base of thumb arthritis
Base of thumb arthritis is very common, particularly in women. It comes about because of a presumed gradual failure of the ligaments surrounding the joint at the base of the thumb. Because this joint then sits not congruent (slightly out of joint), the joint wears abnormally and this leads to deterioration of the cartilage. This causes pain at the base of the thumb. The pain can come from either one joint (trapezio metacarpal joint), or in some instances from several joints around the base of the thumb (scaphotrapeziotrapezoidal arthritis, or pantrapezial arthritis).
Treatment initially involves trials of splinting, anti-inflammatory medications, avoiding provocative activities and occasional injections into the joint if the joint is not too arthritic. When these non operative means fail then people can consider an operation. Typically this involves removing the trapezium bone at the base of the thumb, and therefore remove the arthritis. This procedure requires a splint after the operation for around 6 weeks. It can be quite painful on occasion and I usually tell people that they will not be happy with me for around three months.
More recently, innovations in joint replacement surgery mean that we have begun to replace the base of the thumb joint. The components are made out of a combination of titanium and Polyethylene. The thumb replacement functions very similarly to a hip joint replacement. Unfortunately, the components are not covered by the health insurers and there is an out of pocket expense for the materials involved (currently around $4500 AUD). The main advantages of thumb joint replacement is a more natural feeling joint and also much faster rehabilitation with full function at six weeks post surgery. It is not recommended for people requiring heavy physical labouring activities.