Member Case Study: Femoral Acetabular Impingement (FAI)

author : AMSSM
comments : 2

Question from obakesan82

Ok gang, here is a case for you:

46 year old 195lb male with significant right hip pain and a provisional diagnosis of Femoral Acetabular Impingement (FAI).

Medical History:

I had an athletic background throughout my youth and early adulthood in multiple sports to include: football, crew, martial arts, swimming, and cycling. Workouts continued on an intermittent basis throughout adult life in the military (had to be able to pass a 2 mile run at least twice per year). Right ankle Arthroscopic debridement due to osteoarthritis 20 years ago with no residual symptoms. Right foot has a long history of significant pronation which is managed with motion control running shoes (Brooks Beast). Prior history of plantar fasciitis in right foot which is resolved. No prior history of hip/pelvic area pain other than occasional pulls/strains in my youth and my martial arts days.

Training/Injury History:

I started crosstraining approximately 16 weeks ago using the 3 workouts per week per sport training plan that was slightly modified for upcoming sprint triathlon races. Ran primarily on treadmill to reduce wear and tear on body since I am relatively heavy and had a prior history of ankle/foot problems. Training program went fine with no training increases beyond 10% per week. Ran/Walked 1st 5k on 09 Feb (week 7) with no problems. Ran/Walked 2nd 5k on 23 Feb (week 9) and noticed mild right anterior hip pain upon foot strike. Thought the pain was due to a pulled adductor so I iced it, used NSAIDs and kept training.


I stopped running on 11 Mar (week 12) due to hip pain which was now present when walking. Cycling seemed to have no negative (or positive) effect on the injury so I maintained cycling. Transitioned to deep water running with a float to continue training (Docs thought I might have iliopsoas syndrome). Noticed some pain (a dull ache) in posterior of hip and increased stretching exercises (Docs thought piriformis might be an issue). Found stretching helped the posterior hip pain but did nothing for the anterior hip pain.

Tested running on an indoor track for 30 meters on 04 April (3 weeks water training) and had immediate anterior hip pain upon heel strike so no load water running had no effect. X-rays showed no severe abnormalities or arthritis but the Radiologist recommended evaluation for Femoral Acetabular Impingement (FAI) with possible labral tear. Physical Therapist concurred and I am now having to wait a month for the MRI to be complete.


Docs have informed me if this is confirmed the only option is hip arthroscopy or open hip surgery as this will not heal by itself. Docs said I will be on crutches for approximately 4 weeks with the arthroscopy and 8 weeks with open hip surgery both followed by 2 months of rehab. Since I’ve never had hip issues before this is a bit of bad news.

Here are the questions:

1. Can I still cycle or spin on a stationary bike? Docs were equivocal on that as it still moves the joint. Said if it hurts then don’t do it. I’d really like to continue but don’t want to do more damage either.

2. What exercises other than swimming and lifting weights can I still do to try and minimize the downtime? Yoga? Kicking in the Pool?

3. Is surgery really the only option? What percentage of active patients have positive outcomes? Negative outcomes?

4. How soon can I start training after surgery? What can I do? What about walking the run portion of a race? Can you use crutches on the "run" part of the race?

5.Are there specific stretching exercises I should add to minimize injury to this area again?

I realize that by the time the answers arrive I will probably be further into my treatment but it is quite possible the surgery would not happen until early June and I am really going to be focused on rehab as I don’t want this to kill the entire season. I thought I might not be the only one out there who has managed to do this to themselves.

Thanks much for the help!

Answer by Michael D. Milligan, MD

Member AMSSM

Your history of anterior and posterior hip pain with foot strike and walking while training for a triathlon raises concern for a few diagnoses. In addition to iliopsoas syndrome, piriformis syndrome, femoral acetabular impingement (FAI), and hip labrum tear, stress fractures of the femoral neck or pelvis and degenerative changes of the hip joint must be considered in the differential.

With the seemingly progressive symptoms and appropriate relative rest you have undertaken, it certainly seems appropriate to proceed expeditiously with an MRI of the hip and pelvis. I would recommend a MRI with dye injected into the joint (an arthrogram). Fortunately, each of these entities can be assessed with appropriate imaging technique and attention to each of these areas when reviewing the MRI images.

Among the differential diagnoses the most concerning is a stress fracture of the femoral neck. Femoral neck stress fractures have a risk of progressing to complete hip fractures. Depending on location, these are routinely managed with either limited weight bearing or surgery. Unfortunately, all stress fractures cannot be assessed on routine x-rays.

Based on the above information, I will try to answer your questions the best I can.

Allowed current activities


Decisions about how much activity is allowable with an injury are very physician-dependent and must take into account the risk, particularly when the diagnosis is still in question. In your case, until the MRI results are known I believe you must listen to your body and avoid all activities that cause pain. I believe it would be prudent to consider placing you on crutches until the results are known due to the possibility of a stress fracture. Stationary or spin bikes seated at an easy to moderate pace and swimming would may be reasonable assuming no pain. I would recommend avoiding standing cycling, spin classes, and weight bearing exercises including weightlifting and yoga.

If your MRI rules out a stress fracture and demonstrates findings compatible with FAI, a labral tear of the hip, and/or degenerative changes of the hip then I would generally suggest “activities as tolerated.” At age 46 with a lifelong active lifestyle it is highly likely that some level of degenerative (wear and tear) changes of the hip will exist, including labral tears, cartilage damage, and osteophyte formation. Additionally, we must consider that a study out of Vail, CO demonstrated concomitant labral tears in 99% of patients with FAI and cartilage damage of the hip in 82%.

How is your problem managed if FAI is diagnosed?

First, we must have a basic understanding of the diagnosis. FAI is a relatively new diagnosis in the medical literature. The current concept is that this is a disorder that occurs at the contact points of the ball and socket that is your hip joint. A lack of adequate space for motion of the femur within the acetabular socket causes impingement of the neck of the femur onto the cartilage surface of the rim of the acetabulum with hip flexion and internal rotation leading to cartilage damage and breakdown, including labral tears. This leads to pain, inflammation, and may be a precursor to hip arthritis.


Three Types of FAI


Currently, three types of FAI are recognized: cam, pincer, and combined. Briefly, cam-type refers to a bump on the rounded head of the femur that pinches onto the rim of the acetabulum socket. Pincer-type occurs when the acetabular socket, for any of a variety of reasons, covers the femoral head more than it should, limiting space and causing impingement of the femur onto the acetabulum. Combined FAI occurs when a patient exhibits both entities as a cause of their symptoms.


FAI Diagnosis

Diagnosis of FAI relies on appropriate clinical suspicion correlated with patient history, physical exam findings, and imaging results. Patient history generally includes pain in the groin, lateral hip, buttock, and/or sacroiliac joint. Stiffness, weakness, clicking or snapping, and feelings of instability may also occur. Limitation of activity is common. Examination generally demonstrates decreased hip flexion, decreased internal and external rotation, and impingement pain with hip flexion and internal rotation.


Plain X-rays can often demonstrate the femoral bump seen in cam-type FAI and excessive coverage of the femoral head by the acetabulum seen in pincer-type FAI. Degenerative changes of the hip joint may be demonstrated on X-ray if progressed far enough. MRI arthrogram should clearly assess damage to the cartilage surface of the hip and the presence of labral tears.


FAI Management and Treatment

Once all of the pieces of the puzzle are put together and a diagnosis of FAI is made, management is based on your level of symptoms and how much it interferes with your life. Most research on management of FAI is related to open or arthroscopic surgical correction. There is little literature available on non-surgical interventions. That being said, I would suggest that if a diagnosis of FAI with or without labral tears or cartilage damage is made that a reasonable treatment consideration prior to surgery would be an injection of steroid into the hip joint under fluoroscopic guidance. This has been studied and shown to have benefit for those suffering from hip arthritis, in which cartilage damage and labral tears are also seen. Otherwise, surgery is the only current management option.


Open versus arthroscopic surgery depends on the surgeon’s skill, experience, and preference and the location and degree of pathology. Early studies demonstrate reasonably good success rates with both techniques, with arthroscopic techniques seeming to be gaining favor. Duration of time before you are allowed to bear weight post-operatively will depend predominately on whether labral repair and/or acetabular microfracture are necessary.

Though your enthusiasm for your sport is appreciated, a necessary part of being an athlete is understanding when you must rest and allow an injury to heal. If you do undergo surgery for FAI, then I would strongly encourage almost excessive prudence in following your surgeon’s advice on when to begin training again. Also, I would strongly discourage participating in the run/walk portion until your surgeon clears you to do it under your own power without the assistance of a crutch or cane.


Phillippon et al. Clinical presentation of femoracetabular impingement. Knee Surgery, Sports Traumatology, Arthroscopy 2007, May 12

Khanduja and Villar. The arthroscopic management of femoroacetabular impingement. Knee Surgery, Sports Traumatology, Arthroscopy (2007) 15:1035-1040

Manaster and Zakel. Imaging of femoral acetabular impingement syndrome. Clinics in Sports Medicine 25(2006) 635-657

Phillippon and Schenker. Arthroscopy for the treatment of femoroacetabular impingement in the athlete. Clinics in Sports Medicine 25(2006) 299-308

Michael D. Milligan, MD
University of Nevada School of Medicine – Las Vegas


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date: June 4, 2008



The American Medical Society for Sports Medicine (AMSSM) was formed in 1991 to fill a void that has existed in sports medicine from its earliest beginnings. The founders most recognized and expert sports medicine specialists realized that while there are several physician organizations which support sports medicine, there has not been a forum specific for primary care non-surgical sports medicine physicians.




The American Medical Society for Sports Medicine (AMSSM) was formed in 1991 to fill a void that has existed in sports medicine from its earliest beginnings. The founders most recognized and expert sports medicine specialists realized that while there are several physician organizations which support sports medicine, there has not been a forum specific for primary care non-surgical sports medicine physicians.


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