Non-anatomic repair of medial meniscus posterior root tears to the posterior capsule provided favourable outcomes in middle-aged and older patients

Purpose: To describe a non-anatomic arthroscopic all-inside repair technique for middle-aged and older patients with medial meniscus posterior root tears (MMPRTs) and to evaluate the short- to mid-term clinical and radiologic results. The hypothesis was that this procedure would yield good clinical outcome results and structural healing in middle- and older-aged patients. Methods: This was a retrospective study evaluating patients who had undergone MMPRT repair by suturing the meniscal root directly to the capsule, rather than by the transtibial technique, between 2013 and 2016. This all-inside repair technique was performed for patients with type II MMPRTs who were over 40 years old. Exclusion criteria included tibial osteotomy due to malalignment, concomitant multiple-ligament injuries and follow-up time less than 2 years. The Lysholm score, Tegner activity score and International Knee Documentation Committee (IKDC) score were evaluated preoperatively and at the final follow-up. Medial meniscal extrusion, the International Cartilage Repair Society (ICRS) grades of the medial compartment, and the healing status of the medial meniscus root were assessed on magnetic resonance imaging preoperatively and at the final follow-up. Results: Twenty-nine patients (mean age 61.7 ± 7.9) were included; the mean follow-up duration was 46.2 ± 7.9 months. The mean Lysholm score significantly improved from 33.7 ± 20.9 preoperatively to 81.7 ± 19.9 at the final follow-up (p < 0.001), the median Tegner activity score improved from 1.0 (range 1–4) to 3.0 (range 2–4, p < 0.001), and the mean IKDC score improved from 20.1 ± 16.4 to 69.6 ± 16.2 (p < 0.001). On MRI, 9 (31%) cases had complete healing; 17 (59%) had partial healing; and 3 (10%) had failed healing (ICCs ≥ 0.92). Mean meniscal extrusion significantly increased from 2.3 ± 1.7 mm preoperatively to 3.5 ± 1.5 mm postoperatively (p < 0.001, ICCs ≥ 0.92). Conclusion: Non-anatomic arthroscopic all-inside repair of MMPRTs to the posterior capsule yielded good to excellent clinical results and a high rate of healing in the medial meniscus root on MRI in middle-aged and older patients at short- to mid-term follow-up, despite increased meniscal extrusion. This method is an alternative to the transtibial pullout repair technique for treating MMPRTs in middle- and older-aged patients. Level of evidence: Level IV.