What is FAI? FAI is a common hip deformity

‫תשע"ו‬/‫אלול‬/'‫ז‬
Cam – definition
•
A rotating or sliding piece in a mechanical
linkage used especially in transforming
rotary motion into linear motion or vice
versa
Ehud Rath MD
The unit for minimally invasive orthopedic surgery
Orthopedic division, Tel Aviv Souraski medical center
Sackler faculty of medicine, Tel Aviv University, Israel
FAI is a common hip deformity

24% - 67% in asymptomatic athletes

Flexion internal rotation increase the risk for labral
impingement and hip injury

Impingement test
OA of the hip was believed to be the result of an intrinsic
abnormality of articular cartilage or of an eccentric
overload
Radiographic Abnormalities Common in Senior
Athletes With Well-functioning Hips but Not
Associated With Osteoarthritis Anderson et al 2015

83% FAI, 67% Cam type

An increased risk of FAI in athletes participated in
competitive sports during early adult years

Lifetime participation in competitive sports were at
an increased risk of OA
1
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‫תשע"ו‬/‫אלול‬/'‫ז‬
Etiology of Cam morphology

Idiopathic, male>female (X4)

Slipped capital femoral epiphysis

Legg–Calve–Perthes disease

Congenital or acquired coxa vara

High-impact sports participation during growth

A result of structural adaptation to high-impact
Adolescent Femoroacetabular Impingement:
Gender Differences in Hip Morphology Hooper et al, 2016

More significant intra-articular disease

more labral damage and more advanced cartilage
changes

possible causal relation between physeal injury and cam
deformity (Carter et al)
sporting activities during growth?
Agricola R, et al. A cam deformity is gradually acquired during skeletal maturation in
adolescent and young male soccer players: a prospective study with minimum 2-year followup. Am J Sports Med 2014;42: .806– 798
Carter et al. The relationship between cam lesion and physis in the
skeletally immature patients. J Pediatr Orthop 2014;34: .579-584
Evaluation
Cam type FAI

History

Physical examination

Radiographs
Pistol grip deformity Solomon, Haris 1984, 1986
Anatomic levels

Standing

Supine

Lateral

Prone

 Capsule
Hal D Martin, physical examination of the hip youtube.com
2
Bones – Impingement, IOH, AVN
– tightness, instability

Muscles – Snapping, rupture, tendenitis

Neurovascular – Neurologic,
Piriformis, Miralgia
‫תשע"ו‬/‫אלול‬/'‫ז‬
Imaging studies
Specific examination tests

FADDIR – anterior impingement test

Lateral center edge angle

Toennis angle

Alpha angle 35-500

Head neck offset

Crossover sign

Ischial spine sign

Protrusio acetabuli

Coxa profunda
Cam – radiography
Anterosuperior femoral head-neck junction
•
Alpha angle > 55 (cross-table lateral view or
Dunn view on plain radiographs)
•
Head-neck offset index < 0.15
Cross-table axial
3
‫תשע"ו‬/‫אלול‬/'‫ז‬
Head-neck offset index < 0.15
CT

Accuracy in characterizing proximal
femoral morphology

Femoral version, , neck–shaft angles

Characterization of cam morphology

Acetabular morphology – version, AIIS
Treatment
MRI arthrogram

Conservative: modification of activity, PT,
NSAIDS

Surgery: Femoral osteochondroplasty to a
sufficient head–neck offset

Labral tear
4
Anterior migration of the
femoral head into the
cartilage defect
Ideal patient: young athletic, cam deformity,
joint space > 3mm, normal CE, ACE, normal
femoral and acetabular version
‫תשע"ו‬/‫אלול‬/'‫ז‬
Arthroscopic cam resection

Central first than release traction – 300 flex

Visualization of the periphery

Define Cam borders

Define head – neck junction

Adequate osteoplasty, complete lateral - ext

Dynamic exam

Repair capsule ?
Under-Correction and OverResection




5
Over-resection - cortical notching or femoral neck
fracture
4 - 6mm cortical notching depths resulted in
significant load to failure
> 30% resection significantly decreased the amount
of energy required to produce a fracture
Use intraoperative fluoroscopy to control resection
depth
‫תשע"ו‬/‫אלול‬/'‫ז‬
Avascular Necrosis of
Femoral Head


Distraction, partial capsulectomy, and insult to the
lateral epiphyseal branch of the medial femoral
circumflex artery

Crutches 2 weeks – WBAT

PT – motion motion motion
The lateral
synovial fold

HO prophylaxis COX2
Summary

Preop planning

Use intraoperative fluoroscopy

Dynamic assessment for residual
impingement
6
Postop

Avoid lateral synovial fold

Repair the capsule

Cox 2 inhibitors 2 w for HO prophylaxis
inhibitors 2 weeks
Thank you for your attention