Meniscal transplant systems are designed for meniscal allograft implantation with rigid fixation at the horn attachments. Specifically, the Dovetail Meniscal Allograft Set fashions a trapezoidal meniscal allograft, which is more easily reproducible, for a bone-to-bone interlock with a patient’s similarly shaped tibial trough. Generally used for lateral meniscus transplants, the dovetail meniscus allograft can also be used for medial meniscus transplants.
Visit the Orthobiologics section for more information on allograft techniques.

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The segmental meniscus transplant technique addresses failed repair of the meniscus while avoiding total replacement. Patients who have irreparable defects can benefit from a partial replacement, completed using the segmental meniscus transplant technique, which provides the same tibiofemoral joint compartment biomechanics as an intact meniscus.1-3 This technique helps preserve the native biomechanical loading principles of the knee while keeping intact native hoop fibers.
References
1. Strauss E, Caborn DNM, Nyland J, Horng S, Chagnon M, Wilke D. Tissue healing following segmental meniscal allograft transplantation: a pilot study. Knee Surg Sports Traumatol Arthrosc. 2019;27(6):1931-1938. doi:10.1007/s00167-019-05355-z
2. Seiter MN, Haber DB, Ruzbarsky JJ, Arner JW, Peebles AM, Provencher MT. Segmental meniscus allograft transplantation. Arthrosc Tech. 2021;10(3):e697-e703. doi:10.1016/j.eats.2020.10.059
3. Nyland J, Campbell K, Kalloub A, Strauss EJ, Kuban K, Caborn DNM. Medial meniscus grafting restores normal tibiofemoral contact pressures. Arch Orthop Trauma Surg. 2018;138(3):361-367. doi:10.1007/s00402-017-2849-x

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Segmental Meniscus Allograft Transplantation

Patrick A. Smith, MD (Columbia, MO), performs a segmental meniscal allograft transplantation procedure. The entire technique and several pearls are included, including defect preparation and measurement as well as graft preparation and fixation. Stable fixation is achieved using the ZoneNavigator™ device to complete inside-out suture delivery and the FiberStitch™ implant for side-to-side fixation.

video

Segmental Meniscus Transplantation Surgical Technique

So this is a left knee. And we're going to demonstrate a segmental meniscal transplant today. Left knee. This patient had a partial medial meniscectomy. You can see here a pretty classic tear that's been trimmed to the posterior horn. Here's our route. And this was the transition of removing the tear. So the first order of business is we want to prepare for the allograft segmental transplant. So I like to remove much of the native remaining meniscus back to about a millimeter or so for the meniscal sites to help regrow into the allograft segmental transplant. So first thing we do is we've got to prepare this rim. So I'm going to come in in the area of the tear, come back toward the capsular attachment and remove the remaining meniscus. Here, a millimeter or two to the rim is what I like to do. And then we'll prepare the rim with a rasp. To further enhance the ability for this incorporation of the allograft. So I try to leave a 90 degree angle here to the back, where we'll suture the segmental to the native area of the posterior horn, there and here, up to the anterior aspect of the area of the tear. So there's our preparation. You can see we've got back about a millimeter or two of the native rim, and that's where our segmental meniscus is going to fit in. Now I take my meniscal rasp, and I want to stimulate bleeding from the native capsular attachment here. This is where the blood flow is to the meniscus coming from the periphery. So I'll go here a little bit underneath the capsule. To help enhance the healing here. And then we've got to measure our defect. So these are two millimeter marks so we can measure. There's ten is the bold mark there 2022 looks like 24 there in terms of our anterior posterior dimension. So we're going to use our ZoneNavigator. And we're going to pass our four sutures in the native remaining meniscal Rim, and that is how we will pull the segmental meniscus into the joint and attach it and actually suture it to the capsule. So we have the ZoneNavigator and we're going to pass first the posterior superior suture. So here's our needle loaded. Passing through the native rim of meniscus. And retrieve that needle percutaneously on the posterior medial side. So there's good position of that needle. And now we're going to pass a suture a shuttle suture. So we have our TigerLink. We'll pass the free end. And the loop part of the link will allow us to pull the meniscal sutures in for the actual segmental transplant. Okay. Perfect. So that's our first suture. Now we're going to place our second suture. Posterior. Inferior. [00:03:10] Put it in. Now we'll do the same thing. We'll take another tiger and pass it through the loop part of our wire. So for distinction. So we know which one is superior. This is just a straight FiberWire suture. Fiberwire. And this is a SutureTape. So it has a double black on it. So this will orient us so we know which one is posterior superior and which one is posterior inferior. When we pass the corresponding sutures placed in the segmental meniscus posteriorly. So now we're going to take our ZoneNavigator. I've moved the scope to the medial portal. And I'm going to come in laterally now and make our pass for the anterior superior. Anterior inferior. So here's the anterior superior. Again we're passing our needle which has the loop on the end. And we use that loop to pass through our sutures. And here we're going to use a blue FiberWire and a blue SutureTape to distinguish. So here's our blue FiberWire which will be our anterior superior shuttle suture for the graft. And now we'll pass our anterior inferior. Right. So you get a feel here of our management of these four sutures. And these four sutures will pull the graft in oriented the two posterior ones super inferior, the two anterior ones the anterior inferior. So the last thing I'm gonna do is I'm just going to check the depth from the capsule rim to the free edge. And this is a probe. Those are marks are five millimeters. So it looks like it's about ten for the depth of our segmental graft. So our next step here for suture management is we place the 12 millimeter passport in the medial portal. We have our four quadrant divider. So now we can separate our four sutures which will make a big difference in terms of later passage. So I'm going to come through here first. And I'm going to grab the posterior superior TigerWire suture and pull it out one slot. So now I'll come in just below that and grab the posterior inferior. So this is really helpful to keep these separate. So when we pass our graft we'll have our sutures all in the right spot. Now I'll come in and grab the anterior-superior through the top left divider. So now we'll get the anterior inferior, which is right there through our last segment down here. So now you can see the divider. We've separated the posterior superior posterior inferior anterior-superior anterior for. So we're in those quadrants now which will make the passage of our sutures in the meniscal segmental transplant much easier when we pull it into the joint. And then we'll tie those sutures that we pass directly on the capsule for our fixation. So before we go and create the exact match for the segmental meniscal, the last measurement I want to do is just how far I am from the posterior defect to the root. So when I go to the to the specimen, I can match that up. So you can see here to the root attachment I'm about six millimeters Maybe seven. So that will allow me when I go back and cut the specimen, I'll try to leave seven millimeters from the root of the specimen. And then of course, cut 25 to the front. Just a reference point that I think is helpful. Now we'll go back to our back table and prepare our segmental meniscal specimen to fit. This is our meniscal allograft medial meniscus. So now we're going to cut the suitable segmental allograft. And based on our measurements intraoperatively, we're going to measure seven millimeters from the root and make a mark right at the ball there. And then we're going to make our first cut. And we remembered our orientation which was slightly oblique. So it's not so much in that plane. But we remembered what we did. We were slightly oblique. We're going to come back to the capsule in that plane. And we want to take a little bit of this capsule attachment for blood supply. Apply. If we're a little bit big, we could trim the inner aspect if we need. But we think for healing we need this capsular attachment. So intraoperatively we measure 25 with our anterior posterior. But I think for sizing purposes, cutting one millimeter or less is best. So we make sure that the segmental meniscus fits ideally. And then we can tension it with additional suturing if we need to. But I do not want it to be too big anterior to posterior, because then you'll have to cut it again. So our experience has been to cut it one millimeter less. So here's our mark. We're going to go to 24 kind of from the mid portion of the viscus where we measured from make our posterior mark there. So now we're going to make our second cut. And this one is a little bit oblique in the opposite angle. So we're not going to cut like this. We're going to cut more like that. So remember our angle visually. So we're going to make our cut in this plane right here. So there were put our measuring device. We're right at 24, which is what we wanted one less than what we measured intraoperatively. And what I was saying is we might be a touch long here. We're measuring about 12 to the rim. But if we needed to trim a little this on the free edge, we could. This is the working part of the meniscus. Your circumferential hoop fibers. That's what you're trying to preserve here. So now we have to pass our sutures in the peripheral aspect of the meniscus that will tie to the capsule using our shuttle sutures that we placed on the joint side. So if you put the meniscus on end here's the posterior aspect. So first I'm going to pass with this small needle with a loop on it. I'm going to go through the posterior inferior segment of the meniscus here through the capsule getting a good bite. And we'll pass now the black and white which corresponds to the posterior inferior suture we passed on the joint side. We're going to create a cinch here. So this will give us good purchase in the meniscus. So that's our first pass. So now we're going to create our cinch. Give us good purchase in this peripheral aspect of the meniscus. [00:10:23] Okay. That's not going to work. Okay. So that's our posterior inferior. So we're passing posterior superior. So we have our shuttle loop. This is for our other cinch black and white. And we'll create this cinch. [00:10:54] Oh that's hard. So what you can see here is when we tie to this the capsule, we're going to tie these two on the outside of the native capsule to pull the meniscus and hold it in place. And you get great purchase because of the thick circumferential hoop fibers peripherally with the meniscus. So this really gives you a really good purchase. So here's our prepared segmental allograft getting ready to transplant into the patient. So as we've been talking about for suture management purposes, we have passes through the peripheral aspect of the meniscus posterior inferior double black hair and posterior superior single black. And that will correspond to the same suture we placed earlier for passage. And then the anterior aspect anterior inferior is striped and the anterior superior is plain blue. So blue in the front, black in the back through the peripheral aspect of the meniscus. And those are cinch sutures. So we have a good purchase the meniscus. And then we're going to tie the anterior superior to the anterior inferior posterosuperior posterior inferior directly on the capsule to get our fixation. So again here's our graft oriented. Remember the two black cinches in the posterior of the meniscus. The two blues anterior. We've got a great team helping me here. So we're going to now pass the corresponding double black with the previously passed suture through the posterior inferior aspect of the meniscus. And now let's pass. We'll pull that through. And we'll pass the posterior. Superior. Now again, we're color coordinated to keep things straightforward. Then we'll use those two with the KingFisher to deliver our graft into position. So now we're going to come through our meta portal. We had taken of course the passport cannula out. So use the KingFisher to guide my graft in. We made that portal just a little bit bigger. So now you can see we delivered the posterior part in. We'll maintain traction on that. And now we very simply just pass our blues for the anterior and we secure our meniscus. We'll just double check to make sure our passport helped us. We'll make sure we're not crossed it all. There's our bottom, so we're clear there. So there's no soft tissue bridges. So we're clear. And again the passport with the dividers allowed us to do that. So now the double blue is the posterior inferior. You can see there on the screen coming through. Okay. Perfect. So you can see what we're doing now we've passed these and we'll tie those directly to the capsule. It'll give us great fixation with the peripheral aspect of the allograft transplant to the native capsule, which we prepared earlier, including the rasp, to help get some good healing. And then we'll finish the repairs needed with some FiberStitch all-inside sutures. So you can see it looks like we have a nice fit. And again, if we needed to trim a little this free edge, we could. I'm more interested in having that good, secure capsular tissue for security of the meniscus. So if we had to trim a little bit of this in the back, we could. But we'll see. We might make that up with the FiberStitch in the back. We'll put a FiberStitch here and here and one in the front. So I'm tying these sutures down to the capsule, and that's reducing the meniscus even more. So through a small medial incision, we're tying directly to the capsule. That's what I'm doing here for our posterior superior. Posterior inferior. Now I'm going to tie my anterior-superior. Anterior inferior. So you can see we've got this peripherally sewn. And here we might trim a little of this, but that's okay. So now we're going to put an on side FiberStitch in. And just to help reduce that just a bit better in the front. So we put our half pipe in. For our FiberStitch we have different curves. So we're just delivering our FiberStitch. Then come to the front of the native. Take our probe. Bring our mattress down and complete it. So this is the cutting device. So we've loaded the suture. We just bring it down to the knot. Push and cut. So you can see we've got an excellent reduction now anteriorly. Now we'll put one posteriorly. So here's our completed segmental meniscal allograft transplant. And I just trimmed a little bit of that back edge. Remember this. This graph was not matched to this patient. So but you think I think we had a very good fit. You can see here's my spanning suture to the posterior horn. Anterior horn I've got two the capsular sutures tied. And we put that additional vertical mattress. So it's totally stable. Can't displace it at all. We replaced the meniscus. It's pretty normal. So really happy with how that came out. Put the knee through a range of motion. Flexion. All the sutures hold. Fine. You can see the meniscus. Femur rolls back. Meniscus goes with it right there. Meniscus going back with the femur. Normal rollback. So really happy with that transplant.

J. Lee Pace, MD (Plano, TX), discusses the scientific support for segmental meniscus replacement to treat irreparable meniscal deficiencies. Dr. Pace also reviews biomechanics and surgical considerations when treating these deficiencies.

Segmental Meniscus Transplantation for Irreparable Meniscal Deficiencies

Hello. Lee pace here from Farmington, Connecticut. Today I'd like to talk about something new and exciting. And this is the concept of segmental meniscus transplantation. As we are all aware, there is a significant burden of meniscus injury in this country and around the world, with societal costs ranging from 500 million to 5 billion annually. This is due to the historical treatment of these meniscus tears to include mainly partial meniscectomy, although it does provide good short term results. The rate of osteoarthritis is proportional to the amount of meniscus removed, so there has been a large shift in thinking and practice to save the meniscus. Over the past decade or so, there has been a lot of focus and energy on innovating new techniques and new products for meniscus repair, as well as research to study its outcomes and feasibility. Here's an example of a complex lateral meniscus tear, which in the past would have been meniscectomy. But now, with products such as the knee Scorpion, we can now perform a very reliable repair. Here's another example of a more complex posterior horn medial meniscus tear, in which there are two separate tears present. In the past, this would have been at least partially meniscectomy. Nowadays we can do a robust and reliable repair. This is an inside out technique using the ZoneNavigator and this also went on to complete healing. In fact, these meniscus tears are in the same patient and she's doing great. However, we do encounter the problem of meniscus deficiency. We have some meniscus tears that are chronic or just too complex to fix, and we are left with a situation where someone has a subtotal loss of meniscus tissue. For many years now, we have been able to successfully perform and improve our techniques with meniscus transplantation. To help with this very difficult problem of meniscus deficiency, we have now identified sort of a new problem when it comes to meniscus preservation segmental deficiency. There are some meniscus injuries that behave as a complete meniscectomy, where you still have a lot of native meniscus tissue left, but you have a defect present that makes the meniscus behave as if it was a complete meniscectomy. A classic example is here with a segmental radial defect. You can perform a complete meniscus transplantation here, but it requires a removal of a lot of native meniscal tissue. And in this example here you can see that I had to remove the entirety of the posterior and anterior horns of this lateral meniscus so that I could perform a complete meniscus allograft transplantation. So the question is, is can we perform a focal segmental meniscus transplantation? So let's now dive into the science that's been looked at so far with this question. First off let's look at what's been done with biomechanics. This is a study out of Kentucky looking at an animal model. This is a 4K model in which 12 knees were evaluated by creating a segmental radial defect. In the medial meniscus. There were three states intact the segmental defect and then the grafted defect. An axial force was applied in differing degrees of knee flexion, and they collected data on mean and peak pressure, peak pressure location, and peak pressure area. The results are fortunately not surprising. What they showed was that in the segmental defect model, there was increased pressure, a mean pressure and peak pressure, as well as a decreased peak pressure area in the segmental defect, and that by performing the segmental replacement that it restored all of these parameters back to normal. So from a biomechanical status, this can be performed. Now the next step is biology. Will this heal? Can you get an allograft meniscus to heal on the borders successfully? In this animal study from the same group looking at segmental meniscal transplantation in a sheep model, they were able to evaluate the histology at the borders of the native and transplanted meniscus at 90 days. Now, interestingly, three sheep were euthanized early, and so they were able to be evaluated at 40 days, which created sort of an internal control for the sheep that were evaluated at 90 days. What they found was very interesting that even in the sheep that were euthanized early, there was evidence of partial healing, particularly at the areas of the side to side repair. And then in the sheep evaluate at 90 days. This healing trend continued, and we should take these results in context, because the repair construct that was performed was rather basic and did not take advantage of all of the tools that are currently available. And further, it was performed in a rather hostile animal model in which there was no ability to have protected weight bearing after the meniscus transplantation. Now, to take the next step, there is now a published technique for performing an open segmental meniscus transplantation in a human, and this technique comes from Matt Provenza's group with some pictures shown here. You can see the segmental grafted defect in the medial meniscus here with a robust fixation construct. So now let's talk a little bit about indications. Obviously this is early. And so these indications will be evolving. However we think that prime indications for this include segmental defects between 2 to 4cm due to either failed prior repairs or irreparable segmental defects. Classic examples of this would be radial tears or irreparable posterior horn tears of the medial meniscus. It would require intact meniscal roots as well as appropriate cartilage, stable ligaments, and neutral alignment. The next step in the evolution of this is reliable arthroscopic techniques. Using some of the tools that are available to us to include the ZoneNavigator, the knee Scorpion, and the FiberStitch. And in fact, these are pictures from my work in the lab successfully performing an all arthroscopic segmental meniscus transplantation of the posterior horn of the medial meniscus. There is still a lot of work to do. We do need further animal and biomechanical data, and we want to follow that up with clinical studies looking at further indications, patient reported outcomes, rehab protocols and expected functional levels after surgery. In conclusion, segmental meniscus transplantation represents the next step in meniscus preservation and restoration. We have lots of work to do. However, I think we're all looking forward to some very exciting results.

Matthew T. Provencher, MD (Vail, CO), presents a case of focal meniscus deficiency treated with a segmental meniscus allograft transplantation. Dr. Provencher also shares several technical pearls and concomitant procedure considerations for this case, in addition to his rehabilitation protocol.

Segmental Meniscus Allograft Transplantation for a Focal Meniscal Deficiency

Hi, I'm Matthew Provencher from Vail, Colorado, and I'm going to talk to you today about a segmental meniscus transplant, a case study. This is a 37 year old, very active female who's had several knee surgeries prior, including an ACL reconstruction with a failed prior meniscus repair, and then had two subsequent partial meniscectomy on the medial side. She presented with medial persistent pain and an inability to return to her activities, including just activities of daily living. She also had a problem with her knee due to some malalignment, as well as some early grade chondromalacia and focal grade four defects of the medial femoral condyle, as well as a focal meniscus deficiency. Her preoperative weight bearing imaging, as well as her hip to ankle radiographs, demonstrate overall pretty well preserved joint space, no significant osteophytes, and overall a varus right knee weight bearing axis right around 25%. Her preoperative MRI on the axial demonstrates the focal segmental medial meniscus deficiency. It's approximately 15mm from anterior to posterior, but she does have intact anterior and posterior horns as well as intact roots of the medial meniscus. Her coronal view also highlights a focal cartilage defect that's focal grade four, but also highlights very nicely her focal medial meniscus deficiency right in the center portion of the medial meniscus. So we have a young female with a focal segmental medial meniscus deficiency, approximately 1.5cm from anterior to posterior, but intact anterior and posterior horns of the meniscus, as well as intact roots. She has a focal medial femoral condyle defect, grade four, and also varus malalignment at about 25%. The treatment plan for her was a focal segmental medial meniscus transplant. To address her focal deficiency of about that 15mm or so, as well as a additional medial opening wedge high tibial osteotomy to correct her varus alignment back to neutral, as well as a fresh osteochondral allograft implantation of the focal defect on the medial femoral condyle. Her diagnostic arthroscopy reveals a focal medial meniscus deficiency. As noted here, when measured and templated intraoperatively, this is about 18 to 20mm. After you get back to a very nice stable anterior and posterior rim. Of note, her anterior and posterior limbs of the meniscus were intact, started first with the alignment and condyle damage addressing with a focal osteochondral transplantation of two plugs, followed by a high osteotomy using a wedged osteotomy plate. The segmental medial meniscus transplant starts after you trim the meniscus back to stable normal borders. This was measured at 20mm after the medial meniscus was adequately debrided to a good stable rim, which is important to accommodate the side to side transplantation sutures. After this is done, we use a variety of spinal needles or other passing devices to come under, as well as on top of the meniscus, and pass some initial sutures to shuttle the meniscus in from both front and back. The graph preparation is shown here. We obtain a medial meniscus transplant. It is measured out and templated and matched to her defect after preparation. This is right around 18 to 20mm, depending on where it's measured in the meniscus. We then harvest the segmental portion of the meniscus that we're going to transplant, leaving the remaining meniscus on the back table. Once this is done, we then do progressive stitch shuttling through the medial meniscus such that the sutures will match up to the sutures that were passed in the knee. This is the final construct prior to implantation, where we have multiple vertical mattresses that match up with our prior past sutures. Because we had already done the osteochondral Allograft as well as the osteotomy. We have an open arthrotomy which facilitates approach as well as graft positioning and placement. Of course this can be done all arthroscopically, but since we were already open, it was chosen to be done this way just for ease of passage. The graft is passed in with something such as a KingFisher and put into position as the assistant. Gently tensions down the sutures through the capsule from an inside out type of repair. Two FiberTak anchors, 2.6mm size, are utilized to help fix the meniscus at both the front and posterior portions. These are placed right on the most medial margin of the tibia, and then cinch down. After transitioning one of the sutures that had already been passed in the meniscus, and then put in through one of the anchor knotless sutures for fixation. Thus, the final construct is five vertical mattresses pass through the capsule and tied inside out. The anterior and posterior portions are also incorporated into native tissue with number two non-absorbable suture. And then it's further anchored to the tibia with a 2.6mm knotless FiberTak suture anchor. This is the final construct as demonstrated here. And you can see the side to side radial type of suture, as well as the sutures that are placed through the capsule. And then deep at the tibia margin are the two FiberTak anchors. Her post operative imaging is demonstrated here showing the osteotomy construct bone graft. And you can also see some small hint of bone tunnel for the tack anchor post-operatively. This patient will be touched down weight bearing for a total of five weeks, with a hinged range of motion brace starting at 0 to 90 degrees right away, with both passive as well as active assist motion, and working on quad sets as well as hamstring activation. The hinge knee brace will be discontinued after about five weeks, when range of motion as well as weight bearing will be progressed and she'll be allowed to return to full activity between 5 to 6 months.

Segmental Meniscus Transplant

Child (D)

For meniscal allograft transplant, the double bone plug technique involves medially implanting the meniscal allograft with rigid fixation at both horn attachments. The technique can also correct meniscal deficiency using bone plugs and minimally invasive suspensory fixation and allows the meniscal allograft to maintain functional hoop stress.

Double Bone Plug Meniscus Reconstruction

Double Bone Plug

The technique used with the Dovetail Meniscal Transplant Set creates a trapezoidal bone block allograft for a bone-to-bone interlock, requiring no additional bone graft fixation. The soft tissue/meniscus portion of the graft still needs to be sutured/fixed. The instrumentation easily and consistently prepares the patient's recipient trough and the trapezoidal shape of the allograft's bone block.

Meniscal Allograft Transplantation Featuring Dovetail Meniscal Allograft

Matthew T. Provencher, MD (Vail, CO), discusses the surgical techniques, shares technical pearls, and reviews patient outcomes pertinent to meniscal allograft transplantation.

Meniscal Transplant Systems

Segmental Meniscus Transplant

Double Bone Plug

Dovetail Meniscal Allograft Set