Joint injury (inc dislocation)

Question 1

What are the classifications of joint injury, in order of decreasing severity?

Answer 1

Dislocation, subluxation, strain or contusion.

Question 2

What is the purpose of a ligament? How does it accomplish this?

Answer 2

Prevent abnormal movement at a joint.

Not always reliant on intrinsic strength; reflexive contraction of supporting muscles protect under increased stress.

Question 3

What is a joint dislocation?

Answer 3

When articular surfaces of joint are wholly displaced from each other so that all apposition is lost between them.

Question 4

What is joint subluxation?

Answer 4

Articular surfaces are partially displaced but retain some contact with one another.

Question 5

What are the complications of joint dislocation?

Answer 5

• Infection (after open dislocation)
• injury to soft tissue (artery, nerve)
• avascular necrosis a bony end
• recurrent dislocation/sublux due to instability
• stiffness from adhesions, post traumatic ossification
• OA from damage to cartilage

Question 6

What are the principles of managing dislocation?

Answer 6

-Reduction of displacement: closed manipulation, surgery
-Treatment of ligamentous injury: self resolution, surgery.
Encourage early mobilisation.

Question 7

What are the exclusions to early mobilisation of an injured joint?

Answer 7

1) Rupture of an important ligament responsible for joint stability (e.g. MCL of knee)
2) high risk of post traumatic ossification (elbow, +/- hip)
3) severe pain

Question 8

What is a strain?

Answer 8

Incomplete rupture of a ligament. May be acute or chronic.

Question 9

What are the clinical features of a strain?

Answer 9

• Hx of injury that would impose stretching force
• local pain and tenderness
• moderate swelling
• +/- visible ecchymosis
• mvt aggravates pain in direction that tenses ligament

Question 10

How should strain be diagnosed?

Answer 10

Largely clinical. Xray to ensure not fractured/subluxed (may need to stretch joint in direction of injury to ensure ligament not ruptured).

Question 11

Management of acute strain?

Answer 11

Depends on ligament and severity.
Basically encourage early mobilisation, avoid external splints if possible.
If severe, plaster UP TO 2-3 weeks.

Question 12

What is a joint contusion?

Answer 12

Contusion may involve capsule, synovial membrane and possibly articular cartilage. Injury initiates local inflammation with swelling and serous exudate.

Question 13

Clinical features of joint contusion?

Answer 13

Hx of direct blow to joint, swelling and local tenderness on palpation, movement may be reduced due to effusion.

Question 14

Mx joint contusion?

Answer 14

Healing spontaneous.

Symptomatic Rx only.

Question 15

Which cruciate ligament more commonly torn?

Answer 15

ACL

Question 16

Where does the ACL run?

Answer 16

From medial wall of lateral femoral condyle to the anteromedial and posterolateral intercondyloid eminence of the tibial plateau

Question 17

What is the mechanism of ACL injury?

Answer 17

Sudden deceleration.

Hyperextension and internal rotation of tibia on femur

Question 18

Important Hx features in ACL injury?

Answer 18

• Audible “pop”
• Immediate swelling
• Knee “giving way”
• Inability to continue activity

Question 19

What are the examination features of ACL injury?

Answer 19

• Effusion (haemarthrosis)
• Posterolateral joint line tenderness
• Positive anterior drawer test
• Positive Lachmann
• Pivot shift

Question 20

How should ACL tear be managed?

Answer 20

Stable knee with minimal functional impairment.
Immobilise for 2-4w with early ROM and strengthening.
Demanding lifestyle: reconstruction

Question 21

Where does the PCL traverse?

Answer 21

Lateral wall of medial femoral condyle to posterior intercondyloid eminence of the tibial plateau.

Question 22

Mechanism of PCL tear?

Answer 22

Sudden posterior displacement of tibia when knee is flexed or hyperextended (dashboard MVA injury).

Question 23

Exam features of PCL tear?

Answer 23

• Effusion (haemarthrosis)
• Anteromedial joint line tenderness
• Positive posterior drawer
• Reverse pivot shift
• Ligamentous/bony injuries

Question 24

Hx features of PCL tear?

Answer 24

• Audible pop
• Immediate swelling
• Pain with push off
• Cannot descend stairs

Question 25

What is O’Donoghue’s triad?

Answer 25

O’Donoghue’s Unhappy Triad:

1) ACL rupture
2) MCL rupture
3) Meniscal damage

Question 26

What are the Ottawa Ankle Rules?

Answer 26

Ankle imaging required if there is pain in malleolar zone and any of:

1. Bone tenderness at posterior edge or tip of lateral malleolus
2. Bone tenderness at posterior edge or tip of medial malleolus
3. Inability to bear weight both immediately / in ED

Question 27

What are the Ottawa Foot Rules?

Answer 27

Foot imaging required if there is pain in any midfoot zone and any of:

1. Bone tenderness at base of 5th metatarsal
2. Bone tenderness at navicular area
3. Inability to bear weight both immediately / in ED

Question 28

Mechanism and Mx of avulsion of the base of 5th metatarsal?

Answer 28

• occurs with inversion injury

- supportive tensor or below knee walking cast for 3/52

Question 29

Features of calcaneal #?

Answer 29

• Ass/w fall from height

- Associated injury may involve ankles, knees, hips, pelvis, lumbar spine

Question 30

What are the Ottawa Knee Rules?

Answer 30

A knee Xray required only for acute injury pts with 1+ of:

• Age 55+
• Tenderness at head of fibula
• Isolated tenderness of patella
• Inability to flex to 90”
• Inability to bear weight both immediately and in the ED (4 steps)