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.
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.
