The following is a great article written by Dr. David Greer regarding knee injuries.
In the 7 signs your knee injury is serious article, Dr. Greer notes symptoms indicative of ligament and meniscal tears. The signs that I would like to focus on are the popping, inability to bear weight, locking and specific pain symptoms.
1: If your knee makes an audible “pop” at the time of injury you may have seriously injured a ligament or meniscus. The important thing to be aware of is that your knee may make noises that shouldn’t be alarming. In particular, pain-free noises from your kneecap region is not necessarily indicative of a serious injury. Additionally, grinding types of sounds may be more likely related for arthritis rather than an acute injury.
2: If you are physically unable to walk more than 2-3 steps than you may have injured your knee seriously. This is especially true after a fall.
3: Occasionally people will tear their meniscus in such a way that they are physically unable to straighten or bend the knee. The knee will become literally locked in place. Often these people will have to manually manipulate their knee and leg to get the knee moving. If your knee is locking in this way it may a sign of a serious knee injury.
4: Very localized pain may be a sign of a serious condition. If your pain is at a very specific spot on a bone after a fall, you should seek medical attention. Pain that is very diffuse around your knee is likely more a chronic condition rather than an acute injury. This is especially true of diffuse pain over the front of the knee.
If you think you have seriously injured your knee, these are some of the signs that you should look for. In addition to family physicians and orthopedists, physical therapist are a great resource for screening orthopedic problems and knees particularly. Also, physical therapy can greatly benefit chronic conditions and knee pain that may not be an acute injury.
Jon Hill DPT, Siskiyou Physical Therapy