- A joint is dislocated when its articular surfaces are completely displaced, one from the other, so that all contact between them is lost.
CLASSIFICATION ON THE BASIS OF AETIOLOGY
- CONGENITAL DISLOCATION
- Congenital dislocation is a condition where a joint is dislocated at birth e.g., congenital dislocation of the hip (CDH).
- ACQUIRED DISLOCATION
- Acquired dislocation may occur at any age.
Types of Acquired Dislocation
- TRAUMATIC DISLOCATION
- Injury is by far the commonest cause of dislocations and sub-luxa tions at almost all joints.
- The force required to dislocate a particular joint varies from joint to joint.
DIFFERENT TYPES OF TRAUMATIC DISLOCATIONS
|ACUTE TRAUMATIC DISLOCATION||This is an episode of dislocation where the force of injury is the main contributing factor .||Shoulder dislocation|
|OLD UNREDUCED DISLOCATION||A traumatic dislocation, not reduced, may present as an old unreduced dislocation .||Old posterior dislocation of the hip|
|RECURRENT DISLOCATION||In some joints, proper healing does not occur after the first dislocation. 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|
|FRACTURE-DISLOCATION||When a dislocation is associated 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|
- 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.
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
Rarely, a ligament may withstand the force of 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 ‘shaved off’
Producing an osteochondral fragment within the joint.
- Loss of function
- Restricted mobility
- X-ray should always be taken in two planes at right angles to each other
- CT scan may also be of help.
|RecurrenceMyositis OssificansPersistent InstabilityJoint Stiffness||RecurrenceOsteoarthritisAvascular Necrosis.|
- ACUTE TRAUMATIC DISLOCATION
- urgent reduction of the dislocation by:
- Conservative methods
- A dislocation may be reduced by closed manipulative manoeuvres.
- Prolonged traction may be required for reducing some dislocations.
- Operative methods
- Operative reduction in case of:
- Old unreduced dislocations
- RECURRENT DISLOCATIONS
- An individual episode is treated like a traumatic dislocation.
- For prevention of recurrences, reconstructive proce -dures are required.
DISLOCATION OF SHOULDER JOINT
- When the head of humerus is displaced and loses contact with the glenoid cavity, the condition is called dislocation of shoulder.
|ACUTE DISLOCATION||Anterior Dislocation||In this injury, the head of the humerus comes out of the glenoid cavity and lies anteriorly.|
|Posterior Dislocation||In this injury, the head of the humerus comes to lie posteriorly, behind the glenoid.|
|Inferior Dislocation (Luxation Erecta)||The head comes to lie in the subglenoid position.|
- ACUTE DISLOCATION
- ANTERIOR DISLOCATION
- In this injury, the head of the humerus comes out of the glenoid cavity and lies anteriorly.
- Fall on hand with external rotation of shoulder.
- Violence of the joint with upper arm in abduction.
- Wide range of movement.
|Preglenoid||The head lies in front of the glenoid.|
|Subcoracoid||The head lies below the coracoid process. Most common type of dislocation.|
|Subclavicular||The head lies below the clavicle.|
|Bankart’s lesion||Avulsion of a piece of bone from antero-inferior glenoid rim.|
|Hill-Sachs lesion||This is a depression on the humeral head in its postero-lateral quadrant.|
|Rounding off of the anterior glenoid rim||Occurs in chronic cases as the head dislocates repeatedly over it.|
|Associated injuries||Fracture of greater tuberosityRotator-cuff tearChondral damage|
- Extreme pain and swelling of affected shoulder joint.
- Pt. resents any movement of shoulder.
- Arm may not always lie by the side, may be in slight abduction.
- Gap under the edge of acromion due to absence of humeral head.
- On palpation just below the coracoid process, head of humerus may be felt there.
- Flattened shoulder.
- Abnormal prominence of acromion due to absence of humeral head.
- Few tests are performed:`
|Dugas’ Test||Inability to touch the opposite shoulder.|
|Hamilton Ruler Test||Because of the flattening of the shoulder, it is possible to place a ruler on the lateral side of the arm. This touches the acromion and lateral condyle of the humerus simultaneously.|
|Callway’s Test||Vertical circumference of axilla is increased in comparison to the other side.|
|Bryant’s Test||Anterior & posterior folds of axilla are at different levels.|
- X-ray – Trans Lateral View.
- CT scan
- Reduction under sedation or general anaesthesia
- Followed by immobilisation of the shoulder in a chest-arm bandage for three weeks.
- After the bandage is removed, shoulder exercises are begun.
TECHNIQUES OF REDUCTION OF SHOULDER DISLOCATION
|KOCHER’S MANOEUVRE||This is the most commonly used method. The steps are as follows: Traction— with the elbow flexed to a right angle steady traction is applied along the long axis of the humerus; External rotation—the arm is rotated externallyAdduction—the externally rotated arm is adducted by carrying the elbow across the body towards the midline; Internal rotation – the arm is rotated internally so that the hand falls across to the opposite shoulder.|
|HIPPOCRATES MANOEUVRE||In this method, the surgeon applies a firm and steady pull on the semiabducted arm. He keeps his foot in the axilla against the chest wall. The head of the humerus is levered back into position using the foot as a fulcrum.|
|GRAVITATIONAL TRACTION||Manoeuvre is performed without GA. Pethidine 200 mg is administered. Pt. lies prone on the table. Place a sandbag under the clavicle and arm is allowed to hang over the side of table. Maintain the same position Shoulder is reduced within an hour|
- POSTERIOR DISLOCATION
- Due to fall on outstretched hand and internally rotated head.
- Direct blow on the front of the shoulder.
- Forced internal rotation of the abducted shoulder.
- Local tenderness
- X-Ray – Axial lateral or translateral view
- Arm is abducted at 90⁰ and traction is applied
Then externally rotated
On complete reduction, arm is rested in a broad arm sling.
- RECURRENT DISLOCATION
- When the shoulder dislocates repeatedly with decreasing trauma, the condition is known as recurrent dislocation.
- It is usually an anterior dislocation.
- Dislocation of shoulder with trivial trauma.
- Self-reduction of shoulder.
- Sudden external rotation of shoulder.
- Putti-Platt operation
- Bankart’s operation
- Bristow’s operation
- Arthroscopic Bankart repair
DISLOCATION OF THE ELBOW JOINT
|CRITERIA||POSTERIOR DISLOCATION||ANTERIOR DISLOCATION|
|DEFINITION||Forearm is pushed backwards.||Forearm is pushed upwards.|
|CAUSES||Fall on outstretched handSpasm of triceps muscle||Fall on the elbowAssociated with fracture of olecranon, humerus shaft, ulna, radius.|
|C / F||Deformity and swelling of elbowPt. supports affected elbow with hand||———————-|
|TREATMENT||Reduction under anaesthesia followed by immobilisation in an above-elbow plaster slab for 3 weeks||Reduction by traction|
|COMPLICATIONS||Joint stiffnessMyositis ossificansMedian and Ulnar Nerve injuryVascular injury|
DISLOCATIONS OF THE HIP JOINT
|ACQUIRED DISLOCATION||Pathological Dislocation||May be seen in TB or RA.|
|Paralytic Dislocation||Following poliomyelitis|
|Traumatic Dislocation||Anterior Dislocation|
DESCRIPTION OF DISLOCATIONS
|CRITERIA||POSTERIOR DISLOCATION||ANTERIOR DISLOCATION||CENTRAL DISLOCATION|
|DEFINIITON||The head of the femur is pushed out of the acetabulum posteriorly.||This is a rare injury||In this common injury, the femoral head is driven through the medial wall of the acetabulum towards the pelvic cavity.|
|CAUSES||The injury is sustained by violence directed along the shaft of the femur, with the hip flexed. It requires a moderately severe force to dislocate a hip, as often occurs in motor accidents. The occupant of the car is thrown forwards and his knee strikes against the dashboard. The force is transmitted up the femoral shaft, resulting in posterior dislocation of the hip. It is, therefore, also known as Dashboard Injury.||Legs are forcibly abducted and externally rotated. Fall from a tree when the foot gets stuck and the hip abducts excessively, or in a road accident.||Fall on side or a blow on greater trochanter which breaks floor of the acetabulum and drives the head of femur through the floor of the acetabulum into the pelvis.|
|TYPES||REGULAR DISLOCATIONIliofemoral ligament is placed anteriorly and remains intact when the dislocation of hip has taken place.IRREGULAR DISLOCATIONWhen iliofemoral ligament is completely torn.||PUBIC TYPEWhen the head of fgemur lies in front of pubis. OBTURATOR TYPEWhen head lies in front of obturator foramen i.e. almost in the perineum.||———————————————|
|C / F||H/O severe trauma followed by pain, swelling and deformity (flexion, adduction and internal rotation).Shortening of the leg. One may be able to feel the head of the femur in the gluteal region.||The limb is in an attitude of external rotation, flexion, abduction. There may be true lengthening, with the head palpable in the groin.||Swelling and bruises in the trochanteric region|
|CRITERIA||POSTERIOR DISLOCATION||ANTERIOR DISLOCATION||CENTRAL DISLOCATION|
|INVESTIGATIONS||X-Ray : Shenton’s Line is distorted.CT scan||X-Ray : Shenton’s Line is distorted.||X-Ray:shows fracture of floor of acetabulum femoral head is displaced medially into pelvis.|
|TREATMENT||Technique of Closed Reduction The patient is anaesthetised and placed supine on the floor An assistant grasps the pelvis firmly The surgeon flexes the hip and knee at a right angle and exerts an axial pull Usually one hears a‘sound’ of reduction, after which it becomes possible to move the hip freely in all directions The leg is kept in light traction with the hip abducted, for 3 weeks. ImmobilisationFixed skin traction in a Thomas Splint for 4 weeks and then moblisation on bed for further 2 weeks before wieght bearing.Skeletal traction for 3 weeks through tibial tubercle||Reduction :Same as posterior dislocation .Under GA, hip is flexed, abducted, and external rotation are corrected by medial rotating and adducting the hip.ImmobilisationFixed skin traction in a Thomas Splint for 4 weeks and then moblisation on bed for further 2 weeks before wieght bearing.Skeletal traction for 3 weeks through tibial tubercle||Reduction :Under GA, pull thigh strongly and femoral head is levered outwards by adducting the thigh.Immobilisation :Traction is applied distally and laterally for 3 weeks with 15 pounds weight.Rehabilition :After traction has been pulled off, patient may be allowed up with crutches.No weight bearing for 8 weeks.|
|COMPLICATIONS||Injury to the sciatic nerveAvascular necrosis of the femoral headLate OA of hipMyositis ossificansUnreduced dislocation||Femoral nerve injuryObturator nerve injuryAvascular necrosis of femoral headSecondary OA||OsteoarthrosisHip stiffnessMyositis ossificans|