George McKee of Norwich, England, was the first to use
metal-on-metal articulation with modified Thompson stems and a
one-piece cobalt chrome socket combination in THR in 1953. The
design was primitive, but many lasted for more than 14 years. In
1986, August et al. reviewed 657 total hip arthroplasties
performed by McKee and Farrar. The combined survival rate of the
hip and stem at fourteen years was 84.3%. Loosening was cited as
the main cause of failure, and bone cement was cited as the main
culprit. The authors never implicated metal-on-metal
articulation as a reason for complications in their paper.5
Although metal wear was detected in devices that were revised,
McKee did not observe any undesirable effects of that debris on
the soft tissues or the bone.6 The early history of
metal-on-metal devices, including Dr. Amstutz ' experience with
the McKee device in New York, has been previously published.7-9
More than four decades have elapsed since the widespread
adoption of total hip arthroplasty for the treatment of
arthritic disorders of the hip joint. The treatment has proved
to be one of the most important surgical developments of the
20th century, providing substantial pain relief and improved
quality of life for chronic arthritic conditions in elderly
patients. In recent years, as with many areas of medicine,
substantial research has been undertaken in an attempt to
optimise both materials and design of hip replacement devices.
The very early days of hip arthroplasty centred around use of
metal-on-metal bearings, developed largely in England. These
produced widely varying clinical results, due primarily to
vagaries in design and manufacturing capabilities. By the
mid-1970’s, metal-on-metal arthroplasty was all but abandoned as
Sir John Charnley’s technique for low friction hip arthroplasty,
using metal-on-polyethylene bearings, became widely accepted.
The primary cause of failure of conventional
metal-on-polyethylene total hip arthroplasty is component
loosening. In many cases this loosening phenomenon is associated
with an osteolytic reaction, caused by the body’s response to
particles of polyethylene debris released from the bearing
surface. Inevitably, with the younger more active patient group,
this process is accelerated, potentially leading to earlier
failure of the implant and the consequent need for a difficult
revision procedure. As younger, more active patients presented
with osteo-arthritic hip conditions, the determination of how to
treat this potentially high risk group of patients became more
important. Once again, metal-on-metal hip arthroplasty came back
into consideration.
|
