Baby Boomers' Joint Replacement Questions Answered

Baby boomers continue to receive attention as they reach different milestones of life.  One particular piece of attention currently revolves around the growing number of younger populations, particularly baby boomers, who are receiving joint replacement surgeries.

Baby boomers are simply not slowing down from their active lifestyles with which they grew up.  As a result, statistics from the American Academy of Orthopaedic Surgeons show that more than 418,000 total and partial knee replacements are performed each year, 15 percent of them on baby boomers; of the 328,000 total and partial hip replacements done, boomers are the recipients of more than 20 percent.

To better understand the terminology and most up-to-date surgical procedures, five baby boomer specific questions were posed to the orthopaedic physicians at Guilford Orthopaedic and Sports Medicine Center, a division of Southeastern Orthopaedic Specialists in Greensboro, NC.

One baby boomer asked about hip resurfacing joint replacement surgery (HRA).  In particular, the boomer wanted to know what HRA was and its advantages or disadvantages versus a traditional total hip arthroplasty (THA) procedure.

Dr. Frank Rowan answered this question about one of the most current hot topic surgical procedures by saying, “HRA involves a similar surgical incision and approach as a traditional THA.  With a THA, the ball at the top end of the femur (thigh bone) is removed and a large metal stem is cemented or press fit into the shaft of the femur.  With HRA the surface of the ball is removed and a hemispherical cap is placed over the remaining femoral head.  With both procedures the hip socket is reamed to remove any remaining cartilage and a hemispherical metal shell is press fit into the bone.  The metal shell may require a plastic or metal liner to mate with the femoral head.”

In terms of advantages and disadvantages Dr. Rowan continued, “ HRA may conserve more bone since the femoral neck and a portion of the femoral head are not removed.  This may make future revision surgery easier.  Disadvantages include possible femoral neck fracture from weakened bone, limited weight bearing for the first six weeks, and a higher revision rate.  Overall, the THA allows more stability and earlier full weight bearing than HRA.”

Dr. Rowan also addressed new technologies used in both HRA and THA, “Large head metal on metal bearing surfaces used in both systems markedly decrease friction, increase safe range of motion, and show no measurable wear after ten-plus years.  Patients are able to resume activities such as tennis, water skiing, and jobs with greater than 50 lbs lifting.  These activities caused dislocations and excessive wear with the traditional small head metal on plastic hips.”

Another baby boomer posed the following question, “I heard that Jimmy Connors had a minimally invasive hip surgery and was back playing tennis in six weeks.  If my friends or I needed a hip replacement, could we have the same surgery he had?

Dr. Peter Dalldorf answered the baby boomer with, “Minimally invasive surgery (MIS) is a general term used to describe a surgical procedure that utilizes a smaller incision(s) than conventional surgery. In some MIS procedures the amount of soft tissue (muscles and tendons, etc.) that are disrupted during surgery may also be reduced.  The potential benefits may be a smaller scar because of the reduced incision and the potential for a faster recovery because of less tissue disruption as well as the potential for less blood loss.  Disadvantages to minimally invasive hip surgery include the potential for inappropriate visualization of the surgical area, which can lead to malposition of the components and possible fractures.  Longer operative time, limited scientific data, and unknown long-term results are also disadvantages.”

In terms of being a candidate for MIS, Dr. Dalldorf replied, “Candidates for MIS are determined by a person’s weight being proportionate to his or her height.  Extremely tall patients, overweight patients, or patients with poor bone quality typically have a better result with a traditional total hip replacement procedure.”

A third baby boomer posed a group of questions.  “My neighbor had a total knee replacement using a computer assisted system.  What is a computer assisted knee replacement?  What are the advantages of this kind of surgery?  Is it a standard procedure for all orthopedic surgeons?  What are the disadvantages?”

Dr. John Lee Graves responded, “Computer assisted knee replacement is a relatively new idea.  Your surgeon places pins in your bone above and below the knee joint during the surgery.  Attached to these pins are little spheres that can be read by a computer.  By a simple method of reading multiple straight lines from each of these spheres, the computer can tell the surgeon the center of hip rotation and the center of the ankle joint and allow him or her to align these points directly over the center of the new knee.  This is what we have been trying to do all along and we have instruments that have made us much better, but for the first time we can be nearly perfect.  These pins are removed at the end of surgery.”      

Dr. Graves continued, “Our long term studies show us that if you align the joint within 2.5 degrees the need for revision surgery drops significantly.  For the first time we know that we are aligning the joint within parameters that we cannot see with the naked eye. Another advantage of computer assisted knee surgery is that you do not open the canal of the femur (the bone above the knee).  This leads to much less bleeding into the joint after surgery and some surgeons feel leads to earlier and better knee motion with less total pain post-operatively.  Computer assistance also allows us to balance the flexion and extension spaces accurately which enhances smoother range of motion.”

Dr. Graves addressed the questions further, “Not all surgeons use computer assistance because it is complicated and takes longer to do the surgery.  There is a tremendous amount of data that has to be evaluated during the surgery, which can sometimes be confusing, but with proper training and continued use these problems can be minimized though not eliminated.  It will be many years before we will know definitively whether computer assistance minimizes need for revision surgery and those surgeons that believe in it will continue to use it accepting that it has minimal downside risk.”

The fourth baby boomer asked, “My doctor said I need a shoulder replacement and that he would do a hemi-arthroplasty.  What is a hemi-arthroplasty?  My husband had a complete shoulder replacement, what is the difference between complete replacement and hemi-arthroplasty?”

Dr. Vincent E. Paul responded to this question, “Hemi-arthroplasty refers to a partial joint replacement.  When dealing with the shoulder, generally only the end of the upper arm bone, called the humeral head, is replaced.  Patients who do not have any arthritic damage to the glenoid (socket) do not need to have the socket replaced.  During the replacement of the humeral head, the ball at the top end of the humerus is removed and a metal stem is cemented or press fit into the shaft of the humerus.”

Dr. Paul continued, “During a total shoulder replacement, the humeral head and the socket are replaced.  The humeral head is replaced the same way as during a hemi-arthroplasty.  The glenoid is replaced by reaming away any remaining cartilage and a metal replacement shell that is under a polyethylene lens is cemented into the bone.  However, in almost all situations a hemiarthroplasty is preferred due to a higher incidence of loosening of the glenoid replacement.  Loosening of the glenoid replacement would necessitate removing the socket component later.”

Dr. Paul added, “Most shoulder pain from osteoarthritis is the result of the end stage of a non-repairable rotator cuff tear and often can be relieved by hemiarthroplasty alone.”

A final but very important question was posed.  The fifth baby boomer asked, “What cutting edge surgical procedures for total joint replacement are just around the corner or soon to be available?”

Dr. Graves replied, “Joint replacement is all about alignment and materials. If you had materials that could not wear out you would not have to worry about alignment and if you had perfect alignment you would not need materials that could not wear out.  Significant advances in alignment have been made and are continuing with sophisticated instrumentation and the beginnings of computer assisted surgery for both hips and knees.  Materials such as metal, ceramic, and improved plastic are adding to the longevity of joint replacement which allows us to continue to offer these surgeries to younger and more active patients reducing the fear that they will wear out the new joint in a short period of time.”