From the Guidelines
Hip joint aspiration should be performed under sterile conditions with imaging guidance, typically ultrasound or fluoroscopy, to confirm the presence or absence of infection and identify the causative organism. The procedure begins with patient positioning in supine with the affected hip slightly internally rotated. After identifying anatomical landmarks, the skin is prepped with antiseptic solution and draped. Local anesthesia (1-2% lidocaine) is administered to the skin and subcutaneous tissues. Using the anterior approach, the needle is inserted 1-2 cm lateral and distal to the palpable femoral pulse, directed posteriorly and slightly superiorly toward the femoral head-neck junction. A 20-22 gauge spinal needle of sufficient length (typically 3.5-5 inches) is required to reach the joint. Once positioned correctly, synovial fluid is aspirated and collected in appropriate tubes for analysis. Common tests include cell count with differential, crystal examination, Gram stain, culture, and glucose. After aspiration, the needle is removed, pressure is applied to prevent hematoma formation, and a sterile dressing is placed. Patients should limit weight-bearing for 24 hours post-procedure. Potential complications include bleeding, infection, pain, and neurovascular injury, though these are rare when performed by experienced clinicians with proper imaging guidance 1.
Some key points to consider when performing hip joint aspiration include:
- The use of imaging guidance, such as fluoroscopy or ultrasound, to ensure accurate needle placement and minimize the risk of complications 1.
- The importance of sterile technique to prevent infection and ensure accurate test results 1.
- The need to collect and analyze synovial fluid for various tests, including cell count, crystal examination, Gram stain, culture, and glucose 1.
- The potential complications of the procedure, including bleeding, infection, pain, and neurovascular injury, and the importance of taking steps to prevent these complications, such as applying pressure to prevent hematoma formation and using proper imaging guidance 1.
It is also important to note that joint aspiration with synovial fluid analysis remains probably the most useful test for confirming the presence or absence of infection and identifying the causative organism, as stated in the acr appropriateness criteria® imaging after total hip arthroplasty 1.
From the Research
Procedure for Joint Aspiration of the Hip
The procedure for joint aspiration of the hip involves several key steps:
- The patient is typically positioned in a way that allows easy access to the hip joint, such as on their side or back 2.
- The skin over the hip joint is cleaned and disinfected to minimize the risk of infection 3.
- A local anesthetic may be administered to numb the area and reduce discomfort during the procedure 3.
- A needle is inserted into the hip joint under sterile conditions, and fluid is aspirated for analysis 4, 5, 6, 2.
Indications for Joint Aspiration of the Hip
Joint aspiration of the hip is typically performed to:
- Diagnose or rule out infection in the hip joint, particularly in patients with suspected septic arthritis or periprosthetic joint infection 4, 5, 6, 2.
- Obtain synovial fluid for analysis, which can help diagnose conditions such as crystal arthritis or inflammatory arthritis 3.
- Administer intra-articular injections, such as corticosteroids or hyaluronic acid, to treat joint inflammation or other conditions 3.
Diagnostic Accuracy of Joint Aspiration of the Hip
The diagnostic accuracy of joint aspiration of the hip has been studied in several research papers:
- One study found that joint aspiration had a sensitivity of 92% and a specificity of 97% for diagnosing infection in patients undergoing revision total hip arthroplasty 6.
- Another study found that the sensitivity and specificity of joint aspiration for diagnosing infection were 0.82 and 0.91, respectively, in patients with moderate to high risk of infection 2.
- A study on the diagnostic accuracy of aspirations performed on hips with antibiotic cement spacers found that the optimal threshold for synovial white blood cell count was 1166 cells/µL and for synovial polymorphonuclear neutrophil percentage was 68% 5.