so you don’t need to hold them as you stir ingredients. A mat can also help you turn faucet handles and open gas caps.
- Choose garden tools that help ease thumb pain. A weeding tool can loosen weeds before you pull them. Enlarged handles or sponge grips on gardening tools can take stress off your thumbs.
- When cutting, use spring-loaded scissors. These are available at fabric or craft stores.
- When writing, use a modified pen such as Pen-Again, whose unique grip places most of the stress of writing on your forefinger rather than your thumb.
- Whenever possible, use electric appliances such as an electric can opener, electric toothbrush, or electric screwdriver.
- Use adaptive devices such as bottle openers and pull-tab grabbers to open containers and packages. When possible, choose containers that are easier on your thumbs. Zip-top bags with a sliding zipper may be easier to open than standard zip-top bags. If using a standard zip-top bag, place it on the table and use your index finger instead of your thumb to close it. Look for shampoos and lotions that come in bottles with pump dispensers instead of bottles that need to be squeezed.
Heat and cold therapy for CMC arthritis
Applying heat or cold to the thumb can help to relieve OA pain. Ice or cold packs can be useful for reducing inflammation, muscle spasms, and pain. However, cold treatment does contribute to stiffness, so it is best not to use it before doing hand exercises. You can buy reusable cold packs and keep them in the freezer, or you can make your own cold pack with a bag of frozen vegetables or a plastic bag filled with ice. Place a towel between the pack and your skin, and apply the pack for 10–15 minutes at a time.
Many people prefer the soothing sensation of heat therapy to cold therapy. Heat therapy can help to reduce pain, decrease stiffness and muscle tension, and relieve muscle spasms. You may find it helpful to use heat therapy before doing activities in which you will need a lot of mobility in your thumb, such as playing the piano. You can apply heat to your hand using hot packs, heating pads, or a paraffin bath. You can buy a hot pack filled with gel or flaxseed, heat it in the microwave, and apply it to your hand. Or you can make your own hot pack by taking a sock, filling it with uncooked rice, and tying off or sewing the end. Before each use, put the sock in the microwave for 1 minute and shake to distribute the heat. You can rest your hand on the sock or wrap the sock around your hand. An electric heating pad can also be helpful. With any hot pack or heating pad, place a towel between your skin and the heat source, and apply the heat for up to 20 minutes at a time.
Another effective way to apply heat to the hand is to use a paraffin bath. Paraffin baths are small tubs in which you heat a mixture of paraffin wax and mineral oil. You dip your hand into the wax mixture several times (letting the wax harden each time) to form layers of heated wax. You then place your hand in a plastic bag and cover it with towels or an insulated mitt to retain the heat.
Sometimes the muscles around the thumb can become tight. You can do a self-massage by rubbing the area around your thumb with your other hand or by placing a golf ball or tennis ball on a table and rolling your hand over it. You can also use an empty roll-on deodorant container to perform the self-massage.
Here’s another idea: Join your hands at the space between the thumb and the index finger and push your hands into each other. This way both hands both get a stretch and a gentle massage without placing a lot of stress on the thumbs.
Exercises for thumb arthritis
Doing hand stretching and strengthening exercises can help to keep your thumb flexible and the joint stable. Often in thumb OA, the tissue between your thumb and index finger feels very tight. You can reduce tightness and improve thumb flexibility by using heat, doing the massage techniques mentioned above, and then gently stretching your thumb to maintain or increase mobility. Strengthening the muscles around the thumb can help to improve stability at the CMC joint. For sample stretching and strengthening exercises, see Thumb Exercises.
Splints for pain relief
Hand splints can help to relieve thumb OA pain by supporting the joint and reducing its movement. A hand therapist or occupational therapist can fabricate a custom plastic splint that you can then wear during daytime activities or at night. In many cases, the therapist will recommend wearing the splint continuously for three to six weeks. After that, pain usually diminishes, and you can wear the splint just for the activities that contribute to pain, such as gardening or needlework. A research study found that wearing a custom-made splint resulted in some pain relief right away for 76% of people in an early stage of OA. Other research has shown improvements in hand pain and function in people who wore a custom-made splint at night compared with those who did not wear a splint. If the arthritis affects just the CMC joint, then a simple hand-based design may work well. However, if the arthritis affects other carpal bones, then it may be best to choose a splint that immobilizes the thumb and wrist.
Some commercially made splints may provide support. In a recent study in the Journal of Hand Therapy, researchers compared a prefabricated neoprene thumb splint with a custom-made neoprene and plastic splint. Study participants found the softer prefabricated splint to be more comfortable, but they got better pain relief from the custom splint. A hand therapist or occupational therapist can help you choose the splint that is best for you. One study showed that the majority of people who used a splint and were given advice and tools to make everyday tasks easier did not want surgery seven years later. As OA progresses and symptoms worsen, however, splinting may be less helpful.
Some people get pain relief from taking a pain reliever such as acetaminophen (brand name Tylenol) or one of the nonsteroidal anti-inflammatory drugs (NSAIDs). Whereas acetaminophen acts to relieve pain, NSAIDs, which include ibuprofen (Advil, Motrin IB) and naproxen (Aleve, Naprosyn), can also decrease inflammation. Often, acetaminophen is tried first because it does not have the gastrointestinal side effects of NSAIDs, which include stomach upset, ulcers, and bleeding. The risk of side effects increases when you take NSAIDs at high doses for a long period, and when you take other medicines that can cause similar side effects. Be sure to discuss all your medicines, whether prescription or over-the-counter, with your physician.
Injections for the CMC joint
If your pain is not relieved with splints and medicine, your physician may consider injections. Injecting a corticosteroid such as methylprednisolone directly into the CMC joint may relieve some pain and reduce inflammation for up to several months. However, most physicians do not recommend having more than three or four corticosteroid injections a year because of concerns that more frequent use of corticosteroids may lead to weakening of the joint capsule and further breakdown of cartilage.
When other options fail, there are many surgical options available. If you have persistent pain and disability that affect most daily activities despite the use of splints, exercises, and medicine, you may want to seek a surgical consultation. Whether a surgical procedure is right for you depends on the severity of your pain and loss of function, the state of the cartilage and other tissues in and around the joint, and how much mobility you require in your thumb to do your daily activities. Some procedures, such as ligament reconstruction, can be done in the early stages of OA to help relieve symptoms and slow the progression of OA. Surgical options in the later stages of thumb OA include arthroplasty, or joint replacement, and arthrodesis, or joint fusion.
Arthroplasty involves replacing or reconstructing part or all of the affected joint. In a procedure called ligament reconstruction and tendon interposition, the surgeon removes the trapezium, places a graft from one of your tendons into the open space, and repairs the ligament that connects the trapezium to the metacarpal bone. Research indicates that this procedure resulted in pain relief and satisfaction for 85% of the people who underwent it. In a similar procedure called a suture suspension arthroplasty, the trapezium is removed without being replaced by a tendon graft, and a sling of suture material is used to keep the metacarpal bone in position.
Some arthroplasties use a silicone or silicone-plus-metal implant to replace the parts of the joint that are removed. However, surgeons tend to prefer using tendon grafts instead of joint implants because implants can wear or cause other complications.
This procedure involves using pins, plates, or screws to fuse the trapezium and the metacarpal bone together. Arthrodesis provides stability and relieves pain, but the fused joint loses mobility, so it may not be possible to open the joint wide and grasp large objects. Arthrodesis is best for people who have advanced OA in the CMC joint but are young and need good grip and pinch strength over mobility.
A hand surgeon can perform arthroplasty or arthrodesis on an outpatient basis. (You can find a hand surgeon in your area at the Find a Hand Surgeon section of the American Society for Surgery of the Hand Web site. After surgery, you will probably wear a splint or cast on your thumb and wrist for as long as six weeks. Afterward, you will work with a hand therapist to regain hand strength and mobility, and you should be able to get back to your normal activities within six months.
Thumb pain related to OA doesn’t have to be disabling. Consulting with a certified hand therapist or occupational therapist may provide some useful strategies for relieving pain and improving mobility and strength to allow you to keep doing the activities you enjoy. You can find a hand therapist at the Hand Therapy Certification Commission Web site. To find an occupational therapy or rehabilitation clinic, visit the American Society of Hand Therapists Web site. If you protect your thumbs, they’ll serve you well for a long time to come.