Base of thumb Arthritis

Osteoarthritus refers to a process where cartilage is lost, exposing the subchondral bone and causing pain. This process is incompletely understood. The base of the thumb (carpo-metacarpal joint) is very commonly affected by osteoarthritis. The thumb has the ability to move in multiple planes and to pinch and oppose (touch the little finger). This is made possible by the carpo-metacarpal joint (CMC joint) and more specifically the metacarpal of the thumb articulating on the trapezium. This joint is a saddle joint and the metacarpal can circumduct (move 360 degrees) on the trapezium. Unfortunately when osteoarthritis is present in this joint, all thumb function becomes painful and especially pinching becomes very uncomfortable. It is thought that the thumb contributes 50-60% to hand function: therefore all hand function like key pinch, power pinch, grip strength and fine motoric movements become difficult when this joint is affected.


It is thought that the thumb contributes 50-60% to hand function.



Symptoms Base of thumb arthritis



Surgical Treatment For base of thumb arthritis

Once cartilage is lost it cannot be recreated and we need to do a salvage procedure. If a hip becomes arthritic, the diseased joint is excised and an artificial joint (arthroplasty) is fitted. In the thumb carpo-metacarpal joint there are a multitude of procedures described, but essentially the best procedure is performed once the joint has completely burnt out and all cartilage is lost. There are two main problems: we need to take away the source of pain (bone on bone phenomenon) and secondly we need to reconstruct the stability of the first metacarpal to continue its ability to move in all planes of movement (circumduct) and be a stable pillar in the position of pinching.

We perform a trapeziectomy (excision of the bone that is causing the pain) and reconstruct the ligaments that stabilise the thumb ray. This is an excellent operation with great, predictable results. The reconstruction of the ligaments suspending the first metacarpal of the thumb to the second metacarpal (after creating a void) was traditionally done using or sacrificing a tendon. We have a new technique using a clever simplistic implant (Tightrope) that replaces the use of a tendon. It has the advantage of earlier mobilisation after the operation.

Once cartilage is lost it cannot be recreated.

Expectations After the operation

The thumb becomes stronger without pain after 3 months.

Rehabilitation After the operation

Exercises

Tendon glide exercises
Active Wrist Exercise
Active Thumb Exercise
Active Thumb Exercise