Femoroacetabular impingement (FAI) is a hip condition caused by a mechanical mismatch between the femoral head and acetabulum. There are three types of FAI - cam, pincer, and mixed - which describe deformities of the femoral head or acetabulum that can cause pain and restricted movement. FAI is typically diagnosed based on symptoms like groin pain worsened by activity, and imaging tests may confirm deformities. Treatment starts with rest, modifications to activity, and physical therapy, while surgery can reshape bone structures for severe cases or when other options provide no relief.

1. What​ ​is​ ​Femoroacetabular
Impingement?
Femoroacetabular Impingement (FAI)​ is a hip condition which
describes a mechanicalmismatch between the hip "ball" and the
"socket".
There are three described types of femoroacetabular impingement:
Cam Type FAI
'Cam' type femoroacetabular impingement​ describes a 'bump' on the
surface of the femoralhead (ball) which jams on the rim of the
(acetabulum) socket. This typically affects youngathletic men.
Pincer Type FAI
'Pincer' type femoroacetabular impingement​ describes an increased
coverage by theacetabulum over the anterior femoral head. This typically
affects middle aged women and isless common.
Mixed Type FAI
Often there can be a combination of both cam and pincer types, which is
termed

2. What Causes Femoroacetabular Impingement?
It is believed that many normal people have 'bumps' or slightly over-deep
sockets andcould potentially develop femoroacetabular impingement--
this is just the way we are builtand develop.
The result of these deformities is increased friction between the
acetabular socket andfemoral head, which may result in pain and
decreased range of motion.
However, the hip has to also be provoked in some way to cause
damage. This explains thetendency for athletes, sporting professionals
and active people to be more susceptible tothis form of injury.
Symptoms of Femoroacetabular Impingement?
● FAI often presents as hip and groin pain with restricted range of
hip motion.
● Symptom onset can be acute, following injury, or insidious after
prolonged exertion.
● Pain is often provoked with prolonged sitting, walking, crossing the
legs as well asduring and after sport and exercise.
● There will typically be a restriction in hip flexion and internal
rotation range ofmotion.
● Pain is primarily felt deep in the groin at the front of the hip, more
rarely it can be onthe side of the hip or the buttock.
How is Femoroacetabular Impingement Diagnosed?
Physical examination involves a series of hip tests. Diagnosis is 90%
positive withreproduction of symptoms on the ​impingement test​--
flexion adduction and internal rotationof the hip.

3. When testing hip range of motion there may be restriction in hip flexion
and internalrotation. Provocation of pain by flexion abduction and
external rotation (​FABER test​) mayprovoke pain but is generally
non-specific.
Radiology Tests for FAI
Radiology investigations for femoroacetabular impingement can be
undertaken to confirm thediagnosis with AP X-rays of the pelvis and
lateral X-rays of the hips being the first lineof investigation.
Femoroacetabular Impingement Treatment
An initial trial of non-operative treatment is advocated for most patients,
as the pain isrelatively self-limiting.
Physiotherapy can assist FAI by using a variety of techniques to:
● mobilise the hip joint that stretch any tight structures eg joint
capsule or muscles
● improve soft tissue flexibility and length
● strengthen the deep, intermediate and superficial hip muscles
● progress hip muscle, proprioception, joint position sense and
functional control todynamically control your hip
Use of painkillers and anti-inflammatories may temporarily help the pain
reduce the localanti-inflammatory reaction.
Hip Surgery for Femoroacetabular Impingement?
If your symptoms continue to remain unchanged on return to sport, then
referral to anorthopaedic surgeon is recommended.
Surgical treatment for FAI is performed either by arthroscopic
debridement or can beperformed by open surgical debridement. While

4. the techniques are quite different, theoperations both aim to address the
mechanical and pathological changes around theneck/acetabulum
junction.
Post-FAI Hip Surgery Rehabilitation
A supervised hip rehabilitation program with your physiotherapist is an
essential part ofyour post-surgical FAI recovery.
Recovery from hip arthroscopy typically takes 3-4 months, while open
hip debridement istypically 12 months. Hip arthroscopy has been the
preferred method in recent years and hasreported excellent results with
80% of patients asymptomatic by 3-4 months and up to 95%having
improved symptoms by one year.
For more advice about femoroacetabular impingement, please ask your
physiotherapist ordoctor.
Hip Impingement Symptoms
You can have hip impingement for years and not know it, because it is
often not painful inits early stages.
When hip impingement causes symptoms, it may be referred to as hip
impingement syndrome.The main symptoms are stiffness in the groin or
front of the thigh and/or a loss of yourhip's full range of motion.
At first, you may only feel pain when you move the hip near its limits. As
the conditionprogresses, however, you may feel pain with more subtle
activities, such as sitting for along time or walking up a hill. Pain that
occurs at night or when walking on flat groundsuggests that the cartilage
cushioning the ball and socket has begun to break down andwear away,
a condition known as osteoarthritis.
Hip Impingement Causes
There are two main causes of hip impingement:
A deformity of the ball at the top of the femur (called cam impingement).
If the head isnot shaped normally, the abnormal part of the head can jam
in the socket when the hip isbent. This may occur during activities such
as riding a bicycle or tying your shoes.

5. A deformity of the socket (pincer impingement). If the front rim of the
socket (called theacetabulum) sticks out too far, the area of the thigh
bone (femur) just below the ball,called the neck of the femur, may bump
into the rim of the socket during normal hipflexion movement.
In some cases, there is a problem with both the ball and the socket.
Other problems thatcan cause hip impingement include conditions such
as:
● Legg-Calve-Perthes disease, a disease in which the ball part of the
hip joint doesn't getenough blood, which causes the bone to die.
● Slipped capital femoral epiphysis, a separation of the ball from the
thigh bone at theupper growing end (growth plate) of the bone in
adolescents. It is more common in childrenwho are obese.
● Coxa vara, an unusual condition in which the thigh bone and ball
do not grow at the samepace in children. This discrepancy leads to
deformity of the hip joint.
Hip Impingement Tests and Diagnosis
If you have symptoms of hip impingement, your doctor can diagnose the
problem based onyour description of your symptoms, a physical exam,
and the findings of imaging tests.These tests may include one or more of
the following:
● X-ray, a test that produces images of internal structures on film.
X-rays can showirregularities in the shape of the ball or top of the
thigh bone or excess bone around therim of the socket.
● Magnetic resonance imaging (MRI), a procedure that uses large
magnets, radio waves, and acomputer to produce detailed pictures
of tissues inside the body. An MRI can show frayingor tears of the
cartilage, including that which runs along rim of the socket
(labrum).
● CT scan, a technique that combines special X-ray equipment with
sophisticated computers toproduce multiple images or pictures of
the inside of the body. These images can beexamined on a
computer, printed, or transferred to a CD. A CT or MRI scan can
help adoctor decide whether you need surgery.

6. Hip Impingement Treatments
Treatment for hip impingement should begin with:
● Resting the affected hip
● Modifying your activities to avoid moving the joint in a way that
causes pain
● Exercising as recommended by your doctor or physical therapist to
strengthen the musclesthat support the hip
● Taking anti-inflammatory and pain medications
If these treatments do not relieve pain, your doctor may recommend hip
impingementsurgery.
The type of surgery needed will depend on the problem causing hip
impingement and how muchcartilage damage has occurred.
If the affected hip does not have too much cartilage damage, the
surgeon may use tools toreshape the ball and/or the outside edge of the
socket that is catching on the thigh bone.In a technique called
microfracture, the surgeon may also cut away the frayed cartilagethat is
causing pain or drill holes into patches of bone where cartilage has worn
away inorder to stimulate cartilage growth. Microfracture is being used
less frequently.
Often, surgery for hip impingement can be performed arthroscopically.
This techniqueinvolves inserting a lighted scope and thin tools through
small incisions over your hipinstead of making a large incision.
Arthroscopy is usually an outpatient surgery. Thismeans you can go
home the same day.
The earlier you have surgery, the greater your chances of a complete
recovery. But even ifcartilage has been damaged, surgery may still
reduce pain and improve range of motion.
If cartilage damage is severe, however, hip replacement may be the only
treatment thatwill relieve pain and improve function.
However, there are promising treatments, including one in which parts of
your own bloodare injected into joints to stimulate cartilage growth.

7. What Kind of Physical Therapist Do I Need?
All physical therapists are prepared through education and experience to
treat patientswho have hip impingement. You may want to consider:
● A physical therapist who is experienced in treating people with
musculoskeletal problems.Some physical therapists have a
practice with a sports or orthopaedic focus.
● A physical therapist who is a board-certified clinical specialist or
who completed aresidency or fellowship in sports or orthopaedic
physical therapy. This therapist hasadvanced knowledge,
experience, and skills that may apply to your condition.
You can find physical therapists who have these and other credentials
by using Find a PT,the online tool built by the American Physical
Therapy Association to help you search forphysical therapists with
specific clinical expertise in your geographic area.
General tips when you're looking for a physical therapist (or any other
health careprovider):.
● Get recommendations from family and friends or from other health
care providers.
● When you contact a physical therapy clinic for an appointment, ask
about the physicaltherapists' experience in helping people with hip
impingement.
● During your first visit with the physical therapist, be prepared to
describe your symptomsin as much detail as possible, and say
what makes your symptoms worse.

8. https://nydnrehab.com/what-we-treat/hip-pain/fai/