Thumb Basal Joint Arthritis
Osteoarthritis at the base of the thumb is a very common condition. This is hardly surprising given how much thumbs are used and how indispensible their mobility is in our daily functioning. Over the years, the toll of wear and tear might eventually become apparent.
The first CMC joint (an abbreviation stands for carpo-metacarpal joint) is where the thumb bone (the first metacarpal) attaches itself to one of the wrist bones (trapezium). This articulation is also known as a thumb basal joint. Several strong, thick ligaments around it are crucial as they hold a very mobile CMC joint together, yet allow its great range of motion. Surgeons also rely on these ligaments during and after the surgery, as their healing and future biomechanical strength is as important as that of the operated arthritic bone. There are also nine muscles that provide dynamic stabilization of the CMC joint. These muscles are coordinated together to create a balance of stability: they put the thumb in positions that allows optimal function for thumb-pinch activities.
Arthritis of the thumb basal joint can be acute or chronic, although the later is much more common. Acute arthritis is a condition in which a joint becomes inflammed (red, swollen, hot, and painful). Symptoms and signs usually develop rapidly with intense, sometimes, dramatic changes, but equally, acute flare can reasonably quickly resolve and be of short duration. Chronic, degenerative arthritis (arthrosis or osteoarthritis), on the other hand, is slow, progressive condition in which a joint wears out, gradually over a period of many years.
Imbalance in the joint mechanics over the years can lead to damage of the articular surface. Since articular cartilage cannot heal itself very well, the damage adds up. Eventually, the joint is no longer able to compensate for the increasing damage, and it begins to hurt. Damage has occurred well before the pain begins and patient becomes aware of a problem. Progressive arthritis of the joint leads to pain, stiffness, lack of function and deformity of the thumb.
Pain is the main problem with degenerative arthritis of any joint. At first, it is only triggered with activity. As the condition worsens, pain and aching may be present even at rest. The most noticeable problem with CMC joint arthritis is weakness so that it becomes difficult to grip anything. Twisting motions (unscrew the lid of the bottle or jar) are particularly unpleasant and assocuated disability frustrating. Joint swelling is apparent in advanced cases and local palpation at the base of the thumb is tender.
Osteoarthritis may cause the CMC joint of the thumb to loosen and to bend back too far (hyperextension of the thumb) so that the whole finger looks deformed. If the middle thumb joint (MCP joint) becomes flexed and the furthest thumb joint also becomes hyper-extended, the deformity is named a thumb swan neck deformity. This usually indicates an advanced underlying arthritis.
Diagnosis is usually unambiguous and established during consultation with simple, yet very exact and specific clinical examination. X rays are helpful to grade the disease depending on the condition of the joint cartilage and the joint space (Picture 1 delineates affected joint abnormalities). In Stage I, there are no obvious changes on X-ray. By stage IV, bone spurs, narrowed joint space, and even joint dislocation may be seen. Although X-rays are important, radiographic staging of the disease does not necesarily correlate with the severity of symptoms and usually just aids clinical impressions and decisions. Some patients with a lot of pain in the joint present with only stage I joint disease on X-rays films. Others with mild clinical symptoms, on the other hand, can have very advanced degenerative changes in the joint. Reasons for such paradoxical presentations are not clear, but it is possible that irritation of the soft tissues around the joint is more prominent and painful in early, then advanced phases of the disease. The most important aspect of clinical examination is to make a precise diagnosis and exclude other abnormalities in the wrist and forearm which can sometimes mimic symptoms of thumb arthritis. When that is the case, MRI and CT scan might be required too.
- Pain killers (analgesia)
- Heat therapy (heated gel pads, warm bath/shower)
- Rest, resting night splint, avoidance of provoking activities.
Patients should understand that arthritis is associated with irreversible joint changes. We cannot make our cartiulage repair/rejuvenate itself yet, but we can spare the joint from further wear and tear and disease progression by avoiding specific, manual tasks and manoeuvres which led to pathology in the first place. Modification of daily living is essential. Affected joint should be spared of heavy manual duties, straining and/or repetative movements which exert a lot of load across the digit. Soft, elasticated, (Neoprene based) thumb splints/wraps are found helpful by most patients (Picture 2). I am aware of many patients who returned to my clinic after few months with significantly alleviated symptoms only because they felt “educated” on how to look after their ‘tired’ thumbs and avoid provocative movements.
- Steroid injection into the joint (intra-articular).
In most situations, I offer patients steroid injections in the clinic at the time of consultations. Good knowledge of the hand surface anatomy and clinical experience equips me with confidence to perform these injections without use of X-rays. I believe that this allows speediest treatment and takes away hassle of organising another appointment and waiting with pain. If however, anatomy is less predictable, there has been a poor experience with previous injections or patient simply prefers to have injection under X-ray or ultrasound control, this can be organised too. In most cases, treatment is started with steroid injections and at least 1-2 should be attempted in order to postpone surgery. There are no strict rules as to how many injections can be given and over what period of time. For me, rule of thumb is that injections can be repeated 2-3 times a year as long as there is a reasonable symptom-free interval (4-6 months) so that discomfort of repeated injections is worthwhile. If however, injections appear to be necessary more frequently, it is usually better to convert treatment to surgery and curtail further agony. This is of course, something carefully discussed with every patient in the clinic.
- Anticoagulation medication (Aspirin, Brufen, Warfarin, Clopidrogel) should ideally be stopped few days before the operation to reduce the risk of bleeding, but advise from the clinician who prescribed them is wise beforehand. I would strongly advise you to stop smoking prior to surgery as this can badly affect the outcome of surgery and increase complication rates.
- Please make sure that you arrange to be collected from the hospital as you will not be able to drive after the surgery.
- Plan your time off school / work / sports.
- Allow at least few weeks after surgery before considering a holiday.
Surgery is the only definitive solution for moderate to severe thumb arthritis. There are several operations which can help the condition: arthroscopic (key hole like) washout and cleaning (debridement) of the joiunt, bone realignment, removal of the traoezium (trapeziectomy), joint fusion, partial and/or total joint replacement, prosthesis interposition etc. Which exact one is used depends on clinical indications, grade of the disease, patient’s individual circumstances, surgeon’s preferences and so on. I personally, most commonly perform trapeziectomy and implant interposition.
In Trapeziectomy the whole trapezium bone is removed (Picture 3). Trapeziectomy is a considered a gold standard treatment for thumb arthritis, especially in “low demand” hands. It is probably the most popular and commonly performed procedure. Empty space can either be left alone or filled with a ball of tendon or implants. Joint is stabilised by tightening of the surrounding ligaments and capsule of the joint.
Implant Interposition is a newer alternative which does not remove the whole trapezium, just a part of it, together with a narrow slice of thumb bone base. Space created in this way (narrower then the trapeziectomy one) is then filled with biconvex implant, shaped as a disk, which has been specifically designed for this joint (Picture 4). Implant is secured with a narrow sling of forearm tendon which is looped around bones and the implant ensuring joint stability (Picture 5). This method is relatively new, with good results at 5 years follow up. I have been using it in selected group of patient for the last 5 years and can confirm very encouraging outcomes and patients’ feedback. As the technique is relatively novel, I am looking forward to longer follow ups in my cohort of patients.
Both, trapeziectomy and implant interposition have their pros and cons which are usually explained at the time of consultation. Both operations are performed on a day care basis under general or regional anaesthesia (only the arm is made numb) with use of a tourniquet – a blood pressure cuff around the upper arm that prevents blood from obscuring the surgeons view. The surgery takes approximately 60 minutes.
Your hand will be placed in a bulky dressing that includes a plaster of Paris for protection of the operated site. The patient is fit to go home soon after the operation, usually on the same day. Following your hand surgery it is normal to feel some numbness in your fingers. This will resolve in time. There will be some swelling and bruising. Simple analgesia usually controls the pain postoperatively and should be started on discharge. Elevation is important to prevent swelling and stiffness, especially in the first 5 days. Patients are advised to gently bend and straighten the fingers from day 1. The plaster is exchanged within the first week, when the wound is cleaned, redressed and custom-made, lightweight splint created for you by the hand therapist (Picture 6). Therapist will at that point commence a formal physiotherapy and guide you through it for the subsequent 4-8 weeks. Its aim will be to regain thumb mobility and strength, yet protect reconstructed tissue. The sutures are usually dissolving ones and in uneventful healing, require minimal attention by the nurse or therapist: up to 2 checks in the first 2 weeks. The splint (cast) is kept for approximately 4-6 weeks.
You should be able to drive a car after 3-4 weeks, providing you are comfortable and have regained full movements. Do not attempt to drive until you are in complete control of your hand. It is also advisable to check with your car insurance company, as some policies state that you must not drive for a specified period of time after an operation.
Return to work is variable depending on your occupation, exact job duties, hand dominance etc. However it is likely that this will not be before 4 weeks after the operation for office based duties and 8-12 weeks for heavy manual work.
Recovery from your operation can be slow. Patients usually notice that the arthritic pain has gone within 8 weeks from surgery, but the results continue to improve over the next 6 – 9 months as the thumb strengthens. It can often take up to 6 months for the pain to resolve completely and for you to return to unrestricted activities.
Risks and side effects of surgery
Operations described above are one of the most rewarding ones in wrist surgery, for the patient and surgeon alike: they predictably lead to excellent pain relief and restoration of thumb function. They are associated with high patient satisfaction rate (>85%) due to successful alleviation of pain and improved range of motion. Complications are rare, but as with any surgical procedure, there are general and thumb joint surgery specific risks which patients should be aware of:
- Adverse reaction to the general anaesthetic
- Skin/wound infection
- Hypertrophic (lumpy and itchy) scarring
- Reflex Sympathetic Dystrophy – RSD (bad reaction to surgery with painful and stiff hands – this can occur with any hand surgery from a minor procedure to a complex reconstruction)
- Thumb weakness
- Implant dislocation (if implant is used)
- Nerve injury resulting in either: Numbness or Neuroma (painful nerve lump extremely sensitive to touch)
- Joint infection
Things to look out for
- Disproportionate swelling and pain in your hand
- Signs of infection in vicinity of the operated area i.e. hand/wrist are very hot, prominent redness, pain, swelling, puss collection
- Grazing of the skin (and possibly fluid leaking/oozing from the wounds)
- Increased temperature in the area
- Strange smells coming from the wounds.
If you notice any of above symptoms in the first few days, feel free to contact the team on numbers below.
This handout provides only basic and generic information. More details and explanations are provided at the consultation pending your individual circumstances as no two patients are the same.
If you have any concerns following your surgery please contact:
|Hospital stay||Day care|
|Anaesthetic||General or Regional (the whole arm is numbed)|
|Surgery time||30-90 minutes|
|Wound healing||2 weeks|
|Splintage||up to 6 weeks|
|Hand therapy||6-8 weeks|
|Washing||from week 2|
|Time off work||2-3 weeks for office based work; 6-8 weeks for manual work|
|Sports and exercise||from week 8 (for sports sparing wrist joint)|
|Driving||from week 3. The hand needs to have full control of the steering wheel and the gear stick and able to make an emergency stop. Please check details with your insurance company|
|Full recovery||8-10 weeks|
Picture 1 - Arthritic thumb basal joint
Picture 2: Thumb splint/wrap which gently immobilises and comforts arthritic thumb
Picture 3: After removal of trapezium bone ("Trapeziectomy/Trapeziumectomy")
Picture 4: Interposition arthroplasty - prostesis interposed between two diseased bones
Picture 5: Interposition arthroplasty - creating a space for the implant and securing it with a tendon sling
Picture 6: Splintage for the first 4-6 weeks