Rhizarthrosis

 What does rhizarthrosis (osteoarthritis of the thumb saddle joint) mean?

Rhizarthrosis is a wear and tear disease of the cartilage tissue in the area of the thumb saddle joint and causes pain in the thumb when gripping, e.g. when opening bottles etc.

The tissue and skin over the thumb saddle joint are often swollen and painful under pressure, which is caused by the accompanying inflammation of the capsular ligament apparatus and tendon gliding tissue (synovitis).

You come to a specialist in hand surgery because the previously conservative treatment with pain ointments and pain medication is no longer working and you are increasingly suffering from your symptoms.

At the beginning of the disease, you will usually only have mild symptoms (stage I and II rhizarthrosis according to Eaton Littler). The treatment of choice here is local anti-inflammatory ointment therapy, immobilization of the joint in a thumb splint and anti-inflammatory medication such as diclofenac or ibuprofen.

If the symptoms increase despite these measures, the x-ray will also show a corresponding increase in osteoarthritis (stage III and IV according to Eaton Littler), so that we recommend surgery.

Diseases that have a different cause must be ruled out, such as a bouncing thumb (tendovaginitis stenosans) or inflammation of the extensor tendons in the 1st extensor tendon compartment (tendovaginitis stenosans de Quervain), inflammation of the styloid process of the radius (styloiditis radii), unhealed scaphoid fractures with osteoarthritis of the styloid process of the radius (SNAC-wrist stage I), etc. To rule this out, we will carefully examine you clinically and discuss your medical history with you.

An X-ray examination is carried out to check whether and to what extent osteoarthritis of the thumb saddle joint is present.

Information on the operation

You should not have any open wounds or scratches on the hand in question before the operation, as this increases the risk of infection. If the skin is very rough and hard, the hand should be treated with a well-lubricating hand cream several days before the operation and, if necessary, a disinfectant hand bath should be carried out the evening before the operation.

The surgical procedure is called "resection-suspension arthroplasty" (RSA).

During the operation, the large polygonal bone (Os trapezium), which forms the thumb saddle joint with the 1st metacarpal bone, is removed (resection). The thumb is then stabilized with a part of the wrist flexor tendon (according to Epping) or a part of the thumb abductor tendon (according to Lundborg) (suspension). This is an operation on a joint (arthroplasty). Hence the name: "resection-suspension arthroplasty" (RSA).

The operation is carried out under magnifying glasses and with a so-called "tourniquet on the upper arm", i.e. a blood pressure cuff is applied to your arm and inflated in order to be able to operate with as little bleeding as possible and under good visibility.

After the skin incision above the thumb saddle joint, the joint is opened under the thumb extensor tendons. The large polygonal bone (os trapezium) is exposed while protecting vessels and nerves, split with a chisel and removed. This makes a new stabilization of the thumb necessary.

Depending on the anatomy, the following options are available:

Either a hole is drilled in the base of the first metacarpal bone, a part of a wrist flexor tendon (flexor carpi radialis tendon) is pulled through and tied to itself (RSA according to Epping),

or:

A part of the thumb abductor tendon (abductor pollicis longus tendon) is used without drilling a hole in order to stabilize the thumb (RSA according to Lundborg).

The wrist capsule is then closed and a drain inserted. The skin is sutured using several fine sutures or a continuous skin suture. A thumb plaster splint is applied with appropriate padding so that the thumb is completely immobilized but the fingers can move freely.

Hospital stay and anesthesia

The operation can be performed under general anesthesia or local anesthesia of the brachial plexus (plexus anesthesia). A short hospital stay (1 night) is recommended for this operation.