The universal joint at the base of the thumb, between the metacarpal and trapezium bones, often becomes arthritic as people get older. It is osteoarthritis, which is loss of the smooth cartilage surface covering the ends of the bones in the joints. The cartilage becomes thin and rough, and the bone ends can rub together.
Osteoarthritis can develop at any age, but usually appears after the age of 45. It may run in families, and it sometimes follows a fracture involving the joint many years before.
Arthritis of the basal joint of the thumb is common in women and rather less common in men. X-rays show it is present in about 25% of women over the age of 55, but many people with arthritis of this joint have no significant pain.
1. Pain at the base of the thumb, aggravated by thumb use.
2. Tenderness if you press on the base of the thumb.
3. Difficulty with tasks such as opening jars, turning a key in the lock etc.
4. Stiffness of the thumb and some loss of ability to open the thumb away from the hand.
5. In advanced cases, there is a bump at the base of the thumb and the middle thumb joint may hyperextend, giving a zigzag appearance.
The options for treatment include:
1. Avoiding activities that cause pain, if possible.
2. Analgesic and/or anti-inflammatory medication. A pharmacist or your family doctor can advise.
3. Using a splint to support the thumb and wrist. Rigid splints (metal or plastic) are effective but make thumb use difficult. A flexible neoprene rubber support is more practicable.
4. Steroid injection improves pain in many cases, though the effect may wear off over time. The risks of injection are small, but it very occasionally causes some thinning or colour change in the skin at the site of injection. Improvement may occur within a few days of injection, but often takes several weeks to be effective. The injection can be repeated if needed.
5. Surgery is a last resort, as the symptoms often stabilise over the long term and can be controlled by the non-surgical treatments above. There are various operations that can be performed to treat this condition. These are listed below:
a. Osteotomy, which means cutting and realigning the metacarpal bone next to the arthritic joint.
b. Removal of the trapezium which is removal of the bone at the bottom of the thumb, which forms one surface of the arthritic joint, sometimes combined with reconstruction of the ligaments.
c. Fusion of the joint, so that it no longer moves.
d. Joint replacement, as in a hip replacement.
e. Denervation, which means cutting small nerve branches that transmit pain from the arthritic joint.
Removal of the trapezium is the most commonly performed operation. Mr Mason will advise you on the best options for your thumb.
This involves removing the arthritic joint at the bottom of your thumb and replacing it with an artificial joint.
When is surgery needed?
This operation is performed to relieve pain in the arthritic joint at the bottom of your thumb. Most surgeons would encourage you to try painkillers, splints, activity modification, aids to help with certain tasks (opening jars etc) and steroid injections into the painful joint before considering surgery. The majority of patients with thumb base arthritis can manage their symptoms in this way without ever needing an operation.
Which operation is the right one for me?
The results from replacing this joint have only just started to be reliable enough for this operation to be recommended. Your surgeon will discuss other options with you in clinic because of this. To be considered for a replacement of this joint the next joint along should not be arthritic and the trapezium bone must still be big enough for the replacement to sit in (see diagram). You should read the list of possible complications for this operation carefully and comparethem to those for the standard operation for this condition (see ‘Trapeziumectomy’). It is helpful to consider this type of replacement compared to hip and knee joint replacements.
By 10 years after a hip or knee joint replacement most surgeons would be unhappy if less than 98% of their patients did not still have their replacement in place working well. That would mean that 2 in 100 patients would have had to have the joint taken out or re-done for some reason or another. For replacements of the thumb base joint results from modern designs are only just becoming available for up to 5 years after surgery. For these replacements 90% of the joints are now still in and working at that stage. That means that 10 of 100 patients will have had the joint taken out or re-done for some reason by 5 years after their first operation. These results are reasonable but are not as good as hips and knees yet. Surgeons who offer this sort of joint replacement believe that recovery is slightly quicker with this procedure than a trapeziumectomy and that the function of the thumb is slightly better than with a trapeziumectomy. Nobody has conclusively demonstrated this yet however.
Post Operative Course
Day 1 – 14
• A dressing and padded bandage with a plaster is applied after the operation
• Keep the dressings clean and dry
• Keep the arm elevated in a sling or on pillows to reduce swelling
• Start moving all the joints that are not immobilised as soon as possible to prevent stiffness
• Take painkillers before the anaesthetic wears off and as necessary thereafter
2 – 3weeks
• An appointment will be made for you to see the hand therapy team
• They will check your wound and show you exercises for your thumb.
3 Months
• By this stage most people will have returned to most activities.
• Hand therapy will continue if needed.
Driving
You may drive when you feel confident to control the car, even in an emergency. For this surgery it can be up to two months before many people feel this confident. The Hand Therapy team will discuss this with you in more detail. You should discuss with your insurer if you are considering driving with a splint in place.
Time off Work
This will vary depending on the nature of your job. Sick notes can be provided on the day of your operation, at your clinic visits and by your own GP.
