Blog post by Erika Lassig
If you have pain in your wrist or thumb when you write, use scissors, hold a knife or pinch things and you’re over 50, you may have base of thumb arthritis. This painful condition can prevent you from doing basic everyday things as well as leisure activities such as gardening or knitting. The good news is that you don’t need to give up four favourite hobbies!
The problem occurs from wear and tear of the mobile joint at the base of the thumb where it joins the wrist. We call this the first carpometacarpal (CMC) joint. The CMC joint is a saddle joint where the long bone of the thumb (first metacarpal) forms the rider and the small wrist bone (trapezium) is the saddle. The joint is highly mobile, allowing for the ability to oppose and rotate the thumb to form a wide variety of grip patterns from open grasp to pen grip to key pinch.
Unfortunately, forces at the tip of the thumb are magnified twelve times at the base, meaning that 1kg or pinch force translates into 12kg of force through the first CMC joint. For many people over time the smooth protective cartilage that covers the joint surfaces wears away. What’s left is bone rubbing on bone which is painful and causes swelling of the joint which in turn stretches the supporting soft tissues. Over time the joint may slip out of alignment causes a “z” deformity of the thumb.
There is a surgical joint replacement procedure that can be done in very painful cases, but the surgery is painful and has a 6-month recovery time. Despite the wear and tear nature of first CMC arthritis, therapy can be very helpful in reducing pain and preventing progression of the disease.
Hand therapy for base of thumb arthritis takes a three-pronged approach. Firstly, a small thumb splint helps to rest the CMC joint, minimise forces through the joint and reduce pain during functional tasks. Secondly, exercises aim to strengthen the supporting muscles around the joint to prevent it slipping out of alignment. Lastly, your therapist will discuss activity modification and show you how to do the things that are important to you without pain and to reduce load on the CMC joint.
So, if you’re experiencing any base of thumb arthritis pain, don’t wait. Contact The Hand Recovery Centre today and get back to what you love sooner!