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One moment, your knee feels fine. The next, it locks or gives way, stopping you in your tracks. Each step can feel unpredictable, and you may find yourself asking: What is happening inside my knee?
Often, these symptoms are caused by a loose body, a small fragment of bone or cartilage that moves freely inside the knee joint. Also called “joint mice,” these fragments can cause discomfort and make everyday movements difficult.
What Causes Loose Bodies?
Loose bodies can develop due to trauma or underlying joint conditions. The most common cause is a knee injury.
A hard impact during sports, a fall, or a sudden twist can break off small pieces of bone or cartilage that remain loose inside the joint.
Prior knee surgery may also result in loose bodies due to small fragments of bone or cartilage left in the joint.
Other causes are related to chronic joint conditions, such as:
- Osteoarthritis
- Rheumatoid arthritis
- Osteochondritis
In these cases, the bone or cartilage weakens over time, and small pieces can break away.

What are the Signs I Should See a Specialist?
Loose bodies in the knee can cause symptoms that are difficult to ignore, such as:
- Pain
- Locking or catching
- Instability
- Swelling
However, these symptoms can also occur with other knee problems, including meniscus tears,patellar tendon injuries, or ACL damage.
If you’re experiencing any of these signs, visit an orthopedic surgeon. They can identify the cause of your symptoms and help you find the right treatment.
Book a Consultation with Dr. Pamela Mehta, MD
The Best Orthopedic Surgeon in San Jose
Dr. Mehta is a board-certified orthopedic surgeon who can help you recover from your joint condition. If you:
- Are Suffering From Pain and Mobility Issues
- Need Orthopedic Assessment and Advice
- Want Treatment From a Top Orthopedic Doctor
We Can Help
How Do We Diagnose Loose Bodies?
Often, your orthopedic surgeon can tell from the very first visit whether loose bodies are likely causing your symptoms.
A conversation about your history, along with a thorough physical exam, usually points us in the right direction.
To confirm the diagnosis, we may use one or more of the following:
- X-ray shows loose pieces of bone well, but may miss loose cartilage.
- MRI detects loose cartilage and other soft-tissue problems inside the joint.
- Arthroscopy (gold standard): A small camera is inserted into the knee through tiny incisions to view the joint directly.
A major advantage of arthroscopy is that we can diagnose and treat the problem at the same time.

Treatment Options for Loose Body in the Knee
Surgery
An arthroscopic surgery is the most effective way to treat loose bodies. The procedure is minimally invasive and takes 30 to 60 minutes. Using an arthroscope through small incisions helps reduce pain and speed up recovery.
Many people notice improvement in their symptoms immediately. You’ll usually go home the same day, just a few hours after surgery.
A few people may need a larger incision for more complex cases. This is called an open arthrotomy and is for situations where arthroscopy alone isn’t sufficient.
Non-Surgical Treatment Options
Rest, pain relief medications, and physiotherapy can help manage symptoms. However, loose bodies may continue to cause discomfort or knee locking. For many people, surgery is the most effective way to resolve the problem.
Dr. Pamela Mehta understands that the idea of surgery can feel overwhelming. She will never recommend surgery unless she truly believes it is in your best interest.
You will always have time to ask questions, discuss concerns, and feel confident in your decision.

Recovery and Prevention
Most people notice improvement right after surgery and are able to go home the same day. Returning to normal activities gradually helps your body heal safely, and Dr. Mehta will guide you every step of the way.
Your post-surgical care is personalized to address any underlying conditions, such as rheumatoid arthritis or osteochondritis. This may include medication management and regular follow-up appointments to support your recovery.
At Resilience Orthopedics, we work with trusted physical therapists throughout the Bay Area to support your recovery.

Why Patients Trust Resilience Orthopedics for Treatment of Loose Body
Loose bodies in the knee can cause pain, catching, and instability. But, they shouldn’t hold you back from living fully. At our San Jose clinic, your care is focused on restoring comfort and movement.
After training at some of the nation’s leading orthopedic programs, Dr. Mehta founded Resilience Orthopedics. Her goal is to provide each patient with care that is compassionate and personal.
When you visit Resilience Orthopedics, you can expect:
- Expert diagnosis and treatment using both non-surgical and surgical options
- One-on-one support throughout your care
- Rehabilitation and regenerative medicine options tailored to your needs
Ready to Recover?
Take the first step in getting back to your normal self, and book an appointment with Dr. Mehta today.
We’re ready when you are!