Anterior impingement test for labral lesions has high positive predictive value

Area of Science:

• Orthopedic surgery
• Diagnostic imaging
• Hip biomechanics

Background:

• The anterior impingement test is used to identify anterosuperior acetabular labral lesions.
• Previous studies show high sensitivity in treated patients, but its diagnostic accuracy in unselected hip pain populations is unknown.

Purpose of the Study:

• To determine the sensitivity, specificity, positive predictive value, and negative predictive value of the anterior impingement test.
• To evaluate these parameters in unselected hip pain patients and specific subgroups: hip dysplasia, femoroacetabular impingement (FAI), and intact joint space.

Main Methods:

• Prospective study of 69 patients (15 men, 54 women; mean age 57.2 years) with 107 hips evaluated.
• The anterior impingement test was performed by one observer.
• Anteriosuperior labral lesions were diagnosed using radial MRI.

Main Results:

• Overall sensitivity was 50.6% (45/89), specificity 88.9% (16/18), positive predictive value 95.7% (45/47), and negative predictive value 26.7% (16/60).
• Parameters were similar across subgroups of hip dysplasia, FAI, and intact joint space.

Conclusions:

• The anterior impingement test demonstrates insufficient sensitivity for detecting anterosuperior acetabular labral lesions in this population.
• Despite low sensitivity, the high positive predictive value indicates the test remains a useful clinical tool.