Drs. Carrie Bissell, Aaron Fox, and Kendrick Lim are Emergency Medicine Residents at Carolinas Medical Center and are interested in emergency medicine and medical education. With the guidance of Dr. Michael Gibbs, a notable Professor of Emergency Medicine and Dr. Laurence Kempton, an Orthopedic Surgeon, they aim to help augment our understanding of emergent imaging. Follow along with the EMGuideWire.com team as they post these educational, self-guided radiology slides that focus on Adult Orthopedic cases. This set will cover: - Hip Dislocations

1. Native Hip Dislocations
Carrie Bissell, MD1, Ainsley Bloomer, MD2,
Aaron Fox, MD1, Kendrick Lim, DO1, Andrew Rees, MD2
Departments of Emergency Medicine1 & Orthopedic Surgery2
Carolinas Medical Center & Levine Children’s Hospital
Michael Gibbs, MD1 and Laurence Kempton, MD2 - Editors
Adult Orthopedic Imaging Mastery Project
Presentation #2

2. Disclosures
▪ This ongoing imaging interpretation series is proudly sponsored by the
Emergency Medicine and Orthopaedic Surgery Residency Programs at
Carolinas Medical Center.
▪ The goal is to promote diagnostic imaging interpretation mastery.
▪ There is no personal health information [PHI] within, and all ages have
been changed to protect patient confidentiality.

3. Visit Our Website
www.EMGuidewire.com
For A Complete Archive Of Imaging Presentations And Much More!

4. It’s All About The Anatomy!

5. Hip Dislocations
Cases From Carolinas Medical Center

6. Native Hip Dislocations
The Native Hip Joint Is Inherently Stable And Therefore A Significant Amount
Of Force Is Required To Cause A Native Hip Dislocation. These Are Classified
Based On The Position Of The Dislocated Femoral Head.
Posterior 85% Anterior 10% Central <5%

7. Posterior Hip Dislocations Occur When The Patient Is Seated With Both The Hip And Knee Flexed And An
Inciting Force Drives The Femur Posteriorly, As Might Be Seen Following A Head-On Car Crash.

8. Anterior Hip Dislocations Occur When There Is Forced Extreme External Rotation Of The Leg, Levering The
Femoral Head Out Of The Acetabulum Anteriorly, As Might Be Seen Following A Sporting Event Collision.

9. Anterior Hip Dislocations Occur When There Is Forced Extreme External Rotation Of The Leg, Levering The
Femoral Head Out Of The Acetabulum Anteriorly, As Might Be Seen Following A Sporting Event Collision.

10. Central Hip Dislocations Occur When There is Severe Axial Loading Of An Extended Leg, Driving The
Femoral Head Into The Acetabulum, As Might Be Seen When A Patient Falls From A Height On Their Feet.

11. Case 1:
65-year-old male
involved in an
automobile collision.

12. Case 1:
65-year-old male
involved in an
automobile collision.
Right Posterior Hip
Dislocation.

13. Posterior Hip Dislocations
• Mechanism of action: high-energy axial load on the femur -
especially likely when the hip is flexed and adduction, and the knee
is flexed (dashboard injury)
• Exam: ipsilateral shortening, adduction, internal rotation of the leg
• Imaging: AP pelvis and hip X-rays, complemented by pelvic CT
• Associated injuries:
• Femoral head fracture
• Posterior wall acetabular fracture
• Sciatic nerve injury
• Ipsilateral knee dislocation (seen in up to 25% of cases)

14. Back to Our Patient
• The Allis Technique was
successfully applied to
achieve closed
reduction in the ED.
• After reduction, an
associated posterior
acetabular fracture is
well seen on X-rays and
3-D pelvic CT imaging.

15. Following A Native Hip Dislocation, The Vascular Supply Of The Femoral Neck/Head Is Subject To
Stretching, Ischemia And Direct Injury. This Is Especially Likely When The Injury Is Severe Or When The
Period Of Dislocation Is Prolonged. This Places The Patient At Risk For Avascular Necrosis Of The Hip.

16. Archives Of Orthopedic Trauma Surgery 1986;106:32-35.
Traumatic Posterior Dislocation Of The Hip – Prognostic Factors
Influencing The Incidence of Avascular Necrosis Of The Femoral Head
Objective:
To elucidate the factors important for development of avascular necrosis of the femoral head following
traumatic posterior dislocation of the hip.
Methods:
98 adult patients with 100 hip dislocations were reviewed after a minimum follow-up of 5 years.
Results:
• Avascular necrosis of the femoral head was found in only 4.8% of the hips reduced within 6 h, but in 52.9%
of the hips reduced more than 6 h after the injury.
• A significantly higher incidence of avascular necrosis was found in Grade-III and Grade-IV dislocations than
in Grade-I and Grade-II dislocations.
Conclusions:
Timely reduction of posterior hip dislocations is critical, and the goal should be to accomplish this in <6 hours.

17. Journal of Orthopedic Trauma 2016;30(1):10-16.
Systematic Review and Meta-Analysis of Avascular Necrosis and
Posttraumatic Arthritis After Traumatic Hip Dislocation
Objective:
To determine the incidence and predictive factors for the development of avascular necrosis (AVN) and
posttraumatic arthritis (PTA) after hip dislocation and correlate these with the time to reduction.
Methods:
Systematic review and meta-analysis of English language studies of adult patients through April 2014.
Results:
• The odds ratio of developing AVN for dislocations reduced after 12 hours versus those reduced before 12
hours was 5.627.
• Injury severity was the most important predictor of an increased likelihood of both AVN and PTA.
Conclusions:
• Injury severity is the highest predictive factor of both AVN and PTA.
• The risk of AVN is 5.6 times higher when reductions are delayed beyond 12 hours.

18. Annals of Emergency Medicine 2022;79:554-559.
Hip Reduction Basics
• Obtain adequate imaging to confirm the diagnosis and assess for associated injuries,
• Prioritize prompt reduction to the dislocation to reduce the risk of avascular necrosis,
• Ensure adequate procedural sedation and analgesia,
• Consider regional anesthesia (e.g.: femoral nerve block, fascia iliaca block, pericapsular
nerve group block),
• Apply slow, controlled, and steady traction in-line with the dislocation,
• Obtain additional help stabilizing the pelvis at the anterior superior iliac spine,
• A failure of closed reduction is not always operator error. A subset of dislocations will
require open reduction despite appropriate technique.

19. Fascia Iliaca Compartment Block In The Reduction Of Dislocation Of Total Hip
Arthroplasty.
American Journal Of Emergency Medicine 2014.
Ultrasound-Guided Femoral Nerve Block To Facilitate Closed Reduction Of A
Dislocated Hip Prosthesis.
Clinical Practice And Cases in Emergency Medicine 2017.
Landmark-Guided Pericapsular Nerve Group (PENG) Block For Reduction of
Dislocated Hip Prothesis: A Case Report.
Journal Of Anesthesiology And Clinical Pharmacology 2022.
There Is Literature Demonstrating The Safety Of Regional Anesthetic Techniques For Reduction Of Prosthetic
Hip Dislocations. This Can Also Be Considered In Patients With Native Hip Dislocations, Provided The
Neurovascular Exam Is Normal And The Patient Is Not At Risk For Co-Incident Compartment Syndrome.

20. Annals of Emergency Medicine 2022;79:554-559.
Traditional Allis
Modified Allis
Allis From Standing Position
Allis Technique
• The patient lies supine with the affected hip
and knee flexed at 90 degrees.
• The provider stands on the bed and grasps
the patient’s leg under the knee.
• If using the “Modified” Allis, the provider
will stand to the side of the bed, place the
patient's leg on their shoulder, and gently
stand to apply traction.
• The provider applies axial traction while an
assistant stabilizes the pelvis at the anterior
superior iliac spine.

21. Annals of Emergency Medicine 2022;79:554-559.
Rocket Launcher Technique
• The patient lies supine with the affected hip
and knee flexed at 90 degrees. Patient is
positioned at the end of the bed.
• The provider sits at the end of the bed,
places patient’s knee over their shoulder,
and gently leans forward and stands.
• The provider can gently exaggerate
deformity by adducting and internally
rotating prior to standing.

22. Annals of Emergency Medicine 2022;79:554-559.
East Baltimore Lift
• The patient lies supine with the effected hip
and knee flexed at 90 degrees.
• Two providers stand on either side and lock
arms under the patient’s knee.
• A third provider stabilizes the pelvis.
• Providers gently stand to apply axial
traction.

23. Annals of Emergency Medicine 2022;79:554-559.
Tulsa/Rochester/Whistler
• The patient lies supine with the hip and
knee flexed and the pelvis stabilized against
bed
• The clinician places his/her arm under the
affected side and hand on the contralateral
knee
• The clinician then slowly standing up using
the arm to provide traction while the other
arm slowly rotates the leg internally and
extenally

24. Annals of Emergency Medicine 2022;79:554-559.
Captain Morgan Technique
• The patient lies supine with the affected hip
and knee flexed at 90 degrees.
• The provider places their hand under
patient’s knee and their own knee under
the patient’s distal thigh
• The provider uses the contralateral hand to
stabilize the leg at the ankle
• The provider plantarflexes at the ankle to
apply axial traction.

25. Annals of Emergency Medicine 2022;79:554-559.
Stimson Technique
Modified Stimson Technique
Stimson Technique
• The patient lies prone on the bed with the
affected hip and knee flexed at 90 degrees
and hanging of the bed.
• The provider applies downward force to the
lower leg with one arm while internally and
externally rotating patient’s hip with the
other hand.
• In the Modified Stimson Technique, the
provider can place their knee instead of
their hand on the patient’s popliteal fossa.

26. Annals of Emergency Medicine 2022;79:554-559.

27. Post-Reduction Care Basics
• While under sedation, assess hip for stability by gently ranging the hip in all plains,
• Perform repeat X-rays (or a pelvic CT) to assess for loose bodies or fractures that may not
have been previously identified,
• Given high mechanism required to dislocate hip, a large percentage of patients have other
injuries. Always perform a comprehensive trauma evaluation,
• Generally, passive and active range of motion exercises recommended upon discharge,
• Toe-touch weight bearing or non-weight bearing,
• Ensure timely orthopedics follow up.

28. Posterior Hip Dislocations -Emergency Medicine Essentials
Mechanism of
Injury
• High axial load on the femur, especially in a position of flexion and adduction of the
hip, or axial load through a flexed knee
Physical
Examination
• Ipsilateral shortening, adduction, internal rotation of the leg
ED Imaging • Pelvis and hip X-ray, complemented by pelvic CT imaging
Associated
Injuries
• Femoral head fracture, posterior wall acetabular fracture, sciatic nerve damage,
ipsilateral knee dislocation
Consultation
And Follow-Up
• Early Orthopedic Surgery consultation to facilitate closed reduction, and/or open
reduction when required
Reduction
Techniques
• Allis Maneuver
• Rocket Launcher Technique
• East Baltimore Lift
• Tulsa/Rochester/Whistler
• Captain Morgan Technique
• Stimson Technique
Failed Closed
Reduction?
Skeletal traction, close reduction with percutaneous screws, open reduction with plating,
and iliofemoral external distraction, and one-stage total hip arthroplasty

29. Case 2:
17-year-old male on a
moped collides with a
vehicle at high speed.
He complains of right
hip pain.

30. Case 2:
17-year-old male on a
moped collides with a
vehicle at high speed.
He complains of right
hip pain.
What Is The Position Of
The Right Femoral
Head?

31. Case 2:
17-year-old male on a
moped collides with a
vehicle at high speed.
He complains of right
hip pain.
Anterior Hip
Dislocation (Iliac)

32. 17-Year-Old Male On A Moped Collides With A Vehicle At High Speed.
Anterior Hip Dislocation

33. Anterior Hip Dislocations
• Mechanism of action: high-energy mechanism
• Superior (pubic): forceful abduction of the thigh while externally rotated
and extended,
• Inferior (obturator): forceful abduction of the thigh while externally rotated
and flexed.
• Exam: leg externally rotated and shortened
• Imaging: AP pelvis and hip X-ray complemented by pelvic CT
• Associated injuries:
• Femoral head fracture
• Injury to anterior structures in the femoral triangle (nerve, artery, vein)

34. Back to Our Patient
The patient underwent successful closed reduction in the ED.
Post-Reduction

35. Case 3:
19-year-old
unrestrained rear seat
passenger in a motor
vehicle crash complains
of severe left hip pain.

36. Case 3:
19-year-old
unrestrained rear seat
passenger in a motor
vehicle crash complains
of severe left hip pain.
Left Anterior Hip
Dislocation (Obturator)

37. Case 3:
19-year-old
unrestrained rear seat
passenger in a motor
vehicle crash complains
of severe left hip pain.
Left Anterior Hip
Dislocation

38. The Patient Underwent Closed Reduction In The Emergency Department

39. CT Imaging Reveals Associated Impaction Injury Of The Femoral Head

40. Archives Of Orthopedic Trauma Surgery 2011;131:1273-1278.
Long-Term Outcomes After Anterior Dislocation Of The Hip
Objective:
To assess the outcomes in patients with anterior hip dislocations.
Methods:
Retrospective analysis of 100 patients with native hip dislocations, 10 of which had anterior dislocations.
Results:
In the 10 patients with anterior hip dislocations:
• Four patients had impaction fractures of the femoral head,
• Three patients had fractures of the anterior acetabular wall,
• One patient presented as an open dislocation,
• Three patients required surgery.
Conclusions:
• There was a high incidence of associated fractures of the femur and acetabulum.
• Surgery was required in 30% of patients.

41. Injury 2021;51:2327-2332.
Anterior Hip Dislocation: Characterization of a Rare Injury and
Predictors of Functional Outcome
Objective:
To describe injury characteristics, treatment, and outcome in patients of anterior hip dislocation.
Methods:
Single Trauma Center retrospective review for 2010 – 2017. 31 patients met the inclusion criteria.
Results:
Obturator Anterior Dislocations: 69% Iliac Anterior Dislocations: 31%
• 78% of cases had associated fracture of the femoral head or acetabulum,
• Iliac dislocations were more likely to have associated fractures and to require surgical repair,
• For patients initially treated with closed reduction, subsequent total hip arthroplasty was rare,
occurring in only 1 of 16 patients.

42. Anterior Hip Dislocations - Emergency Medicine Essentials
Mechanism of Injury • Forceful abduction of the thigh while the leg is externally rotated
Physical Examination • Leg externally rotated, pain with movement
ED Imaging • Pelvis and hip X-ray, complemented by pelvic CT imaging
Associated Injuries • Femoral head and neck fractures, acetabular fractures, injury to
structures in the femoral triangle (nerve, artery, vein)
Consultation & Follow-Up • Early Orthopedic Surgery consultation to facilitate closed reduction,
and/or open reduction when required
ED Management And
Splinting Techniques
• Hold the patient’s hip and knee in flexion while assistant stabilizes pelvis
• Apply gentle traction downwards along long axis of the femur, you can
internally rotate and adduct to assist
• Follow reduction with repeat imaging
Failed Closed
Reduction?
Skeletal traction, close reduction with percutaneous screws, open reduction
with plating, and iliofemoral external distraction, and one-stage total hip
arthroplasty

43. Case 4:
53-year-old female
involved in a motor
vehicle crash.
What do you see?

44. Case 4:
53-year-old female
involved in a motor
vehicle crash.
Left acetabular fracture
with central dislocation
of the femoral head.

45. Case 4:
53-year-old female
involved in a high speed
automobile crash.
A CT scan confirms the
injury pattern.

46. Central Hip Dislocations
• Mechanism of action: high-energy mechanism creating a direct
axial load through the greater trochanter while in abduction
• Exam: Shortening of ipsilateral extremity with external rotation
• Imaging: AP pelvis and hip X-ray complemented by pelvic CT
• Associated injuries:
• Acetabular fractures
• Femoral head and femoral neck fractures
• Neurovascular injuries

47. Back To Our Patient
In The Emergency Department
• The patient was aggressively resuscitated
with crystalloid and blood products.
• A femoral traction splint and distal
femoral traction pin were placed for
stabilization of the left lower extremity.

48. Back To Our Patient
Definitive Management
• After all injuries were identified and
stabilized the patient was admitted to the
Trauma Service.
• The patient was taken to the operating
room for an open reduction and internal
fixation of the left transverse and posterior
wall acetabulum fractures, and closed
reduction and percutaneous fixation of the
left sacroiliac joint.

49. Central Hip Dislocations - Emergency Medicine Essentials
Mechanism of Injury • High energy trauma with direct axial load on abducted femur
Physical Examination • Shortened, externally rotated extremity
ED Imaging • Pelvis and hip X-ray, complemented by pelvic CT imaging
Associated Injuries • Acetabular fracture, femur fracture, neurovascular injury, associated
pelvic and abdominal visceral injuries
Consultation & Follow-Up • Early Orthopedic Surgery consultation essential given the high rate of
associated injury and need for operative intervention
ED Management And
Splinting Techniques
• Literature remains controversial between closed reduction, skeletal
traction, open reduction, and total hip arthroplasty

50. Hip Dislocations
Cases From Carolinas Medical Center
Test Your Knowledge!

51. Dislocation Type?

52. Central Dislocation

53. Dislocation Type?

54. Posterior Dislocation

55. Dislocation Type?

56. Posterior Dislocation

57. Dislocation Type?

58. Anterior (Obturator) Dislocation

59. Dislocation Type?

60. Posterior Dislocation

61. Dislocation Type?

62. Posterior Dislocation

63. Dislocation Type?

64. Anterior (Obturator) Dislocation

65. Dislocation Type?

66. Posterior Dislocation

67. Dislocation Type?

68. Central Dislocation

69. Dislocation Type?

70. Posterior Dislocation

71. Native Hip Dislocation Essentials
• Native hip dislocations are the result of significant energy transfer. Always perform a
comprehensive trauma examination.
• Native hip dislocations are classified by the position of the dislocated hip, i.e.: posterior
(85%), anterior (10%), and central (<5%).
• The two most important predictors of avascular necrosis in patients with hip dislocations
are: (1) injury severity, and (2) delays in reduction >6 hours.
• Numerous reduction techniques have been described.
• Adequate sedation and analgesia is crucial to optimize the success of closed reduction.
• Provided there is no evidence of neurovascular compromise or risk of compartment
syndrome, regional anesthetic techniques may be a useful adjunct during reduction.

72. References:
Traumatic Posterior Dislocation Of The Hip – Prognostic Factors Influencing The Incidence of Avascular
Necrosis Of The Femoral Head. Archives Of Orthopedic Trauma Surgery 1986;106:32-35.
Systematic Review and Meta-Analysis of Avascular Necrosis and Posttraumatic Arthritis After Traumatic
Hip Dislocation. Journal of Orthopedic Trauma 2016;30(1):10-16.
Managing Posterior Hip Dislocations. Annals of Emergency Medicine 2022;79:554-559.
Long-Term Outcomes After Anterior Dislocation Of The Hip. Archives Of Orthopedic Trauma Surgery
2011;131:1273-1278.
Anterior Hip Dislocation: Characterization of a Rare Injury and Predictors of Functional Outcome. Injury
2021;51:2327-2332.

73. See You Next Month!