Microinstability of the Hip: An Emerging Diagnosis in the Athlete

Microinstability of the Hip: An Emerging Diagnosis in the Athlete

By: Christine Foss MD, DC, M.S.Ed, ATC, DACBSP, DACRB, ICSC

Editor’s note: Dr. Foss is presenting the webinar “Rehab Principles for the Lower Extremity of the Athlete” for the Illinois Chiropractic Society on February 9, 2023. You can register for the course here.


With femoroacetabular impingement and labral repair surgeries staggeringly increased in the last couple of years, we need to step back and better understand intraarticular lesions of the hip.  Hip microinstability is best described as increased intraarticular joint motion or slipping in the femoroacetabular joint with activity. The increase of joint play degrades the joint and overworks the regional supporting structures. This increased joint motion causes cumulative microtrauma or acute injury to the structures of the hip.  MIcroinstability could be a result of previous injury, intra or extra-articular pathology of the hip, congenital hip dysplasia, or simply joint laxity.

 Microinstability of the hip has multiple ramifications, such as labral tears, femoroacetabular impingement, premature osteoarthritis, and soft tissue injury (1).  We see the increase incidence of hip microinstability with activities that require repetitive motions, such as running, pivoting, cutting, or jumping.  It is essential that we as practitioners effectively evaluate and diagnose hip microinstability to ensure that an effective treatment plan is in place, to avoid compensatory motion and an intraarticular lesion,  such as a labral tear of the femoroacetabular joint. 

Diagnosis of microinstability of the hip can reach a 95% confidence interval if we implement three basic tests of the hip (1).  The prone instability test (PI), the Abduction-hip-extension-external rotation test (AB-HEER), and the hyperextension external rotation test (HEER).  Each test will challenge the femoroacetabular joint for excessive motion in several planes of action. 

The prone instability test (PI), (2), is performed by beginning with the patient in the prone position.  The knee is flexed to 90 degrees, the hip is passively placed into external rotation.  The practitioner places a hand on the greater trochanter, applying pressure posterior to anterior on the greater trochanter. A positive test is the reproduction of pain in the anterior hip.  Excessive joint play may be felt with careful attention to the joint gapping. In the instance of the evaluation of joint laxity or instability, it is always advised to offer a bilateral comparison with the unaffected limb. See figure 1 below.

The abduction-hip-extension-external-rotation test (AB-HEER) as described by Domb, et al (2), is performed with the patient in the lateral decubitus position. The hip is passively abducted to 30-45 degrees, extended, and externally rotated. The practitioner places a contact on the posterior aspect of the greater trochanter of the femur and applies posterior to anterior pressure to the joint.  A positive test reproduces pain in the anterior hip. Once again, the practitioner should pay close attention to any findings of abnormal joint motion.  See figure 2 below.

The anterior apprehension test, again as described by Domb, et al (2), is performed with the patient starting in the supine position with the legs hanging off the end of the table.  The patient pulls the unaffected knee to the chest.  The symptomatic leg is then given gentle downward pressure at the knee while the leg is externally rotated.  A positive test will produce anterior hip pain.  Once again, the practitioner is encouraged to compare the joint play to the unaffected side.  See figure 3 below.

Figure 1Figure 2Figure 3

In using these three hip instability tests together, the practitioner will have a significant increase in the diagnostic sensitivity and specificity of the microinstability of the hip.  This accurate diagnosis is imperative to ensure the initiation of the proper treatment care plan. Treatment for this condition would begin with reestablishing the stability that the hip is lacking. This is done with the initiation of stabilization training, global strengthening, and perturbation retraining. Progressions of this retraining should be strictly adhered to and the athlete returned to sport when stability is returned. 

Dr Christine Foss



Advanced Sports Medicine & Physical Therapy Center, Riverdale NJ

2020 ASASC Sports Chiropractor of the Year


  1.  Hoppe DJ, Truntzer JN, Shapiro LM, Abrams GD, Safran MR. Diagnostic Accuracy of 3 Physical Examination Tests in the Assessment of Hip Microinstability. Orthop J Sports Med. 2017 Nov 27;5(11):2325967117740121. doi: 10.1177/2325967117740121. PMID: 29226163; PMCID: PMC5714089.

        2.       Domb, Benjamin G., Marc J. Philippon, and Brian D. Giordano. “Arthroscopic capsulotomy, capsular                   repair, and capsular plication of the hip: relation to atraumatic instability.” Arthroscopy: The Journal of                Arthroscopic & Related Surgery 29.1 (2013): 162-173.

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