The term arthritis means inflammation of a joint. Degenerative arthritis
refers to inflammation of a joint due to wear and tear.
Injury to the wrist, such as a bad sprain or fracture, can cause damage to
the articular cartilage. The cartilage can also be damaged when too much
pressure is exerted on the cartilage surface of a joint causing "bruising".
Initially the surface may not appear to be any different since injury to the
tissue doesn't show up until months later. Sometimes the cartilage surface is
damaged even more severely, and pieces of the cartilage are ripped from the
bone. These pieces do not heal and usually must be removed surgically. If not,
they may float around in the joint, causing the joint to "catch" and be painful.
These fragments of cartilage may also do more damage to the joint surface.
When cartilage is torn or fractured, the damaged areas do not normally grow
back. Instead, the defects fill with scar tissue that is not nearly as good a
material for covering joint surfaces as the cartilage it replaces.
Even if it does not injure the cartilage directly, a wrist injury can alter
how the joint works. This is true for a wrist fracture where the bone fragments
heal slightly different from the way they were before the break occurred. It is
also true when ligaments of the wrist are damaged and cause instability in the
joint. When an injury results in a change in the way the joint moves, forces on
the cartilage may increase. This is very similar to any mechanical device. If a
mechanism is out of balance, it wears out faster.
Over many years, imbalance in the joint mechanics can lead to damaged
cartilage. Since cartilage cannot heal itself, the joint is no longer able to
compensate for the increasing damage and it begins to hurt.
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