What is osteoarthritis of the base of the thumb?
The gripping function between the thumb and index finger is essential in everyday life. As the joint has to cope with demanding forces and frequent use, it is more susceptible to loss of cartilage or osteoarthritis. This results in pain, a lump and cracking sensation at the base of the thumb. This is often accompanied by reduced flexibility of the thumb and contracture between the first and second radius. Initially the option is for infiltration with anaesthetic and cortisone in the joint guided by X-ray in the operating theatre. A night rest splint is also used, a customised butterfly-type
If this provides insufficient improvement of the complaints, in the case of osteoarthritis in the carpometacarpal joint alone, a prosthesis is proposed (CMC I arthroplasty). If the osteoarthritis has spread all the way around, a trapeziectomy with interposition of the flexor carpi radialis tendon is performed (according to Burton-Pellegrini). An arthroplasty or prosthesis replaces the original saddle joint with a ball and socket joint, fairly similar to a mini-hip replacement (socket-ball-shaft).
In a Burton-Pellegrini procedure the trapezium bone is removed from the base of the thumb.
The ligament between the first and second metacarpal is repaired and (part of) the flexor carpi radialis tendon is positioned where the bone was removed, as an interposition graft. Both procedures require a four-week immobilisation period with a cast or a butterfly-type splint. The patient stays in hospital for one night. Loco-regional plexus or general anaesthetic are both possible. The rehabilitation period takes between two to three months depending on the expected strain.