I'll be presenting on our clinical and radiographic outcomes for patients that underwent post-remedial meniscal root repair. Funding for this study was provided by an internal NYU resident grant. So loss of the PMMRT attachment may lead to extrusion, loss of the ability to generate hoop stresses, increased contact pressures within the tibiofemoral articulation, and ultimately early development of osteoarthritis. Multiple studies have demonstrated that non-operative management and partial meniscectomy may lead to more rapid Kellgren-Lawrence progression. Root repair is considered the preferred treatment method in properly selected patients as it may better restore native knee biomechanics. A prior study by the Current Authorship Group evaluated two-year outcomes in patients that underwent a PMMRT repair and found that while functional scores significantly improved, extrusion and ICRS grades worsened from the preoperative state, and only one out of 18 roots appeared radiographically healed. Therefore, the purpose of this study was to evaluate the same patient cohort at midterm follow-up. The hypothesis was outcome scores would deteriorate to match cartilage status and patients would have worsening arthritis. This was a single-center retrospective study evaluating patients that had undergone PMMRT repair. All 18 patients from the original two-year follow-up study were invited to participate. Exclusion criteria for the original study included coronal malalignment greater than five degrees, as well as prior ipsilateral ligamentous or other knee injury. For repair, the trans-tibial pull-out technique with two lock-and-cinch sutures was used. Sutures were passed through a retrograde drilled tunnel, then tied over a cortical button on the anterior tibia. IKDC and Lyshom scores were recorded preoperatively, then at two-year and five years postoperatively. Three tMRIs were also performed at these time intervals and reviewed by two MSK Fellowship trained radiologists, including one from the original two-year study. Genomic measures included extrusion, as can be seen here, assessed on mid-coronal images. Cartilage status was assessed using the ICRS classification consisting of grades one through four for both the medial femoral condyle and tibial plateau. And root healing was graded based on criteria previously described by Kim et al., including healed, partially healed, or not healed. Of the original 18 patients, 15 agreed to fill out updated functional score surveys for an 83% retention rate, while three could not be reached. Of these 15, two patients chose not to come in for a repeat MRI due to the pandemic, two had moved prohibitively far, and one had undergone a subsequent unilateral knee arthroplasty, leaving 10 patients available for repeat MRIs. Intra- and inter-rater reliability were excellent for all measurements based on intra-class correlation coefficients for extrusion and weighted kappa for cartilage. PRO scores both significantly increased from pre-op to two years and from pre-op to five years, but did not significantly change between the two- and five-year follow-up. Extrusion significantly worsened between the pre-operative state and two-year follow-up, but did not change significantly in five years. The number of roots that appeared healed non-significantly increased from one to three at five-year follow-up. Regarding cartilage, however, medial femoral condyle ICRS scores significantly worsened at each time interval. Similarly, medial tibial plateau ICRS grades worsened at each time interval. So the major findings of the study include patients did maintain improved PRO scores at five years. However, radiographically, they had significantly worse medial femoral condyle and tibial plateau ICRS grades. Extrusion remained increased relative to the pre-operative state, and only three roots appeared healed. So the poor root healing and residual extrusion are likely ultimately responsible for the progression of arthritis. Kritsch et al. demonstrated that extrusion may be due to a degenerative cascade, including plastic deformation and meniscus tibial tearing, of which the final step is a root tear. It follows that repairing the root in isolation may not be sufficient to resist stress generated with axial load, particularly in deep flexion. One possible mechanical solution to this problem may be centralization techniques, as described by Koga et al. and Dainey et al. This adds a secondary point of fixation to the meniscal body, either through an anchor or additional trans-tibial tunnel. In addition to reducing extrusion directly, this could synergistically take stress off the repair, mimicking the torn meniscal tibial ligaments. Decreased stress could potentiate healing, ultimately allowing the meniscus to better absorb load and generate stress, hoop stress. So limitations of the study include the limited number of repeat MRIs available for analysis, as well as the use of ICRS score evaluation via MRI instead of de-gemeric assessment or second look arthroscopy. Conclusions of the study include, at five years, patients did maintain their improvement in functional outcomes. However, patients continue to have pathologic extrusion and worsening medial compartment cartilage degeneration on MRI. Surgeons should consider alternative techniques to augment repairs in the future. Thanks.

meniscal root repair

osteoarthritis

extrusion

cartilage degeneration

functional improvements