This document discusses femoro-acetabular impingement (FAI), which occurs when there is reduced range of motion of the hip due to uneven surfaces of the femoral head or acetabulum. It can be caused by congenital or acquired factors. FAI is classified into cam, pincer, and mixed types. Cam FAI involves a bump on the femoral head-neck junction, while pincer FAI is due to overcoverage of the acetabulum. Clinical features include groin pain exacerbated by activity. Imaging can identify bone abnormalities, and treatments range from activity modification to surgical procedures like arthroscopy or osteotomy.

1. Femoro-acetabular
impingement ( FAI )
BY
DR.LOKESH SHAROFF
ORTHOPAEDIC SURGEON,MUMBAI,INDIA

2. SYNONYM
--CERVICO-ACETABULAR IMPINGEMENT,
--ACETABULAR RIM
SYNDROME

3. ABOUT
There is reduced range of motion of hip due to uneven surfaces of the
head of femur or acetabulum or both.

4. CAUSES
1> CONGENITAL
increased retroversion
2> ACQUIRED
-post traumatic -- #neck femur
-following femoral osteotomy
-perthes disease
-scfe

5. CLASSIFICATION
GANZ ET AL
3 TYPES
1> cam
2> spincer
3> mixed

6. CAM TYPE
--refers to an abnormal bony bump at the
head neck junction of the femur .
--This nonspherical portion is usually found
anterosuperiorly .
--This abnormal ‘bump’ or insufficient concavity of
the femoral head-neck junction decreases femoral
head-neck offset and causes impingement on the
acetabular labrum and articular cartilage with daily
activities.

7. CAM PATHOPHYSIOLOGY
• Cartilage is affected
delamination of articular cartilage
then labrum is displaced outwards and superiorly.

8. PINCER TYPE
Pincer impingement is an acetabular sided morphologic
abnormality characterized by over coverage of the femoral
head
The femoral head makes contact with the acetabulum due to
overcoverage

9. Pincer pathophysiology
Unlike cam type ,labral lesions occurs before the cartilage
lesions
labrum is crushed causing intrasubstance tears and
sometimes para labral cysts.
With time , articular cartilage is also damaged.
Healing of labrum forms an ossified rim which further
worsens the acetabular coverage.

10. PINCER SUBDIVISION
FOCAL – due to retroversion
GLOBAL – due to protruso acetabuli

11. CLINICAL FEATURES
-- active young adult (atheletes and ballet dancers)
-- slow growing groin pain
-- increased by prolonged walking or sitting
-- can be referred to the knee
--GAIT – antalgic
--ROM – flexion and internal rotation will be restricted

12. TESTS
-- ANTERIOR IMPINGEMENT TEST
-- POSTERIOR IMPINGEMENT TEST

13. IMAGING

14. IMAGING
ACETABULAR RETROVERSION ( FOR PINCER LESIONS)
1> CROSS OVER SIGN – MILD
MODERATE
SEVERE
2>POSTERIOR WALL SIGN

16. The posterior wall sign: Normally the center of the femoral head lies medial
to the posterior wall. When it lies lateral to the posterior wall, the posterior wall
sign is said to be positive and implies a retroverted acetabulum. The sign also
reflects how much posterior wall coverage exists

17. GLOBAL OVERCOVERAGE

18. IMAGING
FOR CAM LESIONS
--cross leg lateral view ,-- dunn view ,--modified dunn view
1– circle is drawn over femoral head which shows a smooth
contour .any lesion outside is a cam lesion.
2—ALPHA ANGLE – normal 42 , if > 50.5 diagnostic of a cam
lesion

21. CT SCAN / MRI
CT SCAN – 3D CT helps to identify exact size and location of
patholgy that helps in surgery
MRI SCAN – helps to find out soft tissue lesions like labral
tears , paralabral cysts, articular cartilage defects , cartilage
delamination, ossification of acetabular rim and loss of
sphericity of femoral head due to fibrocystic changes .

22. NON SURGICAL MANAGEMENT
--initial trial of conservative management includes
restriction of atheletic activities and Nsaids .
But sx rx is usually unsuccessful and operative rx is
preferred early.

23. Surgical treatment
INDICATIONS –
-- joint space narrowing of 1-2mm
-- extent of damage to acetabular labral chondral complex
--severe acetabular retroversion
--femoral head asymmetry
--high riding GT in cam impingement

24. SURGERIES
1– SURGICAL DISLOCATION AND TRIMMING OF CAM AND
PINCER LESIONS
2– CORRECTION BY ARTHROSCOPY
3– PERIACETABULAR OSTEOTOMY FOR FOCAL
OVERCOVERAGE
4– TOTAL HIP REPLACEMENT

25. SURGICAL DISLOCATION OF HIP
INDICATIONS –
-- cam type lesion
-- pincer type lesion
cam type lesion with 1mm of joint space reduction as this
approach would allow conversion to arthroplasty if needed.

26. ARTHROSCOPY
INDICATIONS
--Cam type lesion without proximal femoral deformity.
--isolated acetabular retroversion with or without cam type
deformity

27. LIMITATIONS OF ARTHROSCOPY
-- steep learning curve
-- injury to neuro-vascular structures from the entry portals
-- incomplete removal or
-- excessive removal of bone at the cam lesion leading to a
fracture

28. ARTHROSCOPY
CONSISTS OF 2 COMPONENTS
1– CENTRAL COMPARTMENT – which consists of labrum
and all parts medial to it
2– PERIPHERAL COMPARTMENT – which consists of parts
lateral to labrum but within the capsule and includes the
head neck junction

29. PERIACETABULAR OSTEOTOMY
INDICATIONS –
--acetabular retroversion with an associated posterior wall
sign
(cartilage in the antero-superior area must be intact)

30. THANK YOU