Dislocations Flashcards
What is a dislocation?
It is a displacement of a bone from its natural position in the joint; the two bones fully separate from each other (complete loss of articulation of bone ends within the joint capsule).
What is the most common dislocated joint?
The shoulder
What causes an anterior shoulder injury and what is the associated nerve injury?
- Ocurs as a result of forceful abduction and external rotation
- Axillary nerve injury (palsy) occurs in approx. 10% of anterior dislocations
- Associated with labrum/rotator cuff injury
- MOST COMMON shoulder dislocation is anterior and occurs in young athletes; may reoccur
What causes a posterior shoulder injury?
- Results from forceful internal rotation and adduction
- although rare (2-5%), it is usually from seizure- falling prone onto face/shoulder causing shoulder to dislocate
What causes a superior shoulder dislocation?
Falling on outstretched arm
What causes an inferior shoulder injury and what is the associated nerve injury?
- Caused by sudden forceful arm hyperabduction
- Less commonly, direct loading force on fully abducted arm, with extended elbow and pronated forearm
- The humeral head is forced against the acromion, usually with resultant inferior glenohumeral capsule rupture and rotator cuff disruption.
- Axillary nerve injury occurs in approx. 50% of inferior shoulder dislocation
What causes an anterior knee dislocation?
- There is loss of ACL integrity normally by hyperextension of joint
- If both the integrity of the ACL and PCL is absent, it is considered a MEDICAL EMERGENCY- unstable knee
What causes a posterior knee dislocation?
- Caused by a loss of PCL integrity
- Can occur in a ‘dash board’ impact as in an MVA
- High incidence of popliteal artery disruption
- If both the integrity of the ACL and PCL is absent, it is considered a MEDICAL EMERGENCY- unstable knee
What vascular injuries can occur with knee dislocations?
- Popliteal artery injury/disruption occurs in 20-40% of knee dislocations
- Higher occurrence in posterior knee dislocations
What are some subjective/physical exam findings associated with bone dislocations?
Subjective Findings
- Pain over the affected area
- Loss of sensation/numbness over the affected area or distal to the injury
Physical Exam Findings
- Joint deformity
- Shortening of the affected limb
- Swelling
- Contusion
- Decreased or absent peripheral pulses distal to joint
- Decreased or absent ROM of joint or distal to joint
- Decreased or absent sensation distal to joint
- Paresthesia distal to injury
What lab/diagnostic tests would you order for patients with bone dislocations?
- CBC – WBC may be elevated due to trauma/stress response
- Hgb/Hct – check in case of bleeding or hematoma
- X-rays-
- Antero-posterior and lateral films should be ordered on all possible dislocations
- May consider oblique films if fracture is a concern
- Ultrasound or arteriogram- for all POSTERIOR knee dislocations due to high incidence of popliteal artery disruption
- Monitor compartment pressures in knee dislocations WITH vascular compromise > 6 hours post injury
How do you initially manage a patient with a bone dislocation?
- Early anatomic reduction: either closed (no fractures present) or surgical reduction (if fractures are present)
- Post reduction immobilization: either splints, cast, immobilizers, slings
- Cold compresses to reduce swelling
- Elevation of extremity
- Surgical repair of ligamentous injuries
- PT for strengthening
- Occupation therapy: if assistive devices are required due to neurovascular injuries
- NSAIDS
- Muscle relaxants if needed- Cyclobenzaprine, Metaxalone, Methocarbamol, Baclofen, Tizanidine (ALL CAUSE DROWSINESS and increase fall risk potential)
- Narcotics for short term use only
- Skeletal traction – in limited cases only
