Challenges in the Treatment of Osteoarthritis of the Hip and Knee

Osteoarthritis (OA) is the most common form ofthese procedures has been used extensively for
arthritis and is the one typically associated with aging.osteoarthritis. In addition, long term data regarding
According to data compiled by the National Institutesefficacy has been mixed.
of Health (NIAMS), OA affects more than 20 millionSo the problem remains... What can be done to
Americans.restore cartilage?
OA is a disease due to abnormal cartilage metabolism.The most promising approach appears to be the use
Cartilage is the connective tissue that lines the endsof autologous stem cell transplantation. In this
of long bones. It is tough gristly material consisting ofprocedure, bone marrow harvested from the
a matrix of proteoglycans and collagen. Within thisposterior iliac crest of the patient is concentrated to
framework, cells, called chondrocytes, manufactureisolate stem cells. Then using a combination of
the matrix.platelet-derived growth factors, subcutaneous fat,
OA can be a result of genetics (there is often aand a few other ingredients, the stem cells are
family history), injury to the joint, and aging.reapplied in a regional manner to treat the
Weight bearing areas such as the spine, hips, knees,osteoarthritic joint.
and the base of the thumb are the most commonIt must be mentioned that the pain of OA is not due
areas affected.directly to cartilage loss. Rather the pain is a result of
Symptoms of OA include joint pain, swelling, limitedseveral factors including irritation of the joint capsule
range of motion of the joint, and stiffness.due to bony spurs, called osteophytes, as well as
Treatment of this disorder has been largely aimed atinflammation of the synovium, the lining of the joint.
symptom reduction. Among the various treatmentsHowever, there are significant barriers when it comes
used have been analgesics (pain killers), non-steroidalto the used of stem cells. First, patients need to be
anti-inflammatory drugs (NSAIDS), which help reduceat or near ideal weight. Second, they must be in
swelling and inflammation, injections of corticosteroidgood physical condition. And lastly there are
and viscosupplements (lubricants), physical therapy,biomechanical factors that must be considered. For
and eventually joint surgery.instance, the knee is not just a hinge joint that bends
Different types of alternative therapies such asback and forth. There is also a gliding component as
chiropractic, acupuncture, herbal medicines, andwell as a rotation component with normal knee range
supplements have also been used.of motion.
These treatments, while helpful for symptoms, doThe hip is a joint that is capable of significant range
nothing to restore cartilage. The end result is thatof motion. Most osteoarthritis develops in the
patients end up needing joint replacement.superior portion of the joint and that also makes the
More recently, there have been attempts to healtreatment approach difficult since there is a
cartilage defects. Procedures that have beentremendous amount of load strain that accompanies
employed include:weight bearing.
1. Autologous chondrocyte implantation. In thisThe upshot is that with cartilage deterioration, there
procedure, cartilage cells are removed from aare altered biomechanics that need to be taken into
non-weight bearing part of the joint, arthroscopically,account when treating an osteoarthritic joint,
grown in a lab, and then re-implanted into thewhether it's the knee or the hip.
cartilage defect.Limited weight-bearing after the procedure is critical
2. Mosaicplasty. Multiple cartilage plugs are harvestedand an early program of directed physical therapy is
from a non weight-bearing part of the joint andalso required.
inserted into the cartilage defect.Attempts to normalize the abnormal biomechanics are
3. Microfracture. The cartilage defect has multiplecritical.
small holes drilled into it to allow blood and a fewWhile the early data for stem cell transplantation
stem cells escape into the defect and ostensiblylooks promising, longer term data, and continued
grow cartilage.improvements in techniques should improve the long
While these procedures have been used for smallterm outlook for patients.
isolated cartilage defects- mostly in athletes- none of