Loose Bodies

Loose bodies in the knee, also known as joint mice, are small pieces of bone or cartilage that break off from the joint surfaces and float around inside the joint space. They can occur in all age groups for a number of different reasons. These fragments can cause pain, inflammation and damage to the surrounding tissues and may lead to episodes of locking or catching in the knee joint.

In addition to loose bodies, there are several other conditions that can cause episodes of locking or catching in the knee joint. These may include:

• Meniscal tears, which occur when the C-shaped cartilage in the knee (meniscus) is torn due to trauma or overuse.
• Osteochondritis dissecans, a condition in which a piece of bone and cartilage becomes detached from the joint surface. This tends to occur in children.
• Ligament injuries, such as anterior cruciate ligament (ACL) tears, which can cause instability and episodes of buckling or locking in the knee.

If you are experiencing episodes of locking or catching in your knee, there are several things you can do to help manage your symptoms and prevent further damage:

• Rest your affected leg and avoid any activities that cause pain or discomfort.
• Apply ice to the affected area for 15-20 minutes at a time, several times a day.
• Take nonsteroidal anti-inflammatory drugs (NSAIDs) to help manage pain and inflammation.
• Gently moving the knee back and forth may free it up. Sometimes just resting the knee in a comfortable position overnight will allow it to spontaneously unlock.

If you decide to wait and see how loose bodies or other causes of locking in the knee turn out, the knee may unlock only to lock up again in the future. The timing of locking is very unpredictable. In children, and occasionally in adults, there is a chance to fix the fragment back into position. For that reason it is wise to seek advice early.

Treatment options for loose bodies and other causes of locking in the knee

Treatment for loose bodies and other causes of locking in the knee will depend on the severity of the injury. In general, treatment options may include:

• Arthroscopic surgery, a minimally invasive procedure in which small incisions are made in the knee to remove loose bodies, repair torn cartilage, or address other underlying issues.
• Occasionally the locking ceases spontaneously but if it occurs multiple times then it probably will not settle for good without the fragment being removed.

Locking is relatively uncommon. I have extensive experience of treating patients with locked knees from childhood to older adults. I am very familiar with the techniques for dealing with all causes of locking in the knee including meniscal repair, fixation of fragments in children and simple removal of fragments. My goal is to help you achieve a full recovery and return to your normal activities as soon as possible.