Thanks for writing to the forum!
“In normal situations, the knee is a smoothly operating mechanism, like a door hinge swinging open and shut," explains Edward J. Resnick, M.D., professor of orthopedic surgery at Temple University Hospital in Philadelphia. "But if you put a jam in the door or an object in the hinge, that smooth movement may be obstructed or frozen in position."
This is what orthopedists call a true locking of the knee: something that physically prevents the knee from fully straightening out or bending and holds the knee rigidly in place. It's often painful, and since it can occur while climbing stairs, sitting on the ground, or being in some other vulnerable position, it can be quite frightening.
Usually, the locking is caused by a torn piece of cartilage, or possibly a loose bone fragment resulting from a bone disorder called osteochondritis dissecans. "The cartilage fragment or bone chip moves freely in the knee cavity until it gets trapped between two joint surfaces, impeding your ability to straighten the knee," says David W. Lhowe, M.D., orthopedic surgeon at Massachusetts General Hospital in Boston and professor of orthopedic surgery at Harvard Medical School.
Sometimes the obstruction is from a misalignment of the bones and muscles around the knee. "Weakness of the muscles on the inside of the thigh or tightness of the outer muscle can throw off the alignment of the kneecap," says Lyle Micheli, M.D., director of the Sports Medicine Division at Boston Children's Hospital and associate clinical professor of orthopedic surgery at Harvard Medical School. "The kneecap comes out of groove with the thigh bone, derails and gets stuck, not allowing you to bend or extend. When the muscle returns to normal, the kneecap gets back on track and movement proceeds normally."
True locking is fairly rare. But many times, say following an injury, a person will experience an inability to move the knee. That can feel like a locking of the knee, but in reality there's nothing physically interfering with the movement of that knee. Doctors call this a pseudo-lock.
"A pseudo-lock is simply a reaction to pain. The pain mechanism won't allow the joint to extend or flex fully," says Phillip J. Marone, M.D., director of the Jefferson Sports Medicine Center at Thomas Jefferson University Hospital in Philadelphia and team physician for the Philadelphia Phillies professional baseball team. Sometimes the pain that creates a pseudo-lock is brought on by a twist or a bump to the knee. Or it could just as easily be a bad case of stiffness from sitting too long. “ Refer: http://www.mothernature.com/Library/Bookshelf/Books/16/127.cfm
Other causes of knee locking are torn medial meniscus, knee cap mal-alignment, osteoarthritis, knee arthritis, torn lateral meniscus, Osteochondritis dissecans - occasional knee locking with instability, Recurrent patella dislocation - may cause knee locking or knee collapse, Chondromalacia patella - occasional locking or knee collapse, Knee alignment problem, Knee fragment or Knee cartilage disorder.
Hope this helps. Do not ignore it. Consult an orthopedic specialist. Please let me know if there is any thing else and do keep me posted. Take care!
Without examination,confirming a diagnosis is tough but the various possibilities for your symptoms are tendonitis (an inflammation of the tendon) , ligament injury,arthritis(rheumatoid,osteoarthritis,psoritic,gout or reactive arthritis) , chondomalacia(softening of the cartilage under the kneecap (patella) , osteomalacia(deficiency of vit D in adults) and bursitis.
Complete physical examination along with investigations like ESR blood, Rheumatoid factor, creatine kinase,x-rays /MRI knee joint,serum levels of vit D may be needed to make a diagnosis.Pls consult an orthopedician or rheumatologist for that.Till then apply warm compresses and take some over the counter anti inflammatory pain reliever like ibuprofen(advil) or diclofenac.You can also apply topical antinflammatory creams.
Hope it helps.Take care and pls do keep me posted on how you are doing or if you have any additional doubts.
I do have a bulging disk in my back and a compressed disk in my lower back that has left my right foot numb for the past ten years. I went to see the 3 B's at PENN hospital and they did a MRI on my back and thats how they found the bulging disks and compressed disk, but they said, besides surgery there wasn't much I could do about it except for some stretching exercises that might help. They were totally against surgery. Could this be causing my knee to lock up and that terrible burning pain I get on the side of my knee ? It just seems strange that after ten years its starting to happen now. My doctor said, if it keeps bothering me he will send me for a X-ray and if that dosen't show anything then a MRI. I think he was even baffled that it would just come on so suddenly like it did.
You need what is called a "3T" MRI to provide a definitive diagnosis. Not a 2T and not a 2T.
X-rays will not show anything worthwhile. It is pointless to take them. Nor will an ordinary 1T MRI.
Your presentation is common, and I am surprised your physician would be "baffled".