The broken wing sign: a new clinical test to detect gluteus medius pathology with and without fatty infiltration

Key Points

1. The broken wing sign demonstrated high diagnostic accuracy.
2. A positive sign suggests abductor pathology and a negative sign rules out massive tears.
3. Unlike the Trendelenburg test it can be done on those with poor balance, increased pain, or assistive devices.

BACKGROUND AND OBJECTIVE

Lateral hip pain following total hip arthroplasty and hip fractures is commonly due to gluteus medius tendon dysfunction including tears and muscle atrophy (1). Currently magnetic resonance imaging (MRI) is the gold standard for assessing tears and fatty infiltration but access and cost limit use (2).

The authors of this paper proposed a new musculoskeletal clinical test for early detection of abductor insufficiency. They particularly were interested in a test that would correlate with MRI findings in a non-weightbearing position. They report the limitations of the Trendelenburg sign and resisted hip abduction and propose “The Broken Wing Sign” as a novel examination to detect gluteus medius tears and assess for muscle atrophy.

Therefore, this study aimed to establish the diagnostic accuracy and clinical utility of the Broken Wing Sign.

Currently magnetic resonance imaging is the gold standard for assessing gluteus medius tendon tears and fatty infiltration but access and cost limit use.

This is a good test to use in the clinic for those who have poor balance, use assistive devices, or have pain in standing which make the use of the Trendelenburg test unavailable.

METHODS

• This was a prospective study of 59 patients that were referred to a specialty clinic for suspected hip abductor insufficiency (75 hips). Clinical MRI examinations were performed on each hip in the study.

• Gluteus medius integrity was categorized as no tear, partial tear, full thickness tear, or massive tear. Any operative information was included. The study notes that there was full agreement on the classification of the tears for each hip.

• Fatty infiltration of the gluteus medius was graded 0 = no fatty infiltration to 4 = extensive fatty infiltration.

• The Broken Wing test is performed in prone with the knee of the tested limb flexed to 90°. The patient was asked to actively extend the hip (lift the leg straight up off the surface) and the position of the lower leg is noted (see Video 1).

• A negative (normal) result is that the leg is lifted straight up and the lower leg remains vertical.

• A positive sign of dysfunction is the hip moving into external rotation, resulting in the lower leg and foot moving towards or beyond midline at least 10°.

• External rotation of at least 30° is “highly positive” and might be indicative of increased pathology.

VIDEO 1 – BROKEN WING TEST

RESULTS

• The broken wing sign was positive in 49 of the 75 hips and negative in 26.

• Patients with positive broken wing signs had significantly more fatty infiltration.

• MRI confirmed gluteus medius tears in 55 hips:

  • 14 partial
  • 13 full-thickness, two had severe fatty infiltration
  • 28 massive tears, 20 had severe fatty infiltration

• The broken wing sign had high sensitivity (81.8%) and positive predictive value (91.8%) for detecting any tear. The diagnostic odds ratio was 17.8.

• For massive tears, the test had a negative predictive value of 96.1% and a diagnostic odds ratio of 30.0 showing effective ruling out of a massive tear with a negative test.

• With an external rotation of 30° or higher the test is 100% specific and predictive.

• The standard of 10° or higher was sensitive for detecting a wide range of tear severity.

• A positive broken wing sign was positively associated with fatty infiltrate. The more external rotation, the more fatty infiltrate.

• In the hips with minimal fatty infiltration the sensitivity was 69.2%, specificity 81.8%, and diagnostic odds ratio of 10.0.

• The authors performed a Trendelenburg sign on patients who could tolerate the test, only 40 of the 75 hips could be tested due to pain, poor balance, or assistive device use. 35 of those also had the broken wing test and when either test was positive the sensitivity, specificity, negative and positive predictive values were 100%.

LIMITATIONS

There was moderate specificity (80%) overall and a false positive could be due to hip arthritis, radiculopathy, pain inhibition, or gluteus maximus insufficiency.

CLINICAL IMPLICATIONS

The broken wing sign as a novel physical examination to identify hip abductor insufficiency resulting from gluteus medius tears demonstrates a high diagnostic accuracy.

This is an easy test to apply for those who can tolerate prone with knee flexion. It is simple, has clear criteria, and can facilitate referral for MRI when used in acute care settings. The authors point out the anatomical relevance of testing the gluteus medius with its attachment to the greater trochanter and the ability to test for tears along the anterior fibers which are at risk for degenerative wear (3).

This is a good test to use in the clinic for those who have poor balance, use assistive devices, or have pain in standing which makes the use of the Trendelenburg test unavailable. Clinically it may prove useful to integrate the broken wing sign into pre-operative evaluations or for patients with suspected gluteus medius pathology, particularly if they are unable to stand or balance.

The authors suggested that in their own practice, they first assess prone hip extension to evaluate gluteus maximus strength and then perform the broken wing sign evaluation with the knee flexed.

This sequence distinguishes gluteus maximus weakness (inability to extend the leg) from gluteus medius weakness (external rotation lag). An external rotation of >30degrees guarantees a massive tear that requires complex reconstruction. Smaller degrees of lag are often associated with reparable or tendinopathic conditions for which conservative management or primary repair is suitable.

+STUDY REFERENCE

Sierra R, Perez S, Restrpo D, Howe B, Tai T (2025) ‘The broken wing sign: A new clinical test to detect gluteus medius pathology with and without fatty infiltration’, Journal of Bone and Joint Surgery, 107(21), 2359–2364

SUPPORTING REFERENCE

1. Pianka, M.A. et al. (2021) ‘Greater trochanteric pain syndrome: Evaluation and management of a wide spectrum of pathology’, SAGE Open Medicine, 9.
2. Bogunovic, L. et al. (2015) ‘Application of the goutallier/fuchs rotator cuff classification to the evaluation of hip abductor tendon tears and the clinical correlation with outcome after repair’, Arthroscopy: The Journal of Arthroscopic & Related Surgery, 31(11), pp. 2145–2151.
3. Ortiz-Declet, V. et al. (2019) ‘Diagnostic accuracy of a new clinical test (resisted internal rotation) for detection of gluteus medius tears’, Journal of Hip Preservation Surgery, 6(4), pp. 398–405.