HIP REVISION SURGERY TOTAL HIP ARTHROPLASTY
Category: Orthopedic Surgery
Abstract : Hip revision surgery, which is also known as revision total hip arthroplasty, is
a procedure in which the surgeon removes a previously implanted artificial hip
joint, or prosthesis, and replaces it with a new prosthesis. Hip revision
surgery may also involve the use of bone grafts. The bone graft may be an
autograft, which means that the bone is taken from another site in the patients
ow
Hip revision surgery, which is also known as revision total hip arthroplasty, is
a procedure in which the surgeon removes a previously implanted artificial hip
joint, or prosthesis, and replaces it with a new prosthesis. Hip revision
surgery may also involve the use of bone grafts.
The bone graft may be an
autograft, which means that the bone is taken from another site in the patients
own body; or an allograft, which means that the bone tissue comes from another
donor.
Purpose
Hip revision surgery has three major purposes: relieving pain in
the affected hip; restoring the patients mobility; and removing a loose or
damaged prosthesis before irreversible harm is done to the joint. Hip prostheses
that contain parts made of polyethylene typically become loose because wear and
tear on the prosthesis gradually produces tiny particles from the plastic that
irritate the soft tissue around the prosthesis. The inflamed tissue begins to
dissolve the underlying bone in a process known as osteolysis. Eventually, the
soft tissue expands around the prosthesis to the point at which the prosthesis
loses contact with the bone.
In general, a surgeon will consider revision surgery for pain relief only
when more conservative measures, such as medication and changes in the patients
lifestyle, have not helped. In some cases, revision surgery is performed when
x-ray studies show loosening of the prosthesis, wearing of the surfaces of the
hip joint, or loss of bone tissue even though the patient may not have
experienced any discomfort. In most cases, however, increasing pain in the
affected hip is one of the first indications that revision surgery is necessary.
Other less common reasons for hip revision surgery include fracture of the hip,
the presence of infection, or dislocation of the prosthesis. In these cases the
prosthesis must be removed in order to prevent long-term damage to the hip
itself.
Demographics
The demographics of hip revision surgery are likely to change
significantly over the next few decades as the proportion of people over 65 in
the worlds population continues to increase. As of 2003, however, demographic
information about this procedure is difficult to evaluate. This difficulty is
due in part to the fact that total hip replacement (THR) itself is a relatively
new procedure dating back only to the early 1960s. Since the design of hip
prostheses and the materials used in their manufacture have changed over the
last forty years, it is difficult to predict whether prostheses implanted in
2003 will last longer than those used in the past, and if so, whether improved
durability will affect the need for revision surgery.
On the other hand,
more THRs are being performed in younger patients who are more likely to wear
out their hip prostheses relatively quickly because they are more active and
living longer than the previous generation of THR recipients. In addition,
recent improvements in surgical technique as well as in prosthesis design have
made hip revision surgery a less risky procedure than it was even a decade ago.
One Scottish surgeon has reported performing as many as four hip revisions on
selected patients, with highly successful outcomes. According to one estimate,
32,000 revision total hip arthroplasties were performed in the UnitedStates in
2000.
While information on the epidemiology of both THR and hip revision surgery is
limited, one study of Medicare patients in the United States who had had either
THR or revision hip surgery between 1995 and 1996 was published in January 2003.
The authors found that three to six times as many THRs were performed as
revision surgeries. Women had higher rates of both procedures than men, and
Caucasians had higher rates than African Americans. Other researchers have
reported that one reason for the lower rate of hip replacement and revision
procedures among African Americans is the difference in social networks.
African Americans are less likely than Caucasians to know someone who
has had hip surgery, and they are therefore less likely to consider it as a
treatment option.Description Hip revision surgery is hard to describe in general
terms because the procedure depends on a set of factors unique to each patient.
These factors include the condition of the patients hip and leg bones; the type
of prosthesis originally used; whether the original prosthesis was cemented or
held in place without cement; and thepatients age and overall health. Unlike
standard THR, however, hip revision surgery is a much longer and more
complicated procedure. It is not unusual for a hip revision operation to take
five to eight hours.
The most critical factor affecting the length of the operation and some of
the specific steps in hip revision surgery is the condition of the bone tissue
in the femur.As of 2003, defects in the bone are classified in four stages as
follows:
• Type I. Minimal bone defects.
• Type II. Most of the damage
lies at the metaphysis (the flared end of the femur), with minimal damage to the
shaft of the bone.
• Type III. All of the damage lies at the metaphysis.
•
Type IV. There is extensive bone loss in the femoral shaft as well as at the
metaphysis.
The first stage in all hip revision surgery is the removal of the old
prosthesis. The part attached to the acetabulum is removed first. The hip socket
is cleaned and filled with morselized bone, which is bone in particle form. The
new shell and liner are then pressed into the acetabulum.
Revision of the femoral component is the most complicated part of hip
revision surgery. If the first prosthesis was held in place by pressure rather
than cement, the surgeon usually cuts the top of the femur into several pieces
to remove the implant. This cutting apart of the bone is known as osteotomy. The
segments of bone are cleaned and the new femoral implant is pressed or cemented
in place. If the patients bone has been classified as Type IV, bone grafts may
be added to strengthen the femur. These grafts consist of morselized bone from a
donor (allograft bone) that is packed into the empty canal inside the femur.
This technique is called impaction grafting. The segments of the femur are then
reassembled around the new implant and bone grafts, and held in place with
surgical wire.
A newer technique that was originally designed to help surgeons remove old
cement from prostheses that were cemented in place can sometimes be used instead
of osteotomy. This method involves the use of a ballistic chisel powered by
controlled bursts of pressurized nitrogen. The ballistic chisel is used most
often to break up pieces of cement from a cemented prosthesis, but it can also
be used to loosen a prosthesis that was held in place only by tightness of fit.
In addition to avoiding the need for an osteotomy, the ballistic chisel takes
much less time. The surgeon uses an arthroscope in order to view the progress of
the chisel while he or she is working inside the femur itself.
After all the cement has been removed from the inner canal of the femur, the
surgeon washes out the canal with saline solution, inserts morselized bone if
necessary, and implants the new femoral component of the prosthesis. After both
parts of the prosthesis have been checked for correct positioning, the head of
the femoral component is fitted into the new acetabular component and the
incision is closed
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