From the Guidelines
Prepatellar effusion in the right knee should be initially managed with the RICE protocol (rest, ice, compression, and elevation) and over-the-counter pain medications such as paracetamol or ibuprofen, with consideration of intra-articular steroid injection for acute exacerbation of knee pain, especially if accompanied by effusion, as recommended by the EULAR guidelines 1.
Diagnosis and Treatment
The diagnosis of prepatellar effusion involves identifying the underlying cause, which can range from trauma, overuse, infection, to inflammatory conditions like bursitis.
- Key considerations in management include:
- Rest, ice application for 15-20 minutes every 2-3 hours, compression with an elastic bandage, and elevation of the affected leg above heart level when possible (RICE protocol) to reduce pain and inflammation.
- Over-the-counter pain medications like paracetamol (500-1000mg every 6 hours, not exceeding 4000mg daily) or ibuprofen (400-600mg three times daily with food) can help manage pain and reduce inflammation, with paracetamol being the preferred first-line oral analgesic 1.
- If the effusion is large, painful, or persists despite these measures, medical evaluation is necessary as aspiration (removal of fluid with a needle) may be required.
- Intra-articular injection of long-acting steroid is indicated for acute exacerbation of knee pain, especially if accompanied by effusion, as it provides short-term benefit in pain relief and functional outcomes 1.
Considerations for Management
- Non-pharmacological treatments such as regular education, exercise (especially those directed towards increasing strength of quadriceps and preserving normal mobility of the knee), appliances (sticks, insoles), and weight reduction are also recommended for the management of knee osteoarthritis, which may be associated with prepatellar effusion 1.
- NSAIDs (oral or topical) should be considered in patients with effusion unresponsive to paracetamol, given their efficacy in reducing pain and inflammation, although they may have gastrointestinal side effects 1.
- The use of symptomatic slow-acting drugs for osteoarthritis (SYSADOA) like hyaluronic acid, glucosamine sulphate, and chondroitin sulphate may be considered, although their effectiveness and suitable patient populations are not well defined, and more studies are needed to establish their role in disease modification 1.
From the Research
Diagnosis of Prepatellar Effusion
- Prepatellar effusion can be diagnosed through various methods, including clinical assessment and ultrasound evaluation 2, 3.
- Clinical tests such as visible swelling, bulge sign, and balloon sign can be used to assess knee joint effusion, but they have relatively low intra- and inter-observer reliability 2.
- Ultrasound evaluation can improve the identification of suprapatellar joint fluid, and methods such as parapatellar pressure and patient-initiated quadriceps contraction can be used to enhance detection 3.
Treatment of Prepatellar Effusion
- Aspiration and corticosteroid injection can be used to relieve swelling and tenderness of prepatellar bursae 4.
- Sclerotherapy has been shown to be effective in the management of recurrent non-septic prepatellar bursitis, with a case report demonstrating successful treatment with intrabursal sclerotherapy using polidocanol 5.
- It is essential to consider other potential causes of prepatellar lesions, such as patellar osteomyelitis, which can be misdiagnosed as prepatellar bursitis 6.
Diagnostic and Therapeutic Injection
- Joint injection of the knee region can be a useful diagnostic and therapeutic tool, with indications including acute and chronic inflammation, osteoarthritis, and rheumatoid arthritis 4.
- Aspiration of the knee joint can aid in the diagnosis of an unexplained effusion and relieve discomfort caused by an effusion 4.
- Injection of the knee can be performed for viscosupplementation or corticosteroid therapy, with indications including advanced osteoarthritis and other inflammatory arthritides 4.