Deep groin pain that sharpens when you sit for long stretches, a catching sensation when you stand up, stiffness that takes the first few steps to shake off. These are the kinds of complaints that bring patients into the office wondering what is going on with their hip. For a meaningful number of them, the answer is femoroacetabular impingement, or FAI. It is one of the more commonly misunderstood hip conditions, partly because it is often confused with a pulled muscle or a back problem, and partly because people live with the discomfort for months or even years before having it properly evaluated.

This guide walks through what femoroacetabular impingement actually is, the different bone shapes that drive it, how surgeons confirm the diagnosis, and what hip treatment options look like from conservative care through arthroscopic surgery.

What Is Femoroacetabular Impingement?

Femoroacetabular impingement is a condition involving abnormal contact between the femoral head (the ball at the top of the thigh bone) and the acetabulum, the cup-shaped socket of the pelvis. In a healthy hip, the ball moves smoothly inside the socket through a full range of motion without the two surfaces pinching or grinding against each other. In FAI, irregular bone shapes on one or both sides of that joint cause the structures to catch and compress during movement, particularly with flexion, internal rotation, and activities that require the hip to move through its end range.

That repeated abnormal contact does not just cause pain in the moment. Over time it can damage the labrum, a ring of fibrocartilage that lines the rim of the socket and plays an important role in joint stability and fluid distribution, and erode the articular cartilage underneath it. Left unaddressed, this pattern of damage is associated with the development of early hip osteoarthritis.

The Three Morphology Types

FAI is classified by where the abnormal bone is located, and the distinction matters because it influences both the symptoms a patient experiences and the surgical correction that may be needed.

Cam morphology involves an irregular contour at the femoral head-neck junction. Instead of a smooth, spherical head that rotates cleanly in the socket, there is a bony prominence, sometimes described as a bump or pistol-grip deformity, that jams into the rim of the acetabulum when the hip flexes. Cam impingement tends to cause chondral damage to the anterosuperior cartilage of the socket and is more prevalent in men.

Pincer morphology originates on the acetabular side. Extra bone around the rim of the socket creates overcoverage of the femoral head, causing the labrum to get pinched between the rim and the femoral neck during hip movement. Pincer impingement is more commonly seen in middle-aged women.

Mixed morphology means both features are present simultaneously. This is actually the most frequently encountered pattern in clinical practice, with research indicating that the majority of patients presenting with FAI show evidence of both cam and pincer changes.

Who Gets FAI and Why

The bony abnormalities that lead to femoroacetabular impingement generally develop during the adolescent growth years. The hip joint is not fully ossified during this period, and there is strong evidence in the orthopedic literature that participation in high-intensity sports during skeletal immaturity can influence how the femoral head and neck develop. Young athletes in sports requiring repetitive hip loading (soccer, hockey, basketball, and football among them) show higher rates of cam morphology compared to non-athletic peers. This does not mean youth sport causes FAI in every case, but it is one of the more significant risk factors identified in the research.

Genetics also plays a role. A family history of FAI-related morphology increases individual risk, and certain structural patterns appear to run in families. Other contributing factors include the mechanics of individual sports, training volume during adolescence, and baseline differences in acetabular depth and orientation.

One important point worth understanding: having cam or pincer morphology on an X-ray does not automatically mean a person will develop symptoms. A meaningful number of people have these anatomical variants without hip pain. FAI becomes clinically relevant, and worth treating, when the morphology produces symptoms, positive physical examination findings, and corresponding imaging changes.

What FAI Feels Like: Symptoms Patients Describe

The presenting complaint in most FAI cases is deep groin pain, often located at the front of the hip in the crease. Patients frequently describe it as a dull ache that sharpens with specific positions or activities. Common triggers include:

  • Prolonged sitting, especially in low chairs or bucket seats
  • Getting up after sitting for an extended period
  • Hip flexion past 90 degrees, such as squatting, pulling on shoes, or climbing stairs
  • Athletic movements involving pivoting, cutting, or deep lunging
  • Long car rides

Beyond pain, many patients notice a catching or clicking sensation in the hip, a mechanical feeling that something is getting stuck rather than moving smoothly. Stiffness after rest is common, particularly in the morning or after inactivity. As the condition progresses, some patients notice decreased range of motion and find that activities they used to manage comfortably have become more limiting.

The symptoms can mimic other hip and groin problems, including hip flexor strains, adductor injuries, and referred pain from the lumbar spine. This overlap is one reason the evaluation process matters as much as it does.

How FAI Is Diagnosed

The Physical Examination

Diagnosis begins with a thorough history and physical examination. A hip specialist will ask about when symptoms started, what activities provoke them, whether there was a specific onset or gradual progression, and what has already been tried.

The examination includes range of motion testing, assessing for asymmetry between sides, and specific impingement provocation maneuvers. The FADIR test (flexion, adduction, and internal rotation of the hip) is the most commonly used clinical test for FAI. A positive result, meaning the patient’s familiar pain is reproduced in that position, supports the diagnosis. The FABER test (flexion, abduction, external rotation) is used to assess both the hip joint and the sacroiliac region. These tests are sensitive screening tools, but no single maneuver is definitive on its own. An experienced examiner reads them as part of a broader clinical picture.

Imaging: X-Ray and MRI Arthrogram

Standard weight-bearing X-rays are the starting point for imaging. They allow visualization of the bony contours of the femoral head and acetabular rim, identification of cam bumps, measurement of femoral head-neck offset, and assessment of the degree of acetabular coverage. X-rays also help rule out arthritis, dysplasia, and other structural problems that can produce similar symptoms.

When soft tissue detail is needed, particularly to evaluate the labrum and the articular cartilage, MRI is the imaging study of choice. MR arthrography, which involves injecting contrast material into the hip joint before scanning, provides the most detailed visualization of labral tears and cartilage damage. Research has demonstrated that MR arthrography is an effective imaging method for identifying labral tears in the setting of FAI, with high sensitivity for labral pathology when performed and interpreted by experienced radiologists.

As with any hip imaging, the findings have to be correlated with the clinical presentation. Imaging confirms and characterizes what the history and examination already suggest. It does not replace that clinical judgment.

Treatment Options for Femoroacetabular Impingement

Conservative Care First

Not everyone with FAI requires surgery. For patients with mild symptoms, a trial of conservative management is typically the appropriate starting point. This usually involves activity modification to reduce loading of the hip through the positions that provoke impingement, a physical therapy program focused on hip and core strengthening, improving movement patterns, and improving muscular control around the joint. Anti-inflammatory medications may be used to manage pain during this period. Corticosteroid or other injections into the hip joint can sometimes serve both a diagnostic and short-term therapeutic purpose.

The goal of conservative care is to reduce symptom burden and maintain function. When it is effective, it may be sufficient. When symptoms persist despite a genuine and sustained effort, or when the hip is mechanically blocked or a labral tear is present, the conversation typically shifts toward surgical evaluation.

Hip Arthroscopy: Osteoplasty and Labral Repair

When surgery is indicated, hip arthroscopy is the preferred approach for most FAI cases. It is a minimally invasive procedure performed through small incisions using a thin camera and specialized instruments. The surgeon views the inside of the joint on a monitor and addresses the sources of impingement directly.

The two primary objectives in FAI arthroscopy are osteoplasty and labral repair, though not every case requires both.

Osteoplasty involves reshaping the abnormal bone. For cam impingement, the prominence at the femoral head-neck junction is contoured to restore a smoother, more spherical shape and reduce the offset irregularity causing impingement. For pincer impingement, the excess rim of the acetabulum is trimmed back. Correcting the underlying morphology addresses the mechanical cause of the problem rather than only managing the symptoms.

Labral repair is performed when the labrum has been torn. The goal is to restore the integrity and function of the labral tissue by reattaching it to the rim of the acetabulum using suture anchors. Preserving the labrum, rather than simply removing the damaged portion, is generally preferred where the tissue quality and tear pattern allow for it, given the labrum’s role in hip stability and joint pressure distribution.

Recovery following hip arthroscopy typically involves a period of protected weight-bearing, a structured rehabilitation program, and gradual return to activity over several months. The specific timeline depends on the nature of the procedure, what was repaired, and the individual patient’s progress. Returning to higher-demand athletic activity generally requires more time than returning to daily walking and work. Dr. Thornton provides personalized post-operative protocols to guide each patient through recovery, and those instructions take precedence over general timelines.

Frequently Asked Questions

Cam impingement involves a bony irregularity on the femoral head that disrupts the smooth ball-and-socket motion. Pincer impingement involves excess bone around the rim of the acetabular socket that pinches the labrum during hip movement. Most patients presenting with FAI show evidence of both types together, which is called mixed morphology.

The underlying bony morphology that causes FAI does not change without intervention. Conservative treatment (physical therapy, activity modification, anti-inflammatories) can meaningfully reduce symptoms for some patients, but it does not correct the structural problem. If a labral tear is present and symptoms persist, the condition generally requires surgical evaluation to prevent further joint damage.

Hip arthroscopy is a minimally invasive procedure performed through small incisions rather than a large open surgical approach. It does not involve cutting through major muscle groups or dislocating the hip. That said, it is a surgical procedure with a recovery period, and it requires a commitment to the rehabilitation process. Results depend significantly on how carefully post-operative instructions and physical therapy are followed.

Candidates are generally patients with symptomatic FAI who have not found adequate relief with conservative care, who have a labral tear or significant cartilage damage, and who do not have advanced hip arthritis. The degree of cartilage wear is one of the most important factors. Significant pre-existing arthritis tends to limit the expected benefit of arthroscopic preservation surgery. An evaluation including physical examination and imaging is needed to assess candidacy.

Recovery varies depending on what was done during the procedure. Patients are typically on crutches for several weeks and begin formal physical therapy shortly after surgery. Return to low-demand daily activities often happens within several weeks. Return to sport or high-impact activity typically takes considerably longer, often four to six months or more depending on the procedure and individual progress. Dr. Thornton provides specific guidance based on each patient’s situation.

There is a well-established association between symptomatic FAI and the development of early hip osteoarthritis. The repeated abnormal contact between the femoral head and the acetabular rim, particularly when it damages the labrum and underlying cartilage, can accelerate joint deterioration over time. Addressing the impingement and repairing the labrum are aimed in part at preserving the joint and slowing that process.

Persistent groin pain that does not resolve with rest and basic care, a catching or locking sensation in the hip, stiffness after sitting, or pain that limits activity and exercise are all reasonable reasons to seek an evaluation. Hip conditions are more reliably identified and treated before significant cartilage damage has occurred, so an earlier conversation with a specialist is generally better than waiting.

Getting Clarity on Your Hip Pain in Dallas

FAI is a structural problem, and understanding it clearly (what type of morphology is involved, whether the labrum is affected, and how much cartilage damage is present) is what makes it possible to build a plan that actually fits the patient in front of you. That process starts with a thorough evaluation, not a guess based on symptoms alone.

Dr. Steven J. Thornton, MD, is a board-certified orthopedic surgeon and fellowship-trained sports medicine specialist at Texas Orthopaedic Associates, seeing patients at convenient locations across Dallas and North Texas. His practice includes femoroacetabular impingement evaluation and hip arthroscopy for patients throughout the DFW metroplex.

To schedule a consultation, contact the office or call (214) 265-3271.

Steven J. Thornton, MD

Dr. Steven J. Thornton, MD, is a board-certified orthopedic surgeon and fellowship-trained sports medicine specialist who founded his Dallas practice in 2004 and is part of Texas Orthopaedic Associates. He completed his medical education at the University of Mississippi School of Medicine, his residency at UT Southwestern Medical Center, and his fellowship at Cornell University’s Hospital for Special Surgery. Dr. Thornton treats shoulder, knee, hip, and elbow conditions with a focus on arthroscopic and minimally invasive surgical techniques.