Differential Diagnosis for Right Knee Pain

Single most likely diagnosis

• Medial Meniscal Tear: The medial aspect of the knee is commonly associated with meniscal tears, which can cause pain, especially with twisting or bending movements. The improvement with movement could be due to the reduction of pressure on the meniscus as the knee moves.

Other Likely diagnoses

• Medial Collateral Ligament (MCL) Sprain: MCL sprains can cause pain on the medial aspect of the knee and can be exacerbated by activities that put stress on the ligament, such as sitting with the knee bent. Movement might alleviate the stress on the MCL, reducing pain.
• Pes Anserine Bursitis: This condition involves inflammation of the bursa located on the medial aspect of the knee, which can cause pain and swelling in that area. It's more common in individuals with knee osteoarthritis or those who are overweight. Sitting can exacerbate the pain due to increased pressure on the bursa.
• Saphenous Nerve Entrapment: The saphenous nerve runs down the medial aspect of the knee and can become entrapped, causing pain, numbness, and tingling in the area it supplies. This could explain the numbing sensation mentioned.

Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)

• Deep Vein Thrombosis (DVT): Although less likely, DVT can present with pain and swelling in one leg and can be associated with numbness or tingling if there's associated nerve compression. It's a medical emergency due to the risk of pulmonary embolism.
• Osteonecrosis of the Knee: This condition involves the death of bone tissue due to a lack of blood supply. It can cause severe pain, especially with weight-bearing activities, but can also present with pain at rest. Sitting could exacerbate the pain due to increased pressure on the affected bone.
• Infection (Septic Arthritis): An infection within the knee joint can cause severe pain, swelling, and reduced range of motion. While less common, it's a critical diagnosis to consider due to the potential for rapid joint destruction and systemic infection.

Rare diagnoses

• Tumors (e.g., Osteoid Osteoma, Osteosarcoma): Although rare, bone tumors can cause localized pain that may worsen at night or with activity. The presence of a numbing sensation could be due to nerve involvement.
• Complex Regional Pain Syndrome (CRPS): A condition characterized by intense burning or aching pain in the hands or feet after an injury or trauma. It can also occur in other areas, including the knee, and is associated with numbness, among other symptoms.