Hip Microinstability: A Comprehensive Review of Diagnosis and Management

Hip microinstability is an increasingly recognized cause of hip pain and dysfunction in young, active patients. The hip joint relies on both static stabilizers (labrum, capsule, ligamentum teres) and dynamic stabilizers (periarticular musculature) to maintain stability, with greater reliance on soft tissue structures for anterior stability due to asymmetric bony coverage. Hip microinstability is a multifactorial phenomenon that can be broadly categorized into six etiologies: bony abnormalities/dysplasia, connective tissue disorders, post-traumatic, microtraumatic, iatrogenic, and idiopathic. The scope of this review is to focus on microtraumatic hip anterior instability, the most common etiology that presents in the outpatient office setting of most sports medicine surgeons. The most common presenting symptoms include anterior hip pain, subjective instability with gait, and mechanical symptoms. Physical examination should include provocative maneuvers such as the anterior apprehension test, abduction-extension-external rotation test, and prone external rotation test, which together demonstrate a 95% positive predictive value for intraoperative confirmation. Imaging evaluation includes radiographs assessing the cliff sign and femoro-epiphyseal acetabular roof (FEAR) index, computed tomography (CT) for three-dimensional bony assessment, and magnetic resonance imaging (MRI) for soft tissue evaluation including capsular laxity and secondary chondrolabral lesions. The 2023 international Delphi consensus established standardized diagnostic criteria for diagnoses of hip microinstability via a combination of minor and major factors from a patient’s history, examination, and imaging. Nonoperative management with physical therapy focusing on dynamic stabilizer strengthening is first-line treatment and is generally trialed for 3 months. Surgical management includes arthroscopic or open plication, capsular reconstruction for unrepairable capsular defects, and ligamentum teres reconstruction for complete tears with multidirectional instability or in patients who have failed prior stabilization procedures.