High Yield Topics

Dislocation in the Adult

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Ovid: 5-Minute Orthopaedic Consult

Editors: Frassica, Frank J.; Sponseller, Paul D.; Wilckens, John H.
Title: 5-Minute Orthopaedic Consult, 2nd Edition
> Table of Contents > Dislocation in the Adult

Dislocation in the Adult
Simon C. Mears MD, PhD
Basics
Description
  • Dislocation occurs when a force across a joint disrupts the restraining capsule, ligaments, and muscles.
  • Dislocated joints may reduce spontaneously or remain unreduced.
  • Dislocations can be associated with periarticular fractures, ruptured ligaments, capsular damage, and cartilage damage (1).
  • The dislocation may result in stretch or injury to the arteries or nerves that cross the joint.
  • Dislocation may occur after prosthetic joint replacement, particularly of the hip.
General Prevention
Use of protective devices and equipment during sporting activity
Epidemiology
Incidence
  • In 1 study, the rate of shoulder dislocation was 17 in 100,000 per year (2).
  • In another study, the rate of dislocation after hip replacement was 3.9% (3).
Risk Factors
  • Sports
  • Car accidents
  • Falls
  • Trauma
  • Joint replacement
  • Skateboarding and in-line skating
Pathophysiology
  • The vector of force on a limb results in particular patterns of injury to the joint (4).
    • When a hip is flexed, a force on the axis of the femur results in a posterior hip dislocation.
    • Force on a hip in an extended position results in an anterior dislocation.
Etiology
Associated Conditions
  • Periarticular fractures
  • Nerve and vessel injury
  • Osteonecrosis
  • Cartilage damage
Diagnosis
Signs and Symptoms
  • Pain and deformity of the joint
  • Inability to bear weight on the affected limb
  • Neurologic compromise
History
Traumatic injury, as from a fall or car accident
Physical Exam
  • A complete neurologic examination is important, and the strength and sensation distally should be noted.
  • Pulses should be palpated and, if not found, Doppler ultrasound should be performed.
  • The remainder of the extremity should be evaluated for swelling or deformity.
Tests
Imaging
  • Radiography:
    • Plain radiographs of the joint should be taken in 2 planes to show the direction of dislocation.
    • Radiographs are repeated after reduction.
  • CT is used to evaluate intra-articular fracture patterns.
  • MRI is used to evaluate ligament and soft-tissue damage around the joint.
Differential Diagnosis
  • Fracture
  • Joint effusion
  • Joint infection
Treatment
Initial Stabilization
  • All joint dislocations should be reduced as soon as possible.
  • Radiographs should be taken 1st to confirm the dislocation and to show fractures.
General Measures
  • Depending on the nature of the injury,
    reduction may require no anesthesia, intra-articular joint injection,
    conscious sedation, or full anesthesia.
    • The hip joint often requires sedation or
      a full anesthetic with muscle relaxant because the muscle forces around
      the joint can be great.
  • After reduction, joint stability should be confirmed by taking the joint through its ROM.
  • Unstable joints should be braced or placed in traction after reduction and usually require surgical stabilization.
  • Plain radiographs should be taken in 2 views to confirm reduction.
  • CT is used in dislocations of the hip and shoulder to assess for fractures or intra-articular fragments (5).
Activity
  • Dislocations that are stable after reduction and do not have fractures usually should be mobilized quickly.
  • Immobilization for a week may help with soft-tissue pain and swelling.
Special Therapy
Physical Therapy
Patients with stable dislocations should begin an assisted program in ROM and joint strengthening.
Surgery
  • Indications for surgery include:
    • Unstable joint dislocations
    • Periarticular fractures:
      • Joint injuries do best when ROM exercises can be started early.
      • Fractures must be stabilized to allow for early ROM.
      • Fractures also must be reduced anatomically to decrease the risk of posttraumatic arthritis.
    • In some cases, ruptured or torn periarticular soft tissue may be treated with surgery.
      • Acute shoulder dislocations in young adults have a high risk of recurrent instability.
    • Irreducible joint dislocations:
      • Soft tissues such as tendons, nerves, or arteries may be caught in the joint.
      • Open reduction is required.
    • Intra-articular osteochondral fragments
Follow-up
  • Confirmation should be made after reduction, taking care to assure joint congruity.
  • Patients should be reassessed in 1–2 weeks.
    • If the joint is stable, early ROM should be started.
  • Dislocation may put the patients at risk for instability, osteonecrosis, or posttraumatic arthritis.

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Prognosis
  • Prognosis depends on the particular joint dislocated and the injuries to surrounding tissues.
  • Injuries to nerves and arteries around the joint have a poor prognosis.
  • Periarticular fractures are at risk for posttraumatic arthritis and the need for later joint replacement (6).
  • Missed joint dislocations have a poor prognosis.
  • Shoulder dislocations have a high rate of redislocation in young adults (7).
  • In active patients, early surgery may be helpful in preventing chronic instability (7).
Complications
  • Stiffness
  • Osteonecrosis:
    • Most common after hip dislocations.
    • Thought to be secondary to damage to the blood supply of the femoral head (8).
    • The length of time to reduction is directly related to the risk of osteonecrosis.
      • Hips should be reduced within 6 hours (6).
  • Posttraumatic arthritis:
    • Depends on the reduction of the fracture and the amount of chondral damage to the joint at the time of injury
      • In 1 study of the outcomes after posterior fracture-dislocations of the hip, poor outcome was seen in 18% of patients (6).
    • Common after hindfoot subtalar dislocation (9)
  • Joint instability:
    • The presence of fracture and damage to surrounding supportive structures of the joint increases the risk of late instability (10).
    • Joints with less innate stability, such
      as the shoulder, have a higher risk of late instability than do joints
      with more stable bony structures, such as the elbow.
  • Nerve damage:
    • Early reduction reduces the amount of time that nerves are stretched.
    • After hip dislocation, patients with longer times to reduction have worse nerve injuries (11).
Patient Monitoring
  • Patients should be monitored with radiographs to check that the joint is reduced concentrically.
  • Additional follow-up is based on the individual injury.
    • Patients with hip dislocations should be
      followed radiographically for the 1st year to assess for posttraumatic
      arthritis and osteonecrosis.
References
1. te Slaa RL, Wijffels MPJM, Brand R, et al. The prognosis following acute primary glenohumeral dislocation. J Bone Joint Surg 2004;86B:58–64.
2. Kroner K, Lind T, Jensen J. The epidemiology of shoulder dislocations. Arch Orthop Trauma Surg 1989;108:288–290.
3. Phillips
CB, Barrett JA, Losina E, et al. Incidence rates of dislocation,
pulmonary embolism, and deep infection during the first six months
after elective total hip replacement. J Bone Joint Surg 2003;85A:20–26.
4. Monma
H, Sugita T. Is the mechanism of traumatic posterior dislocation of the
hip a brake pedal injury rather than a dashboard injury? Injury 2001;32:221–222.
5. Brooks RA, Ribbans WJ. Diagnosis and imaging studies of traumatic hip dislocations in the adult. Clin Orthop Relat Res 2000;377:15–23.
6. Moed BR, Willson Carr SE, Watson JT. Results of operative treatment of fractures of the posterior wall of the acetabulum. J Bone Joint Surg 2002;84A:752–758.
7. Bottoni
CR, Wilckens JH, DeBerardino TM, et al. A prospective, randomized
evaluation of arthroscopic stabilization versus nonoperative treatment
of acute, traumatic, first-time shoulder dislocations. Am J Sports Med 2002;30:576–580.
8. Yue JJ, Wilber JH, Lipuma JP, et al. Posterior hip dislocations: a cadaveric angiographic study. J Orthop Trauma 1996;10:447–454.
9. Bibbo
C, Anderson RB, Davis WH. Injury characteristics and the clinical
outcome of subtalar dislocations: a clinical and radiographic analysis
of 25 cases. Foot Ankle Int 2003;24:158–163.
10. Robinson
CM, Kelly M, Wakefield AE. Redislocation of the shoulder during the
first six weeks after a primary anterior dislocation: risk factors and
results of treatment. J Bone Joint Surg 2002;84A:1552–1559.
11. Hillyard RF, Fox J. Sciatic nerve injuries associated with traumatic posterior hip dislocations. Am J Emerg Med 2003;21:545–548.
12. Everett WW. Skatepark injuries and the influence of skatepark design: a one year consecutive case series. J Emerg Med 2002;23:269–274.
Additional Reading
Dirschl DR, Marsh JL, Buckwalter JA, et al. Articular fractures. J Am Acad Orthop Surg 2004;12:416–423.
Miscellaneous
Codes
ICD9-CM
  • 718.3 Recurrent dislocation
  • 831.00 Shoulder dislocation
  • 832.00 Elbow dislocation
  • 833.00 Wrist dislocation
  • 835.00 Hip dislocation
  • 836.50 Knee dislocation
  • 837.1 Ankle dislocation
Patient Teaching
Activity
Early ROM is started for stable joint dislocations.
Prevention
  • Design of skate parks may reduce the risk of injuries (12).
  • Use of protective equipment may reduce the risk of injuries after falls during sporting events.
FAQ
Q: When should a joint be reduced?
A:
Joint dislocations should be reduced as quickly as possible to reduce
the risk of osteonecrosis, joint damage, and stretch to nerves and
blood vessels.

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