From the Research
The hip dip sign is a significant indicator of hip joint effusion or synovitis, and its presence warrants further diagnostic workup, including imaging and possibly joint aspiration, to determine the underlying cause of hip pain or inflammation, as evidenced by the most recent and highest quality study available 1.
Significance of the Hip Dip Sign
The hip dip sign is a physical examination finding that can be used to detect hip joint effusion or synovitis. This sign is particularly useful in pediatric patients with suspected septic arthritis, transient synovitis, or other inflammatory hip conditions.
- The hip dip sign helps differentiate hip joint pathology from other causes of hip or groin pain, such as muscle strains or referred pain.
- A positive hip dip sign occurs when the patient experiences increased pain as the hip is passively moved from flexion into extension while maintaining abduction.
- This maneuver increases intra-articular pressure, causing pain when fluid or inflammation is present within the joint capsule.
Diagnostic Workup
When a positive hip dip sign is found, further diagnostic workup may be warranted to determine the underlying cause of hip pain or inflammation.
- Imaging studies, such as ultrasound or MRI, can be used to evaluate the hip joint and surrounding tissues.
- Joint aspiration may also be performed to obtain a sample of synovial fluid for analysis.
- The choice of diagnostic tests will depend on the patient's symptoms, medical history, and physical examination findings, as well as the results of initial imaging studies 2.
Anatomical Basis
The anatomical basis for the hip dip sign relates to the hip joint capsule becoming taut in certain positions, which increases pressure on inflamed synovial tissues or stretches the distended capsule when effusion is present.
- The hip joint capsule is a fibrous sac that surrounds the hip joint and attaches to the femur and pelvis.
- When the hip joint is moved into certain positions, the capsule can become taut, increasing pressure on the joint and surrounding tissues.
- This increased pressure can cause pain and discomfort, particularly when fluid or inflammation is present within the joint capsule 3.