What is the diagnosis for a patient with a left knee X-ray showing no fracture or dislocation, but with a small knee joint effusion, mild lateral patellar positioning, and mild prepatellar subcutaneous edema?

From the Guidelines

Given the absence of fractures or dislocations on the X-ray, initial management should focus on symptom relief and monitoring, with consideration for an MRI if symptoms persist, as soft tissue injuries may not be visible on X-rays 1. The X-ray of your left knee shows no fractures or dislocations, which is reassuring. There is a small amount of fluid in the knee joint (effusion) and your kneecap (patella) is positioned slightly toward the outside of the knee with some tilting. There's also mild swelling in the soft tissues in front of your kneecap. For now, I recommend:

• Rest
• Ice for 15-20 minutes every 2-3 hours
• Compression with an elastic bandage
• Elevation of your leg when sitting or lying down (RICE protocol) Take over-the-counter pain relievers like acetaminophen (Tylenol) 500-1000mg every 6 hours or ibuprofen (Advil, Motrin) 400-600mg every 6-8 hours with food as needed for pain. Gentle range-of-motion exercises can help maintain flexibility. If your symptoms don't improve within 2-3 weeks, follow up with your doctor as an MRI may be needed to check for soft tissue injuries like meniscus tears or ligament damage that don't show up on X-rays, as MRI has been shown to be highly sensitive and specific for detecting these types of injuries 1. The patellar positioning noted could contribute to tracking issues and pain with knee movement, especially when climbing stairs or squatting. It's also important to note that ultrasound (US) may be useful in detecting some soft tissue injuries, such as quadriceps tendon tears, but its utility is limited in evaluating the cruciate ligaments, menisci, and articular surfaces of the knee joint 1. However, given the potential for internal derangement or occult osseous injury, an MRI is likely a better next step if symptoms persist, as it can provide more detailed information about the soft tissues and bone marrow 1.

From the Research

Diagnosis and Treatment of Knee Pain

• The patient's left knee X-ray shows no fracture or dislocation, but a small knee joint effusion and minimum lateral patellar positioning with mild/moderate lateral patellar tilt 2.
• The presence of anterior knee pain and effusion may indicate patellofemoral pain or osteoarthritis, which are common causes of knee pain 3.
• Patellofemoral pain typically affects people younger than 40 years who are physically active, and has a lifetime prevalence of approximately 25% 3.
• The diagnosis of patellofemoral pain can be made clinically, and treatment options include hip and knee strengthening exercises, foot orthoses, and patellar taping 3, 4.

Treatment Options

• Conservative management, including exercise therapy, weight loss, and education, is the first-line treatment for patellofemoral pain and osteoarthritis 3, 4.
• Injection therapies, such as platelet-rich plasma and corticosteroids, may be used to treat patellar tendinopathy, but more high-quality clinical studies are needed to determine their effectiveness 5.
• Surgical referral may be considered for patients with end-stage osteoarthritis or severe traumatic meniscal tears 3, 6.

Further Evaluation

• If symptoms persist, an MRI may be necessary to evaluate for internal derangement or occult osseous injury 2.
• A thorough history and physical examination, including specific maneuvers and diagnostic imaging studies, are essential for establishing the correct diagnosis and treatment plan 2.