Extrusion of the medial meniscus (MM) is associated with knee joint pain in osteoarthritic knees. The relationships among MM radial/oblique tears, MM extrusion (MME), and the effect of arthroscopic meniscal repair are not established. Here we evaluated the effects of arthroscopic all-inside MM repair on MME and the clinical outcomes in patients with radially oriented MM tears and mildly osteoarthritic knees. Twenty patients with a symptomatic radial or oblique tear of the MM posterior segment, MME ≥2.5 mm, and mildly osteoarthritic knees were treated using FasT-Fix 360 All-inside Meniscal Suture devices. We used magnetic resonance imaging (MRI) to measure the patients’ MM body width (MMBW), absolute MME, and relative MME. The Japanese Knee Injury and Osteoarthritis Outcome Score, Lysholm, Tegner, IKDC Subjective Knee Evaluation, and Visual Analogue Scale scores were obtained. Arthroscopic all-inside MM repair prevented increases of absolute and relative MME. The preoperative and 3- and 12-month MRI-based MMBW values were similar. Over a 24-month follow-up after the MM repairs, the clinical scores showed significant improvements. Our results suggest that all-inside meniscal repairs would be useful in preventing the progression of MME in patients suffering from symptomatic MM radial/oblique tears associated with mildly osteoarthritic knees
