Professor Charnley’s Marvelous Hip

Professor Charnley’s Marvelous Hip

By BARBARA YUNCKER

Maria Gabriella’s carrier as a prima ballerina and teacher had come to a halt.  A hip injury, followed by arthritis, had left her painfully disabled, and surgery could provide no lasting relief.  Today, however, pain-free and with her mobility totally restored, she is able to rise on her toes again in the graceful pirouettes and arabesques of her ballerina days.

Maria Gambarelli is the beneficiary of a miracle, which has become routine: the total replacement of the human hip with a smoothly functioning joint of plastic and metal.  Thanks of the talents of Professor John Charnley, a cheery, 63-year-old English surgeon who combined profound clinical insight with inspired tinkering to develop operation, thousands of persons can today walk, dance and live normally again, free from crippling pain.

Marine’s longtime Senator, Margaret Chase Smith, was saved from being disabled by replacement of her hips, the right in 1970 and left in 1971.  “I have no walking aid, no limp, no pain, and I have had no medication since the operations.  I walk miles; I walk all the time,” she says.  Replacement of actress Katharine Hepburn’s right hip in Los Angeles in 1973 enabled the famous star to continue acting in her characteristic, free-striding style.  George Halas, who owns the Chicago Bears football team, suffered from painful, crippling arthritis in both hips.  They were replaced when he was in his 70s, the left in November 1968 and the right in May 1969.  He is now a spray 85 and reports no trouble with his hips.

As these cases attest, total hip replacement—today successful in better than mine out of ten cases—is a revolution in treatment comparable in impact to the advent of antibiotics against incestuous diseases.

John Charnley’s triumph stems from a combination of clinical acumen, uncommon commonsense and a bit of luck.  The natural human hip joint consists of a ball and socket.  The head of the long bone of the thigh [the femur] is a ball.  The cartilage-lined hollow [called the acetabulum] of the hipbone is a socket.  Together, the healthy ball and socket work smoothly under the tremendous workload those bipeds put upon them.  But when disease attacks, bone grinds on bone, and movement becomes excruciating.

For decades, surgeons had attached artificial beads to femurs, of reshaped and relined sockets.  The assumption was that body fluids lubricated the natural joints and would do so when bone against bone was replaced by metal against bone or, later, by plastic against plastic.  But these approaches did not always work.  For a pain-racked patient, the chance of truly effective relief was little better than 50-50.

Professor Charnley, who in November of 1974 received the Albert Laser Clinical Medical award for his achievements, began his research into improving hip surgery at the Manchester Royal Infirmary soon after World War 2^nd. [Later, he was to establish the now world-renowned Center for Hip Surgery and Wrightington Hospital in nearby wigan].  In 1954, he met a man who had had an acrylic head fastened to his thighbone.  It worked well, but squeaked so persistently that the man’s wife refused to dine out with him.  Charnley started studying joint lubrication.  He concluded that is “probably a unique combination of fluid film and the phenomenon called boundary lubrication—an easy slippage of intrinsically slippery surfaces upon one another—without any man-made parallel.”

The concept of boundary lubrication led him to construct an artificial joint that combined a stainless-steel ball with a socket of the new plastic, polytersfluorethelene [Teflon], and the freest solid then known.  These new joints produced phenomenal results.  Patients who had been unable to walk were suddenly free of pain and had a near-normal range of motion on their hips.

Elated, Charnley performed some 300 operations.  But within a year things began to go wrong.  For patients with the artificial hips, motion became as painful as it had been with arthritis.  Charnley discovered that the relatively soft Teflon did not remain effective inside the body, because, under the workload of the weight-bearing joint, it simply wore away much too rapidly to be practical.

These were depressing times for Charnley.  His wife, Jill, can remember his sitting “bolt upright in bed, suddenly awake with the cold idea of an avalanche of patients with failing hips descending upon him.”

Meanwhile, Charnley had begun to look for a whole new approach, possibly involving a joint with a sealed bearing.  Early in 1962, luck interceded.  A salesman came to the laboratory with samples of a high-density polyethylene, which he said had good wearing qualities.  Charnley, with the Teflon failure on his mind, told the technician to throw away the samples.

The technician, fortunately, had other ideas.  The apparatus they had used for testing the wear-resistance of Teflon was standing idle, and he put the spurned samples on it just to see what would happen.  To everyone’s astonishment, after three weeks on the matching the material had not worn as much as the Teflon he had worn in 24 hours.  “If my technician hadn’t disobeyed my orders!” says Charnley today. “Oh, yes, there is an enormous amount of luck in research!”

The high-density polyethylene had a surface much less slippery than Teflon, but by another piece of luck had the capacity to be lubricated by synovial fluid [the natural fluid that bathes the body’s joints], so that the rub of the metal femur head against the plastic socket was very smooth indeed.  Charnley started using the new material in November 1962, carefully building into his design an X-ray marker—metal wire exactly the diameter of the plastic socket, which would enable him to check the wear.  X-ray images made of a ten-year period, and superimposed over pictures of the joint when first implanted, show that the average wear has been only 1.5 millimeters.  And ten percent of the artificial joints show no wear at all.

Today the basic Charnley operation [called low-friction arthroplasty] is available at many major U.S medical centers, and it is estimated that over 50,000 such operations are being performed annually around the world.  The surgery takes from 50 minutes to about three hours, depending on the difficulty of the individual case.  The surgeon makes a lengthwise incision alongside the hip and thigh, deftly pulls muscles aside to reveal the hip, sometimes sawing off the knob on the top of the femur [called the greater trochanter], to which hip muscles are tacked.  Then he saws off the head of the femur.

On the pelvis side, working with rasps and other stout tools—an orthopedist has to be half—carpenter—he cleans out and reshapes the hollow in the hip socket to receive the new plastic socket, which he cements securely into place with a substance—methyl methacrylate—used by dentists.  Next he reams out the marrow shaft below the cut end of the femur and inserts first the cement, then the long stem of the steel ball prosthesis. [In this crucial step Charnley was also a pioneer.  Other surgeons had used the cement thinly, as if it was glue, and it had failed to hold.  Charnley slathered it on and packed it in as if he were setting tiles in grout.]  Once both socket and prosthesis have hardened in the cement, if the surgeon has chosen to sever and trochanter, he will wire it back into the femur, where it heals itself laid any other fractured bone.

Four or five days after the operation, the patient is on his feet, gingerly putting weight on the hue hip.  He is usually discharged from the hospital in two to three weeks.  Most patients can abandon even the use of a cane within three months.

The Charnley operation today dominates the treatment of severely arthritic hips.  Dr. Frank E. Stinchfield of Columbia’s College of Physicians and Surgeons, whose 1800 total-hip patients have included ballerina Cambarelli and former Senator Margaret Chase Smith, comments, “Almost every surgeon modifies the operation a bit.  But, basically, we all are using Charnley’s method.  He’s the one who has perfected the principles.  His contributions are now accepted universally.”

Not every individual with a troublesome hip is a suitable candidate for hip replacements.  To determine who can be helped, surgeons weigh many complex factors, involving general health, the soundness of the bone to which the new parts must be attached, the degree to which other joints are also damaged, the psychological attitude of the patient.  Obesity is a serious obstacle to successful surgery, and persistent infection in the hip joint is an almost total barrier.  The majority of patients are 60 or older, but the operation can be done at any age, once growth is substantially completed.  The operation is also possible when cancer has attacked the hip-joint area—depending on the condition of the rest of the pelvis and femur.

Consistent success with the hip-replacement operation has given rise to the popular supposition that getting a new joint for any other part of the body is simply a matter of browsing through the spare-parts catalogue and hiring the necessary technicians.  This is not yet the case.

Finger-joint replacements are, of course, a long-established success.  And other spare parts to replace our aching joints are on the drawing board, in the laboratory and in early clinical trials [with the knee now getting the highest priority].  But most orthopedists would agree with Charnley that so far only the hip is “a universal joy.”