Orthopaedic Knee Conditions

Question 1

Meniscal tear causes

Answer 1

• Acute
  
  • Twisting especially in deep flexion
• Degenerative
  
  • Osteoarthritis
• Medial meniscal tears more common
  
  • More fixed structure
• Unlikely to heal
  
  • Poor blood supply

Question 2

Meniscal Tear Presentation

Answer 2

• Tearing sensation in knee
• Intense sudden onset pain
• Swells slowly over following 6-12 hours
• If Meniscal tear results in a free body within the knee it may be locked in flexion

Question 3

Meniscal tear examination

Answer 3

• Look
  
  • Significant joint effusion
• Feel
  
  • Joint line tenderness
• Move
  
  • Limited knee flexion
• Special tests
  
  • McMurray’s test, Apley’s Grind test

Question 4

What are the main functions of the menisci?

Answer 4

1. Shock absorbers of the knee
2. Increase articulating surface area

Question 5

Differentials for an acutely swollen knee joint following trauma

Answer 5

• Fracture
• Meniscal tear
• Cruciate ligament tear
• Collateral ligament tear
• Osteochondritis dissicans

Question 6

Meniscal tear investigations

Answer 6

• X-Ray - to exclude a fracture
• MRI - gold standard

Question 7

Meniscal tear non-operative treatment

Answer 7

• Rest, ice, compression and elevation

Most small meniscal tears (<1cm) will initially swell however the pain will subside over the next few days as the tear heals

Question 8

Meniscal tear operative treatment

Answer 8

• Arthroscopic surgery for larger tears or those remaining symptomatic
  
  • Outer third of meniscus has a rich vascular supply = repair
  • Inner third of meniscus = resection

Question 9

ACL position

Answer 9

It runs from between tibial eminences to lateral wall of intercondylar notch of femur

Question 10

ACL blood supply

Answer 10

middle geniculate artery

Question 11

ACL function

Answer 11

• Important stabiliser of knee joint
  
  • Primary restraint to limit anterior translation of the tibia (relative to femur)
  • Contributes to knee rotational stability

Question 12

ACL tear cause and female:male ratio

Answer 12

• History of twisting the knee while weight bearing
• Occurs without contact
• Females:male 4.5:1

Question 13

ACL tear presentation

Answer 13

• Rapid joint swelling
  
  • haemarthrosis
• Usually unable to weight bear
• Significant pain

Question 14

ACL tear examination

Answer 14

• Look
  
  • effusion (if recent injury)
• Special tests
  
  • Lachman test
  • Anterior draw test

Question 15

ACL tear investigations

Answer 15

• X-ray
  
  • Segond fracture (bony avulsion of the lateral proximal tibia) is pathognomic of ACL injury
• MRI
  
  • Gold standard to confirm diagnosis of ACL injury
  • Pick up an associated meniscal tears
    
    • Lateral – simultaneous with acl tear (48%)
    • Medial – secondary to shear from chronic instability
  • Pick up MCL tears

Question 16

ACL tear non-operative treatment

Answer 16

• Initial management: rest, ice, compression, elevation
• Conservative management
  
  • Strength training of quadriceps to stabilise the knee

Question 17

Complications of ACL tear

Answer 17

Post-traumatic osteoarthritis is a well established complication of both ACL injury and ACL reconstructive surgery

Question 18

Superficial and deep MCL function

Answer 18

• superficial - primary restraint to valgus stress
• deep - contributes to full knee extension

Question 19

MCL tear pathology and associated injuries

Answer 19

• severe valgus stress
  
  • usually contact related
• associated injuries
  
  • ACL tear
  • Meniscal tear

Question 20

MCL tear symptoms

Answer 20

• May report hearing a ‘pop’
• Immediate medial joint line pain
• Swelling follows after a few hours

Question 21

MCL tear examination

Answer 21

• Feel
  
  • tender medial joint line
  • tender femoral insertion of MCL
• Move
  
  • Increased laxity with testing MCL via the valgus stress test

Question 22

MCL tear investigations

Answer 22

• X-Ray
  
  • To exclude any fractures
• MRI
  
  • Gold standard
  • Assess location and severity of injury

Question 23

MCL tear non-operative treatment

Answer 23

• Majority
• RICE, NSAIDs
• Physiotherapy
• Depending on grade of injury: knee brace +/- crutches