Choosing a Doctor
The best indicators of success of a surgeon is the number of surgeries performed per year, experience with the tools and device, and the number of hip replacement surgeries per year for the hospital. If a doctor is doing 50 hip replacements or resurfacings per year, he or she is doing at least one per week and is more likely to have experience with a wide variety of patients and surgical challenges and is more likely to be on top of the latest techniques and hardware than a surgeon doing fewer. Generally speaking orthopedic hospitals have lower incidences of infections and other complications because they have fewer severly ill patients in the building. Hospitals who treat a lot of hip replacement patients have staff who are familiar with the orthopedic recovery issues including risks of infection, blood clots and dislocation. You don’t want a surgeon’s good work to be harmed by a hospital employee unfamilar with post-op dislocation precautions, for example.
Physical therapists and nurses in orthopedic wards can be good sources of information about the success rates and quality of treatment of surgeons in your area. The physical therapists may be able to tell who’s patients do better in the short term and which surgeons have more experience with cases similar to yours (age, sex, orthopedic diagnosis). Beyond short term success, however, one should still be considering the long term wear and dislocation issues, as the recovery period is relatively short compared to the rest of one’s life.
Selecting the Device
Of course the selection of the device used is ultimately up to the surgeon, he or she will be able to consider all relevant issues to get the patient an implant that will fit well, operate smoothly, and provide many years of comfortable use. The patient should be aware that a surgeon and/or hospital are commonly under contract to work with just one or two of the orthopedic device manufacturers. In the United States a representative of the orthopedic company will be in the operating room to literally make the sale and hand off the implant during the surgery. The sales representative has the surgeon’s ear for a good bit of time. Thusly the advice the patient gets from a single surgeon regarding specific devices will reflect the brands that he is able to offer, and may be colored by that company’s marketing efforts.
Walking into a surgeon’s office is a lot more like walking into a car dealership than many are willing to admit. A car dealer selling Ford is not likely to mention a competing brand, or be completely familiar with a car option that is offered by Chevy and not Ford. Or, if Ford has a better product, the Chevy factory representative has likely pumped the dealer with some confounding issues to use to convince auto shoppers that innovations offered by competitors are risky or unproven.
While a car dealership flies the Ford or Chevy flag promenintly throughout their property, it is not common to see such commercial displays at the surgeons office. Perhaps this will appear subtly by brands printed on informational brochures in the waiting room. So the orthopedic consumer will need to ask specifically which company or companies the surgeon and/or hospital works with.
At this time the United States there is quite a disparity among the various companies in what they can offer in terms of the most recently-developed technology. In fact only one company (Wright Medical) offers a full line of hard bearings (metal and ceramic) as well as the crosslinked poly. For these reasons, if you get a second opinion it is a good idea to select a surgeon who works with a different orthopedic manufacturer. If you are interested in a specific device you may want to contact the manufacturer, get a list of surgeons who deal with that company, and begin your surgeon search in that way.
Surgical Approaches and Dislocation
The most common surgical approach is known as the posterier approach. The surgeon accesses the hip capsule by separating muscles in the gluteous maximus. The surgeon can then get a good view of the femoral head and surrounding structures. The gluteous is a large muscle which is relatively easy to rehabilitate and the posterior approach has the lowest risk of affecting nerves that run through the hip and thigh region. The anterolateral or direct lateral approach is generally done to try to reduce the short-term dislocation risk. Normally for the posterier approach there is the “90-degree rule” where the patient is not supposed to bend at the hip more than 90 degrees. This is not required with the anterior or lateral approachs because different muscles and tendons are affected by the surgery. The patient is not allowed to bend their leg backward, however. A study done at one large surgical center found they could reduce the short term dislocation rate (first year post-op) from 2% to 1% when they switched from posterier to a direct lateral approach. A review of other studies showed no significant change in the first year dislocation rate using the anterolateral approach.
However, there is no free lunch, the occurrence of limp at one year post-op was higher for the direct lateral approach. The approach cuts closer to nerves, which severed can cause foot-drop and also the muscles which are affected may be more difficult to rehabilitate. Physical therapists are more likely to be experienced with designing rehab for the very common posterior approach.
Aside from the short term dislocation risk, one should be aware there is a continuing, long-term risk of dislocation. A recent study of patients who where treated at the Mayo Clinic found that the dislocation rate was on the order of 2% for the first year, then an additional 1% for each 5 year period subsequently. In that way, a patient who might be fortunate enough to have their implant last to 25 years without revision would have a cumulative risk of dislocation of about 7% (1 in 14). The study found more dislocations in females, in those who are older than 75 years old, and in revision cases. These results are for some of the best surgeons in the business; there is reason to believe the results for all surgeons in the country are not as good.
The continuing risk of dislocation risk may have more to with the mechanics of the joint, and the laxity of the ligaments in the hip joint area. The mechanics of the joint operation will be affected depending on the degree of hip dysplasia (if any) which was corrected, the ability of the surgeon to implant the device at the best functioning angles and also on the size of the femoral head that is used.
There is an inherent mechanical limitation for the typical hip replacement when the typical 50 mm natural head is replaced with the artificial head which is often 28 mm in diameter. The neck of the implant can impinge on the edge of the cup at angles much lower than the natural range of motion. Once there is impingement, the stem can lever the ball from the socket. There are now large metal-on-metal THRs and hip resurfacing that are designed to eliminate the long term mechanical risk by remaining true to the original head diameter. The larger diameter increases significantly the range of motion before impingement and the additional size then presents a much greater distance in order to have the ball levered completely from the cup. Those two factors combined, along with a normal rehabilitation of the surrounding muscles and ligimants serve to make the large diameter joints as nearly dislocation-free as the natural hip joint.
Thus, for those devices preserving the original head diameter, the surgeon can impose the 90 degree rule for 6-12 weeks until the muscles and ligaments have healed, and then give the patient an all clear. Personally, I found the “worry free” long term to be very attractive.
Bilateral Surgery vs. Two Hip Surgeries
I had both hips resurfaced on the same day. Often patients requiring two hip replacements are advised to have each hip repaired in separate surgeries. This then requires two rehab periods, of which 6 weeks is just for waiting around for healing of the pelvic bone and hip- joint capsule. With bilateral surgery both hips can be healing at the same time. I had no problem with getting around on crutches after about 4 days despite having two recently- repaired hips. In fact, because of the weight-bearing pain I was having before surgery I think it might have been harder to get around with a still-unoperated hip.
Traveling for Surgery
I had to travel by plane for this surgery and was somewhat concerned about the trip home. I flew back after a 5 day hospital stay and 3 additional days in a condo in So. Calif. I took advantage of the airline wheelchair service to make my connection (which was quite a hike) and the sky cap service for baggage handling. I was able to walk on crutches down the jetway and in the airplane aisle. I sat on some “eggcrate” foam that was given to me by the hospital PT staff, and buckled my seatbelt over my lap and that. That was no problem. I had a bulkhead seat for one of my flights, and I found no advantage to having the bulkhead seat, in fact I found the regular coach seat had a little more leg room given the post-surgical hip restrictions.
Heterotopic Ossification (HO)
Heterotopic ossification (HO) is unwanted bone growth (osteophytes) around the implant that cause pain and reduced range of motion. HO is primarily a risk factor for men and for anyone that has shown such growth in the past. Those with ankylosing spondylitis are most at risk. HO can be prevented by low doses of radiation applied to the surgical site immediately before or after surgery. Often it is done the day before to avoid having the patient moved around right after surgery. The dose administered is very precisely aimed at the region around the implant and is one tenth that administered for a single cancer treatment. HO can also be prevented by taking Indocin, an anti- inflammatory, for 5 days after surgery. To be safe, both treatments can be used. If osteophytes appear after surgery and they cause pain, the only solution is to remove them surgically. A year wait may be required before such surgery in order to be sure the bone has matured and the osteophytes won’t grow back after removal.