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Differential Diagnosis for Unilateral Knee Pain

  • Single most likely diagnosis
    • Osteoarthritis: This is a common condition that affects the knee joint, leading to pain, stiffness, and limited mobility. The unilateral presentation could be due to uneven wear and tear, previous injury, or asymmetric biomechanics.
  • Other Likely diagnoses
    • Meniscal tear: A tear in the cartilage of the knee can cause pain, locking, and catching sensations, typically on one side of the knee.
    • Ligament sprain: Injuries to the ligaments surrounding the knee, such as the medial or lateral collateral ligament, can cause unilateral knee pain.
    • Tendinitis: Inflammation of the tendons around the knee, like the patellar tendon, can lead to pain and stiffness, often on one side.
    • Bursitis: Inflammation of the fluid-filled sacs (bursae) that cushion the knee joint can cause localized pain and swelling.
  • Do Not Miss diagnoses
    • Septic arthritis: A bacterial infection within the knee joint can cause severe, unilateral pain, redness, and swelling, requiring prompt antibiotic treatment.
    • Osteonecrosis: A condition where the bone tissue dies due to lack of blood supply, which can cause sudden, severe knee pain, often on one side.
    • Tumor: Although rare, a tumor in or around the knee can cause unilateral pain and should not be missed.
    • Deep vein thrombosis (DVT): A blood clot in the deep veins of the leg can cause pain, swelling, and warmth, which may be mistaken for knee pain.
  • Rare diagnoses
    • Osgood-Schlatter disease: A condition that affects the upper tibia, causing knee pain and swelling, typically in adolescents.
    • Sinding-Larsen-Johansson syndrome: A rare condition that causes pain and swelling below the kneecap, often in young athletes.
    • Plica syndrome: A condition where the folds of tissue within the knee joint become inflamed, causing pain and stiffness.
    • Complex regional pain syndrome (CRPS): A chronic pain condition that can cause severe, burning pain in one limb, including the knee.

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This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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