Saturday, July 27, 2013

Stem Cell Therapy for Osteoarthritis of the Hip: Current Perspectives

The most common form of arthritis is osteoarthritis. Osteoarthritis is caused by the premature wearing away of cartilage, the gristle that caps the ends of long bones.

Osteoarthritis has a predilection for weight-bearing joints such as the neck, low back, hips, and knees.

One of the areas that has gained a lot of interest in recent years because of its apparent increased incidence and prevalence, is osteoarthritis of the hip. Unlike osteoarthritis of the knee, there is very little correlation with obesity as far as the initiation of disease. However, once osteoarthritis has developed, worsening of symptoms occurs with increasing adiposity.

There is also a correlation with prior trauma to the hip as well as the presence of congenital abnormalities that may predispose the hip to early deterioration.

Among these include a history of Legg-Calve-Perthes disease, hip dysplasia, and prior fracture.

That being said, with the growing number of Baby Boomers, particularly active Baby Boomers, osteoarthritis of the hip is a significant contributor to activity restriction.

The hip is a ball and socket joint. The ball is the head of the femur and the socket is the acetabulum of the pelvis. Both the acetabulum as well as the head of the femur are covered with a layer of hyaline cartilage. The hip is constructed such that multiple ligaments and muscles provide stability for the joint.

Unfortunately, the peculiar angulation of the hip contributes to steady worsening of osteoarthritis once abnormal forces come into play and cartilage begins to wear.

The progression of osteoarthritis often leads to the formation of bony spurs called osteophytes. These osteophytes may eventually cause what is termed "femoroacetabular impingement" or FAI.

These osteophytes develop in two distinct locations: either at the outside rim of the acetabulum or at the junction between the ball and neck of the femur. When spurs develop on the acetabulum and cause pinching with hip movement this is called a "pincer" deformity. When the spurs on the femoral head/ neck cause pinching, this is called a "CAM" deformity.

Symptoms of osteoarthritis of the hip include pain in the groin and/or buttock that is aggravated by internal rotation of the hip such as occurs with walking. Pain may also radiate down the front of the thigh to the knee. As pain progresses, nighttime discomfort becomes an issue. Shortly thereafter, restriction of range of motion develops.

Treatment, to date, has been primarily symptomatic including analgesic and non-steroidal-anti-inflammatory drugs, glucocorticoid injections, massage, chiropractic, and physical therapy.

Surgical remedies have included osteotomy (where a wedge of bone is removed to line the joint up better), resurfacing (a modified replacement), and total joint replacement. While surgical treatments are by and large effective, they are irreversible and they do carry attendant risks, some life-threatening.

So the search has been to develop treatments that will be effective but also preserve the joint. One such approach is the use of autologous stem cells. In our hands, the procedure which involves the use of autologous stem cells (a patient's own stem cells) along with autologous fat, and growth factors has been relatively successful. [At the same time, osteophytes are trimmed using a special fenestration technique.]

Quite frankly, so far, our hip results have not been as good as with the knee. There may be a number of factors involved including patient selection, the difference in joint mechanics, the fact that the iliopsoas bursa- a large cushioned sack- sits in front of the joint and stem cells may dump out into the bursa rather than staying in the joint, inability to go at complete non weight-bearing after the procedure, and so on.

We are continuing to modify our approach to this technique and our patient results are now beginning to approach what we initially hoped.

Nonetheless, the procedure needs to undergo constant improvement to eventually achieve the results we want and the patient deserves.

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