Synovial chondromatosis is a joint disorder where the synovium (the joint lining) forms small cartilage nodules. These nodules can break loose and become “loose bodies” that move inside the joint. It is most often discussed in orthopedic care when evaluating joint pain, swelling, catching, or locking. The knee is a common location, but other joints can be affected.

OCD knee usually refers to **osteochondritis dissecans (OCD) of the knee**. It describes a problem where **bone just under the knee cartilage** becomes injured and may affect the overlying cartilage. It is commonly discussed in **sports medicine, orthopedics, and physical therapy** when evaluating knee pain in active people. It can involve monitoring, rehabilitation, and sometimes surgery, depending on the lesion.

Osteochondritis dissecans is a joint condition where a patch of bone just under the cartilage becomes injured. It can affect the overlying cartilage, sometimes leading to a partially detached or fully loose fragment. It is most often discussed in sports medicine and orthopedics in relation to the knee. It can also occur in other joints, such as the ankle or elbow.

An Osteochondral defect is an area of damage involving joint cartilage and the bone directly beneath it. In plain terms, it is a “pothole” in the smooth joint surface, sometimes with weakened or injured underlying bone. It is most commonly discussed in the knee, but it can also occur in other joints such as the ankle. Clinicians use the term in orthopedic and sports medicine settings to describe a specific type of joint surface injury and to guide evaluation and treatment planning.

Loose bodies are free-floating pieces of tissue inside a joint. They most often involve small fragments of cartilage, bone, or a mix of both. They are commonly discussed in knee care, especially when symptoms feel “mechanical,” like catching or locking. Clinicians use the term to describe a finding that can help explain pain, swelling, or intermittent loss of motion.

A Degenerative meniscus tear is a wear-related tear in the knee’s meniscus cartilage. It often develops gradually rather than from a single twist or impact. It is a common clinical term used in orthopedics, sports medicine, and physical therapy when evaluating knee pain in adults.

Meniscal degeneration is gradual wear-and-tear change within the knee’s meniscus tissue. It is commonly described on MRI reports and in orthopedic clinic notes for knee pain. It can occur with aging, repetitive loading, or alongside osteoarthritis. It helps clinicians explain symptoms and choose an appropriate evaluation and care pathway.

A Bone marrow lesion is an MRI finding in the bone near a joint. It often appears as a “bone marrow edema–like” signal change rather than a true fluid pocket. In knee care, it is commonly discussed in osteoarthritis, overuse injuries, and trauma. Clinicians use it to help explain pain patterns and to guide further evaluation.

Bony edema is a medical term that describes extra fluid within bone marrow. It is most commonly identified on MRI scans rather than on X-rays. In the knee, it often appears near areas of impact, overload, or cartilage wear. Clinicians use it as a clue to what may be causing pain or inflammation.

Subchondral cysts are small cavities in the bone just beneath joint cartilage. They are most often seen on imaging in joints affected by wear-and-tear arthritis. In the knee, they commonly appear near the ends of the femur or tibia. Clinicians use the term to describe an imaging finding that helps characterize joint disease.