Total Knee Replacement Demonstration Dr. Eric Janssen

00:00:08.707,00:00:10.379 Hey, I'm Dr. Eric Janssen and today we're going to 00:00:10.519,00:00:14.930 demonstrate what we call a dry bones model for total knee replacements. 00:00:15.302,00:00:19.520 This is just a model of the femur, the thigh bone, and the tibia bone down below. 00:00:19.735,00:00:25.240 But when we first make our incision we make a skin incision directly in the front 00:00:25.240,00:00:30.674 of the knee and then we go inside and we actually rotate out the knee cap to where 00:00:30.698,00:00:33.924 we can get to it. I just kind of want to, on this model, 00:00:33.924,00:00:39.079 demonstrate. We'll rotate the knee cap out right here and then what we actually do is we take 00:00:39.126,00:00:43.584 off the spurs or what we call the osteophytes and then make a cut where we 00:00:43.584,00:00:46.747 make it flat on the patella and then put a plastic button on. 00:00:46.974,00:00:50.643 So once we've prepared the patella we invert it out and we have a retractor that 00:00:50.689,00:00:54.544 holds it out of the way and a retractor from the center side that holds the soft 00:00:54.637,00:00:59.327 tissue and we actually have good access to the knee once again through a limited incision. 00:00:59.791,00:01:04.064 We'll next use a drill to make a little pilate hole into the end of the bone right 00:01:04.064,00:01:08.940 here in the femur and we'll actually drill that down into the femoral canal. 00:01:09.312,00:01:14.048 And the reason we do that is that we have to have a guide to give us our alignment 00:01:14.048,00:01:18.553 when we put that first jig on. I'll go ahead and place in this alignment 00:01:18.600,00:01:24.085 rod and it has a cutting block attached to it and it sets the angle for our cut. 00:01:24.544,00:01:28.398 And normally we're going to set in general five-degree cut on this distal 00:01:28.491,00:01:31.231 femur unless there's something that dictates that we do differently. 00:01:31.603,00:01:35.132 So next we move over to this side of the table and we actually pin this little 00:01:35.132,00:01:36.711 block into place. 00:01:36.965,00:01:40.937 So we'll place that down and we'll put the second pin in to give it good 00:01:40.937,00:01:46.696 stability then next we'll release this and pull the alignment rod off. 00:01:47.114,00:01:50.922 Now if we like our distance we can actually adjust this so if we don't feel 00:01:50.922,00:01:54.748 we're getting enough bone off or we need more bone or we want to correct the angle 00:01:54.962,00:01:56.448 we could do that at this point. 00:02:00.835,00:02:05.829 And once that cut is made where we have it nice and flat and smooth we'll then go 00:02:05.829,00:02:07.826 ahead and remove our pins. 00:02:11.191,00:02:17.950 We're going to use a sizing guide to figure out what size femur we want to use. 00:02:18.296,00:02:23.940 So what we do is we put these feet down up underneath the bone right here 00:02:23.940,00:02:27.981 and we'll place the block up on there and we use this little stylus up on top of the 00:02:27.981,00:02:32.114 bone to make our decision. And we'll actually read it off of this 00:02:32.207,00:02:35.690 area right here. We'll put little drill pins into this 00:02:35.876,00:02:48.600 guide and then we'll put on our cutting block next and next we'll have to pin that 00:02:48.786,00:02:52.780 in place once again to keep it good and stable but this block will make our front, 00:02:52.873,00:02:57.424 back cuts, and we call our chamfer cuts. So once again this will be two pins to 00:02:57.424,00:03:00.349 stabilize this block, I'll go ahead and make these cuts. 00:03:00.489,00:03:15.489 So we'll start on the top here and then we'll make our chamfer cuts and then we'll 00:03:15.489,00:03:17.207 come up and make this top chamfer cut. 00:03:20.990,00:03:23.941 Once again the next step would be to remove the pins. 00:03:26.517,00:03:31.557 So after we've removed all the bone - and at this point any excessive spurs that are 00:03:31.557,00:03:35.412 on here we'll take out as well. The next thing is that - this model 00:03:35.458,00:03:37.594 doesn't demonstrate it - but there are some ligaments. 00:03:37.734,00:03:40.938 This represents the posterior cruciate ligament and the anterior cruciate 00:03:40.938,00:03:44.700 ligament would come up in this direction here so we would go ahead if they're still 00:03:44.700,00:03:48.043 present and take those two ligaments out with this particular implant. 00:03:48.322,00:03:51.805 We would leave our collateral or side ligaments which are represented by these 00:03:51.898,00:03:53.987 bands right here. 00:03:54.195,00:03:58.399 At that point we would also go ahead and remove any remaining meniscal cartilage 00:03:58.492,00:04:02.393 tissue off of that area but for the most part at this point we've got the femur 00:04:02.443,00:04:05.923 prepared where we want. We then would bring the tibia forward 00:04:05.923,00:04:10.520 and start to prepare that. Next this is a personal preference of mine 00:04:10.520,00:04:13.864 where I like to take of the tibial spines to make it flat where I can drill the next 00:04:13.864,00:04:17.022 drill in but now we're working on the tibial side. 00:04:20.805,00:04:26.774 And once I have a good flat surface to work with we'll come in and actually put 00:04:26.867,00:04:32.440 our drill in again for our rod and we'll use an intramedullary rod and there are 00:04:32.473,00:04:35.709 several different ways to do this. You can do this with an extramedullary 00:04:35.776,00:04:38.848 rod but I like using the rods that go down the bone, I think we'll get a little bit 00:04:38.848,00:04:42.424 better read on the alignment if we want. So next the rod will be placed down the 00:04:42.424,00:04:48.554 tibia, we want to determine how far down the tibia we're going to make the cut. 00:04:48.879,00:04:52.595 Usually all we're trying to do with these implants when we make our cuts is to make 00:04:52.595,00:04:56.403 enough cut on the bone to get the implant in to the level that we want. 00:04:56.610,00:05:01.279 When we get to that height we want to lock that in and then we'll go ahead 00:05:01.279,00:05:03.229 and place our pins again. 00:05:08.499,00:05:11.914 Usually we're doing a pretty flat cut here with just a little bit of slope to 00:05:12.007,00:05:13.260 the back. 00:05:18.065,00:05:24.499 So the block will come back off, go ahead and remove our pins now. 00:05:24.558,00:05:27.564 So next similar thing, we want to measure the size of this. 00:05:27.564,00:05:31.233 We have multiple sizes to mix and match so we get the perfect fit on the patient. 00:05:31.604,00:05:31.604 The next step would be to pin this in place. 00:05:34.064,00:05:39.336 So next we have a little tower that goes onto this and we'll put this in place. 00:05:39.915,00:05:45.188 Then we'll go down to the depth of the indication on this reamer here to make our 00:05:45.188,00:05:48.982 hole for our stem that goes on this particular component. 00:05:51.247,00:05:56.566 And then there's a punch with these fins that matches up to what we'll put in for 00:05:56.566,00:06:00.095 our final implant. So once we've prepared the tibia we'll go 00:06:00.095,00:06:02.138 ahead and remove this handle off of here 00:06:03.785,00:06:07.015 and then we'll go back and turn our attention back to the femur now. 00:06:07.479,00:06:09.104 We'll put our femur into place. 00:06:10.333,00:06:14.259 Next to finish the groove for where the patella will ride on the implant we'll 00:06:14.259,00:06:22.061 make a little cut along here and to finish this so we can try it we'll go ahead 00:06:22.200,00:06:25.869 and put this plastic piece on to the trial. 00:06:26.169,00:06:30.457 So now the femur's completely prepared and now we have to determine what the size of 00:06:30.491,00:06:35.297 our polyethylene component, the piece that will fit between the two metal components, 00:06:35.343,00:06:38.036 will be. So we'll go ahead and snap this into 00:06:38.129,00:06:43.516 place and then we have our trial implant on. So we'll drop the knee cap back into 00:06:43.516,00:06:47.557 place, take our retractors out, and we'll actually put this knee through a range of 00:06:47.650,00:06:52.479 motion, make sure that we can get it fully straight, fully bent back down, and we 00:06:52.479,00:06:56.055 want to check the stability of the knee, make sure that it's all stable and within 00:06:56.055,00:06:59.585 the constraints of the ligament. And we have the ability to pop this 00:06:59.585,00:07:03.625 component out and go with a thicker piece. And so once we've figured that out we now 00:07:03.657,00:07:07.433 know what the size of our femoral component is, our tibial component, 00:07:07.572,00:07:12.402 the polyethylene that goes in between, and our plastic button for the patella. 00:07:12.634,00:07:16.767 So at this stage we'll go ahead and remove all the trials out and we'll open up the 00:07:16.767,00:07:21.504 final implants, we'll wash off the bony surfaces real well, and then we'll cement 00:07:21.597,00:07:24.476 those components on. The cement takes maybe about five minutes 00:07:24.544,00:07:28.099 to harden and then we're basically finished and we'll close up the wound at 00:07:28.099,00:07:29.027 that point. 00:07:29.188,00:07:33.053 Essentially this operation takes us about an hour to an hour and 15 minutes. 00:07:33.532,00:07:37.665 So that's basically how the total knee replacement is done with the dry bones model. 00:07:37.990,00:07:44.422 For more information on this and other procedures go to www.sportsmedalabama.com.