Potential participants will be identified at their initial PI's outpatient clinic at which the PI will meet with the patient and determine if the patient should be treated surgically due to a diagnosis of FAI. Once the PI identifies the patient as a surgical candidate, the research study team in the clinic will approach the patient with study information to discuss. If the patient would like to participate, the patient will sign an informed consent document (assent document for minors) and begin completing study-specific information. If the patient would like to take the study documents home to consider participation, the research team member will provide his/her contact information to the patient.

SPECIFIC AIMS:

1. Determine the predictors of mid-term patient-reported outcomes (PROs) and treatment failures in an established prospective longitudinal cohort of Femoroacetabular Impingement (FAI) surgeries.
2. Determine the impact of three-dimensional femoral and acetabular morphology on PROs at short-term follow-up in a novel prospective longitudinal cohort of arthroscopic FAI surgery.
3. Determine if the new Patient-Reported Outcome Measurement Information System (PROMIS) correlates with legacy PROs in patients undergoing FAI surgery.

DATA COLLECTION:

1. Retrospective Follow-up (FAI-1): The original cohort includes previously consented participants in a closed-to-enrollment study who underwent FAI surgical treatment in the past. This cohort will be followed to investigate the most important predictors of FAI surgery outcomes. In Specific Aim 1, we propose to analyze mid-term follow-up (minimum 8 years) of the FAI-1 cohort to identify important predictors of treatment outcomes and failures in FAI surgery.
2. Prospective Enrollment (FAI-2): Consented participants, in the actively enrolling study, will be enrolled in a new multicenter longitudinal prospective arthroscopic FAI surgery cohort and followed to a minimum 2 years post-surgery (T2). The primary outcome measures will be the collection of the patient report outcomes (PROs) that will be analyzed in order to improve surgical care and outcomes. These clinical outcome metrics will be assessed at baseline, 3 months, 6 month, 1 year, and 2 year postoperatively.