This sounds like a very painful injury. A lateral meniscus tear is something that actually occurs much less frequently than a medial meniscus tear. The treatment depends on the severity of the tear. It sound like from your description that this is bad tear. The severe tears most often needs repaired surgically. If this is a more minor tear, then the injury can be treated conservatively. Conservative treatment includes rest, ice, and then slow return to exercise. If this works, then you could avoid having to go under the knife. If it doesn't then you will need surgery
. Surgery for this type of injury is most often done arthroscopically. This means that the surgeon
can use three small holes to introduce instruments which can be used to fix the torn cartilage. There is quicker recovery and less pain associated with this type of procedure.
I suggest that you schedule an appointment with an orthopedic surgeon
. He or she can perform a thorough physical exam of your knee and review all the imaging including that MRI that showed the macerated lateral meniscus. From there, the surgeon can recommend conservative management with physical therapy or aggressive management with surgical correction. If I had to guess, you will likely need surgery.