MINIMALLY INVASIVE TOTAL HIP REPLACEMENT VANDERBILT UNIVERSITY MEDICAL CENTER, NASHVILLE, TN Broadcast April

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1 NARRATOR MINIMALLY INVASIVE TOTAL HIP REPLACEMENT VANDERBILT UNIVERSITY MEDICAL CENTER, NASHVILLE, TN Broadcast April For the more than 200,000 people who undergo hip replacement surgery every year, there s a revolutionary new technique that is less painful and allows for a faster recovery. Surgeons at Vanderbilt University Medical Center use a minimally invasive procedure that causes no muscular damage. They work through very small incisions and work between the muscles, rather than remove tissue from the bone. The advantages are certainly causing less trauma to the muscles. That causes much less pain afterward and causes patients to have a stronger limb and walk better after the procedure and recover much more quickly. NARRATOR Surgeons also are able to use fluoroscopy in the operating room for a more detailed view of the hip. It allows them to precisely position components within the hip. During the next hour, you will see doctors at Vanderbilt University Medical Center perform a minimally invasive hip replacement surgery. You may questions to the physicians in the OR by clicking the MDirectAccess button at any time. This program represents the medical center s ongoing efforts to bring the latest developments in health care to the community. Welcome to Vanderbilt University Medical Center in Nashville, TN. Today we are going to be doing a live webcast of a minimally invasive hip replacement. I m Dr. Jack Bowling, your host for today s webcast. Dr. Andrew Shinar will be performing today s surgery. Dr. Shinar, will you introduce your team in the OR? Thank you. Welcome. My team in the OR here includes, Dr. Price, anesthesia team; Jeff Macaulay, my assistant; Dr. William Curtz, who is going to be doing a fellowship in joint replacement; Eric Snyder, our scrub; Lisa Tanksley; Dora Haney; and Sally Griffiths; and Blake Arzimeret. 1

2 Dr. Shinar, could you give us just a little bit of background information on this patient before we get started? This patient is a 63-year-old woman who has had hip arthritis for a period of time that has gradually worsened on her, to the point where her pain has become constant and her x-rays have shown narrowing of the cartilage. Thus, she has elected to proceed with hip replacement. In choosing to perform a type of minimally invasive procedure, there are certain goals that you would hope to achieve. Can you give me a couple of those goals? The goals are the same as with any hip replacement; that is, reducing pain and getting back to doing the activities that one likes. Other goals with the minimally invasive surgery are doing it quicker and having less pain in the recovery period. There are cosmetic considerations too, but those are pretty minor. Great. I d also like to add that I think this procedure allows you to improve your implant positioning and I think we all want to make sure that we maintain the present standards for traditional hips, including our complication profiles. I certainly agree with that and I think having the fluoroscopy involved, as you ll see on this webcast, allows us to put the components in with a great deal of precision. What we ve done so far is removed the ball of the femur and opened up the capsule. We ve gone between some muscles here. The muscle on the outside is the tensor fascialata. The muscle on the inside is the sartorius and the rectus. We ve opened up the capsule, put retractors about it, and now we have inserted our first reamer. We can see the reamer on our fluoroscopy there. So now we re going to remove this reamer. This actually is a little difficult to do, but we minimize the number of reamers we place in doing this. I think one of the important things when you re preparing to ream is where to put the retractors for this type of procedure. If you can get a view of the fluoro image, I think 2

3 you ll see that these retractors are placed over the superior rim and then the second retractor, which is the medial retractor, is placed just over the anterior rim. One of the cautions is not to place that in the obturator foramen, where the obturator nerve exits. That will cause you some problems with your adductor muscles postoperatively, which is obviously something we don t want to do. One of the things that surgeons will ask us is why are we going to do this with two incisions when there are other minimally invasive type procedures out there that only use one. If I may, one of the slides we re going to put up is going to show the two-incision pathway. It really employs a direct access. I think one of the problems with the mini or single incision procedures is that you kind of compromise your position. We hopefully are going to show you today that by putting the incisions directly over the part we re working on, in this case the acetabulum, Dr. Shinar is able to have a direct view, which is unobstructed, into the pelvis, from which to work. I think he ll concur with that; this technique gives us probably the best view. It also has the advantage of being able to use fluoroscopy, as mentioned above, so as he is reaming the pelvis, he is able to not only visually see the size of the pelvis and the position of the reamers, but also confirm that on fluoro, which he has taken several pictures of. What we re doing now is just taking the reamers in and out. We sometimes knock the retractors out and we just put them back in when we do that. Andy, I notice you re using lights on the end of the retractors to help visualize. This is really interesting. They developed lights that fit right into the retractor, so that really illuminates our cup. We do see it on fluoro, but we get a pretty decent direct view. I ll get this retractor in and then show you the cup here, then I ll step back from the camera here and we can show inside the cup and see what kind of view we get. I think that s important because a lot of criticisms would be that with not cutting any muscle or taking down any of the tissue, that you re going to have difficulty not only placing the reamers, but when you get to the impaction of the cup, you re going to catch some soft tissue and bring in. I think you re showing a pretty nice picture there where we can see the inside periphery of the acetabulum. You can see how you could pass a cup directly into there without any involution of tissue. 3

4 Right. We have the retractors holding those tissues out of the way as well, so that s going to help us. You can see that the bone down at the bottom there is nicely reamed. We need to do a little bit more around the rim and then we ll be able to put our cup in. I ll take this second just to remind everyone who s watching this live that you can questions to us into the OR by clicking on one of the buttons on the bottom of the screen. I ve received a couple of questions that we ll go ahead and answer real quickly while Dr. Shinar is finishing off the reaming of the acetabulum. The first one is a patient who is scheduled for a standard procedure total hip who has some issues with congestive heart failure and was concerned whether this type of technique would decrease their cardio stress during and after the surgery. I think really on this type of procedure, it s still a total hip, which should be considered major surgery. There can be similar risks with respect to blood loss as well as respect to operative stress. After the surgery, there may be a slight benefit in that these patients are typically up the same day and at least up the following day, which I think would probably decrease the amount of down time or bed time, but to really think that this is going to make a dramatic decrease in the cardio stress probably is not valid. One other quick question to answer, because I think it s pertinent here, is there s a question describing the detail of a profile for a candidate for this procedure. I think the candidacy for the procedure is partially patient-related, partially surgeon experience and expertise, but for most surgeons who have developed this type of procedure, any patient is a candidate. It s easier to describe the patients who are not candidates. Typically those fall into three categories: patients who have had significant previous hip surgery; patients who have significant or morbid obesity, and that s always a relative term; and then patients who have significant bone destruction. Dr. Shinar, you d agree that patients who have a significant amount of acetabular or femoral bone loss really probably aren t a candidate to try to work through these small holes? I would definitely agree. You can see how much torque we re putting on the bones while we re doing this. For patients who have severe problems in the acetabulum, you do need a little more exposure than this to do the procedure, so I would definitely agree with that. There s no reason to push the envelope here. This is definitely an excellent technique, but I don t think it s there for absolutely everyone. The last question, before we move on to impaction of the cup we want to make sure we get that is a patient who is 65 years old, 115 pounds, who is a very active person who likes to ski, play tennis, and bike. Apparently they have been holding off on a hip 4

5 replacement by taking some medications. The question is would this procedure allow them to continue to be as active? There was a follow-up question to that also, stating whether this can be done with metal or ceramic bearings. This really is a technique advancement. The implants are really, truly up to the surgeon and patient s discussion and preference. Metal on metal has been done through this technique, as well as ceramic hips, so those are possible. With respect to playing tennis and skiing, because the muscle is maintained throughout the procedure, there really isn t any scarring that develops in the muscle itself or tendon that has to heal or repair, so I think patients overall tend to be a little more active after this operation, but the decision to either ski or play tennis is really a surgeon and patient preference. These are implants that wear over time, so high level activities such as that may lessen or shorten the longevity of this prosthesis. Let s flip back to Dr. Shinar. One thing we do before we put the part in is check the position of the pelvis. We ve been pulling on this leg, so we ve pulled it down a little ways, so we ll check that. This is where fluoro really is nice for you, isn t it, Andy, because with the traditional technique, pulling around on the pelvis, you really can t go back and kind of level yourself off, can you? That s right. I find this just a huge help in terms of getting the components in position. One of the things that I ve found in my own experience has been that my accuracy, specifically with cup abduction, has been markedly improved by using fluoroscopy. Yeah. We ve looked at that with our results compared to our non-two incision patients. We find that our abduction is much improved or at least the reproducibility of it is much improved with this technique. I see you ve chosen to use a multi-hole cup. Can you use any type of implant, a no hole or cluster hole or even a spiked cup, on this technique? 5

6 I think a spiked cup would be pretty hard. The problem is that these implants have locking rings on them. You really need to see that locking ring to make sure that your liner is down appropriately. I really want to have this in the position I need, so I think the best cups to use are either the no holes or multi holes in this circumstance. I agree. It s also nice, I think, to have the fluoroscopy for placing screws. That s always been a little bit of a concerning point of the procedure and with fluoro you can really be accurate with respect to where you put those screws and get the best size screw possible for it. Any particular tricks to getting the cup past the soft tissues? I wish there were. It takes just a bit of pushing and pulling. I think realizing that you do have to pass this cup through an incision that s not much bigger than the cup does require a little bit of a mobile window technique. If you have your assistant pulling hard on both ends, sometimes you tighten up the soft tissue such that it makes it very hard to pass the cup. I have found that a lot of times I ll take the retractors out when I m passing the cup and that helps me a little bit, but I agree with you; there s really no easy technique to get this cup in. What I find is the retractors just kind of fall themselves out as you re going along, as you re getting the cup in. The other area where sometimes this will catch up is sometimes on the femoral neck. Sometimes if it s difficult, I ll have my assistant put a little traction on the leg. Yeah, Eric s been doing that throughout and helping us a huge deal. As we work, we work it and get it around the soft tissues as we go down there. The curved or dog leg inserter really makes a difference. This patient s not too large, but some of our heavier patients, that really makes it easy to get the appropriate version as you re putting those in. 6

7 What I m doing now is switching it so that the locking ring is right on top so I can see it. That s why you need the multi-hole cup to be able to do that. I m just getting around the final soft tissue there to get right up on the rim. It s a little bigger than the acetabulum that we ve reamed. It s 2 mm bigger, so that s going to make it get a nice fit in here. This is a guide that we use to gauge the position of the cup. I ve drawn the line that s level with the patient s pelvis and now I m going to take this line and make it either level with it or just a little more horizontal than that, just to make sure that we don t tilt it up too much, which is a position you don t want to be in. I have this level to the ground and that gives me about 20 o of flexion forward. This is the part that I think really is advantageous. At this point, you re up to the point where you ve done everything you can to get it exactly where you want it. Now you bring in fluoro and really can kind of confirm that before you impact it. So we ve got a good way to go there before it gets all the way in. We need to work it a little bit there. There could be a little soft tissue caught, so I m just going to work this cup in a little bit more. Sometimes these things can be a little bit difficult to pass through there, but I m sure you ll get that through in just a second. One of the questions that always seems to arise when we talk about different types of cups that can be implanted is what about the new trabecular metal cups? I don t know if you ve had much experience with those, but my experience has been twofold with the trabecular metal cups. Because of the porosity on the outside of the cup, they sometimes will catch that soft tissue and make it even more difficult than we re finding here to get the cup fully seated, so although they are definitely an option and have clearly been used by surgeons throughout the country, they are a little bit difficult. Sometimes we recommend, if you re going to take on the TM cup, a little experience with the standard Trilogy cups first. I m going to take this back out and make sure we ve got all the soft tissue out of the way before we impact it any further. 7

8 This gives a good time to back up just a little bit on the PowerPoint presentation and just give you a little road map as to how we got to where we are on the procedure. We kind of skipped through, I think, a little bit of the important landmark identification. One of the things that Dr. Shinar did to start the procedure was to bring in fluoro and obtain a level pelvis. That is a step that s sometimes overlooked. If you re going to use fluoro during the procedure to guide you, it s important that you start off level, as he did before placing the cup, and made sure at the end of the femoral head removal, he had leveled it again. When you re looking at the anterior incision, as he mentioned, the true intervals between sartorius and tensor fascialata, these are true intranervous intervals, so they are easily identified on the patient and, once identified, can be bluntly dissected down all the way to the capsule. Once down on the capsule, there are a couple of ways to open up the capsule. Most surgeons are using an inverted T, as you see on the picture in front of you. Some surgeons are also using an H type configuration or even a J type configuration. It s all designed to give you good access and good visualization of that anterior aspect of the femoral neck. Once that s been identified, you usually can see that under fluoro and make sure you re in the appropriate plane with the neck and then make the incision. There are a couple of ways to make it. Some make it vertical and some will make it along the intertrochanteric axis to get good access down to the femoral neck. Either way works well. There s been a lot of talk and concern about the lateral femoral cutaneous nerve. By remembering that nerve runs typically on the sartorius muscle, trying to make the incision slightly lateral, makes it a little easier to get down while protecting that. Once down on the neck, we re typically remove our retractors that are intracapsular and expose the neck and resect it. There are a couple of ways to do that, either a wafer type technique where we take out a section, or to take the head out in its entirety, but once the head is removed, then it s time to proceed to the acetabular portion. Retractors are placed, as we previously described. Once those are there, we can begin reaming. Once the reaming is completed, we can go ahead and impact the cup. I ve got a couple of additional questions that have come through. I ll take a moment here to answer those. The question is, is there an upper age limit for this type of procedure? Really, the answer to that is no. The oldest patient that I ve done with this type of procedure has been 89 years old and the youngest has been in their early 30s. This is really a technique, so if the patient is a candidate for a hip replacement, in general, and with the type of instrumentation and type of implants that we re talking about today, then they re a candidate for this type of procedure. There may be other medical comorbidities that may make them less of a candidate for one, either traditional, mini, or 2-incision technique, and that really needs to be discussed with the surgeons, but from the standpoint of just simple age discrimination, there really should not be any. The second question is do we see if there is any significant bone loss and do we think the patient will be able to get back to gardening soon? The answers to those questions are on x-ray there really is minimal bone loss. I think that this patient absolutely should 8

9 recover well from this type of procedure. Gardening is an activity that many of the patients from my hometown in Wilmington, North Carolina, enjoy and I think she will be able to get back to that very soon. Let s see where we re at here on the cup insertion. I think Dr. Shinar has gotten some of the soft tissue out. On our fluoro picture, if we can get a spot of that image, what we re seeing is that we re able to get past some of the soft tissue and hopefully be able to impact this. Andy, how are you doing with the soft tissue? Doing good. I think I got it all out of there. I m just making sure my locking ring is at the top now. We re getting right in there nicely now. You can see how he has closed the distance there to the floor of the acetabulum, so he has gotten past that soft tissue. I think this brings to light an important attribute of the surgeon interested in this type of technique and that is patience. When you re working through smaller incisions, it does sometimes take backing out, as Andy did, reassessing and getting the tissue out of the way as necessary before proceeding on. I think that leads to good success. As you can tell, we re impacting the cup now and you can start to see that cup seating a little bit deeper into the acetabulum. Just like with traditional hips, the acetabulum is prepared in the standard fashion and the cups are impacted in the same way, which is malleted into place, so there are no tricks in getting the cup in. Again, with the 2 mm press fit, it is tight and we expect good ingrowth with this. Going ahead and then relaxing allows that pelvis to expand a little bit and accept this cup without fracture. It looks like it s almost down, Andy. Just about there. In between hits with the mallet, are you a person who likes to use screws? I do. I don t think they re critical, but I think it s a safer thing to do, especially since you re putting in a femoral component that could be pinching on the edge of the cup as you re tapping it in. 9

10 Watching how hard it is to get this, I think you have an excellent press fit, but I would agree; I also would use screws on all my cups. It just gives me a better feeling of torsional control. I agree that a trabecular metal cup would get a better grip, but this is a pretty good grip, as you can see. A trabecular metal cup would certainly drag in a lot of soft tissue. At this point, you get a nice look at the incision. You can kind of see the sartorius there on the medial or inside aspect of the thigh and the tensor fascialata there on the outer side. You can see that even after passing the reamers and cup and getting soft tissue out of the way, we really haven t done much to upset or violate any of the muscle belly, so I think you can really see how this procedure is truly muscle-sparing. Can you see those tie-ins pretty well, Andy? Yeah, we re seeing it pretty nicely. I m going to look through the screw holes here. I don t know if the camera is going to be able to see through them, but I ll be able to see through them. I can see through the screw holes in the cup and the cup is nicely down. It s got a great grip. I m going to put in the screw here. I think that matches too what we see on the fluoro image. It really looks down against the floor. One of the places where the use of fluoroscopy is really helpful is in patients who have some acetabular deficiency, such as protrusio or even some superior migration, I think it enables us to keep the cup in the true anatomic hip center, restore the biomechanics of the hip slightly better than we can do through an open technique. Just as with the traditional technique, these are stilled and measured in the same fashion. I typically use only one screw, but with multi-hole, Dr. Shinar has the ability to use as many as he feels necessary. Andy, if I can jump ahead just a second, have you chosen a liner option for this patient? I m going to use a neutral liner. I use a cross-linked polyethylene. I think it has so far clinically shown excellent results at about 5 years or so. 10

11 I agree. Obviously the cross-linked polyethylene is one of our alternative bearing surfaces and I think their results are fairly similar to that with the metal and ceramic hips. I concur; I use cross-linked poly on most of my patients. Do you have a certain age cutoff that you will use a conventional or traditional poly? I really think that it s pretty good for everyone at this point. I don t really see any down side to it. I agree and it just doubles your inventory and there s no need to do that if this is actually better. What size screw is that, Andy? That s a 25 mm screw. I think it s going to get a nice grip. As you can see, there s really not a good way to trial this, or you just feel that there s no need to trial with this type of technique? I don t think we really need to trial it. I think our anteversion we can see very clearly on the fluoro images. Our abduction we can see very clearly. I think that you d just be in trouble if you tried to trial this because when you have to put in your real poly, when you trialed it would be after you put in the femoral stem, and I sure don t want to do that. I think that makes a good point. Traditionally we ve used trials because we haven t had the confirmation that the cup is in the best place. I think with the confirmation we receive from fluoro, we feel pretty comfortable that we put this cup back where it is. Again, our good view of the acetabulum helps us reference it off the native acetabulum, make sure that also matches. So I think we have two good feedbacks and if those are good, then I think I agree that trialing is not really necessary. I do know surgeons, however, who will go ahead and trial the liner. In talking with them, they will tell you that it s a little more difficult to get that liner back in once the femoral component is in, as you alluded to, but it is possible, if that is a must for a surgeon out there, you can definitely trial the liners if you need to. Again, you ve chosen the neutral liner. Have you really found a need for lip liners? 11

12 I haven t. I think that there could be some disadvantage to doing that as well. I think that you could impinge on the front of the liner if you put the lip in anteriorly, so I d really prefer not to do that. I think what most people are finding with this technique is that the stability really is better than what we see with traditional technique and the dislocation rate across the board has been lower. I know in my series, I haven t had a dislocation and I think that does make us feel a little more comfortable getting away from lip liners. Yeah. I haven t had any dislocations either and I ve done about of these. Once that liner is positioned, again there s a little trick getting them past the soft tissues. Once that s done, we typically will impact it and those times that he made such careful attention to making sure they were visible will be critical to determine that the liner is actually locked in place. I think that s really critical here and that s a huge advantage of this Zimmer cup, having a very positive locking mechanism. I know in my own personal experience, I really won t move forward to the femoral side until I can see those. Unfortunately, that created some longer times in the OR initially, when there s times where inferiorly or underneath any bone ridges, etc., so I think you ve done the right thing in making sure it s right where you can see it. Yeah. If you have it in the wrong spot, you re in big trouble at this point. Just a reminder that if you do have any questions, go ahead and those to us. We ll be happy to answer those today while we re doing the live surgery. Here come a couple right now, on cue. What kind of hip device are we installing and the age of this patient? This patient is age 63. The cup that we have chosen to place in her is a Zimmer Trilogy 12

13 cup. It is a multi-hole cup. As we have just been talking about, we placed a longevity cross-linked polyethylene liner, which is an alternative bearing surface or a highly crosslinked poly, and then when we get to the femoral side, I think Dr. Shinar has chosen a full coat, is that correct, Andy? Yeah, I m going to do a full coat stem. I think that the results have been more predictable with that than a proximally coated stem. I also agree. I think the cylindrical portion of this type of stem really fits this technique and we ll go through that as we get to the femoral side here in just a moment. The next question is a patient who is very young, age 36. She s going to be having hip replacement done soon. She s on her feet at least 8 hours a day and wants to know how long until she ll be able to return to a full day at work. A lot of that would depend on what she actually does for 8 hours a day. Obviously there are some job descriptions that are a little more labor-intensive and in those patients we may want to wait a little bit longer before returning them. It s a very variable thing. At age 36 and with healthy medical conditions, many patients can return to work as early as 2 weeks after this operation. There have been some superstars, as you may call them, who have gone to work the same week of the procedure. In my own experience, it tends to be motivated patients who really want to return to work soon. If that s the case and everything goes well in the intraoperative period, we really don t have a set time frame to return the patient to work. We ll turn over now and look at the posterior incision. Andy, how did you determine where you re going to make that incision? If you look at the fluoroscopy image, you can see I ve put the awl directly over the lateral cortex. We re not going to put the awl down the canal, but that s where we want to make our incision because we need to work the tissues out laterally a little bit. Then I intersect that line with the line going down the thigh. I can feel directly inside, exactly where I want that awl to go, and I ll make an intersection of these two lines here. I think it s critical to do it that way. Kind of through residency, I was taught when we were placing intramedullary nails for finger fractures, to use the same type technique. I think that helps you. This really, as you can see, is more of a superior approach to the hip, as opposed to a lateral or posterior approach. Wouldn t you agree, Andy? 13

14 I would agree. Your analogy there of a femoral nail is right on. That s exactly what it s like. I think that also contributes to the stability of these hips. A lot of people would say, well, why is this hip more stable, even given the fact that the muscle has been taken down? Part of that, I think, is because we re really violating the superior capsule as opposed to the posterior capsule and I think that provides the most stability, so I do think that this does help. I would second that. I really think that the posterior capsule is the key element here in making the hip stable. That, I think, is a bigger advantage than the splitting through the muscles that this technique does. You can see on our PowerPoint picture that the incision site is the gluteus maximus split and the entry point is really at the piriformis. When Andy is feeling from the inside out, he can feel the piriformis tendon as it attached on the tip of the greater trochanter as well as the medius tendon and there typically is a soft spot or a space between the two and that s kind of our targeting goal to our entry into the femur. The other thing that is critical, I think, is to make sure that the incision is directly in line or longitudinally in line with the femur. The tendency is to make this incision more anteriorly and come at the femur from a top to bottom approach. That makes it very hard in reaming and preparing the femur, as we re going to see. One of the tools I think Dr. Shinar is using now is a lateralized reamer. These are some excellent tools in that they allow us to get the appropriate longitudinal orientation. They re able to take away some of the bone that may exist after removal of the femoral head in the area of the piriformis and allow us to get a direct longitudinal pathway, and you can see how he has done that on our fluoro images that are now visible. Do you use the lateralized reamers on every case, Andy? I do. Sometimes I barely need to touch it. It all depends on the strength of the bone in that area. I also do and I think one of the big advantages of using that is sometimes there will be a little overgrowth or a lip on the tip of the greater trochanter. In an effort not to catch that 14

15 when you get to the broaching portion, these lateralized reamers will remove any of that overhang. I noticed you re only going down to just below the level of the lesser trochanter also. Yeah. I think that s a key move in using these reamers. These are very aggressive and they could do some damage if they gripped on the sides down to where you don t want them to grip. I think we can see a direct pathway right down the center of the bone there. I think that looks very good. One of the things that I can see on this view too, Andy, is the height of the neck cut. Gone are the days of one finger breadth above the lesser trochanter, right? Yeah. In this circumstance, that would have worked out, but it all comes from templating. We drew out exactly what we wanted before the procedure to see exactly where we needed it. I ve found that s been very helpful in restoring leg length on these patients. One of the things that will make a patient most unhappy after a hip replacement is to have a great hip replacement with no pain, no instability, but a leg that is ½ longer than the other one. I think being able to use the templating as well as the intraoperative fluoro to really match that template is a big advantage to this procedure. I notice you re also using the flexible type reamers. I do use the flexibles as well. I think they get a good grip here and I think it s just a little safer to do this than starting off with the rigid ones. Not only is it safer, but I think one of the concerns we all have is passing these sharp instruments through this small incision in the back. Are we going to do any damage to the muscles that we ve split? I think using the flexible reamers with just the ball tip reaming device until we get to the level that we ve templated in helpful in protecting those muscle tissues. 15

16 This is another real big advantage of this procedure and the use of fluoro. As you re reaming, if you get some chatter and it doesn t quite match what you ve templated, you have the ability to take some images, both in AP and, as Andy is doing now, a lateral to make sure that the orientation inside the bone looks appropriate. That looks very good. It looks like it s sitting in the canal nicely. It s always good to be careful whenever you re doing this. When we talked earlier about patients who are contraindications, when we talked about bone deformities, one of the things that I think really needs to be taken into consideration with these type techniques is the lateral bow of the femur. Sometimes that bow can be pretty extensive. However, if it s at the center portion or distal and in that case it really won t affect this type of technique, but if that bow is significant up in the upper third, I think you re going to have trouble with a cylindrical type stem. In that case, Andy, would you go to a different type stem? I have in certain circumstances. I ve put in a tapered stem when there s been a real big bow, but I worry, doing that, just because you re not really seeing the neck of the femur while you re doing this technique and if you re getting your grip proximally, you have some risk of putting it in in a different position than the neck of the femur. And we all know what happens if that s the case. Typically those are where you result in fractures of the femur, so everything you can do to minimize the chance of that is what we re going to do. I think what Andy was saying is that looks exactly down the center of the canal and he is able to judge the depth so that he doesn t ream past the length of the implants and take away any bone that s not necessary. I like to check with the rigid reamers to make sure they re not doing anything eccentric on the femur with the lateral view. More distal, it looks nicely down the canal. Right down the center. That looks like that s getting you good contact. How did that feel? 16

17 It feels great. It s got a very rigid grip and you can see that femur s got a bow to it, but I think we ll be able to put something straight into it, just by machining it here. As you can see, that bow is right at the tip, so I agree with you. I think you ll be able to put the cylindrical stem in without much difficulty on that. You can see he s got a soft tissue protector in place. All of these are designed to protect the gluteus maximus from any damage as we pass these reamers in and out, so we re cognizant of the fact that we are splitting through the maximus muscle and we try to take every precaution we can to minimize any soft tissue damage. I agree. You can t completely have no soft tissue damage. We re putting in a big implant through an area where some muscles travel, but I really think if you re going to have to go around these muscles, splitting them like this, rather than taking them off the bone, is going to give a big advantage. That s what we notice in these patients postoperatively. I think that view also showed fairly nicely how truly superior this approach really is. If you get a chance, Andy, show us the tip of the trochanter just on the lateral side so we can show how much above that you really are with this approach. You can see that we re sitting right about there. Actually, I m going to come just a little more distal. We re judging how deep to put these. It goes between the 2 and the 3 mark on the reamer as about what the stem needs to be. Do you have the bump inflated now, Andy? I do. I leave the bump inflated throughout the whole case. I just move the x-ray machine. I find that a lot easier. I just have the x-ray machine arced to match the bump. There s a bump under this hip, right along in there, that tilts the pelvis. When I m working on the acetabulum, I have the machine tilted back. When I m working on the 17

18 femur, I have the machine straight up and down. I like having that bump up through the whole case because it keeps these tissues sterile. I think having the bump up or down really is a surgeon s preference, but I agree with Andy wholeheartedly that when you re preparing the femur, the bump absolutely has to be up. It just delivers that femur up nicely so you can get good access to it. If you try to do this with the bump down, the tendency is to ream some of the anterior cortex, which can be a problem. I notice you re putting a pair of scissors into the posterior incision. What I m doing now is cutting the superior capsule. I m leaving the posterior capsule intact, but this is just cutting the superior capsule because our broaches are going to have to go through there. The broaches are the rough devices we use to shape the canal and our stem is going to have to go through that area too, so I m just cutting...i can feel exactly what I m cutting here. I m cutting the superior capsule between the acetabulum and the femur. The bandage scissors are shaped exactly right to do that, just by chance. Some purists would say you really don t even need to cut that, but I agree, I think it makes passage a little bit easier and I ll tell you, whether you cut it with scissors or whether you cut it with cutting flutes on the rasp, you re going to turn that cylindrical capsulotomy into a triangle at some point to get that triangle down. These broach designs are very nice. One of the things that they have is a different locking mechanism. The worst problem at this point would be for the broach handle to come off the broach. Although it is possible to get the broach handle back on, this would be done through a blind grasp and that can be somewhat hard and significantly lengthen your operative time. I know Andy has checked the tension on those to make sure they re solid. That s a good point. You can make your day a little longer if the broach handle comes off. That fluoro image also showed nice how the broach handles are set a little medial, thereby protecting the tip of the trochanter as you impact these, so as not to impinge there and cause any trochanteric problems. 18

19 That s a good point. I ll show you that in just a second. That really does help a lot. Zimmer has really designed these broaches very well for this technique. The last, I think, positive thing about the broach handles is there s always concerns about how do you determine your version there. Andy, since you re not able to see the proximal femur, how do you know that you re putting it in in the anteversion that you want? What they have in these handles are holes that go directly into it. I m looking straight down on it, so I can look straight down onto these holes. The hole is looking straight at me. I know it s 15 o. Will over there has got the leg straight up and down, so I know I m putting in this femur at 15 o of anteversion. I ve also found that to be a very safe, reproducible alignment guide. The other thing that I ll tend to do is, from the anterior incision, when you remove one of the early broaches, you can really either look visually by replacing retractors over the trip of the trochanter and over the medial portion of the femoral neck. You can actually look at the cutout that your broach has made and determine the version off of that. What you can also do is sometimes you can feel the teeth right through the anterior incision. I think it s definitely a confidence part of the procedure. Once you ve done a few of these, as Andy mentioned he s done 80 of these, he s very comfortable when he passes the broach back and forth to make sure he s got his proper alignment. This really is the more difficult portion of the case. Many of us who do this on a regular basis will tell you that femoral preparation is really the key to success on this operation. What size did you ultimately get to, Andy? I reamed it to 13 and that s the last broach that I m using here. You can see it s taking a little work to get this last one down, so I think it s going to get a very nice fit. I reamlined the line and that gets enough grip with these fully coated stems. We re just about there. Half a tooth. 19

20 Are you going to use a collared stem? They all have collars on the full coat, unless they ve made one that I don t know about yet. So this bar is straight up and down, showing that we have 15 o of anteversion on that. While you re getting that last broach out, I m going to answer a couple of questions. This is from the United Kingdom, a physical therapist who is interested in the rehab protocol that we use. What I ll do, Andy, if it s okay with you, is I ll give them my rehab protocol and then maybe you can throw yours in at that point. I m sure mine resembles yours. One of the things with these type of techniques, using the fully coated or cylindrical type stems, I typically let these patients weight bear immediately, so later in the evening, a patient would be up and out of bed, would be able to stand on this and walk with a walker, weight bearing as tolerated. I really don t have any specific precautions because I haven t found that anterior-posterior hip precautions are necessary. You can see that by the stability testing that we do at the end of the procedure. I have gone ahead and allowed these patients with activities as tolerated. That sometimes can be a little bit of a problem because many of these patients feel very good within just a couple of days and some have tried to do activities such as mowing the grass, going back to work, going to sports activities, so I think we really have to advise these patients to use a word of caution. This is major surgery and they need to maintain a little bit of patience and reserved activity when getting started after a hip. Let me show the stem before I put it in. What it has here is a coating on it that the bone grows into. You can see this one is coated all the way down the stem. It has a collar here that sits on the bone that we cut on the femoral neck and this gets a tremendous grip within the canal. Now I m just going to put it through the soft tissues here. One of the tricks is getting it through the soft tissues, isn t it, Andy? 20

21 Yeah. Sometimes it can be tricky. One of the tricks is to start it out backward. It always looks odd when you do that, but that helps it a lot. I think a critical pearl on this is to get that stem in the appropriate anteversion position before impacting it. One of the things you really can t do with these full-coated stems is kind of screw home. In other words, as you re hitting them in, rotate them into the right position. If you start hitting this in 30 o anteverted, it s going to end up 30 o anteverted. Wouldn t you agree? That s very correct and that s why we have this marker on our broach handle and on the stem inserter that tells us exactly at what anteversion we re putting it in. One of the areas that always seems to catch on me is right when you get to the collar to the capsule. Wouldn t it be nice if they didn t have collars on this stem? That is true, but the collar does serve a purpose, so I think it does do something positive. I agree. I think with a little bit of technique, one of the pearls that I ll do is hit the implant down, leaving it about 1 cm out, then pull a little longitudinal traction and that will allow that collar to pop through the capsule and then you can impact it the rest of the way. One of the things you don t really want to do is, if you buttonhole or pull the posterior capsule down between the collar and the calcar, that can make reduction pretty difficult. Usually you can feel that from the front, as Dr. Shinar is doing here, making sure that collar has popped through the posterior capsule before he completes the impaction. Looks like your cut s going to be just about perfect for accepting that collar. Yeah, there it is. I think that s just about on there. I ll give it a couple of confidence taps. That s right on there. Okay, so what we ll do now is pull the neck of the stem into the anterior incision and I ll push on this as well as pull on that leg. 21

22 I think for people who are watching this, if you re thinking about this as a posterior hip dislocation, it kind of helps you, in your mind, recreate the maneuver you re going to need to bring the trunion through the posterior capsule and into the anterior one. There s just a little bit of capsule stuck there, so we re going to probably need to incise that a little bit. I think that s a common problem. It always catches just a few fibers. Sometimes you can pop that over the trunion with a hemostat and sometimes you have to cut it, but I haven t found that it really changes any stability at all to cut that. Have you? Oh, no. This is completely superior. We just about have it here. It just has a tiny bit to go. One of the questions, while we re getting that capsule off, is when the femur gets to the stem, will the stem be stronger, like when a broken bone heals? There s a certain amount of stability that s inherent in bone. It has a certain strength. When you see that it breaks, what the implant will actually do is make the construct, meaning the proximal femur, stronger. However, the trade-off for that is that just distal to the stem tends to be a transition zone where you have a stiffer upper femur and an area below that that s the normal bone stiffness, so therefore, specific trauma, like a fall or a car accident or something of that nature could fracture the bone. Typically we fracture below the stem and sometimes if these stems loosen over time, you can end up with a fracture of the bone at the area where it does knit to it, so it doesn t really make it stronger, but because of putting a rod inside, the overall bone stiffness probably is slightly improved. The last question that I have here is why are some orthopedic physicians critical of this procedure? We could have a whole hour-long discussion on the benefits of this procedure and how they compare against other minimally invasive techniques that are out there. Unfortunately, don t have that much time left. I think there are a lot of reasons that people are critical of the procedure. It can be anything from inexperience with the procedure, not understanding the procedure, etc. I think if you re interested in this type of procedure, discussing it with your surgeon is important. If the rationale that he gives you just doesn t make sense, then there are always ways to find surgeons, through the internet, etc., that believe in this type of procedure. 22

23 I didn t mean to cut that short, but I don t want to miss the trial positioning. One of the critical things that I ve done and I think I saw on Andy s hip ball was to go ahead and put a suture through the ball. There have been a couple of instances where the ball has dissociated from the stem during trialing and that can become a little bit difficult to fish out if it ends up underneath some of the muscle of the gluteus or around the pelvic rim. You did have a suture in that trial ball, didn t you? Yeah. We still do. What we ve done is we ve cut the capsule a little superiorly and we ve pulled the stem into the anterior incision to put a trial ball on and now we re checking our leg lengths. The way we do this now is to put a big ruler across the pelvis to show us how the pelvis is tilted. What I have to do is get this exactly equal. I really think we re just about right on in our leg lengths. What we compare is the lesser trochanter versus that ruler. You can see that the distance between the lesser trochanter and the ruler on both sides is equal. We have our trochanters rotated about equally, so we re pretty happy with that. I m going to show you the stability. This is the part that really always amazes me. It really can t go out this way. It s really set there. Nothing is impinging and the hip really won t dislocate there. We can flex it up to 90 very easily here and rotate the leg pretty much any way we want. If you did this with a posterior approach, that ball would be clunking, so this is really stable. We re real happy with that. Now I noticed you were going to use a ceramic ball. Yeah. In younger patients, and in this day and age, what young is is different than what it was in the old days, but you know, at 63, this patient is very active and she s got a lot of years left to live, so I think there might be an extra advantage to doing that. I agree and I have the same criteria. Again, I concur with you. I ve seen many patients who are in their late 70s who could, from a physical fitness standpoint, probably run circles around most of us, so age really is not a chronological number anymore, but it s really about how the patient feels and their lifestyle. We ve used a fair amount of ceramic heads for that reason also. 23