Arthritis of The Thumb
Arthritis of the 1st Carpometacarpal Joint
The first carpometacarpal joint (CMCJ) is the joint at the base of the thumb, where it joins the wrist. It is a remarkable joint because it permits the thumb to move in many directions. However, it is susceptible to arthritis, particularly in women and in older patients. There are several ways it can be treated.
What is the First Carpometacarpal joint?
The bone that connects the thumb to the wrist is known as the first metacarpal (the second to fifth metacarpals are the bones of the palm of the hand, connecting the fingers to the wrist). The carpusis the cluster of small bones that make up the wrist. One of these bones is called the trapezium, which is the bone on which the first metacarpal bone pivots to give the thumb its range of motion. Together this joint is called the first carpometacarpal joint or, less commonly, the trapeziometacarpal joint (TMC).It plays a crucial role in all the movements we count on our thumbs to perform: many everyday activities rely on gripping, twisting and manipulating movements. When arthritis develops in this joint it can have a profound effect on quality of life.
About First CMCJ Arthritis
The type of arthritis that usually affects this joint in isolation is osteoarthritis, characterised by a degradation of the cartilage that protects the bone surfaces. Osteoarthritis causes pain which typically results in decreased movement; this in turn can cause muscle loss and weakness in the joint.Many sufferers first notice an ache at the base of the thumb, sometimes also perceived in the thumb itself or the nearby areas of the wrist and forearm. This can be the first sign of osteoarthritis affecting the first CMC joint. The main symptoms are stiffness, swelling, and pain, which are sometimes relieved by gentle use but cannot stand up to repeated movement. Since our thumbs are used in so many activities, first CMCJ arthritis can be a rather disabling condition.
Women are affected disproportionately to men, particularly with age. The condition is noted to affect postmenopausal women in particular, who have around a twenty times higher incidence of first CMCJ arthritis than the general population.
Treatment for First CMCJ Arthritis
Treatments to control the pain of First CMCJ Arthritis fall into three main areas: support and protection, joint therapy and surgery. Using a brace or support can be very helpful in reducing pain associated with specific activities, for example work or regular household tasks. Some ready-made supports are available, or it may be that a made-to-measure support is necessary - it depends on the person and the specific difficulties.
Physiotherapy often gets results with strengthening and pain relief. An alternative treatment is a cortisone injection directly into the troublesome joint: this can help reduce the inflammation, which in turn gives relief from the pain for a period of time - typically for weeks, or possibly for up to a year.
Three different types of surgery are among the options, as follows:
This procedure involves removing the small bone at the base of the thumb, called the trapezium, and creating a fibrous ‘false’ joint using soft tissue from the adjacent area. The aim is to reduce pain and leave the thumb with adequate movement. Trapeziectomy is usually followed by 6 weeks in a cast to allow a stable joint to form.
Depending on the condition of the trapezium and scaphoid bones, it may be an option to join them together (fusion) to create a stable base for movement and reduce the friction in areas affected by arthritis.
Thanks to advances in technology it is now possible to consider replacement of the surfaces of the joint using a surgical implant. It is not necessarily the best option as there is a likelihood of needing another operation at some point in the future should the implant become loose or require maintenance. Nevertheless, it is an option you may wish to consider when fully informed. The immobilisation period following the operation is usually a minimum of 6 weeks; most patients will be able to return to normal activities within 3 months, although it can take a year or more to regain full strength and stamina in the thumb.