DR. SU SUMMARIZES THE 20TH Year Celebration of the BHR
Hi Debbie, yes, it was wonderful to have the 20th year celebration of the BHR…
Here are some notes:
This was a gathering of experienced and enthusiastic hip resurfacing surgeons from mostly the US, but a couple of surgeons from Europe. It was nice to see that Smith and Nephew put forth the resources to get us together. Since it was a S&N meeting, the results and emphasis were on the Birmingham Hip Resurfacing, the first of which was performed in 1997!
The first section was an update of resurfacing from around the world: US, Europe, Australia, Canada. Starting with the UK, Andrew Manktelow summarized some of the results in the UK registry and other studies. Some of the results showed 97% survival of the BHR from revision, at 10 years, and about 95% at 15 years. Unfortunately, the negative press has taken its toll in the UK, and few surgeons are still performing it, and those who are, are very selective with their criteria. He said that he personally is resurfacing only male patients with large bones, and avoiding it in patients who have AVN or dysplasia.
Next, I did an update of the US experience, using data from our 10 year FDA study. In a multi center study with 359 hips (254 male, 75 females), there have been 19 revisions. The reasons for revision include: femoral neck fracture, implant loosening, and metal related problems, both metallosis and hypersensitivity. The survival curve for the BHR in the entire group of patients was 94% at 10 years, and was higher in male patients (96%) vs. females (87%), For the patients who still have their BHR, activity levels are high, and clinical score parameters are great.
Next, in Canada, Dr. Schemitsch looked at some of the data. 97.4% of resurfacing male patients still had their hip in place. He stated that in Canada, since the healthcare is regulated, very few surgeons performed resurfacing in women, so they were very selective in the beginning and remain selective.
Finally in this section, Antonio Moroni discussed the italian experience with resurfacing. He stated that very few surgeons in Italy perform resurfacing, because of the negative attention from the media. He attributed his excellent results with resurfacing to careful selection, and using a good implant.
Next, I gave the keynote speech for the course, and I titled my talk: BHR 20/20: 20 years of history, and perhaps 20 years forward? I spoke about the history of resurfacing and how we have learned from some mistakes in the last 20 years. In particular, that the implant specifics must be carefully examined, so as to avoid the ASR debacle. Also, the importance of surgical positioning, in order to create a good fluid-film for lubrication. I shared some of Derek McMinn’s 20 year results, since he has had the longest experience with resurfacing. His results show about 97% survival of the BHR in all patients at 20 years, slightly better in men (98%) than women(95%).
The major benefit I believe to patients, besides bone preservation, is the higher activity level. I described the BHR as the first artificial joint to have professional athletes who have returned to sport: the NHL with Ed Jovanovski, MLB with Colby Lewis, and NBA with Tiago Splitter. I then also showed the activity level possible with professional wrestling (the Undertaker), and showed some video. Smith and Nephew made me read a disclaimer that said that this level of activity was not representative of all patents, and they could not condone this level of activity for patients!
I also showed video of my patient, an olympic fencer, who won the gold medal in 2016 with a hip resurfacing. So very compelling evidence that hip resurfacing patients are much more active than THR patients! A participant from the audience asked whether Bo Jackson could have had a more successful return to sports if he had had a BHR vs. a THR. Yes, I definitely think so….
The next section of the course focused on some of the differences between THA and resurfacing. Dr. Schemitsch spoke about the scientific literature, and how there really isn’t compelling data for either side. But some of the scientific information suggests resurfacing is better in terms of a normal gait, as compared to THR. Specifically, walking uphill and stride length were more normal for the resurfacing patients.
Dr. Brooks, my co-chairman of the course, next gave a lecture on a possibility difference between mortality in resurfacing vs. THR patients. This is a controversial topic that was first described by Derek McMinn in 2012. He used the UK joint registry and compared the 5-10 year mortality rates of patients who had a resurfacing vs. an uncemented THR, or a hybrid (partially cemented THR). He used complex statistical analysis to adjust for factors such as age and co-morbidities, trying to limit the comparison to resurfacing vs. THR. He found that the post-surgical mortality of resurfacing patients was significantly lower than that of THR patients. At 6 years, BHR patients had a 4.4% greater chance of still being alive as compared to a THR patient.
The theory is that it might have something to do with the emboli from bone debris, when instrumenting the femoral canal with a total hip. Another possibility is that the activity level of resurfacing patients is ultimately higher, which increases their longevity. Others believe that there is some confounding variable that couldn’t be corrected for with the statistics.
However, Dr. Brooks showed another paper from Oxford that was written by statisticians, that also showed the same results (of course, using the same data set from the UK registry). He states that emerging data from Australia also seems to support this claim. He is trying to show the same findings from his data in the US, but he doesn’t have the complete information to be able to control for some of the variables as in the UK studies.
Next, we had several lectures on how resurfacings may fail…the top 3 reasons are femoral neck fracture (early on, within 3-4 months of surgery, usually); implant loosening, or femoral head collapse, and metal related issues. We talked about monitoring techniques, such as using metal ion information, MRI, ultrasound, and X-rays. I finished with a series of cases to ask my panel of expert surgeons, and we had a lively discussion with the participating surgeon attendees.
The final session was talking about possible future bearing materials. We give a few teasers about the next generation resurfacing implants, which might be using highly cross-linked polyethylene, or using oxinium on oxinium. It is a difficult decision whether a new implant is even necessary or not, given the outstanding 20 year results of the BHR…however, because the smaller sizes have been taken off the market, we concluded that it IS necessary in order to bring resurfacing back as a possibility for women and smaller sized men.