Arthritis of thumb (Basal joint arthritis)
What is arthritis of thumb?
Arthritis of thumb base is a disabling condition, which significantly impairs activities of daily living. It’s because thumb constitutes around 40-50% of hand function and most of our activities involve using our thumb. The cartilage at the ends of bones in normal joints is essential for smooth gliding of the joints. In patients with arthritis, the cartilage is gradually lost, leading to pain, stiffness and swelling of joints. Arthritis could be due to wear and tear (osteoarthritis) or due to inflammatory disease (Rheumatoid, Psoriasis, Gout etc) that affects one or more joints of the hand. It usually affects both hands.
It is more common in women than men (10:1) with the age of 40 years and above. The risk factors of arthritis in the thumb are jobs causing repetitive stress on the thumb, injury or a fracture, long-term computer work and obesity. Thumb base arthritis reduces pinch grip and patients struggle with simple activities like opening a jar, turning doorknob or a key.
What are the symptoms of arthritis of thumb?
The common symptoms of arthritis are pain, swelling and tenderness at the base of the thumb. You may feel the pain most when you perform activities such as opening a door, turning a key etc. In advanced stages pain can be present even at rest and could wake you up from sleep. Discomfort is felt after a prolonged use of the thumb and you may also feel grinding or grating sensation in the thumb. There can be a loss of strength especially when you grip or pinch anything. The joint can sublux leading to a bony prominence or bump that can be seen at the base of thumb. In advanced arthritis, the hand span (thumb and index finger) reduces and will lead to compensatory hyperextension of the thumb metacarpo-phalangeal joint.
How is it diagnosed?
Your surgeon will discuss your symptoms, past medical history and prior injury. He will perform a physical exam to check the range of motion and crepitus (a grinding sound) in your thumb. He will order an X-ray test to find out the extent of damage, bony spurs (bony projections) and joint subluxation. In some cases your surgeon can ask for further investigations like CT scan, Ultrasound scan and MRI scan. He may also check for carpal tunnel syndrome if the arthritis is located at the base of the thumb.
What happens if nothing is done?
If arthritis of thumb is left untreated, it leads to severe damage to the thumb resulting in severe pain, swelling and tenderness at the base of the thumb. You will not able to perform simple activities with the thumb – like buttoning your shirts, tying shoelaces etc. Your condition will worsen over time as arthritis is a progressive disease. In advanced stages the joint can sublux/dislocate, reduce hand span and will start affecting other thumb joints causing laxity and weak grip.
How is it treated?
Arthritis cause different symptoms in different individuals. There is no cure for arthritis, treatment can alleviate your symptoms. It can be treated both conservatively and surgically. Conservative treatment involves anti-inflammatory medicines, splint application, steroid injection, activity modification and hand therapy.
Surgery is indicated in-
- Failure of conservative treatment
- Advanced arthritis
- Severe pain
- Unstable joint
- Joint subluxation/dislocation with reduced hand span
- Patient preference
What are the non-operative treatments?
The non-operative treatment includes-
- Activity modification- you should limit all the activities that can provoke pain. Repeated use of the thumb should be avoided.
- Immobilisation- your surgeon can give you a splint to wear to protect the thumb from injury. It supports the joint and relieves the stress on the joint during frequent use.
- Cold application- In flare ups of arthritis, application of ice packs helps to reduce pain and swelling of the thumb. You can apply ice packs 5-15 minutes many times a day.
- Medicines- Painkillers like paracetamol or codeine are given to relieve pain. Topical painkillers are given in the form of gel or cream that can stimulate nerve endings and reduce pain by blocking their supply to the brain.
Anti-inflammatory medicines such as aspirin or ibuprofen are prescribed to control swelling and pain. It is advisable to take these medicines for a short term with food as they can damage your stomach and kidneys.
- Steroid injection– steroid injection (cortisone) in the affected joint relieves pain. However, it usually provides temporary relief of pain and inflammation of the thumb.
- Hand therapy-Hand therapy is recommended to the patient to restore normal function and strength of the thumb. The affected joint is treated with heat application, splinting and the patient is encouraged to regularly exercise the thumb. The exercises can improve the strength and can help in regain the full range of motion of the thumb.
What does the operation involve?
The operation aims at the restoration of range of motion and function of the thumb with the relief of the pain. The options are debridement, trapeziectomy & stabilisation and CMCJ replacement.
Trapeziectomy +/- stabilisation: The arthritic bone is removed with a small cut in the base of your thumb. Though majority of the patients cope well with this simple procedure, some notice weakness of pinch grip, pain and instability. The author usually stabilises the thumb with anchor, tight rope or tendon based on the activity level of the patient.
Joint replacement: The affected joint is replaced with a plastic cup and metal ball like hip replacement. Though the early outcomes are encouraging, there are no long-term results in the literature. Even if the arthroplasty fails, there is still the option of trapeziectomy & stabilization.
Arthroscopic debridement: This procedure is the least invasive and could be beneficial in early stages of arthritis with stable joint and failed conservative treatment.
Fusion: Though this has been suggested for younger patients, the procedure could lead to stiffness, non-union etc.
Denervation: Transect (cut) the nerves that transmit pain around the joint. This will reduce pain, however the deformity will remain the same.
- The operation is conducted as a day case under local anaesthesia. An incision is made on the skin of base of the thumb.
- The Skin is closed using absorbable sutures. The operation takes usually 1-2 hours and the majority of the patients are discharged on the same day.
What happens after surgery?
- The local anaesthetic wears off 4-10 hrs after surgery, patients are encouraged to start taking painkillers before the pain starts i.e. on return home and for at least 48 hours from there. This way most of our patients report little or any pain.
- Your thumb is rested in a half cast for 2 weeks to protect it from injury and allow proper healing. You have to keep your hand and wrist elevated (above the level of your heart) and keep moving your fingers, elbow and shoulder to maintain the flexibility and stiffness of its joints.
- The patient is reviewed in clinic around 2 weeks following the operation for wound check and hand therapy. Usually the half cast is removed and splint applied for next 4-8 weeks and the exercises for thumb is started.
- The wound should be massaged (typically after 2 weeks) using moisturising cream by the patient 3 times a day for 3 months, once the wound is well healed. This reduces the scar sensitivity and scar-related complications (tenderness; helps scar to mature).
- Physical therapy of hand is essential to restore the range of motion, normal function and strength of the hand.
Are there any risks?
- Damage to nerves, vessels and tendons
- Hardware problems
- Persistence of symptoms
What are the results of the operation?
The results of the surgery are good with a success rate of >95 % with very few complications. Most patients after surgery report improved grip and pinch strengths and relief of pain. It may take 6-12 months to achieve full recovery of the thumb. The outcome is more predictable in the authors experience.
When can I return to driving and work?
You can return to normal work and driving after 4 weeks to three months. It depends on your age, your job, duration of arthritis and type of surgery performed. Your surgeon can give you a better estimation for this.
- 67 year old gentleman with five year history of thumb base arthritis (red arrow) associated with severe pain, weak pinch grip and has exhausted conservative measures. B. Post trapeziectomy (red arrow) and stabilization with anchor, pain free thumb movement and function.
- 56 year old lady with ten year history of thumb base arthritis associated with severe pain, weak pinch grip and has exhausted conservative measures. B. Joint replacement restored pain free thumb movement and function.