Loose bodies are small loose fragments of cartilage or bone that float around the joint. The loose bodies can cause pain, swelling, locking and catching of the joint. Loose bodies occur if there is bleeding within the joint, death of tissues lining the joints associated with tuberculosis, osteoarthritis, and rheumatoid arthritis. Other causes include fractures, trauma, bone and cartilage inflammation, and benign tumors of the synovial membrane. Loose bodies are commonly found in individuals who participate in sports since they are more susceptible to fractures and other sports injuries.