Femoroacetabular Impingement (FAI)

Femoroacetabular Impingement (FAI) Overview

The hip joint consists of a perfectly round ball (the femoral head) that inserts into a perfectly round socket or cup (the acetabulum). Both surfaces are coated with hyaline cartilage, a firm slippery material that is bonded to both bones and reduces friction to almost nothing.

These joint surfaces are held together by a tough fibrous material called a capsule. This capsule inserts into the hip socket and contains the labrum, which is an extension of the acetabular rim (the cup). This labrum extends the depth of the hip socket and prevents the capsule from intruding into the joint.

Development of FAI

The femoral head and acetabulum are both designed to grow when we are young. This means there are growth plates present on both sides of this joint. These growth plates can displace or partially slip when developing in the growing adolescent. When the slip is substantial (called a slipped femoral capital epiphysis or SCFE) the slip becomes painful and will be addressed by a physician as the child will complain of hip pain and have great difficulty to walk.

Partial slips however may not be symptomatic but will leave the femoral head or the acetabulum “out of round”. The small “hump” remaining on the femoral head or the acetabulum due to the slip may not cause symptoms until much later in life.

When the hip is brought into certain positions, femoroacetabular impingement will occur between this boney bump and the labrum causing erosion of cartilage and a possible tearing or degeneration of the labrum.

The two different impingement types are cam and pincer mechanisms. If excess bone forms around the hip ball, it is called a cam impingement. If the impingement occurs from an overgrowth of the acetabulum (socket), it is called a pincer type.

Certain sports can induce labral degeneration. Sports that require significant hip rotation are commonly associated with labral tears. These include golf, tennis, soccer, wrestling, track events, ice hockey and ballet.

This activity causes onset of the symptoms and can lead to further erosion and eventual arthritis (wearing of the cartilage surface of the ball and socket).

(Click to Enlarge)

(Click to Enlarge) A-Normal hip (ball of femur is on the left and cup of acetabulum is on the right) B-Cam type impingement (stippled area is extra bone in the front of the ball) C-Pincer type impingement (stippled area is extra bone in the front of the socket) D-Combination of can and pincer impingement

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(Please keep reading below for more information on this condition.)

Symptoms of Femoroacetabular Impingement

The majority of pain is found within the hip joint. This is the area around the front of the groin. The pain will typically be felt as a “deep” ache. Many patients will demonstrate their pain by grabbing their hip using their hand as a “c” (index finger in front and thumb in back towards the buttocks in the shape of a “c”- the C sign).

Pain can radiate to the side of the hip or even the sacroiliac joint region and can mimic lower back pain. I have seen an occasional patient presenting with pain that radiates below the knee mimicking a radiculopathy (nerve pain).

A catching or clicking sensation can occur if there is a labral tear. The catch may occur when the patient rises from a chair or exits/enters a car. Climbing or descending stairs can also cause this pain and “catching” sensation.

Sports that require frequent change of direction can cause the same pain. Getting on and off a bicycle will do this and squatting can also cause the catch or sharp momentary pain.

Eventually, prolonged sitting can cause symptoms to occur. Patients may complain of a “stiff” hip joint.

Differential Diagnosis

Where confusion can occur is with the differential diagnosis of spinal disorders that cause similar pain as femoroacetabular impingement and labral tears. That is, determining which disorder really exists so the correct treatment can be instituted.

Referral pain to the hip can occur with nerve compression of L1 through L3 and even occasionally L4. Referral pain from the L4-5 disc can cause occasional hip and groin pain.

In turn, the labral tear can refer pain to the back of the pelvis and even refer down the front of the leg below the knee (rare).

Typically, hip symptoms occur with walking, crossing over the legs, climbing and descending stairs, getting in and out of a car and on-off a bicycle. Spine symptoms occur with stretching the nerve root (from a disc herniation) or are reproduced from standing and walking. As you can see, there are overlap symptoms that are shared between hip and spine disorders.

The easiest way to differentiate between these two disorders is with an anesthetic block of the hip joint. This numbs the joint and any structures inside it temporarily. Injection of this joint is now relatively easy with ultrasound guidance and can be performed in the office. If the hip joint injection relieves symptoms for 2-3 hours, the diagnosis of hip joint disorder is normally confirmed. Hip joint injection will typically not relieve pain generated from the disc or nerve.

For additional information on femoroacetabular impingement (FAI) and its association with lower back pain, please contact the Vail, Aspen, Denver and Grand Junction, Colorado area office of back doctor and spine specialist Dr. Donald Corenman.

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Donald Corenman, MD, DC

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81 reviews

Eric S

Sep 26, 2021

by Eric S on Donald Corenman, MD, DC

Successful pars repair at 46 years old

Back in November of 2018 (at 46 years old) I came from Vancouver BC to have a pars repair done with Dr. Donald Corenman at the Steadman Clinic in Vail Colorado. I'm finally posting this review nearly three years later in late 2021. The reason I waited so long was I wanted to know the final result before I posted my review. Unfortunately in that time Dr. Corenman has retired. Nevertheless, I want to post this review of Dr. Corenman and his staff at the Steadman Clinic in their excellent treatment of my L5 pars interarticularis.

I fractured my pars at age 42 back in 2014 when rolling on the gym floor, and was denied treatment by the Canadian healthcare system, probably due to my age. First my GP told me there was no surgical option for a pars defect, which was quite incorrect! I tried to live with it, but the symptoms worsened (periodic random spine slippage and weeks of resultant pain after just bending over to tie my shoe, so I eventually learned to mostly squat and hardly bend). When I finally consulted with Canadian spine surgeons, I was told they believed my pars defect had been congenital (since birth). This was absurd, considering I had done extreme martial arts (including jiu jitsu) for years prior, as well as 5 years of reinforcing steel full time in my 20s, probably the hardest job on the back you can find. No pars defect like mine would possibly have allowed this--ergo it was impossible that I had had the defect since birth. I did however have an asymptomatic congenital spina bifida occulta that made me more susceptible to a pars fracture. In 2014 in one instant, I went from having the strongest back people I knew said they'd ever seen, to being unable to safely bend over and tie my shoe without a non-negligible risk of my spine slipping randomly (which would lead to weeks of pain after each occurrence). This was due to the unilateral L5 pars defect, otherwise known as spondylolysis. It was when lying in pain on the floor 4 years later after maybe the 6th spine slippage event post injury, that I had had enough, and resolved to have surgery. If Canada's "universal health care" said no, I would make lemonade from lemons, and find the very best surgeon in the world at pars repairs. That was Dr. Donald Corenman. Dr. Corenman back in 2018 ran a website https://neckandback.com/ that dedicated many pages to the science of every aspect of pars repairs, from eligibility (good discs on MRI), to best surgical techniques (minimal open compared to minimally invasive), best imaging to use (i.e., O-Arm with Stealth imaging vs. older fluoroscopy), the ideal amount of BMP to use and why not use too much or too little, and much more, all to do with pars repairs, pages upon pages of his site just on the pars, with scientific references and his own extensive expert opinion. As a health research statistician, I was very impressed with this. It was in stark contrast to the websites of other spine surgeons which barely gave the pars a word or two, focusing almost exclusively on fusions. I had found the best surgeon in the world for pars repairs, and so after Dr. Corenman personally screened my MRI to ensure my discs were healthy, I booked the surgery.

Being 46 years old at the time of surgery in 2018, with a 4-year-old pars fracture from 2014 combined with a congenital SBO meant my pars fragment was somewhat atrophied, but it was "very solid", said Dr. Corenman in the operative report. Nevertheless, it was challenging with two things to fix, the pars and SBO, and OR time was around 4 hours. Recovery over the following months was guided by a very clear "Spine binder" from the Steadman Clinic with strict rules of "no BLT" (no bending, lifting or twisting), and illustrated physiotherapy guidelines. They even warned patients to avoid fish oil supplements, which could excessively dampen inflammation and hence slow bone healing. They answered many questions I had during months of recovery, with responses coming from the very supportive Lori Fugate (then director of Dr. Corenman's practice), and Ehrich Bean (then physician's assistant at the practice), as well as a couple calls with Dr. Corenman himself after two of the CT scans. Ehrich Bean offered great advice for taking the spine binder conservatively due to the nature of pars repairs vs. fusions. The final post-op CT scan I had was a couple weeks ago at 34 months post-op, and Dr. Corenman had retired, but I got a very positive and informative call from Eric Strauch (current PA at the Steadman Clinic under Dr. Corenman's replacement there, and who had also worked with Dr. Corenman previously). The staff at the Steadman Clinic were extremely supportive all the way through the process. I should mention, the local Canadian spine surgeon did offer me very good post-operative support including antibiotics as needed to deal with a mild surface incision-site infection early on, booking numerous x-rays when I felt something was amiss, as well as booking all four of my post-op CT scans. I am very grateful for that support also.

My final result shows plenty of solid bone across the pars and a healed SBO, with my vertebral body now a solid bone ring instead of being broken at two places as it was pre-op. Does my spine hold up in the real world? You bet! I have recently dug and moved several yards of dirt and sand and gravel by myself (shovel and wheelbarrow!) to fix our water main, pulled roots from the yard, moved several "portable" (these are HUGE) air conditioners up several flights of stairs my myself, and lifted weights. I now run 2 miles (3.2 KM) several times weekly with a hard 100 meter dash in the middle. I bend deeply before each run I go on, with no spine slippage. My spine feels amazing. I can bend over to do exercise, or real word tasks, with no risk of spine slippage.

My sincere thanks to God, Dr. Donald Corenman, Lori Fugate, Ehrich Bean, Eric Strauch, and the Steadman Clinic, as well as the Canadian spine surgeon who offered me excellent post-operative care back in Canada. You have all given me a new lease on life.

Sincerely,
Eric S

Robert S

May 11, 2021

by Robert S on Donald Corenman, MD, DC

Back Fusion Surgery

I had my entire lumbar spine fused in November of 2018. I had scoliosis , with pinched nerves that were so painful I could hardly walk - and standing for more than a few minutes was impossible. Even sitting was painful.
The fusion surgery produced immediate relief! And the recovery was much easier than I expected.
To this day I can do all the activities I love from hiking, to standing in a stream fly fishing to riding my bike long distances - or just walking down the street with my wife.
Kudos to Dr. Corenman and his staff, (including the two Erics) for taking such good care of me!

Leslie R

Jul 9, 2020

by Leslie R on Donald Corenman, MD, DC

TLIF

I had my TLIF surgery on 6/24/2020 by Dr. Corenman, I can not say enough good things about the Dr or his staff. I was always treated with respect and explained everything throughly, that made it easy for everyone to understand. I highly recommend Dr. Corenman and the Steadman Clinic.

Femoral Acetabular Impingement Syndrome (FAI) Hip Impingement Syndrome