The Mets' injury woes continue as pitcher Jonathon Niese becomes the latest starter to be placed on the disabled list. Earlier this week, news came out that he will need arthroscopic knee surgery to repair a torn mensicus in his left knee. This primer will share what the meniscus is and the rehabilitation process post-surgery.
What is the meniscus?
The meniscus is a piece of cartilage that is between the bones that comprise your knee: the femur (thigh bone) and tibia (shin bone). There is a meniscus on both the medial (inner part of the knee) and lateral (outer part of the knee) that primarily acts to absorb shock as force transmits from your feet to your knees after the foot lands from walking or running. In addition, the menisci serve to lubricate the knee joint to assure the bones move smoothly as you flex and extend the knee while also contributing to the stability of the joint.
How is the meniscus usually torn?
Meniscal tears usually occur when the knee is flexed (bent) and a twisting motion occurs. Knee flexion compresses part of the meniscus and with the combination of rotation, the meniscus is unable to tolerate the force needed to stabilize the knee. It is tough to say how Niese’s left knee became injured but improper mechanics while running, excessive twisting at the knee from swinging a bat, or landing that left foot awkwardly after a pitch are all plausible methods that can contribute to the mechanism of injury. Of course, a tear can also occur from general "wear and tear" of the body, however given that Niese is relatively young, a likelier scenario is the injury is from a traumatic incident or a scenario described above.
It is unknown which meniscus in the left knee is torn, but a medial tear is more common, though the lateral meniscus is not uncommon to tear. Depending on the severity and location of the tear, the meniscus does have the capability to heal on its own and surgery would not be required; in this case, surgery was elected with hopes of a quicker recovery and to minimize a chance of re-injury.
How long is the recovery process?
The surgery that Niese will undergo is called a partial meniscectomy; this means the surgeons will drill a hole into the knee, slide in a camera to see the meniscus, and use tiny scissors to trim the meniscus and remove the injured portion.
In terms of rehabilitation, Niese should be able to walk with a crutch a day or two after surgery while working towards independent walking a week after surgery. He will be able to return to daily activities after about 2-3 weeks once the knee achieves full range of motion and regains all the strength it lost from inactivity. The knee cap may become stiff so physical therapists will help it move through manual techniques and exercises will be given to loosen up any tight muscles that need to be stretched.
The rest of the recovery process will fix body mechanics during walking and everyday activities as well as improving strength and balance of his lower body as he prepares to start sport-specific training. Given the relative quick time to recovery, cardiovascular endurance and upper body strength should be maintained throughout this process yet are not a key focus of recovery.
Healing from the surgery takes about 3-4 weeks, however full recovery can take up to 6-8 weeks. Given that prognosis, Niese's season is likely over and he will probably be unavailable for any postseason play if the Mets manage to make the playoffs.