Dont think so. It is a physical impossibility that your leg actually became longer after your surgery for a torn meniscus. Perhaps you were walking with a bent knee prior to surgery, and after surgery you normalized your gait and felt as though there was an increase in length.
Not sure. Assuming you underwent a meniscectomy, there's no evidence that suggests that your leg would become longer. You may want to consult the physician who performed the meniscus surgery.