Bae JK, Kim JH, Kim KI, et al. - This study was carried out to evaluate serial change up to 2 years in medial meniscus extrusion (MME) following medial open-wedge high tibial osteotomy (MOWHTO) and to ascertain whether postoperative changes in MME associated with clinical outcomes and arthroscopic articular cartilage status. Researchers enrolled a total of 26 patients from December 2016 to March 2018 who underwent MOWHTO for primary medial osteoarthritis with varus malalignment. They conducted second-look arthroscopy with plate removal at postoperative 2 years. They consecutively assessed MME using coronal MRI at preoperative and postoperative 3 months, 6 months, 1.5 years, and 2 years. They further evaluated which preoperative parameters could reflect the postoperative changes in MME and assessed if postoperative clinical outcomes and arthroscopic articular cartilage improvement would be influenced by the MME changes. The results showed that MME improved with time and was significantly associated with preoperative MPTA after MOWHTO. Nevertheless, after MOWHTO, the changes in MME did not reflect postoperative clinical and arthroscopic articular cartilage improvement.