Hello, this is Jim Carey, and I appreciate the invitation to speak at this course. My topic is meniscus allograft transplantation, why, when, and by whom. My conflicts of interest are displayed here. Let's start right with the why, when, and by whom, and then move into a case to illustrate these principles. Why? Well, sometimes despite meniscus repair and partial meniscectomy, the medial or lateral compartment of the knee remains persistently painful. As an analogy, when the shock absorber is missing, I think, if a woman wearing sneakers steps on my foot, I may experience a little pain, but if that same woman wearing high heels steps on my foot, then I may experience substantially more pain. Meniscus allograft transplantation is consistent with the transplanting principles of replacing like with like, while minimizing involvement of other structures. When? Well, when a patient reports persistent pain in the setting of meniscus deficiency, I prefer to wait more than three months following a partial meniscectomy or failed repair to ensure that the patient's just not experiencing some pain from the surgery. I also ensure that the patient confirms expectations, specifically, they're willing to participate in postoperative rehabilitation that may last 12 to 18 weeks, and the patient confirms understanding that the healing rate and long-term survivorship are not greater than 85%. Contraindications are the compartment receiving the meniscus has arthritis and the patient's unable to comply with postoperative rehabilitation. By whom? Really, by any orthopedic surgeon capable of performing meniscus allograft transplantation, and you'll see one option of a surgical technique illustrated in the following case. And the surgeon should be capable of performing concomitant procedures as well. Specifically, many of these cases have ACL deficiency that requires ACL reconstruction, focal articular cartilage defects that require cartilage repair, and unfavorable malalignment, which may require osteotomy. Let's look at this surgical technique in the following case. Since this is a case-based approach, I'll begin with the case of a 25-year-old medical student who sustained a knee injury while running. Pain localized medially more than anteriorly. She characterized the pain as 8 out of 10 in intensity, and the pain was associated with catching sensations. On physical examination, I observed very minimal entalgia. The left knee range of motion was 3 to 130 degrees. Point tenderness localized to the posterior medial joint line. There was a trace of small effusion, and stability testing was normal. X-rays demonstrated no appreciable arthritis. Ultimately, I confirmed neutral alignment with respect to the mechanical axis. The MRI demonstrated a medial meniscus tear, which I was prepared to repair or treat with partial meniscectomy. At the time of arthroscopy, this was not a routine tear. I found complex multidirectional tearing, tears of different ages running in different directions, and as you can see on the right, some shredded tissue. Overall, about 85% of the medial meniscus was involved for a 30-millimeter longitudinal component. The rest of the knee was confirmed to be healthy. At the first post-operative visit, I carefully reviewed these findings with the patient. She attended physical therapy as directed, however, she continued to experience medial side of pain. My assessment was left knee, medial meniscus deficiency. Fortunately, there was no associated structural pathology. There was a normal ACL, normal articular cartilage, and neutral alignment in this case. I reviewed the risks, benefits, and alternatives to medial meniscus allograft transplantation with the patient. Specifically, I reviewed the post-operative rehabilitation, which includes six weeks of crutches, motion limits, weight-bearing precautions, and a brace, and I reviewed that ultimately there's a subset of these that do not heal well. In fact, probably about 85% heal well. I will narrate these photos that illustrate my meniscus transplantation technique, which is only one of a few possible techniques. The first step is preparation of the compartment. I leave about a one-millimeter rim of native meniscus. Subsequently, I prepare the allograft. I place non-absorbable grasping sutures in the posterior horn and anterior horn. I place an absorbable monofilament suture in the body. The next step is to prepare the posterior horn attachment site. I remove the cartilage with the angled curette or shaver. The middle photo is showing placement of the rigid targeting guide, and then the right photo shows drilling to that point. I then draw the meniscus allograft into the joint. The left photo shows that I first pass two loops of suture to draw in the body. I triple the portal length to allow passage of my finger, and then the meniscus. I visualize the meniscus as it's drawn into the compartment to ensure there's no tangling of the suture, and then on the right I'm evaluating the fit, and I tie the posterior root suture over the button next. I then continue to secure the meniscus allograft. On the left, I'm showing an all-in-side repair of the posterior horn. The middle photo shows me holding the meniscus in position as I perform an outside-in repair of the body, and then the anterior horn, and there's just one technique shown on the right. I then continue securing the meniscal allograft. I place a biocomposite anchor for the anterior horn. Of note, sometimes the anterior horn is too thin for a vertical mattress or even an oblique suture pattern. In these cases, I place one limb through the meniscus and the other through the capsule. That's what I'm showing in the central image. And then on the right, I'm just showing it secured in place, and then I circumferentially assess the stability at all seven points or so of the repair. In the postoperative course, this patient attended physical therapy as directed. She was compliant with the bracing, crutches, and motion limits for the six weeks. At the 18-week visit, she had no pain, so I carefully reviewed the function of transplant tissue again. Specifically, I reviewed that it typically holds up to activities of daily life, and that it may survive more. I expressed concerns of returning to the meniscus-deficient state, and sometimes I'll even review the first office note to remind them about what that was like. This slide summarizes some decision-making pearls, assess alignment and correct malalignment in all these cases. Replace like with like at the same time. So of course, this is a talk about meniscus deficiency and replacing that with a meniscus allograft. And in my practice, about a third of these cases have a cartilage defect that I address at the same time with a fresh ossicondral allograft or autologous connoisseur implantation. And about a third of these cases have ACL deficiency that I'll address with ACL reconstruction. I recommend avoiding meniscus transplantation in compartments with arthritis. Some other advice, please remember that the difference between an explanation and an excuse is timing. At the preoperative appointment, I review that the healing rate in long-term survivorship are not greater than 85%. I try to assess structure through second look MRI and second look arthroscopy whenever possible and whenever it's appropriate. And I try to assess function and patient-oriented outcome measures at long-term endpoints. Here's an example of a second look arthroscopy from a different patient. Integration about the superior and inferior surfaces has been excellent in general. I have seen some synovitis and increased vascularity in some regions of some cases as illustrated here at the bottom. The overall summary, meniscus allograft transplantation is a treatment that can relieve pain, decrease forces on an ACL graft, and possibly prevent post-traumatic arthritis. Correct malalignment and replace like with like to increase probability of a successful outcome. In general, avoid meniscus allograft transplantation in a compartment with arthritis. Estimate structure through MRI and second look arthroscopy whenever possible and patient-oriented outcome measures at long-term time points. Thank you.

meniscus allograft transplantation

persistent knee pain

surgical technique

postoperative rehabilitation

post-traumatic arthritis