ICRS scores worsen between 2-year short term and 5-year mid-term follow-up after transtibial medial meniscus root repair despite maintained functional outcomes

Purpose The purpose of this study was to evaluate the mid-term results of posterior medial meniscal root tear (PMMRT) repair through assessment of functional outcome scores and magnetic resonance imaging (MRI). Methods This was a single-center, retrospective study evaluating patients that had undergone a PMMRT. This was a follow-up to a previously published 2-year outcome study (all original patients were invited to participate). Clinical outcomes included pre- and postoperative International Knee Documentation Committee (IKDC) and Lysholm scores. Root healing, meniscal extrusion, and cartilage degeneration via International Cartilage Repair Society Scale (ICRS) grades were assessed on MRI by two musculoskeletal fellowship-trained radiologists. Results 10 of the original study's 18 patients were able to participate. Mean age and BMI was 48.4 +/- 12.0 years and 29.5 +/- 4.5, respectively, with mean follow-up 65.5 +/- 8.3 months (range 52.0-75.8) (60% female). The IKDC significantly increased from 43 +/- 13 preoperatively to 75 +/- 16 at 5-year follow-up (p < 0.001). There was no significant change in IKDC score between 2-year and 5-year follow-up [75 +/- 16 vs 73 +/- 20, (n.s)]. The Lysholm also significantly increased between preoperative and 5-year follow-up (49 +/- 7 vs 84 +/- 11, p < 0.001). There was no significant change between Lysholm score at 2-year and 5-year follow-up [84.0 +/- 11 vs 82 +/- 13, (n.s)]. Mean extrusion did not significantly change from the preoperative state to 5-year follow-up [4.80 mm +/- 1.9 vs 5.0 mm +/- 2.5, (n.s.)]. Extrusion also did not significantly change between 2-and 5-year follow-up [6.1 +/- 3.2 mm vs 5.0 mm +/- 2.5, (n.s.)]. No patients with > 3 mm of extrusion on preoperative MRI had < 3 mm of extrusion on postoperative MRI. Both medial femoral condyle and medial tibial plateau ICRS grades significantly increased from preoperative to 2-year follow-up (p = 0.038, p = 0.023, respectively). Medial femoral condyle and medial tibial plateau ICRS grades again significantly increased between 2-year and 5-year follow-up (p = 0.014, p = 0.034). Conclusion Patients treated with the transtibial suture pullout technique with two locking cinch sutures had maintenance of clinical outcome improvements at 5-year follow-up. However, extrusion was widely prevalent, with worsening progression of femoral and tibial chondral disease.