Locking means the sudden inability to straighten the knee fully. There are several causes of locking & loose bodies within the knee are an important cause. Locking can be excruciatingly painful & can con?ne the patient to bed for several days till the knee unlocks.
How are these loose bodies formed?
Loose bodies are like the kidney stones of the joint. They are essentially pieces of bone & cartilage from the knee that become dislodged within the joint. They receive nutrition from the joint ?uid & slowly increase in size over several months & years
I had locking, then it suddenly disappeared, can it happen again?
Yes, the loose bodies are subject to the forces of gravity. They may cause locking once & then move to a more spacious corner of the knee. It is highly unpredictable when they might come to the front portion of the knee to cause locking again, unless the loose body is removed arthroscopically.
How do the loose bodies lock the knee?
The loose bodies become mechanically jammed between the joint surfaces & prevent the knee from straightening fully. If they lie in a more spacious portion of the joint like the back of the knee or above the knee cap, then they do not come in the way of knee movement & can remain silent for several years, till they migrate to the front of the knee & start causing symptoms. One simple way of understanding this problem is to imagine having a pebble in your shoe. If the pebble lies beneath the middle portion of the foot, you don’t feel it while walking, but if it migrates beneath the heel, then walking becomes impossible.
- Arthroscopy is required to see the loose body properly & remove it once for all so that the knee unlocks
- ROUTINE X RAYS ARE ALL THAT ARE REQUIRED TO DIAGNOSE LOOSE BODIES. SOMETIMES MRI MAY BE ADVISED