Classification✓pathoanatomy ✓ Diagnosis✓complications✓ treatment✓

1. Assignment on Dislocation &
Subluxation
Submitted by
Divya kumari
Bpt 5th sem
UG1888006004

2. Outline
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Definition
Classification
Pathoanatomy
Diagnosis
Complications
Treatment
Reference

3. DEFINITIONS
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Dislocation: A joint is
dislocated when its articular
surfaces are completely
displaced, one from the
other, so that all contact
between them is lost.
Subluxation: A joint is
subluxated when its articular
surfaces are only partly
displaced and retain some
contact between them.

4. CLASSIFICATION
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Dislocations and subluxations may be classified
on the basis of aetiology into congenital or
acquired.
Congenital dislocation is a condition where a
joint is dislocated at birth e.g., congenital
dislocation of the hip (CDH).
Acquired dislocation may occur at any age.
It may be traumatic or pathological as
discussed below.

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Traumatic dislocation: Injury is by far the commonest
cause of dislocations and sub-luxations at almost all
joints (Table). The force required todislocate a
particular joint varies from joint to joint.
The following are the different types of traumatic
dislocations seen in clinical practice:
a) Acute traumatic dislocation: This is an episode of
dislocation where the force of injury is the main
contributing factor e.g., shoulder dislocation.
b) Old unreduced dislocation: A traumatic
dislo cation, not reduced, may present as an old
unreduced dislocation e.g., old posterior dislo cation of
the hip.
c) Recurrent dislocation: In some joints, proper
healing does not occur after the first dislocation.

6. This results in weakness of the supporting structures
of the joint so that the joint dislocates repeatedly,
often with trivial trauma. Recurrent dislocation of the
shoulder and patella are common.
d) Fracture-dislocation: When a dislocation
isassociated with a fracture of one or both of the
articulating bones, it is called fracture-dislocation. A
dislocation of the hip is often associated with a
fracture of the lip of the acetabulum.

8. 2.Pathological dislocation: The articulating
surfaces forming a joint may be destroyed by an
infective or a neoplastic process, or the
ligaments may be damaged due to some
disease. This results in dislocation or
subluxation of the joint without any trauma e.g.,
dislocation of the hip in septic arthritis.

9. PATHOANATOMY
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Dislocation cannot occur without damage to the protective
ligaments or joint capsule. Usually the capsule and one or
more of the reinforcing ligaments are torn, permitting the
articular end of the bone to escape through the rent.
Sometimes,the capsule is not torn in its substance but is
stripped from one of its bony attachments In fig.
Rarely, a ligament may withstandthe forceof the injury so
that instead of ligament rupture, a fragment of bone at one
of its attachments may be chipped off (avulsed).
At the time of dislocation, as movement occurs between
the two articulating surfaces, a piece of articular cartilage
with or without its underlying bone may be
‘shavedoff’producing an osteochondral fragment within
the joint. This fragment may lie loose inside the joint and
may cause symptom long after the dislocation is reduced.

11. DIAGNOSIS
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Clinical examination: In most cases of dislocation, the clinical
features are sufficiently striking and make the diagnosis easy.
Never-theless, a dislocation or subluxation is sometimes
overlooked, especially in a multiple injury case, an unconscious
patient or in a case where the bony landmarks are obscured by
severe swelling or obesity.
Somedislocations, which are particularly notorious for getting
overlooked are:
(i) posterior dislocation
of the shoulder especially in an epileptic; and
(ii) dislocation of the hip associated with a fracture of the shaft
of the femur on the same side.
The classic deformity of a hip dislocation does not occur, and
the attention is drawn on the more obvious injury – the femoral
shaft fracture.

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Some of the salient reinical features of dislocation
are as follows:
Pain: Dislocations are very painful.
• Deformity: In most dislocations the limb attains a
classic attitude (Table).
• Swelling: It is obvious in the dislocation of a
superficial joint, but may not be so in a joint located
deep.
• Loss of movement because of severe pain and
muscle spasm and loss of articulation.

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• Shortening of the limb occurs in most
dislocations except in anterior dislocation of
the hip where lengthening occurs.
• Telescopy: In this test, it is possible to
produce an abnormal to and fro movement in a
dislocated joint (see Annexure-III).
As with all limbs injuries, specific tests to
establish the integrity or otherwise of major
nerves and vessels of the extremity must be
established in all cases of dislocation

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Radiological examination: In doubtful cases,
the diagnosis must finally depend on adequate
X-ray examination. The following principles
should be remembered:
• X-ray should always be taken in two planes at
right angles to each other, because a dislocation
may not be apparent on a single projection.
• If in doubt, X-rays of the opposite limb may
betaken for comparison. CT scan may also be of
help.
• An associated fracture or an
osteochondralfragment must always be looked
for.

15. COMPLICATIONS
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As with a fracture, complications following a dislocation can
be immediate, early or late.
Immediate complication is an injury to the neuro-vascular
bundle of the limb. Early complicationsare:
(i) recurrence;
(ii) myositis ossificans;
(iii) persistent instability; and
(iv) joint stiffness.
Latecomplications are:
(i) recurrence;
(ii) osteoarthritis; and
(iii) avascular necrosis.

16. TREATMENT
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Treatment of a dislocation or subluxation depends upon
its type, as discussed below:
Acute traumatic dislocation: In acute traumatic
dislocation, an urgent reduction of the dislocation is of
paramount importance.
Often it is possible to do so by conservative methods,
although sometimes operative reduction may be required.
a) Conservative methods: A dislocation may be reduced by
closed manipulative manoeuvres.
Reduction of a dislocated joint is one of the most gratifying
jobs an orthopaedic surgeon is called upon to do, as it
produces instant pain relief to the patient. Prolonged
traction may be required for reducing some dislocations.

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b) Operative methods: Operative reduction may be
required in some cases. Following are some of the
indications:
• Failure of closed reduction, often because
the dislocation is detected late.
• Fracture-dislocation:
(i) if the fracture hasproduced significant incongruity
of the joint surfaces;
(ii) a loose piece of bone is lying
within the joint; and
(iii) the dislocation is difficult to maintain by closed
treatment.

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2. Old unreduced dislocations: This often
needs operative reduction.
In some cases, if the function of the dislocated
joint is good, nothing needs to be done.
3. Recurrent dislocations; An individual
episode is treated like a traumatic dislocation.
For prevention of recurrences, reconstructive
proce-dures are required.

19. Reference
• Essential orthopaedics by J.
Maheshwari (MS Orth AIIMS)
fifth edition.

20. Thank you