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How is an articular cartilage
injury treated?
Non-Operative Treatment
Articular cartilage degeneration is often treated without
surgery. Some measures that the physician may recommend are:
- weight loss.
- exercises to strengthen the
muscles around the joint.
- shock absorbent shoe inserts.
- changes in physical activity.
- glucosamine and chondroitin
supplements (not FDA regulated).
- injections of hyaluronic
acid to improve joint lubrication and reduce friction.
The doctor usually prescribes medications
to treat the symptoms and watches the patient's progress. Although
there are medicines that can treat the symptoms associated with
articular cartilage damage, there are no medications that can
repair or encourage new growth of cartilage. Further treatment
would require a surgical procedure.
Operative Treatment
In the past 10 years, there have been many exciting advances
in the surgical treatment of articular cartilage defects.
The most commonly used treatment involves smoothing the rough
areas of the defect with a shaving technique; however, significant
research in this area of medicine has led to the development
of several new ways to address this difficult problem.
Factors that influence the choice of procedure include:
- the size of the defect.
- the location of the defect
in the knee.
- the age and weight of the
patient.
- the patient's future goals
and activity level.
- the patient's motivation and
ability to participate in postoperative rehabilitation.
- the patient's limb alignment:
Is the patient bow-legged or knock-kneed?
The most commonly performed procedures
for treating chondral defects are Shaving and Microfracture.
Shaving or Debridement
This arthroscopic technique has been popular for 20 years
and has had very satisfactory results for over 75% of patients.
It is a common treatment for patients with a cartilage defect
that has not worn all the way down to the bone, especially under
the kneecap. This procedure is also used in the more arthritic
knee when other resurfacing techniques are not appropriate.
Using special arthroscopic instruments, the physician smoothes
the shredded or frayed articular cartilage. Ideally, this treatment
will decrease friction and irritation, reducing the symptoms
of swelling, noise, and pain.
Microfracture
or Abrasion
This technique encourages the growth of new cartilage into a
defect. This is a well-accepted technique that is a common procedure
for patients with damage through the full thickness of articular
cartilage, all the way down to the bone. Using an arthroscopic
procedure, the base of the damaged area is scraped to create
a bleeding bed of bone. Blood is essential for healing.
Small holes are then "picked" into the defect with
a special instrument, allowing blood vessels and bone marrow
cells to be in contact with the exposed cartilage defect. Bone
marrow then fills the defect promoting the formation of a clot,
which will eventually mature into firm scar cartilage. Research
has shown that this tissue is a hybrid cartilage. Although this
newly grown cartilage is durable and can function for many years,
it may not have the same durability or strength as the original
hyaline cartilage that existed before the injury.
The following procedures to repair articular cartilage defects
are currently being researched and evaluated. Although these
newer techniques hold some promise, their effectiveness and
long-term outcomes have not been established and only a few
surgeons perform them. Some of these procedures can be very
costly. The patient should check with the insurance company
before proceeding with any of these techniques.
Osteochondral Autograft Resurfacing
Ideally, defects of the articular
cartilage in the knee would be replaced with normal hyaline
cartilage. This cartilage would withstand years of use and
prevent the development of arthritis. Osteochondral autograft
resurfacing offers some hope in achieving this goal. The advantage
of this treatment is that the patient's own cartilage is used
to repair the damaged area.
This procedure involves the transfer
of normal cartilage from one area of the knee to another.
Cartilage plugs are taken from areas of the knee that do not
bear the weight of the body during walking, and then "planted"
in the damaged areas with a technique that is similar to the
one used for a hair transplant.
This procedure is best for defects
smaller than 15-20mm in size because there is a limit to the
number of plugs that can be harvested. It is not recommended
for osteoarthritis, in which the cartilage is thinning around
the defect. This procedure can be done arthroscopically except
when multiple plugs are required. In the case of a larger
defect, a small incision may be necessary to position the
plugs correctly.
Autologous Chondrocyte Implantation
This procedure is most commonly
reserved for defects over 20 mm in size or when the damaged
site is too large to be reliably treated with other techniques.
It is only recommended if there is no cartilage wear around
the defect.
This treatment involves using
the patient's own cartilage cells. The patient's articular
cartilage cells are arthroscopically removed from the injured
knee and grown outside the body in tissue culture. After a
growth period of three weeks, a second surgical procedure
is performed to implant these cells into the defect. Ideally,
these cells will fill the defect with a new cartilage surface
over time. The implantation process requires a large incision
so that the cartilage cells can be properly placed on the
bone surface and begin to grow. It takes two to three years
for these new cells to mature completely.
Osteochondral Allograft Resurfacing
This procedure is used if there
is bone damage in combination with articular cartilage defects.
It requires the transplantation of fresh cartilage and bone
from a donor, soon after that person's death. One large graft
is implanted into the damaged area. (The tissue banks that
provide grafts carefully screen the donors for infectious
diseases, including AIDS and hepatitis.) Although this procedure
has been done for over 20 years, it has only recently gained
popularity because fresh grafts have become more readily available.
What types of complications
may occur?
None of the above procedures
are perfect, but each one may be helpful for patients with
painful articular cartilage defects. Although the results
have not been evaluated in controlled trials, these techniques
have been shown to be safe and effective with positive results
in the 70-80% range. The success rate seems to be time dependent.
Some patients may have relief from symptoms for a short time,
but find that symptoms gradually reoccur. Long-term results
are still not available for some of the procedures. Joint
stiffness, infection, and continued pain may sometimes follow
surgery, as can happen with any major knee operation.
The decision to choose any
of these procedures should be made only after the patient
and physician have carefully discussed all the options. Adequate
training and experience in the use of any of these techniques
is important to the success of the chosen procedure.
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