With the continuous progress of diagnosis and treatment technology on knee osteoarthrosis, the concept of "stepwise treatment" and "keeping meniscus as much as possible" has been deeply rooted in people's minds. As an important anatomical structure for maintaining the annular tension of the medial meniscus of the knee, more and more attention has been paid to the posterior root. After the root tear of the medial meniscus, the annular tension loss, leading to the meniscus bearing load function partial or complete loss, and secondary knee medial space narrow, cartilage degeneration and genu varus deformity. In the treatment of root tear of the medial meniscus different scholars hold different views. The treatment of the medial meniscus posterior root tear of the knee is mainly conservative treatment and operative treatment, and the conservative treatment mainly includes non-steroidal drugs, functional exercise, physical therapy, and so on. The surgical treatment mainly included the medial meniscus partial resection of the medial meniscus under the arthroscope, the medial meniscus posterior root repair under the arthroscopy, and osteotomy with medial meniscus posterior root repair under the arthroscopy. Despite the short-term curative effect of conservative therapy and resection is satisfied, long-term follow-up has no obvious improvement with knee pain, function and activity levels, and causes secondary biomechanical change of knee. For patients of age <65, genu varus <5°, Outerbridge cartilage classification < grade III and grade of Kellgren-Lawrence < level III, the curative effect of medial meniscus posterior root repair under the arthroscopy is satisfied, with good healing rate, and can delay the process of osteoarthritis in certain degree. For patients with joint deformities (medial proximal tibial angle < 85°/lateral distal femur angle >90°) genu varus >5°, osteotomy can effectively improve the clinical curative effect. However, whether to repair the medial meniscus posterior root together is still controversial.