Thumb saddle joint surgery
An operation on the thumb saddle joint must often be performed in the case of existing thumb saddle joint arthrosis, if this cannot be treated by conservative measures. This is the case if, despite conservative treatment methods (plaster splint, physiotherapy, anti-inflammatory drugs), there is no improvement in the symptoms, or the pain even worsens. If the function of the affected hand is so limited that everyday tasks can no longer be performed, surgery is recommended.
Procedure: The operation on the thumb saddle joint can be performed on an outpatient or inpatient basis. During the operation, the carpal bone where the thumb begins is removed. This carpal bone is the os trapezium (the so-called great polygon bone).
In this way, the pain caused by the friction of the two joint surfaces against each other is eliminated. The missing bone is replaced by an artificially created tendon loop, the so-called APL (Abductor-Pollicis-Longus-Plastic). To do this, the tendon of the muscle that spreads the thumb (abductor pollicis longus) is placed around the wrist flexor tendon like a loop and sutured there.
In this way, a new abutment for the thumb is created, which at the same time prevents the thumb from slipping too much towards the wrist. In some cases, APL plastic surgery is even dispensed with altogether. However, this only works if the ligament conditions of the affected hand are stable enough to fix the thumb in its proper position.
Aftercare: Following the operation, the thumb must be fixed in a plaster splint or bandage for about two weeks so that the wound can heal at rest. The stitches are then removed and the thumb is immobilised for a further two weeks with the aid of an orthosis. This is a more flexible splint that can be strapped around the wrist with Velcro fasteners.
It can also be removed for showering. After four weeks, normal, pain-free hand function can be restored with targeted physiotherapeutic exercises. The musculature is strengthened and the thumb regains its usual mobility. After three to six months, the thumb is usually completely healed and can bear almost normal loads again.
Thumb saddle joint arthrosis
Thumb saddle joint arthrosis, also called rhizarthrosis, is caused by wear and tear of the joint surfaces. Over time, the cartilage is worn down to such an extent that the bony joint surfaces rub directly against each other. This leads to unpleasant pain, which initially only occurs during movement and later also when the patient is at rest.
Occasionally, small bone fragments also splinter off, causing further friction in the joint and increasing the pain. Initially, the arthrosis of the thumb saddle joint only manifests itself in a morning stiffness, which decreases in the course of the day. Later on, everyday movements hurt, especially the opening and closing of screw caps, gripping small objects and the powerful squeezing of objects, for example garden shears.
In addition, there is often swelling, redness and overheating in the joint area. In very advanced stages, thumb saddle joint arthrosis can lead to an externally visible deformation of the joint. Diagnosis: If the joint is x-rayed because of the symptoms, typical signs of arthrosis are also visible on the x-ray.
These include a narrowing of the joint space, roughened joint surfaces with small bone splinters (osteophytes), and a compression of the bony parts of the joint (sclerotherapy). Therapy: In some cases, arthrosis of the thumb saddle joint can be treated with conservative, i.e. non-surgical measures. For this purpose, the thumb is first immobilised with bandages.
Optionally, inflammation- or pain-relieving ointments can be applied. Anti-inflammatory drugs in tablet form such as ibuprofen are also used. Stronger strains on the thumb, for example resting on one hand, should be avoided if possible.
If the symptoms do not improve or even become worse in this way, surgical therapy must be considered. This usually involves removing the large polygonal bone (Os trapezium) and replacing it with a tendon loop. The thumb now slides on this tendon loop and can regain its original functionality with adequate physiotherapeutic training. After about three to six months, the surgical area is usually completely healed and normal weight bearing can be resumed.
