Hip replacement

What Your Doctor May Not Tell You About Hip and Knee Replacement Surgery
By Ronald P. Grelsamer, M.D.

(Page 5 of 6)

Hip replacement. With hip replacement surgery, you don't have to worry about the bone not healing (there are no longer two pieces of bone that need to heal together!) and osteonecrosis is not a concern because the part of the bone that dies (the femoral head) has been removed! And in an older patient, even crutch walking is not an issue because the surgeon will use a technique that doesn't require it.

However, hip replacements have their own set of complications. They can become infected, they can dislocate, and over time, they can loosen and wear out.

Choosing the right operation. First, the surgeon has to decide whether to fix or replace your hip. The factors he will consider include your age, your level of activity, and the “displacement” of the fracture. The older you are, the more likely he is to pick a joint replacement. This is because the older patient is going to be less tolerant of hobbling for two to three months only to find that she needs to return to the operating room. A hip replacement in an older patient is also less likely to loosen or wear out in his or her lifetime.

The surgeon will also lean toward a hip replacement if you are on the less active side, for the less active you are, the less likely your hip is to loosen or wear out.

The specific nature of the fracture is also a factor. The fracture can be of the nondisplaced type, whereby the fracture consists of a simple crack akin to a crack in the wall.

The two pieces are still connected and haven't moved relative to each other. The femoral head can be impacted, i.e., pushed into the femoral neck as a scoop of ice cream might be pushed into a cone. Finally, the fracture can be displaced: The bone has snapped like a pencil, and the two fragments might as well be in different rooms. In the case of the nondisplaced and of the impacted fracture, the surgeon is dealing with a relatively stable situation. With a little luck, the fracture could heal without any surgical intervention. The surgeon need only place a few orthopedic pins across the fracture to prevent displacement of the fracture, something that might happen if you fell again or took a misstep. Clearly, in the setting of the nondisplaced and of the impacted fracture, a hip replacement is overkill. The more difficult decision comes with the displaced fracture, and this is where the surgeon will review your age and your level of activity.

The older and less active you are, the more likely he is to recommend a replacement; the younger and more active you are, the more likely he is to recommend fixation.

If he's decided to replace your hip, your surgeon must now decide between a total hip replacement and a hemiarthroplasty. In the United States, he will choose a hemi-arthroplasty 99 percent of the time. This is because most patients who break their hip are elderly.

A hemiarthroplasty is a quicker operation than a total hip replacement and therefore theoretically safer (less anesthesia time, less bleeding, less exposure to the air).

The issue of the metal ball rubbing against the acetabular cartilage is less likely to be a significant factor in an older, lighter, less active patient.

A hemiarthroplasty is less likely to dislocate (pop out) than a total hip replacement. This is because the femoral head is larger in a hemiarthroplasty, and larger heads are less prone to dislocate.

But an argument can be made for performing a total hip replacement. Some patients who fracture their hip may also have some early arthritis. If they are still relatively young and active (a healthy seventy-year-old woman actuarially speaking, still has many years to live!), the hemiarthroplasty may become painful in short order. The hemiarthroplasty will need to be changed to a total hip replacement. This is called a conversion even though there is no religion involved. Converting a hemi-arthroplasty to a total hip replacement is much harder than performing a total hip replacement right off the bat. It is associated with many of the risks of revision hip replacement.

In a patient with underlying arthritis, the situation is really a no-brainer, and in this particular situation (fracture plus arthritis) the surgeon will, in fact, get reimbursed more for a total hip replacement than for a hemiarthroplasty (this is because “arthritis” codes pay more than fracture codes). The difficult decision-making comes in the setting of a pure fracture devoid of any arthritic component in a patient who is reasonably active in the community. In theory, the surgeon has to weigh all of the above factors and has to discuss them with you before coming to a decision. In practice, a diagnosis of a displaced femoral neck fracture will nearly automatically lead to a hemiarthroplasty. The urgent circumstances of the fracture and admission to the hospital don't allow for much discussion.

This is another time-honored adage, going back to the earliest days of hip surgery. Since prolonged bed rest leads to medical complications, it was recognized early on that prompt surgical treatment and early mobilization of the patient out of bed into a chair saves lives. Ideally, the subject should have her fracture surgically addressed on the same day as her admission to the hospital.

In the real world, the surgery often takes place the following day or evening. If the patient is not “medically cleared,” i.e., suffers from a condition that won't allow surgery, the surgery is delayed until that condition is cleared up or stabilized. But generally speaking, complications increase with the length of the delay.

Here then is the dilemma: Operate soon and avoid bed-sores, pneumonia, and urinary tract infections, or operate later to evaluate and fully understand, say, the temperature that your mother has been running, or her cardiac function. Your family doctor and the anesthesiologist will usually vote for the latter. This is in part because they don't want intraoperative complications (who does?) and in part because they don't always appreciate the risks associated with delaying the surgery.

Copyright © 2004 by Ronald Grelsamer, M.D.

About the Author

RONALD P. GRELSAMER, M.D., is the chief of hip and knee reconstruction at Maimonides Medical Center, and a staff orthopaedic surgeon at the NYU Hospital for Joint Diseases/Orthopaedic Institute.