Magnetic resonance imaging (MRI) has proven to be one of the best ways to image articular cartilage. A tremendous amount of research has focused on cartilage imaging with an emphasis of early-osteoarthritis (OA) characterization. One of the techniques which has shown great promise is the imaging technique called T1ρ . The advantage of this pulse sequence is that it is sensitive to proteoglycans (PG), a major macromolecule degraded in OA. The study objective is to determine if T1ρ can acutely assess PG content in femoroacetabular impingement (FAI) which may allow physicians to differentiate between normal and early-OA cartilage states in FAI patients.

Magnetic resonance imaging (MRI) is one of the best ways to image articular cartilage. One of the techniques which has shown great promise is the imaging technique called T1ρ (T1-rho). T1ρ is a modified pulse sequence from the standard T1 sequence used in the clinical MRI. Because the initial phases of arthritis occur at the molecular level, the main advantage of the T1ρ pulse sequence is that it is sensitive to proteoglycan. Proteoglycan is a molecule that is important to cartilage structure, and is lost as osteoarthritis develops. If we can show that this non-invasive tool can accurately assess cartilage damage and levels of proteoglycan, the clinical applications are numerous. The results can potentially help determine optimal surgical techniques and timing of surgical intervention to halt or slow the progression of arthritis, and will assist in the study of the effects of FAI and the success of the surgery performed to correct FAI.

Inclusion Criteria:

• Group 1: Patient has been diagnosed by the surgeon as having femoro-acetabular impingement (FAI) of the hip)
• Group 1: Must meet all the following criteria: A) History and Physical Exam 1) Intermittent pain worse with activity 2) Positive impingement test (pain with flexion, adduction, and internal rotation of affected hip) B) X-ray 1) No signs of OA on plain radiological films (i.e. no osteophytes, no loss of joint space) 2) Non-spherical femoral head
• Group 2: Patient has not been diagnosed by the surgeon as having any hip problems.

Exclusion Criteria:

• Previous Hip Surgeries (Pelvic Osteotomies)
• Previous Hip Trauma
• History of Pediatric Hip Pathology: Slipped Capital Femoral Epiphysis or Hip Dysplasia
• Over the age of 40 years