Differential Diagnosis for 1-Day Left Knee Pain
- Single most likely diagnosis
- Meniscal tear: The patient's sudden onset of knee pain, worsening with walking and straightening, and improvement with slight bending, is consistent with a meniscal tear. The history of a cortisone shot many years ago and degenerative changes on x-ray also support this diagnosis.
- Other Likely diagnoses
- Ligament sprain: The patient's description of their knee "going out to the side" could indicate a ligament sprain, which is a common injury that can occur with sudden twisting or bending.
- Osteoarthritis flare: The patient's history of degenerative changes and previous cortisone shot suggests osteoarthritis, and the current symptoms could represent a flare of this condition.
- Patellofemoral pain syndrome: The patient's pain worsening with walking and straightening, and improvement with slight bending, could also be consistent with patellofemoral pain syndrome.
- Do Not Miss diagnoses
- Septic arthritis: Although less likely, septic arthritis is a serious condition that requires prompt diagnosis and treatment. The patient's sudden onset of pain and lack of relief with Tylenol could be consistent with septic arthritis.
- Fracture: A fracture, such as a stress fracture or osteochondral fracture, could also present with sudden onset of pain and should not be missed.
- Rare diagnoses
- Osteonecrosis: The patient's history of cortisone shot and degenerative changes could increase the risk of osteonecrosis, although this is a less common condition.
- Rheumatologic conditions: Conditions such as rheumatoid arthritis or lupus could also present with knee pain, although these are less likely given the patient's history and presentation.