Basal thumb arthritis or osteoarthritis of the first carpometacarpal (CMC) joint is a common condition seen in hand clinics across the UK, Europe and USA. The age adjusted prevalence as referenced by a number of studies varies between 2%-7% in adult men and 8%-15% for adult women. With increasing age and body mass impacting on prevalence of osteoarthritis in the carpometacarpal, as life expectancy increases occurrences of CMC arthritis is likely to increase further. Up to 4 million Britons, 13 million Americans and 20 million Europeans suffer from Thumb Arthritis. The CMC joint is the second most common site where arthritis occurs. The carpometacarpal joint of the thumb is known as nature's universal joint. It is a saddle-shaped joint and allows a wide range of movement in three planes. This high level of mobility does render the joint prone to degeneration. Osteoarthritis is a debilitating disease that causes pain, swelling, instability, deformity, loss of motion and weakness making everyday life very difficult.
Just imagine not being able to open a tin, peel or chop vegetables, dry yourself, pick up a cup of tea. These are everyday activities that we take for granted.
Anatomy of the thumb carpometacarpal joint
The thumb carpometacarpal (CMC) joint is where the metacarpal bone of the thumb attaches to the trapezium (carpal) bone of the wrist (see diagram below) It is sometimes called a basal joint.
What is osteoarthritis?
Osteoarthritis (OA) is the most common form of arthritis and affects mainly the joint's cartilage and surrounding bone tissue.
There are many factors that can increase the risk of developing OA; for example it is more common in females over the age of forty, and is more likely to develop in a joint that has had a previous injury or operation. A joint is where two bones meet to produce movement. Muscles pull on tendons, which are attached to the bone to produce movement.
The ends of the bones are covered in a smooth tissue called cartilage that cushions the joint and creates a space between the two ends of the bone making up the joint.
The joint is held together within a capsule, which contains a thick fluid (synovial fluid), providing lubrication to allow smooth movement. Surrounding ligaments and muscles also maintain the stability of the joint.
When OA develops in a joint, the cartilage gradually roughens and becomes thin, and the bome thickens. The bone at the edge of the joint grows outwards in bony 'spurs' (see diagrams) and excess synovial fluid can be produced causing the joint to swell. This can mean that you avoid using these joints, subsequently causing the surrounding muscles to weaken.
In severe OA, the cartilage can become so thin that it no longer covers the joint surfaces, and damage is caused to the bone ends by them grinding against each other during movement. This can, over time, change the shape of the joint creating a deformity, as the joint is no longer held in it's natural position.
Common symptoms of CMC OA are:
Treatment of arthritis of the CMC joint of the thumb is based on the severity of the condition. The main stay of initial treatment of basal thumb arthritis of any stage is activity modifications, rest, non steroidal anti-inflammatory drugs and muscle strengthening exercises. Corticosteroid injections of the joint can be useful when conservative measures have failed. Once all these measures have failed including injections, surgery may be required. The indications for surgery in patients with basal thumb arthritis are persistent pain and functional disability after failed conservative treatment. Various surgical procedures are available. These range from soft tissue procedures in the early stage of the disease before joint destruction to excision of the trapezium for advanced stages of osteoarthritis.
Cartiva® SCI for CMC
Cartiva® SCI is a revolutionary implant that has been designed to replace the damaged cartilage surface and has been used to provide pain relief and improve joint function in patients suffering from basal thumb arthritis. Advantages of a Cartiva SCI for CMC implantation include a less aggressive, quicker procedure and potentially quicker recovery than other surgical procedures. Also because the procedure preserves normal joint anatomy and other surgical procedures remain viable options if a revision is required at some later date. Cartiva SCI is made from Polyvinyl alcohol (PVA), a material that has been used in a number of medical device applications for more than 20 years. Cartiva SCI is designed to mimic the properties of natural cartilage.