Differential Diagnosis for Knee Pain with Popping Sound
- Single most likely diagnosis
- Meniscal tear: The patient's report of hearing a popping sound followed by knee pain is highly suggestive of a meniscal tear. This is a common injury that occurs when the meniscus, a cartilage structure in the knee, is torn, often due to a sudden twisting motion or direct blow to the knee.
- Other Likely diagnoses
- Ligament sprain: A sprain of the ligaments surrounding the knee, such as the anterior cruciate ligament (ACL) or medial collateral ligament (MCL), can also cause a popping sound and subsequent pain.
- Patellofemoral pain syndrome: Although less likely to cause a distinct popping sound, patellofemoral pain syndrome can cause knee pain, especially after activities that put stress on the knee.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Osteonecrosis: While less common, osteonecrosis (avascular necrosis) of the knee can cause sudden pain and may be associated with a popping sound if a fragment of bone breaks off. This condition can lead to severe arthritis if not promptly treated.
- Septic arthritis: Although rare, septic arthritis is a medical emergency that can cause sudden onset of knee pain and may be accompanied by a popping sound if the infection leads to a joint effusion or gas formation.
- Rare diagnoses
- Spontaneous osteochondrosis dissecans: This condition involves a fragment of cartilage and bone becoming detached from the surrounding bone, which can cause knee pain and may be associated with a popping sound.
- Pathological fracture: A fracture through a weakened area of bone, such as a tumor or cyst, can cause sudden knee pain and may be accompanied by a popping sound.