1.) Hi Dr. Su, can you please first start out by telling us how you got started with Hip Resurfacing and give us a little background on your experience as a surgeon? Where did you train for hip resurfacing? Who trained you? Did you continue your training after starting resurfacing?

I did my residency training for orthopaedic surgery at the Hospital for Special Surgery and stayed afterwards to do a fellowship in joint reconstruction and replacement.

During residency, I had the opportunity to attend a visiting lecture by Dr. Harlan Amstutz on his experience with hip resurfacing, both past and present. I was struck by his commitment to the idea of bone preservation, and the challenge of implant longevity in younger, active patients. This led me to seek additional training in this technique, so I spent about 3 months with Dr. Amstutz to learn from him. I was so excited with the technique that I brought it back to HSS and performed the first modern generation hip resurfacing at our hospital in 2004. I realized that hip resurfacing is a more technically difficult procedure than hip replacement, so I sought additional training from experienced surgeons around the world. I visited Dr. Koen DeSmet, Dr. Thomas Gross, and Mr. Derek McMinn in order to learn from the masters.

Photo: Dr. Su

2.) You started doing neck capsule preservation in your surgeries, can you tell us a little about the reason for doing this and explain to us more in detail exactly what it is?

Neck capsule preservation is a technique described by Dr. Vijay Bose, one of world’s foremost hip resurfacing experts. It is a way of performing the hip capsule release to preserve the soft tissue around the neck. This may help preserve some of the blood supply to the femoral head. It is also a method in which the capsule can be repaired after the resurfacing so that the hip is more stable.

I became interested in the technique when I heard Vijay speak about it at a resurfacing meeting. It made a lot of sense to me, and could perhaps explain the excellent results that he achieved.

3.) Which approach do you prefer to use anteriolateral or posterior?

I like the posterior approach for the excellent exposure that it provides (which is critical for the positioning of the implants) and the ease of recovery for the patient. There are some who believe a trochanteric flip (Ganz osteotomy) or anterolateral approach weight bearing and avoidance of certain movements. Finally, if the muscles that were detached during the anterolateral approach don’t heal back to the bone, then this can be a serious problem. I don’t have much experience with the anterior approach, so I can’t really comment on that.

A final word is that I think there are many ways to skin a cat, and surgeons should use what they feel comfortable with.are better for the blood supply, but we saw from Mr. Treacy’s data that there wasn’t any difference in outcomes between the posterior and anterolateral approaches. Also, the recovery from the anterolateral and trochanteric flip tend to be more difficult, with protected.

4.) What is your opinion on the Direct Anterior approach for hip resurfacing, not the antero-lateral approach where the incision is on the side but the Direct Anterior approach?

I think the direct anterior approach is intriguing in that it is an intermuscular approach, without cutting or detaching any muscles. However, I have witnessed it before and found it to be a struggle with a limited exposure. The potential advantage is a preservation of the blood supply to the femoral head, but as we have discussed before, the NCP approach to the hip via the posterior may be able to do the same thing.

I think the posterior approach is more suitable for the majority of patients because it gives the best visualization for component positioning, can be easily extended, and offers just as quick a recovery.

5.) How long do you feel it takes for the bone to be fully healed, actually grow into the prosthesis?

For the socket, I believe it takes 3 to 6 months before the bone is fully grown onto the implant. I believe the femoral bone is something that continually remodels, since it is alive. I believe that it is weaker initially after surgery, but strengthens with gradual activity, to the point that it is probably strong enough for impact activity at 6 months.

6.) Barring any complications, how many days in the hospital will a patient normally stay?

Usually they stay 2 days (that is, if surgery is Monday, they leave on Wednesday), but some patients have left the day after surgery, and others have stayed 3 days. However, it is something assessed on a daily basis and depends on whether or not it is safe for a patient to be discharged. We look for the ability to get in and out of bed independently, use crutches, and go up and down stairs.

7.) What is your typical recovery time after resurfacing, what is your typical rehab protocol? 90 degree restriction? Walker” Crutches Cane? Amount of time? Blood thinners? TED stockings? Ice? PT?

The typical rehab protocol is weight bearing as tolerated on the operated leg, using a walker the first few times the patient gets up. Then, we will advance you to using two crutches, either the axillary (armpit) or lofstrand (forearm) crutches, depending on your preference. They are used like walking sticks, so you are still putting full weight on the leg and walking with alternating steps. I like you to use the crutches for walking for about 2 to 3 weeks. They are to provide additional stability so that you don't fall and for my peace of mind. Many patients are able to walk 1 mile at a time, at 2 weeks after surgery. At this point, the best thing for your recovery is simply walking, and you will be able to do exercises on your own. We will send a therapist to the house 2-3 times per week to help guide you, but before long, you will be independent. You can also ride a stationary bicycle, swim, and exercise your upper body in the gym during this time. I don't impose any 90 degree restrictions postoperatively. In fact, I find it important to begin mobilizing your hip.

After 2-3 weeks of using 2 crutches, you'll advance to 1 crutch or a cane. Shortly thereafter, within another week or so, you'll be walking without anything to help you. At this point, you will be ready to go to outpatient therapy. The main purpose of outpatient therapy is to mobilize the hip and strengthen the muscles around the hip. In addition, after the first postoperative visit, I will show you some stretches to help you regain the motion. This phase of therapy will last about 1-2 months.

You may begin to play tennis, golf, and cycle outdoors at about 6-8 weeks postoperative. I like you to remember that the hip is still healing at this point, and heavy lifting over 50 lbs and impact activities should be avoided until you are 6 months postop.

After 6 months postoperative, I remove all activity restrictions — it's your hip!

In general, I use a full strength, coated aspirin (325 mg) twice a day for 1 month following surgery as your blood thinner. Certain patients will require stronger blood thinners. TEDS stockings can be very helpful if you experience swelling, and would be used while a patient is up and around during the day (since fluid tends to accumulate by gravity).

8.) How long before a typical patient is allowed to drive a car, return to work?

For driving, usually a left hip patient can drive after about 2 weeks, as long as they are off pain medication. If it was a right hip surgery, you may need an additional 1 to 2 weeks to make sure you can lift the leg from side to side. A manual transmission will take 3-4 weeks postop for either side.

9.) What is the recommended time you tell your patients before they can start to run again/do impact sports? Are there any sports you don’t want your patients to participate in after surgery? Out of the patients you have resurfaced what are some of the sports they have returned to?

As stated above, I remove activity restrictions at 6 months. I would ideally like the hip resurfacing implant to last as long as possible, and I feel that repetitive running on hard surfaces may be detrimental to the implant and it's connection with the bone. If a patient feels strongly about running, I would prefer it be done on a softer surface.

Patients have returned to such activities as: marathons, rugby, volleyball, mountain climbing, hiking, ballroom dancing, performance dance, Thai kickboxing, mixed martial arts, judo, tae kwon doe, soccer, baseball, pitching, basketball, golf, tennis, among others.

10.) What is your take on cementless (femoral) devices for resurfacing?

I think it is an intriguing idea, a natural extension of what we have learned from total hip replacement. However, there is very little known about it at this time, and although I have done it in a few cases, I would like some additional followup information before doing it on a widespread basis. The theoretical advantage is that once the bone grows into the femoral cap, it should be integrated into one's own body and have very little chance of loosening. This might perhaps be better for impact sports. However, the downside is that there may be gaps between the bone and the implant initially because of bone wear or cysts, or there could be a failure of ingrowth. Thus, the failure rate of cementless resurfacings could potentially be higher than cemented resurfacings, if applied to all patients.

11.) Do you have a cut off age for resurfacing patients or do you go on a case by case basis?

I go on a case by case basis, since there is so much variation between a patient's physiologic and chronologic age.

12.) What type of anesthesia do you use general or epidural or ?

At the Hospital for Special Surgery, we use epidural anesthesia, which will then be connected to a pump so that a patient can control their own medication, on demand.

13.) Are there any cases that you will not take in particular, AVN, dysplasia, small cysts? Maybe touch on some of the very difficult cases you have been able to resurface?

There aren't any particular categories of cases that I would not be willing to resurface. However, resurfacing does depend a lot upon the strength and structure of the bone. So there are some cases of large cysts (holes) that have formed in the femoral head, or avascular necrosis that has caused a large portion of the bone to die. In these cases, if more than 50% of the femoral head is deficient, a resurfacing may not have much to support it.

I have been able to do some challenging cases of patients with prior surgery from fractures, slipped capital femoral epiphyses, hip dysplasia, femoroacetabular impingement, Legg-Calve-Perthes, and AVN.

14.) Do you do bilateral surgeries same day, if not how far apart do you recommend?

Yes, I have done over 40 bilateral hip resurfacings on the same day. In certain instances, a period of time may be recommended between surgeries, depending on the medical health of the patient. If a patient is not healthy enough to have the surgery done on the same day, or it would require too much operative time, a patient can still have it performed during the same hospitalization, with 3-4 days between the sides.

15.) What device do you prefer to use for hip resurfacing?

I still use the BHR, Conserve Plus, and Biomet Recap. I think the devices are very similar, but the BHR has the longest track record, which is very important to me. The other devices do have the benefit of more sizes than the BHR for right now (at least in the US), so there are some patients for whom they fit better.

16.) If you can’t perform a hip resurfacing – what THR device do you prefer and why?

If I can't perform a planned resurfacing operation, I would typically use an uncemented THR with a large diameter metal head. If we have another reason for not wanting to do a metal-on-metal bearing, then I generally use a ceramic-on-ceramic THR for my younger, active patients.

17.) What do you consider an adequate number of surgeries for a doctor to be proficient at hip resurfacing?

This is a tough question to answer, because obviously every surgeon has to begin somewhere. Hip resurfacing is definitely a more challenging operation to perform than total hip replacement. That being said, a good hip surgeon who is experienced with THR should be able to make the transition fairly easily.

However, each patient's anatomy is different, and to really appreciate the subtleties of implant placement to produce not only the best short-term, but also long-term results, I think 100 hip resurfacings would be a reasonable number. Also to be taken into account is the frequency of performing them; hip resurfacings should be performed consistently, otherwise the learning curve will not advance. Thus, a frequency of at least 5 to 10 per month is probably the minimum number.