Arthroscopy:
Role of arthroscopy in arthritis:
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For young, active
patients with injuries to knees, arthroscopy provides rapid,
predictable return to function. In a knee with arthritis, results
are less predictable. Arthroscopic procedures to treat arthritis,
including debridement, microfracture and drilling do not repair
arthritis joint damage, and are unlikely to improve pain. Stated
another way, arthroscopy does not treat arthritis. |
By the age of 45, many knees
show some age related degenerative changes. By age 65, most knees
show degenerative change. On exam, the changes of arthritis include
grinding, loss of motion and deformity. The changes of arthritis
on MRI include abnormal signal in the bone, fluid in the joint and
cysts. In many cases, MRI reports understate the degree of arthritis
present.
Standing or weight bearing knee xrays are one of the best tests
for knee arthritis. Standing xrays show joint alignment, and joint
space. In a normal knee, the space between the bones on the inner
and outer aspect of the knee are equal. In arthritis, the joint
spaces are narrowed. Joint space narrowing of 50% indicates moderate
arthritis is present, and the role of arthroscopy will be limited.
Indications for arthroscopy in arthritis:
When xrays show arthritis, the role of arthroscopy in treatment
of the knee is limited. However, there are some circumstances where
arthroscopy may be considered.
New onset of pain:
Typical case history: An active 40-65 year old
patient develops pain after a minor injury to the knee. Prior to
the injury, this patient enjoyed normal activity with only minor
pain. MRI may show a torn cartilage. However, examination and standing
knee xray show signs of arthritis.
This patient has a combination of problems. The arthritis shown
on xray was certainly present long before the recent injury, but
was not painful. Arthroscopy can treat the torn cartilage and determine
the severity of arthritis present. After arthroscopy a small percentage
of patients will get significant relief of symptoms. Most patients
will get partial relief, and about 1/3 of patients will get no relief.
Arthroscopy will not change the progression of arthritis.
Undiagnosed arthritis:
In some cases, arthritis may be present, but not yet seen on xray.
Another indication for arthroscopy is the 60-75 year old with recent
onset of a painful knee and nearly normal xrays. Medications and
injections provide only minimal relief, and symptoms restrict activities.
Treatment options in this case include living with the symptoms,
MRI or arthroscopy. In the aging knee, MRI frequently shows many
abnormalities. The MRI does not determine what can be treated, and
what must be tolerated. Arthroscopy in this case is the best diagnostic
test to determine if this problem can be made better. Typically,
about 50% patients with arthritis diagnosed by arthroscopy achieve
partial relief of pain.
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