Thank you. Our results are on, disclosures are online. So meniscal tears are common in middle-aged patients. Often they have a degenerative tear pattern and typically don't require surgery, though we know they likely accelerate arthritis. Extrusion of a meniscus can be an indicator of disrupted ability to withstand compressive forces and this is often secondary to a meniscal tear, but it can occur without a tear. And there's been some recent studies of middle-aged patients without significant arthritis with short-term follow-up that suggests that it may accelerate OA. So our study question is, with long-term follow-up, what's more reliable on MRI as a risk factor for accelerated OA in this middle-aged patient group with no arthritis or mild arthritis? Is it the tear, extrusion, or both? So to answer this question, we utilized the Osteoarthritis Initiative. This is a large prospective multi-center observational cohort study of which Ohio State's one of the primary study sites. Among the initial 5,000 adults enrolled, we included the 2,200 that had no arthritis or mild arthritis in either knee at baseline. All these patients had MRIs at baseline. They were followed for eight years with weight-bearing radiographs and over nine years for total knee arthroplasty. This study had quite a comprehensive data collection for many different potential risk factors for arthritis, many of which we considered in our analysis. The MRIs were all assessed by MSK radiologists, and they had a standardized way of reporting both tear pattern and location. Meniscal extrusion was evaluated on a mid-cranial slice. This was reported in millimeters relative to the articular margin of the lateral, of the tibial plateau. At baseline, we see that about 20% had a meniscus tear on the medial side. A similar percentage had at least some extrusion. Lateral tears were less common and lateral extrusion even less so. The majority of these tears were posterior horn horizontal cleavage tears. If we look at the menisci that had at least some extrusion, we see that about half had a visible tear and half did not. This is true of both the medial and lateral side. A small percentage had a significant progression of they're away from year to year. Additionally, on average, there was a small but steady increase in joint space narrowing. So if we control for confounding, we do see that both medial and lateral tears are independent predictors of additional joint space narrowing of their respective compartments. Additionally, lateral extrusion further accelerated this. These were typically posterior horn tears, and we can see from this data that horizontal cleavage tears are not benign. Again, after controlling for confounding, we see that lateral meniscal extrusion is actually a strong independent risk factor for total knee arthroplasty, whereas simply the presence of a medial lateral tear was not. Degree of extrusion matters, and a more extruded lateral meniscus had a much higher risk of progression of total knee arthroplasty. So we know that meniscal tears will accelerate joint space less. This is not a surprise, but what we've learned from this study is that these horizontal cleavage tear patterns are not benign. Medial extrusion is more common than lateral, but when lateral extrusion is present, it's particularly troublesome. It further accelerates joint space less and significantly increases risk of progression of total knee arthroplasty. There's some possible mechanisms for this. We know that a competent lateral meniscus is very important for normal load distribution, more so than the medial meniscus on the medial side, and that's been demonstrated by mechanical studies. Clinically, in younger patients, you do occasionally see, after a lateral tear or partial lateral meniscectomy, this scenario of rapid chondrolysis. So what do we do with this information? There's lacking long-term follow-up data for horizontal cleavage repairs. We don't know if it would prevent or slow away progression, but the results from this study suggest that we should look into this. What does remain unclear is what to do with an extruded meniscus without a visible tear. In my opinion, if a patient presents with an extruded lateral meniscus, they're symptomatic and they're beginning to show signs of rapid joint space narrowing, this may be an opportunity to intervene earlier with a treatment such as an unloading osteotomy or partial knee arthroplasty. Thank you.

meniscal tears

accelerated osteoarthritis

Osteoarthritis Initiative

joint space narrowing

total knee arthroplasty