Identifying Radiographic Parameters Associated with Risk of Reoperation for FAI

A study from Scottish Rite for Children in Dallas, Texas, suggests that the presence of a shallow acetabulum on preoperative radiographs predicts the eventual need for a reoperation in young patients undergoing surgery for femoroacetabular impingement (FAI).

The study findings were presented at the American Orthopaedic Society of Sports Medicine’s Annual Meeting 2022.

Study Methodology and Findings

Philip A. Serbin, MD, and his colleagues at Scottish Rite for Children enrolled 87 patients in a prospective study designed to identify radiographic parameters associated with successful and unsuccessful primary surgery for FAI. All patients were under age 19 (average age, 16.27) and most were female (73.6%).

Enrolled patients had either surgical dislocation (56 patients) or hip arthroscopy (31 patients). Ten patients underwent reoperation (11.5%) at an average of 20.6 months postoperatively. No differences were observed in demographics, activity, surgery type, labral disease, or alpha angle between patients who did and who did not need a reoperation.

The Lateral Center-Edge Angle (LCEA), the Femoro-Epiphyseal Acetabular Roof (FEAR) Index, and the Sharps angle were significantly different between groups (P<0.05).

Radiographic Parameters Identified

After analyzing the prospective data, the researchers found that patients with an LCEA score of <21° and a FEAR Index of > -8.8 were at greater risk of reoperation:

  • 46% of patients with an LCEA <21° underwent a reoperation compared with 6% of patients with an LCEA >21°
  • 32% of patients with a FEAR Index < -8.8, underwent a reoperation compared with 5% of patients with a FEAR index > -8.8

Patients who achieved the minimal clinically important difference (61.9%) had a lower BMI, worse preoperative patient-reported outcomes (PROs), and better postoperative PROs at 2 years. Alpha and Sharp’s angles were positively correlated with 2+ year PROs, while the LCEA was negatively correlated (P<0.05).

Dr. Serbin said that in patients undergoing treatment for FAI, reoperation was associated with radiographic signs of hip dysplasia, indicating that patients with a shallower acetabulum are at risk for a repeat operation.

“Surgeons can utilize these parameters to help in surgical decision making, better predict outcomes, and counsel patients about the need for potential subsequent surgery,” Dr. Serbin said.


 Serbin PA, et al. Predictors of Re-Operation in Adolescents Undergoing Hip Preservation Surgery for Femoracetabular Impingement (Paper 22). Presented at the American Orthopaedic Society of Sports Medicine’s Annual Meeting 2022, July 13-17, 2022, Colorado Springs, Colorado.

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