FAI Femoroacetabular Impingement | Hip Impingement
Flawless Physio Logo

FAI Femoroacetabular Impingement

James McCormack
Follow Me
Latest posts by James McCormack (see all)

What is FAI hip?

FAI, or femoroacetabular impingement, is a condition or syndrome that is a common cause of hip pain. The hip is a ball and socket joint, the femoral head and the acetabulum. Impingement of the hip joint can occur when the shape of the ball or socket (or both) causes a pinch in certain positions.

There is normal variation between our skeletons, and different shapes (morphologies) of the femoroacetabular joint are common. If there is additional bone on the femoral head, it can be less round and more oval or can have a wider neck, this can be called a Cam morphology.

If the acetabulum has extra bone, making it too deep or the opening too narrow, this is called a Pincer morphology. Femoroacetabular impingement syndrome can be caused by a Cam or Pincer morphology or a combination of both. 

How common is femoroacetabular impingement?

The painful condition of FAI affects 10-15% of the population, with most symptoms being experienced by patients between 20-40 years old. The sports most associated with this condition are ice hockey, soccer, ballet, dance and gymnastics, rowing and golf (Casta, 2015). Martial arts also have a high prevalence (Lee et al, 2016).

Picture of a person holding a painful hip

Symptoms

One of the main symptoms of FAI (femoroacetabular impingement) is C-sign hip pain. This is the description of pain where the patient places the thumb and index finger in a C shape around the side of the hip. The C sign is a recognised diagnostic sign.

Other symptoms include worsening pain with activity or prolonged sitting, a limp when walking or running, and stiffness of the joint. There is a common pattern of pain felt at the end of the range of hip movement into flexion, adduction and internal rotation.

Occasionally the patient may feel reduced balance or unstable on one leg, and it is fairly common for there to be a palpable and/or audible click or pop.

Diagnosis

Femoroacetabular Impingement can be diagnosed clinically by a sports doctor or physical therapist through a series of clinical tests. These clinical tests include moving the hip through a full range of movements and noting when pain is felt.

Pain with the combined movement of flexion, adduction and internal rotation of the hip is common with FAI affecting the front of the joint. This test is called a FADDIR test, “F” for flexion, “ADD” for adduction and “IR” for internal rotation.

For posterior hip impingement, a FABER test can be performed, “F” for flexion, “ABD” for abduction and “ER” for external rotation.

Picture of FAI hip assessment

While these tests provide some information about irritation in the joint, they are not specific to diagnose FAI when used on their own. Clinicians will use a cluster of different tests to improve the accuracy of their diagnosis. Further confirmation can come from diagnostic imaging such as an X-ray or MRI to show a particular hip morphology relevant to their symptoms.

Best Strengthening Exercises for FAI of the Hip

FAI hip exercises should follow an assessment and should be targeted at improving your weaknesses. Below are a few common strengthening exercises for femoroacetabular impingement that target muscles often weak with this diagnosis.

  • Single Leg Bridge
  • Resisted Hip Abduction
  • Resisted Side Steps 
  • Resisted Hip Flexion
  • Core Strengthening

Single Leg Bridge

This exercise has many variations, so if a single leg is too hard, you can try a double leg or a marching version. For this version, lift one leg off the floor and keep your knee bent to 90º for the leg on the floor.

Lift your pelvis off the floor by squeezing your glutes and feeling your hamstrings working at the back of your thigh.

Repeat 3 sets to fatigue, aiming for about 12 repetitions.

A weight can be added to your hip to make this more challenging.

Picture of James McCormack doing a Single leg bridge

Resisted Hip Abduction

Lie on your side with a resistance band tied around your ankles. Keep your lower leg bent for stability and your body rolled forward to feel your glute work as you lift your upper leg against the resistance band.

Repeat 3 sets to fatigue, aiming for about 12 repetitions.

You can increase the resistance of the band to make this more challenging.

Picture of James McCormack doing a Side Lying Hip Abduction with a Band exercise

Resisted Side Steps

Tie a band around your thighs and lower into a shallow squat while keeping your upper body upright. Step sideways in alternating directions pushing your knees and thighs out into the band.

Repeat 3 sets to fatigue, aiming for about 12 repetitions.

You can increase the resistance of the band to make this more challenging.

Picture of James McCormack doing a resisted side step exercise

Resisted Hip Flexion

Stand on a resistance band with one end tied around your ankle. Keeping an upright and straight body, slowly lift your knee up to 90º, and slowly lower to the start position.

Repeat 3 sets to fatigue, aiming for about 12 repetitions.

A weight can be added to your hip to make this more challenging.

Picture of James McCormack doing a Resisted Hip flexion exercise

Core Strengthening

Lie on your back with your arms up in the air and back pushed down to the floor with a flattened tummy. Lift one leg off the floor at a time, then alternate stretching one leg away from your body.

Repeat 3 sets to fatigue, aiming for 6 repetitions on each leg.

You can alternately stretch the opposite arm with a leg to make this more challenging.

Picture of James McCormack performing a core exercise for a hip labral tear

FAI Hip Stretching Exercises

FAI hip exercises should include stretches and mobility to improve the flexibility of the hip joint. Below are some stretches for muscles that are often muscles with the condition of femoroacetabular impingement.

Hip Flexor Stretch

Kneel on the floor with one leg and step the other leg through. Keep an upright body and tilt your pelvis backwards to flatten your lower back. Shift forwards to feel an increase in tightness at the front of your hip.

Hold for 45 seconds, and you can repeat this 2-3 times daily. 

Picture of James McCormack doing a hip flexor stretch

Adductor Stretch

Stand with your feet wide apart. Take your weight over to one leg, allowing that knee to bend. Keep the other knee straight and feel the stretch increase inside your thigh.

Hold for 45 seconds, and you can repeat this 2-3 times per day. 

Picture of a man doing an adductor stretch

Quadriceps Stretch

Stand on one leg and bend your other knee; reach to hold this leg by the ankle. Push your hip forwards and knee backwards as you take your ankle towards your bottom.

Hold for 45 seconds, and you can repeat this 2-3 times daily. 

Picture of James McCormack doing a Quadriceps stretch

Related Articles:

Hip Labral TearOuter Hip PainHip Pain Chart

_______________________________________

We are specialists in Physiotherapy, with our clinic in Fulham, South West London.

We offer Online Appointments for £70 and Face-to-Face appointments for £90 in our clinics.

Feel Good, Move Well, Be Better.

020 8785 2232Book Online Email