Differential Diagnosis
- Single most likely diagnosis
- Osteoarthritis (OA) of the knee: This is the most likely diagnosis given the presence of tricompartmental osteoarthritis, most severe in the medial compartment, degenerative tearing of the medial meniscus, and mucoid degeneration of the ACL. These findings are consistent with the wear and tear of joint cartilage and surrounding tissues seen in OA.
- Other Likely diagnoses
- Meniscal tear: The degenerative tearing of the medial meniscus with meniscal body extrusion is a common finding in patients with knee OA, and may be contributing to the patient's symptoms.
- ACL injury: The mucoid degeneration of the ACL may be a sign of chronic ACL injury or strain, which can occur in the setting of knee OA.
- Synovial chondromatosis: The presence of a joint body in the anterior lateral compartment could be consistent with synovial chondromatosis, a condition characterized by the formation of cartilaginous nodules within the joint.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Septic arthritis: Although less likely, septic arthritis is a serious condition that can present with joint effusion and should be considered in the differential diagnosis, especially if the patient has a fever, redness, or warmth around the joint.
- Tumor: A joint body could potentially be a sign of a tumor, such as a synovial sarcoma, although this is much less likely.
- Rare diagnoses
- Pigmented villonodular synovitis (PVNS): This is a rare condition characterized by the formation of pigmented nodules within the joint, which could potentially present with joint effusion and a joint body.
- Hemophilic arthropathy: This is a rare condition that occurs in patients with hemophilia, characterized by recurrent joint bleeding and degenerative changes, which could potentially present with similar findings to OA.