The Association of

Femoral Neck Stress

Fractures w/ FAI

Stanford University

Femoral Neck Stress Fx Tension Side

Compression Side

Complete

Cause Unknown

Training Changes

Common in

Runners & Military

Recruits

Femoral Neck Stress Fx Several Athletes

With Femoral

Neck Stress

Fractures

Referred To

Senior Clinician

FAI Treatment

Is There An

Association??

Methods 22 Females

3 Males

Age 19 – 39 y/o

Avg 26 y/o

Charts Reviewed

Sporting Activities

Purported Causes

Treatment

Stress Fracture

Hip Arthroscopy

Methods Imaging Reviewed

Plain Radiographs

MRI

MSK Radiologist

Orthopaedic

Surgeon

PM&R Resident

Orthopaedic Sports

Medicine Fellow

Imaging Reviewed: Fracture

Location of Injury

Type of Stress Injury

FAI

Crossing Sign;

Retroversion; Profunda

Abnormal Fem HN Jxn

FN Fibrocystic Change

Os Acetabulae

Labral &/or Chondral Injury

Alpha Angle; Offset Ratios

Center Edge Angle

Results 18 Right Hips

7 Left

9 Grade 2 Injuries

Marrow Edema on T2

5 Grade 3 Injuries

High T2, Low T1 Signal

11 Grade 4 Injuries - Fracture

Labral Tears: 14

(56%)

Chondral

Damage: 3 (12%)

Fibrocystic

Change: 2 (8%)

Os Acetabulae: 2

(8%)

Results – FAI Findings Abnormal Fem H-N Jxn – XR: 16%

Abnormal Fem H-N Jxn – MR: 20%

Fibrocystic Change on MRI: 8%

Ant Offset Ratio <0.18: 28%

Alpha Angle > 50: 16%

Floor of Acet to I-I Line: 79%

Profunda: 28%

Crossing Sign: 42%

C-E Angle > 350:20%; > 400:12%

Any Pincer: 66%

Pincer

Findings

Cam

Findings

Surgery 4 Femoral Neck

Stress Fractures

Treated with

Surgery

3 Pinning

1 DHS

5 Patients Had

Surgery For FAI

22 mo Follow up

For Those w/

Surgery

12 months for

Non-op Pts

Conclusion Prevalence of

Pincer FAI

Greater in Patients

with Femoral Neck

Stress Fracture

Than General

Population

Possible Mechanism of

Fem Neck Stress Fx Leverage of the Femoral

Neck On Acetabular Rim

Medial Tensile Forces

Thank You