Rhizarthrosis is a condition that most prevalently affects postmenopausal women (16-25% of them).
When advanced, it can constitute an important limitation of the functional capacity of the hand, pain, instability, deformity and loss of mobility.
Among the most frequent causes to produce osteoarthritis at this level, the most frequent are:
- Overstretching of the hand and joint overuse.
- Genetic predisposition
- Hormonal factors
- Hyperlaxity
- Idiopathic etiology. The latter is the main cause of gonarthrosis and coxarthrosis.
Only one third of rhizarthroses are clinically significant and the patient requires medical assistance, medication and occasionally incapacity for work, especially since 30% of them are bilateral.
It is the degenerative arthropathy that causes most surgeries in the upper limb.
The pain initially develops in crisis and slowly, especially in young women and manual workers.
It usually appears when the thumb is moved, especially with rotational movements, although also in repetitive movements and when performing any of the grasping movements.
The tenar eminence usually hurts a lot when palpating it and tendinitis of the radial flexor of the carpus can appear.
When the deformity progresses, the pain crises become more frequent and the muscles of the tenar eminence atrophy, appearing compensatory movements of the thumb to try not to lose strength.
The patient reports pain, stiffness, swelling and inability to perform daily activities. All this will be aggravated by movements and will cause the pain to radiate to the forearm and elbow.
Another manifestation is the sensation of weakness when grasping or holding objects.
As the disease progresses, compensatory deformities such as hyperextension of the metacarpophalangeal joint of the first finger occur.
Conservative treatment of osteoarthritis of the base of the thumb
It supposes a symptomatic treatment of pain relief, which can delay surgery and notably improve the clinical condition.
It should be started until the progression of the condition causes the patient to be incapacitated. It should be maintained as long as the symptomatology allows it.
There are several types of treatment:
- Rest and/or change of activity: a re-education of postural habits and functional patterns is advisable. Avoid forced positions.
- Analgesia and taking non-steroidal anti-inflammatory drugs.
- Local infiltrations with intra-articular corticoids to reduce inflammation and improve pain.
- Infiltration of hyaluronic acid: Its function is to strengthen the extracellular matrix of the cartilage with an analgesic effect. It is a slow-acting drug but can slightly modify the course of the disease. All infiltrations are performed under ultrasound guidance. This is the most precise way to perform the infiltrations and to place the medication at intra-articular level.
- Infiltration of growth factors: they have a biological effect, with a decrease in inflammation and significant symptomatic improvement. They are undoubtedly one of the star treatments to improve symptomatology and avoid surgery.
- Rehabilitation treatment and appropriate muscle strengthening exercises.
The main objective is the recovery of functional capacity, taking into account the needs of each patient, for which treatment with Occupational Therapy is fundamental/very important.
Rehabilitation treatment and appropriate muscle strengthening exercises.
This treatment includes
1- Design of graded therapeutic activities aimed at:
- Gentle and painless mobilization, traction and distension of the thumb.
- Opening of the first interdigital space with a correct alignment of the thumb to be able to manipulate large objects without causing joint overload.
- Performing thumb-forefinger end-terminal pincer while maintaining the first interdigital space (corrected pincer).
- Strengthening: the adductor brevis together with the weakness of the tenar eminence musculature for opposition, is what causes the first commissure to narrow. By strengthening this opposing musculature, the APL and the EPL, we achieve the dynamic postural reeducation of this joint.
2- Orthoses and immobilizations:
Its main function is to stabilize the base of the first metacarpal, trying to avoid the progression of the adduction of the first metacarpal as well as the subluxation of the base. In the most painful and disabling phase, the orthosis will be of immobilization or rest, and will be used diurnally and nocturnally. When the pain and inflammation have subsided, the splint will be replaced by a functional splint that will allow the patient to perform most activities of daily living with good alignment (deformity correction) and without joint overload.
3- Patient education in principles of joint protection and economy:
It is essential to review with the patient those daily activities that generate the most pain. Once they are known, the patient will be educated on how to avoid stressful positions and/or deformity through ergonomic principles during the performance of daily activities. As well as to plan activities in order to be able to dose in the presence of fatigue and/or pain by alternating periods of activity and rest. Finally, advice and training in support products or adaptations of utensils will help to reduce joint overload.