From the Guidelines
The obturator test is not a recommended diagnostic tool for total hip arthroplasty, and instead, regional anaesthesia techniques such as the pericapsular nerve group (PENG) block should be considered for postoperative pain management. When evaluating the obturator test, it is essential to consider its limitations and potential for false positives or negatives. The test is typically used to diagnose appendicitis by assessing for irritation of the obturator internus muscle, but its application in total hip arthroplasty is not supported by recent evidence. According to a systematic review and procedure-specific postoperative pain management recommendations published in 2021 1, promising new regional anaesthesia techniques, such as the PENG block, merit attention for hip replacement surgery. The PENG block targets sensory branches of the femoral, obturator, and accessory obturator nerves, which innervate the anterior capsule of the hip joint. While more research is needed to make a firm recommendation, the PENG block shows potential for effective postoperative pain management in total hip arthroplasty. Key points to consider when evaluating the obturator test and regional anaesthesia techniques include:
- The obturator test has moderate sensitivity but is not definitive on its own for diagnosing appendicitis
- False positives can occur with other pelvic inflammatory conditions, while false negatives are possible if the appendix is not in contact with the obturator muscle
- Regional anaesthesia techniques, such as the PENG block, offer a promising alternative for postoperative pain management in total hip arthroplasty
- The PENG block targets sensory branches of the femoral, obturator, and accessory obturator nerves, which innervate the anterior capsule of the hip joint.
From the Research
Obturator Test
- The obturator test is not directly mentioned in the provided studies, however, the anatomy and function of the obturator externus muscle is described in a study published in 2015 2.
- The study found that the obturator externus muscle helps to stabilize the head of the femur in the socket, and its primary action is to externally rotate the femur when the hip is in neutral position and flexed at 90°.
- Another study published in 2009 discusses the surgical management of obturator nerve lesions, which may be related to the obturator test 3.
- The study found that surgical exploration and decompression or primary repair of the obturator nerve can lead to improved symptoms, including pain relief, numbness resolution, and improved adductor muscle strength.
- Other studies provided discuss osteoarthritis and its management, including the use of NSAIDs, acetaminophen, and surgical interventions such as total hip arthroplasty 4, 5, 6.
- However, these studies do not provide direct information on the obturator test.