Differential Diagnosis for Knee Pain Following Injury

Single Most Likely Diagnosis

• Medial Meniscus Tear: This is a common injury that occurs when the knee is twisted, especially when the foot is planted on the ground. The meniscus is a cartilage structure in the knee joint that can be damaged by a sudden twisting motion, leading to pain, swelling, and limited mobility.

Other Likely Diagnoses

• Ligament Sprain (MCL or ACL): The medial collateral ligament (MCL) and anterior cruciate ligament (ACL) are commonly injured in twisting knee injuries. These sprains can cause pain, instability, and swelling in the knee.
• Bone Bruise or Contusion: A bone bruise can occur when the knee is twisted and the bone is impacted, causing pain and swelling.
• Patellofemoral Pain Syndrome: This condition is characterized by pain in the front of the knee, usually around the kneecap. It can be caused by a twisting injury, especially if the knee is bent or straightened at the time of injury.

Do Not Miss Diagnoses

• Fracture (e.g., Tibial Plateau or Patella): Although less common, a fracture can occur with a twisting knee injury, especially if there is a high-energy impact. Missing a fracture can lead to serious complications, such as arthritis or chronic pain.
• Septic Arthritis: This is a rare but serious condition that occurs when the joint becomes infected. It can cause severe pain, swelling, and redness, and requires prompt medical attention to prevent long-term damage.
• Osteonecrosis: This condition occurs when the blood supply to the bone is disrupted, leading to bone death. It can be caused by a traumatic injury, such as a twisting knee injury, and requires prompt medical attention to prevent long-term damage.

Rare Diagnoses

• Osteochondritis Dissecans: This is a rare condition that occurs when a piece of cartilage and bone becomes detached from the surrounding bone. It can cause pain and swelling in the knee, especially with twisting or bending motions.
• Plica Syndrome: This is a rare condition that occurs when the synovial tissue in the knee joint becomes inflamed, causing pain and swelling. It can be caused by a twisting injury, but is often associated with other conditions, such as rheumatoid arthritis.