Knee problems

Question 1

History taking (what to ask about) in knee problems

Answer 1

Mechanism

• Swelling

• Immediate = haemarthrosis = # or torn cruciates
• Overnight = effusion = meniscus or other lgt

• Pain / tenderness

• Joint line = meniscal
• Med/lateral margins = collateral lgts.
• Locking: meniscal tear → mechanical obstruction
• Giving way: instability following lgt. injury

Question 2

Causes of knee haemarthrosis

Answer 2

Knee Haemarthrosis

1°: spontaneous bleeding

• Coagulopathy: warfarin, haemophilia

• 2°: trauma

• ACL injury: 80%
• Patella dislocation: 10%
• Meniscal injury: 10%
• Outer third

Question 3

Elements of the unhappy triad of O’Donoghue

Answer 3

Unhappy Triad of O’Donoghue → injury of:

• ACL (anterior cruciate ligament)
• MCL (medial collateral ligament)
• Medial Meniscus

Question 4

What’s unhappy triad injury? Cause

Answer 4

The unhappy triad

• occurs due to a lateral blow to the knee → rupture in the anterior cruciate ligament, medial collateral ligament, and meniscus
• injury is most often sustained when a lateral (from the outside) force impacts the knee while the foot is fixed on the ground
• This type of injury occurs often in contact sports such as football, rugby, or motocross
• During the injury, the leg is laterally rotated and over-abducted
• In about 10% of cases, the force is applied to the opposite side of the knee, and the lateral and posterolateral ligaments are torn.

Question 5

Treatment for unhappy triad injury

Answer 5

• usually requires surgery
• An ACL surgery is common and the meniscus can be treated during the surgery as well
• The MCL is rehabilitated through time and immobilization
• Physical therapy after the surgery and the use of a knee brace help speed up the healing process

Question 6

Management of acutely injured knee

Answer 6

• Full examination of acutely swollen knee after injury is difficult
• Take x-ray to ensure no fractures
• Fluid level indicates a lipohaemarthrosis and

indicates either a # or torn cruciate

• If no # → RICE + later re-examination for pathology
• If meniscal or cruciate injury suspected → MRI

Question 7

What’s arthroscopy?

Answer 7

• Direct vision of inside of knee joint by arthroscope
• Can examine knee under anaesthesia (↓ muscle tone)
• Meniscal tears can be trimmed or repaired

Question 8

Ruptured Anterior Cruciate Ligament

• mechanism
• typical presentation
• management

Answer 8

• Sport injury
• Mechanism: high twisting force applied to a bent knee
• Typically presents with: loud crack, pain and RAPID joint swelling (haemoarthrosis)
• Poor healing
• Management: intense physiotherapy or surgery

Question 9

Ruptured Posterior Cruciate Ligamanet

• mechanism
• examination findings
• management

Answer 9

• Mechanism: hyperextension injuries
• Tibia lies back on the femur
• Paradoxical anterior draw test → posterior draw test positive
• Management:
• conservative: aspiration of haemarthrosis, analgesia and physiotherapy
• arthroscopic repair

Question 10

Rupture of medial collateral ligament

- mechanism of injury

• management

Answer 10

• Mechanism: leg forced into valgus via force outside the leg
• often as part of unhappy triad
• Knee unstable when put into valgus position

Management:

• immobilisation in cast for 6 weeks

OR

• surgical reconstruction

Question 11

Meniscal tear

• cause
• presentaiton
• management

Answer 11

• the majority would involve medial meniscus
• traumatic or degenerative causes; rotational sport injuries

Presentation:

• Delayed knee swelling
• Joint locking (Patient may develop skills to ‘unlock’ the knee
• Recurrent episodes of pain and effusions are common, often following minor trauma

Management:

• arthroscopy and partial meniscectomy (total is too risky in terms of premature osteoarthritis) + meniscal repair

Question 12

Dislocation of patella

• mechanism

Answer 12

• Most commonly occurs as a traumatic primary event, either through direct trauma or through severe contraction of quadriceps with knee stretched in valgus and external rotation
• Genu valgum, tibial torsion and high riding patella are risk factors

Question 13

Ix for dislocated patella

Answer 13

• Skyline x-ray views of patella are required, although displaced patella may be clinically obvious

Question 14

Management of patellar dislocation

Answer 14

• Conservative treatment (rehabilitation and physical therapy)
• surgery

Question 15

What’s McMurray’s test?

Answer 15

Test for meniscal tear

• unreliable and difficult
• performed when joint line tenderness is present

Knee is fully flexed + foot externally rotated (with lower leg abducted)

If the knee is extended + click and pain over medial joint line → meniscal tear