My mri says tearing of the posterior horn middle third extending to the inferior articular surface and i have arthritis under my knee cap would you suggest surgery thanks?

Meniscus tear: You essentially have 2 separate conditions affecting your knee, a meniscus tear and patellar arthritis. Surgery for meniscus tears is very successful for treating "mechanical symptoms" (locking/catching along the knee joint lines). Meniscal surgery is less predictable for treating knee pain, especially if there is associated knee arthritis. Recommend consultation with an orthopedic surgeon.