A Joint Venture Is the New Hip Thing
A visit to the factory where part of me was made.
BY JAMES TARANTO
The Wall Street Journal, Friday, May 1, 2009
WARWICK, England--I am a natural-born American, but part of me was made in England. I've come to this town, 25 miles southeast of Birmingham, to find out how.
The hum of machines is ubiquitous in the Smith & Nephew factory, where the floor is divided into "cells" the size of small rooms, each a self-contained assembly line making a particular part. Workers in a cell transform a dull-gray metal piece, cast at another facility, into a gleaming, perfectly shaped finished product, measured to an accuracy of a few microns. Every part is numbered, so that it can be tracked throughout its lifetime, and inspected and cleaned multiple times before shipment. I am grateful for this precision and care. Two of these parts--a ball and a matching socket--are now my right hip.
In 2007 I saw the doctor for a mild but persistent pain in my thigh. After two months of physical therapy, my hip was so stiff that I could barely bend over. An MRI revealed avascular necrosis, a localized degenerative condition in which an insufficiency of blood causes bone loss and eventually arthritis. Friedrich Boettner, an orthopedic surgeon at New York's Hospital for Special Surgery, informed me ominously that X-rays of my femoral head--the ball of the hip joint--showed "signs of collapse," meaning that my hip was too far gone to save. Before the advent of joint replacement, this condition would have meant a lifetime of worsening pain. As it was, within eight months of the diagnosis, I needed a cane and struggled to walk a few city blocks.
A decade earlier, I would have had a total hip replacement, which entails amputating the head and neck of the femur and inserting a stem into what's left of the bone. This is a proven therapy, but it is problematic for younger patients. Most total hip replacements use a plastic socket, which works very well at first but tends to wear out within a decade or two. To slow the socket's deterioration, the ball is smaller than a natural hip, but that poses a risk of dislocation. Total-hip patients are ambulatory and pain-free, but if they are young--I was in my early 40s--they face restrictions on their physical activity and the likelihood that they will outlive the prosthesis and need more surgery.
Now there is an alternative with none of these drawbacks: the Birmingham Hip Resurfacing, named for England's second city, where inventor Derek McMinn practices orthopedic surgery. More than 100,000 BHRs have been implanted world-wide since 1997, with an overall failure rate of less than 4%. Because the BHR preserves most of the femur, it is easier to replace with a total-hip implant if it does fail. Dr. McMinn tells me that among his patients who were under 55 at the time of surgery, "92% play sport, and 62% play impact sport."
The BHR consists of a full-size cap mounted over the existing bone and fitted into a metal socket. Dr. McMinn developed it by combining two previously abandoned technologies. Hip resurfacing had been tried and found wanting, because the large ball caused very rapid wear of the plastic socket. But some early total hip replacements used metal sockets, and in the late 1980s Dr. McMinn noticed that they continued to function well in patients who got them decades before. He persuaded a small company to build a prototype metal-on-metal resurfacing device, and in 1991 he implanted the first one.
After six years of small-scale experimentation, he and fellow hip surgeon Ronan Treacy formed Midland Medical Technologies to mass-produce what became the BHR. They enlisted metallurgist Tim Band, now an executive at Smith & Nephew, who reverse-engineered the decades-old metal implants and helped the two surgeons refine the new device's design. One notable innovation was to coat the inner surface of the socket with tiny spherical beads that allow it to bond directly to the pelvic bone, obviating the need for cement, which can come loose.
By 1998, Midland Medical was marketing the BHR in Continental Europe and Australia as well as Britain. But America was a laggard, because of the Food and Drug Administration's laborious approval process. London-based Smith & Nephew acquired Midland Medical in 2004, in part because the larger firm had the wherewithal to deal with the FDA. Meanwhile, determined Americans traveled as far away as India to get a BHR before the FDA finally approved it in 2006.
When I ask Dr. McMinn to describe the FDA process, he answers in one word: "Hell." The agency put him through an "arduous" series of audits before agreeing to accept his existing data in lieu of clinical trials in the U.S. Yet although the procedures were burdensome, they were not rigorous: "It's a crazy process, because in effect what they're looking for is two-year data. Two-year data is completely inadequate," because serious complications from orthopedic implants often develop later. "We were presenting five-plus-year data. They didn't know what to do with that."
For a patient, though, the U.S. medical system has its advantages. "In Europe, of course, long delays for health-care-provision reasons are terribly common," Dr. McMinn says. While patients wait, they relieve the pain with anti-inflammatory drugs, the regular use of which causes bone damage. "By the time you come back, it's all destroyed, so you're forced into a total hip replacement as the first option, even though on age reasons you may well have wanted to do a resurfacing."
By contrast, when Dr. Boettner decided last May that I was ready for surgery, I had to wait only until he was available to perform it. I received my new hip July 18, and it was the best medical experience of my life. The pain was gone immediately. I was walking on crutches the next morning and using my cane 11 days later. By the last week of August, I was striding unassisted through Denver, where I had gone to cover the Democratic National Convention. The implant sets off airport metal detectors, but otherwise my life is back to normal. Being born in America was a lucky break after all.
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