Osteoarthritis of the Thumb CMC Joint

Written by: Tammy Vanevenhoven PT, DPT, CHT

As the season of fall hovers over us and the leaves begin to fall, the temperatures outside continue to fall as well. For those who suffer from arthritic hands stiffness and pain, it can quickly be felt by the changes in the temperature. Osteoarthritis is the most common of all joint diseases. It often affects the larger weight-bearing joints of the hips and knees, but it also commonly affects the smaller joints of the hands; especially the base of the thumb called the CMC joint (carpometacarpal joint). The CMC joint of the thumb is considered a saddle joint that allows the thumb its vast ability to grasp objects of various shapes and sizes, to open doors, jars, and packages, etc. It also allows pinching-- a more precision type movement for writing, buttoning, using scissors, picking up small objects or turning a key. We need our thumbs as they contribute to 60% of our hand function.

Signs and Symptoms of CMC joint arthritis are:

*pain at the base of the thumb after activity

*pain with active movement of the thumb especially with pinch

*morning stiffness

*joint tenderness to palpation

*crepitus (crunching noise in the joint) with thumb movement

*joint deformity with bony nodules felt at base of thumb

*weakness of hand grip (opening a jar, sealed packages, etc.) or with pinch (writing, buttoning, turning a key, etc.)

How is CMC joint arthritis diagnosed?

Usually a standard radiographic x-ray will show joint space narrowing, bony changes such as spur formation, and joint erosion. Based on the x-ray, the arthritic changes are usually classified as mild, moderate, or severe joint destruction.

What can be done non- surgically to help the painful arthritic thumb?

A certified hand therapist (CHT) or an occupational therapist can be of great help in alleviating pain in the arthritic thumb by fabricating a thumb spica splint that stabilizes the base of the thumb while still allowing use of the thumb tip for light pinch and grip activities. Stiffness can be reduced by using a paraffin bath that is composed of paraffin wax and mineral oil which is then melted to a therapeutic warm temperature which molds around the bony prominences of the hand to help soothe pain and improve movement of the joint. Your hand therapist will also educate you on joint protection by recommending built up handles on objects that are difficult to grip such as tools, scissors, writing and eating utensils. Key adapters can also be placed on your keys to allow ease with key pinch. An electric can opener can also be used to avoid stressing the arthritic thumb with a manual can opener. Protecting the hands from the cold weather is very important. Wearing mittens and using warming packs if you like to be outdoors will help keep your hands from getting stiff and painful while you cross country ski, ice fish or while taking a winter hike.

What does the surgery for CMC joint replacement entail?

CMC joint arthroplasty is the most common joint replacement of the arthritic hand. The beak ligament reconstruction, or the LRTI, is the most common surgical procedure performed. The hand has, thankfully, many muscles that perform the same function. They are called “spare parts.” The eroded CMC joint is removed and one of these extra tendons of the hand/wrist is sacrificed and bundled up to fill in the joint space at the base of the thumb. Patients are placed in a cast and often external pins are inserted for extra immobilization.  At four weeks the cast and pins are removed, and the patients are placed in a forearm-based thumb spica splint and sent to therapy to see a certified hand therapist or an occupational therapist that specializes in treatment of the hand. Therapy includes gentle progressive range of motion to restore normal movement of the thumb, fingers and concurrent wrist; which becomes stiff from being in the cast. Swelling control and pain management are treated by working on scar mobility to avoid tendon adherence. Hypersensitivity often occurs from the surgeons having to retract the superficial radial nerve to perform the operation. Therapists can ease this sensitivity by performing desensitization exercises to calm the nerve pain. Restoring functional hand strength while appreciating joint protection and education of patients for life-long care for the arthritic thumb are just some of the various ways your hand therapist can help.

If you would like more information in treating your arthritic hands you can call Advanced Physical Therapy and ask to speak to a certified hand therapist or occupational therapist that can assist you in answering your questions. APTSM New London phone: (920)982-0100.