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Hip Dislocations
Dr. Harpreet Singh Bhatia
DMC Ludhiana
2015
Introduction
Hip dislocations caused by significant force:– Association with other fractures– Damage to vascular supply to femoral head
Thus, high chance of complications
What To Cover Today
Incidence
Brief anatomy of Hip Joint
Mechanism and types of Hip Dislocations
Techniques of Closed Reduction
Post Reduction disposition and investigations
Incidence
Common in young population with high energy trauma.
Unrestrained motor vehicle accident occupants are at significant higher risk for sustaining a hip dislocation than passengers wearing a restraining device
After Prim THR 3.9 percent experience Hip dislocation in first 6 months.
After Revised THR surgery 15 percent experience Dislocation in 6 months.
Anatomy
Ball and socket typical synovial joint.• Femoral head: slightly asymmetric, forms 2/3 sphere.• Acetabulum: inverted “U” shaped articular surface.• Ligamentum teres, with artery to femoral head, passes through
middle of inverted “U”.
Joint Contact Area
Throughout ROM:• 40% of femoral head is in contact with
acetabulum.• 10% of femoral head is in contact with
labrum.
Acetabular Labrum
Strong fibrous ring
Increases femoral head coverage
Contributes to hip joint stability
Hip Joint Capsule
• Extends from intertrochanteric ridge of proximal femur to bony perimeter of acetabulum
• Has several thick bands of fibrous tissue (3 lig) ===Iliofemoral ligament
• Upside-down “Y”• Blocks hip hyper-extension• Allows muscle relaxation while standing
The ligaments of hip joint
• The primary capsular fibers run longitudinally and are supplemented by much stronger ligamentous condensations that run in a circular and spiral fashion.
Blood Supply to Femoral Head
2. Ascending Cervical Branches• Arise from ring at base of neck.• Ring is formed by branches of medial and lateral
circumflex femoral arteries.• Penetrate capsule near its femoral attachment and
ascend along neck.
• Perforate bone just distal to articular cartilage.• Highly susceptible to injury with hip dislocation.
Sciatic Nerve
• Composed from roots of L4 to S3.• Passes posterior to posterior wall of acetabulum.• Generally passes inferior to piriformis muscle, but
occasionally the piriformis may split the peroneal and tibial components.
Hip Dislocation: Mechanism of Injury
• Almost always due to high-energy trauma.• Most commonly involve unrestrained occupants
in RTAs.• Can also occur in pedestrian-RTAs, falls from
heights, industrial accidents and sporting injuries.
Classification
Multiple systems exist:
• Thompson and epstein• Stewart and milford• AO/OTA Classification
Posterior Dislocation
• Generally results from axial load applied to femur, while hip is flexed.
• Most commonly caused by impact of dashboard on knee.
Types of Posterior Dislocation
• Postero-superior (iliac)
• Posterior
• ischial
Posterior Dislocation POSTERIOR: - flexed, internally rotated, and adducted.
Thomas and Epstein Classificationof Posterior Hip Dislocations
Most well-known
Type I Pure dislocation with or without insignificant posterior wall fragment
Type II Dislocation with large posterior wall fragment.
Type III Dislocation with comminuted posterior wall.
Type IV Dislocation with “acetabular floor” fracture (probably transverse + post. wall acetabulum fracture-dislocation).
Type V Dislocation with femoral head fracture.
Anterior Dislocation
Femoral head situated anterior to acetabulum
Hyperextension force against an abducted leg that levers head out of acetabulum.
Also force against posterior femoral head or neck can produce dislocation
10 % to 15% of traumatic hip dislocation
ANTERIOR: The hip is minimally flexed, externally rotated and markedly abducted
Mechanism of Anterior
Dislocation
• Extreme abduction with external rotation of hip.
• Anterior hip capsule is torn or avulsed.
• Femoral head is levered out anteriorly.
Types of anterior dislocation
• Pubic
• Obturator
• Perineal
Central dislocation
ALWAYS fracture dislocation
Lateral force against an adducted femur
Effect of Dislocation on Femoral Head Circulation
• When capsule tears, ascending cervical branches are torn or stretched.
• Artery of ligamentum teres is torn.• Some ascending cervical branches may remain
kinked or compressed until the hip is reduced.Thus, early reduction of the dislocated hip can
improve blood flow to femoral head.
Associated Injuries
Mechanism: knee vs. dashboard injury
– Contusions or fractures of distal femur
– Patella fractures, knee injuries– Foot fractures, if knee extended
Cont…
• Sciatic nerve injuries occur in 10% of hip dislocations.
*Most commonly, these resolve with reduction of hip and passage of time.
* Stretching or contusion most common.
*Piercing or transection of nerve by bone can occur.
Irregular presentation/appearance if:
• femoral head or neck are fractured
• femoral shaft fracture
• obtunded patient, confused, shocked ……
Neurovascular examination
• Signs of sciatic nerve injury include the following:– Loss of sensation in posterior leg and foot– Loss of dorsiflexion (peroneal branch) or plantar
flexion (tibial branch)– Loss of deep tendon reflexes at the ankle S1,2
• Signs of femoral nerve injury include the following:– Loss of sensation over the thigh– Weakness of the quadriceps– Loss of deep tendon reflexes at knee L3, 4
Radiographs: AP Pelvis X-Ray
• In primary survey as per ATLS Protocol.• Should allow diagnosis and show direction of dislocation.
– Femoral head not centered in acetabulum (loss of parallelism)– Femoral head appears larger (anterior) or smaller (posterior).
• Usually provides enough information to proceed with closed reduction.
Reasons to Obtain More X-Rays Before Hip Reduction
• View of femoral neck inadequate to rule out fracture.
• Patient requires CT scan of abdomen/pelvis to rule out associated injuries.
X-rays after Hip Reduction:
• AP pelvis, Lateral Hip x-ray.
• Judet views of pelvis.
• CT scan with 2-3 mm cuts.
CT Scan
Most helpful after hip reduction.
Reveals: Non-displaced fractures.
Congruity of reduction.
Intra-articular fragments.
Size of bony fragments.
MRI Scan
• Will reveal labral tear and soft-tissue anatomy.• Has not been shown to be of benefit in acute
evaluation and treatment of hip dislocations.
Clinical Management: Emergent Treatment
• Dislocated hip is an emergency.
• The goal is to reduce risk of AVN and Degenerative joint disease.
Benefits of early Reduction
• Allows restoration of flow through occluded or compressed vessels.
• Literature supports decreased AVN with earlier reduction.
• Requires proper anesthesia.• Requires “team” (i.e. more than one person).
Patterns Treated Non operatively
• No associated fracture and congruent reduction
• Posterior wall fracture that is clinically stable with congruent reduction
• Pipkin type I fracture with congruent reduction.
• Pipkin type II fracture with anatomic reduction and congruent joint
Nonoperative Treatment
• If hip stable after reduction, and reduction congruent.• Maintain patient comfort skin traction , analgesia• Avoid Adduction, Internal Rotation.• No flexion > 60o.• Early mobilization usually few days to 2 weeks.• Touch down weight-bearing may be delayed• Repeat x-rays before allowing full weight-bearing.
Reduction Maneuvers
Allis: Patient supine.
Requires at least two people.
Stimson: Patient prone, hip flexed and leg off stretcher.
Requires one person.
Impractical in trauma (i.e. most patients).
The popular methods of achieving closed reduction of The popular methods of achieving closed reduction of the hip:the hip: 1.1.The The BigleowBigleow maneuver , maneuver ,
2.2.AllisAllis maneuver maneuver 3.Stimson3.Stimson gravity technique gravity technique
4.Whistler technique4.Whistler technique
5.Captain Morgan technique5.Captain Morgan technique
Allis Maneuver• Assistant: Stabilizes pelvis
• Posterior-directed force on both ASIS’s
• Surgeon: Stands on stretcher• Applies progressively increasing traction to
the extremity • With continues traction slowly increase the
degree of flexion to 70 degree• Genral rotational motions with slight
adduction help the femoral head to clear lip of acetabulum
• Reduction can often be seen and felt as audible chunk.
Bigelow maneuver
Stimpson Method Described primarily for acute posterior dislocations
Believed to be least traumatic
Pt is in prone position w/ lower limbs hanging from end of table
Assistant immobilizes the pelvis by applying pressure on the sacrum
Hold knee and ankle flexed to 90 deg & apply downward pressure to leg just distal to the knee
Gentle rotatory motion of the limb may assist in reduction
Whistler’s technique
The patient lies supine on the gurney.
Unaffected leg is flexed with an assistant stabilizing the leg. The assistant can also help stabilize the pelvis.
Provider's other hand grasps the lower leg of the affected leg, usually around the ankle.
The dislocated hip should be flexed to 90 degrees. The provider's forearm is the fulcrum and the affected lower leg is
the lever.
When pulling down on the lower leg, it flexes the knee thus pulling traction along the femur.
East Baltimore lift
Irreducible Hip ?
• Requires emergent reduction in theatre.• Pre-op CT obtained if it will not cause delay.• One more attempt at closed reduction in O.T. with
anesthesia.
( Repeated efforts not likely to be successful and may create harm to the neurovascular structures or the articular cartilage.)
Surgical approach from side of dislocation.
Causes of Irreducible dislocation
• Anterior:
Buttonholing through the capsule Rectus femoris Capsule Labrum Psoas tendon
• Posterior:
Piriformis tendon Gluteus maximus Capsule, Ligamentum teres Posterior wall, Bony fragment Iliofemoral ligament Labrum
Indications for open Reduction
• Irreducible dislocation
• Iatrogenic sciatic nerve injury
• Incongruent reduction with incarcerated fragments
• Incongruent reduction with soft tissue interposition
• Incongruent reduction with Pipkin type I femoral head fracture (relative)
Irreducible anterior hip dislocation
• Smith-Peterson approach ,Watson-Jones approach, Extended iliofemoral, ilioinguinal approach.
• Allows visualization and retraction of interposed tissue.
• Placement of Schanz pin in intertrochanteric region of femur will assist in manipulation of the proximal femur.
• Repair capsule, if this can be accomplished without further dissection.
• Kocher-Langenbeck approach.• Remove interposed tissue, or
release buttonhole.• Repair posterior wall of acetabulum if
fractured and amenable to fixation.
Irreducible Hip Dislocation: Posterior
Complications of Hip Dislocation
1- Avascular Necrosis (AVN): 1-40%
– Several authors have shown a positive correlation between duration of dislocation and rate of AVN.
– Results are best if hip reduced within six hours.
2- Post-traumatic Osteoarthritis
• Can occur with or without AVN.• May be unavoidable in cases with severe
cartilaginous injury.• Incidence increases with associated femoral head
or acetabulum fractures.
• Efforts to minimize osteoarthritis are best directed at achieving anatomic reduction of injury and preventing abrasive wear between articular carrtilage and sharp bone edges.
3- Sciatic Nerve Injury
Occurs in up to 20% of patients with hip dislocation.
Nerve stretched, compressed or transected.
EMG studies at 3-4 wks for baseline information and prognostic guidance
With reduction: 40% complete resolution
25-35% partial resolution
4- Recurrent Dislocation
• Rare, unless an underlying bony instability has not been surgically corrected (e.g. excision of large posterior wall fragment instead of ORIF).
• Some cases involve pure dislocation with inadequate soft-tissue healing – may benefit from surgical imbrication .
• Can occur from detached labrum, which would benefit from repair (rare).
5. Heterotrophic ossification
• Higher incidence after open reduction with internal fixation via an anterior approach than a posterior approach
• Ocuurs in 2% of patients and is related to muscular damage and hematoma formation.
• The use of indomethacin may diminish the rate of clinically significant heterotrophic ossification.
• The other choice is to use radiation therapy, usually 700 Gy in one dose. This method is very effective in decreasing the rate of heterotopic ossification, but is not favored in young patients
6- Thromboembolism
• Hip dislocation = high risk patient.
• Prophylactic treatment with: low molecular weight heparin
• Early postoperative mobilization.
• Discontinue prophylaxis after 2-6 weeks (if patient mobile).
Thank you
1. Irreducible Posterior Dislocation with Large Femoral Head Fracture
Fortunately, these are rare.
Difficult to fix femoral head fracture from posterior approach without transecting ligamentum teres.
Three Options
1.Detach femoral head from ligamentum teresrepair femoral head fracture with hip dislocatedreduce hip.
2.Close posterior wound, fix femoral head fracture from anterior approach (either now or later).
3.Ganz trochanteric flip osteotomy.
Best option is not known: Damage to blood supply from anterior capsulotomy vs. damage to blood supply from transecting ligamentum teres. Mm
2. Hip Dislocation with Femoral Neck Fracture
• Attempts at closed reduction potentiate chance of fracture displacement with consequent increased risk of AVN.
• If femoral head is dislocated with neck fracture, then the ability to reduce the head by closed means is markedly compromised.
Thus, closed reduction should not be attempted.
3. Incarcerated Fragment
• Can be detected on x-ray or CT scan.• Surgical removal necessary to prevent abrasive wear of the articular cartilage.• Posterior approach allows best visualization of acetabulum (with distraction or intra-op dislocation).• Anterior approach only if:
dislocation was anterior and,
fragment is readily accessible anteriorly.
4. Incongruent Reduction
• Acetabulum Fracture (weight-bearing portion).• Femoral Head Fracture (any portion).• Interposed tissue.• Achieve congruence by removing interposed tissue and/or reducing and stabilizing fracture.
5. Unstable Hip after Reduction
• Due to posterior wall and/or femoral head fracture.• Requires reduction and stabilization fracture.
• Labral detachment or tear– Highly uncommon cause of instability.– Its presence in the unstable hip would justify surgical repair.– MRI may be helpful in establishing diagnosis.
Results of Treatment
• Pain : normal to severe pain and degeneration.• In general, dislocations with associated femoral head or
acetabulum fractures fare worse.• Dislocations with fractures of both the femoral head and the
acetabulum have a strong association with poor results.• Irreducible hip dislocations have a strong association with poor
results.– 13/23 (61%) poor and 3/23 (13%) fair results.
McKee, Garay, Schemitsch, Kreder, Stephen. Irreducible fracture-dislocation of the hip: a severe injury with a poor prognosis. J Orthop Trauma. 1998.
Recurrent Dislocation Caused by Defect in Posterior Wall and/or Femoral Head
• Can occur after excision of fractured fragment.• Pelvic or intertrochanteric osteotomy could alter the
alignment of the hip to improve stability.• Bony block could also provide stability.
4- Delayed Diagnosis of Hip Dislocation
• Increased incidence in multiple trauma patients.
• Higher if patient has altered sensorium.
• Results in more difficult closed reduction, higher incidence of AVN.
In NO Case should a hip dislocation be treated without reduction.
Sciatic Nerve Palsy:If No Improvement after 3–4 Weeks
• EMG and Nerve Conduction Studies for baseline information and for prognosis.
Allows localization of injury in the event that surgery is required.
6- Foot Drop
Splinting (i.e. ankle-foot-orthosis):
• Improves gait
• Prevents contracture
7- Infection
Incidence 1-5%
Lowest with prophylactic antibiotics and limited surgical approaches
8- Iatrogenic Sciatic Nerve Injury
Most common with posterior approach to hip.
Results from prolonged retraction on nerve.
Iatrogenic Sciatic Nerve Injury
Prevention:Maintain hip in full extension
Maintain knee in flexion
Avoid retractors in greater sciatic notch
? Intra-operative nerve monitoring (SSEP, motor monitoring)
Conclusion
• It is highly stable joint that needs high energy trauma to dislocate,(so, don't miss associated injuries)
• Early reduction of the dislocated hip (within 6 hrs) can improve blood flow to femoral head.
• Up to 5 views of xrays/C-T may be needed for proper evaluation( pre and post reduction)
Cont…..
• Minimize closed trials to avoid the risk of vascular damage and AVN
• Surgical approaches according to the direction of dislocation
• Surgeon experience is highly considered for treatment (as revision surgeies caries a high risk of complications)
