Coming to Grips With Thumb Carpometacarpal Osteoarthritis

By Eva Briggs, MD

Thumb carpometacarpal (CMC) osteoarthritis (OA) is a long name for arthritis at the base of the thumb joint. It’s also called basal arthritis. By the time people reach their 50s and 60s about one third of women and one tenth of men suffer from CMC OA.

I’m one of them.

Suffer really is the right word because that we use our hands all day long. 

The pain of CMC OA is aggravated by gripping objects. The thumb is required for pinching (like holding a car key), fine manipulation and stabilizing heavy objects. 

In other words, almost everything you do with your hands can aggravate CMC OA.

Gender is one risk factor. Women are more often affected than men. The risk increases with age. Occupations requiring repetitive motion or heavy lifting can lead to CMC OA. Examples are waitressing, keyboarding and factory work. People whose joints are loose — think double-jointed or patients with certain connective tissue disorders — are at increased risk. Their thumbs move around while grasping or gripping. This applies abnormal stress to the CMC joint leading to OA.

The symptom people notice is pain at the base of the thumb. X-rays help determine the extent of the arthritis. It’s important to see a doctor for correct diagnosis because other problems, such as tendinitis, cause pain in that area.

The first step in treatment is to wear a brace. That’s easier said than done if you work at an occupation like healthcare, where you must your hands often. On workdays I estimate that I see 50 patients, which means washing or sanitizing my hands well more than 100 times per day: before and after each patient, before eating, when using the bathroom, after playing with my dogs, etc. But even wearing a brace only at night will help. There are different styles of splints, some hard and some soft. The best splint is probably the one that the patient is willing to wear.

The next step may be a steroid injection into the painful joint. The relief is temporary, but could last weeks or months. Steroid pills are not effective and have more side effects. Injections of hyaluronic acid have been tried but are not very effective and are not FDA-approved. Fat cell injections into the joint attempt to relieve pain by providing a cushion between bony surfaces of the joint. Physical therapy can help strengthen the muscles around the thumb. Adaptive devices such as pen and pencil holders can relieve stress on the CMC joint.

Eva Briggs is a retired medical doctor who practiced in Central New York for several decades. She lives in Marcellus.

A few patients’ disease progresses to the point of surgery. Debriding (scraping damaged joint surfaces) done via arthroscopy can help short-term. Surgery to tighten the ligaments and stabilize the basal joint is another short-term surgical treatment. There are several options for more invasive surgical procedures for longer lasting relief. First is complete removal of the trapezium bone, a small wrist bone, which forms part of the joint. I was surprised to learn that this often provides good pain relief and function. Because this can leave the joint loose or unstable, removal of the trapezium is often combined with tendon tightening surgery. A third option is to replace the joint with a prosthetic implant. Implants actually have a higher failure rate. The recovery from surgery involves a splint or cast for four to six weeks followed by six weeks of physical therapy, so it’s not a quick fix. Full recovery of thumb function takes six to 12 months.

Bad news for the younger generation: frequent texting and other cell phone use might lead to earlier development of CMC OA.