Common Symptoms

Sharp or aching groin pain that worsens with hip flexion, such as sitting for long periods or climbing stairs
Pain at the end range of internal rotation and adduction of the hip
Stiffness and reduced range of motion, particularly difficulty crossing the legs or putting on socks
Clicking or catching sensation inside the hip joint during movement
Pain during athletic activities involving pivoting, sprinting, or deep squatting
Gradual onset buttock or lateral hip ache that may radiate to the anterior thigh

Hip Impingement: AI-Powered MRI Analysis

AI-powered hip impingement detection on MRI. Identify cam and pincer morphology, labral tears, and cartilage damage from femoroacetabular impingement. 4 AI models analyze alpha angle and crossover signs.

Overview

Femoroacetabular impingement (FAI) occurs when abnormal bony morphology of the femoral head (cam type), acetabulum (pincer type), or both (mixed type) causes abnormal contact during hip motion. This leads to labral tears, cartilage damage, and eventually osteoarthritis. Imaging is essential for identifying FAI morphology, measuring alpha angles, assessing acetabular coverage, and evaluating associated soft tissue damage. Our AI consortium provides morphological assessment and measurements relevant to surgical planning.

Key Imaging Findings

Cam morphology with elevated alpha angle (greater than 55 degrees)
Femoral head-neck junction bump or asphericity
Pincer morphology with acetabular overcoverage (crossover sign)
Coxa profunda or protrusio acetabuli
Associated labral tear, most commonly anterosuperior
Cartilage delamination at the chondrolabral junction

Frequently Asked Questions

What is the difference between cam and pincer FAI, and how is each identified on imaging?

Femoroacetabular impingement (FAI) has two morphological subtypes. Cam impingement arises from an aspherical femoral head-neck junction — a bony prominence that shears the acetabular labrum and cartilage during flexion. It is quantified on AP pelvis or Dunn-view radiographs by the alpha angle; an alpha angle greater than 55° is the accepted threshold for cam deformity. Pincer impingement results from focal or global acetabular over-coverage, trapping the labrum between the acetabular rim and the femoral neck. It is assessed on AP pelvis radiographs using the lateral center-edge angle (LCEA); an LCEA above 40° indicates coxa profunda or protrusio and suggests pincer morphology. Mixed FAI, combining both subtypes, is the most common presentation.

What does MRI add beyond plain radiographs in evaluating hip impingement?

Conventional MRI and, more definitively, MR arthrogram (MRA) with intra-articular gadolinium provide soft-tissue detail unavailable on radiographs. MRA improves labral tear detection sensitivity to over 90%, delineates cartilage delamination at the chondrolabral junction, and identifies paralabral cysts. Radial reformats — oblique MRI sequences acquired perpendicular to the femoral neck at multiple clock-face positions — map the full circumference of the head-neck junction, allowing precise measurement of the alpha angle in the plane of maximum cam deformity, which is typically at the 1–2 o'clock position on radial imaging.

When is surgery recommended over conservative management for FAI?

Conservative treatment — activity modification, physical therapy targeting hip rotator strengthening and lumbopelvic stability, and anti-inflammatory medication — is the first-line approach for 3 to 6 months. Arthroscopic or open surgical correction is considered when symptoms persist despite adequate conservative care, when MRA confirms a repairable labral tear contributing to mechanical symptoms, or when progressive chondral damage is documented. Early intervention before advanced joint space narrowing yields better outcomes, as significant osteoarthritis (Tonnis grade ≥ 2) is a relative contraindication to joint-preserving surgery.

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Upload your hip MRI to check for Hip Impingement MRI Analysis

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Medical Disclaimer: This page is for informational and educational purposes only. It does not constitute medical advice, diagnosis, or treatment. AI-generated analysis may contain errors. Always consult a qualified healthcare professional for medical decisions. Full Disclaimer