PLC stands for posterolateral corner injury of the knee. This usually means there's been a partial or complete tear of the soft tissue structure(s) around the back, outer side of the knee. There are a number of complex ligaments in this area, along with two muscles: the gastrocnemius (calf) and the popliteus.
All of these ligaments and muscles work together to keep the knee stable. They prevent too much rotation and/or translation (sliding and gliding) of the bones that form the knee joint.
Any ligamentous injury can be classified by grade. Usually, the grade is based on how much disruption has occurred. A sprain of the ligament without joint instability is a grade I. Rest and rehab may be all that's needed for this level of trauma.
Grade II injuries show up as a small amount of joint laxity. There's a partial tear and mild-to-moderate change in joint motion. Grade III injuries result in joint instability and abnormal motion. In grade III PLC injuries, the soft tissues have been completely ruptured.
Treatment is based on the identified grade of injury. Grade I and less severe grade II injuries can be treated conservatively. A physical therapy rehab program often yields good results without surgery. Surgery is advised for more severe grade II and all grade III injuries.
Return to sports play depends on the severity of injury. The timing of treatment as it coincides with the off-season is also an important factor. The sooner the athlete gets the necessary treatment, the greater the chances of returning to play within the next season.