Disorders of the knee

Question 1

Femoral shaft fractures

Answer 1

High velocity trauma but in elderly can be falling from standing position

Question 2

How fragments of femoral shaft fractures look

Answer 2

Proximal fragment = abducted due to pull of glut max and med
Distal fragment = adducted due to action of adductor muscles
Tense swollen thigh

Question 3

Major risks of femoral shaft fractures

Answer 3

Blood loss (in open fractures double that in closed) and hypovolaemic shock

Question 4

Treatment of femoral shaft fracture

Answer 4

Surgical fixation

Question 5

Distal femoral fracture

Answer 5

Youth = high energy sport injury
Elderly = osteoporotic FFSP

Question 6

Vascular effect of distal femoral fracture

Answer 6

Popliteal artery involved if significant displacement

Question 7

Tibial plateau fractures

Answer 7

Diagonal fracture of the condyle of the tibia from high energy injuries, articular cartilage always damaged and end up w post traumatic osteoarthritis

Question 8

Patellar fractures

Answer 8

Direct impact injury or eccentric contraction of quads

Question 9

Treatment of patellar fracture

Answer 9

Displaced = reduction and surgical fixation
Undisplaced = splinting and crutches

Question 10

Test of patellar fracture

Answer 10

Fracture completely splits patella distal to insertion of quad tendon = patient can’t do straight leg raise

Question 11

Normal anatomical variant of patella

Answer 11

Bipartite = failure of union of secondary ossification centre

Question 12

Patella dislocation

Answer 12

Normally laterally and by trauma - internal rotation of femur on planted foot whilst flexing knee

Question 13

Predisposition of patellar dislocation

Answer 13

• Lax ligaments
• Weak quads, esp VMO
• Shallow patellofemoral groove
• Long patellar ligament
• Previous dislocations

Question 14

Treatment of patellar dislocation

Answer 14

Manually reducing patella

Question 15

Meniscal injuries

Answer 15

Tear in the meniscus due to sudden twisting of knee when flexed

Question 16

Patient description of meniscal tear and signs

Answer 16

• Intermittent pain localised to joint line
• Knee clicking/catching/locking
• Joint line tenderness
• Restricted motion - pain or swelling

Question 17

Treatment of meniscal tear

Answer 17

Surgically by removal or repair.

Question 18

Collateral ligament injury

Answer 18

Acute varus or valgus angulation of knee

Question 19

The unhappy triad

Answer 19

Injury to:

1. ACL
2. MCL
3. Medial meniscus

Question 20

Anterior and posterior cruciate ligament injury

Answer 20

ACL weaker than PCL so more commonly injured - changing direction in sport = quick deceleration then hyperextension or rotation

Question 21

Patient description of ACL injury

Answer 21

Could feel it pop and then it immediately swelled, also felt like it was giving way

Question 22

Treatment of ACL injury

Answer 22

• Low functional knee demands = ruptured ACL and joint stabilised by musculature
• Sportsmen and active = surgical reconstruction

Question 23

Common mechanism of PCL injury

Answer 23

Dashboard injury - flexed knee and then large force

Question 24

Knee joint dislocation

Answer 24

Uncommon and always from high energy trauma - need 3/4 ligaments ruptured

• MCL
• ACL
• LCL
• PCL

Question 25

Associated artery injury in knee joint dislocation

Answer 25

Popliteal artery passes through political fossa - Haematoma - Artery crushed = thrombotic occlusion

Question 26

Treatment of knee dislocation

Answer 26

Reduction of knee joint

Question 27

Swellings around the knee

Answer 27

- Bony = Osgood-Schlatter's disease - Soft tissue - localised or generalised - Fluid - inside the joint = effusion, outside the joint

Question 28

Knee effusions

Answer 28

Accumulation of fluid in the knee joint - Haemarthrosis - blood in joint e.g. ACL rupture - Lipo-haemarthrosis - blood and fat in joint

Question 29

Bursitis of the knee

Answer 29

Inflam of a bursa

Question 30

Pre-patellar bursa

Answer 30

Knee pain and swelling, repetitive trauma to the bursa = Housemaid's knee

Question 31

Infrapatellar bursitis

Answer 31

Repeated micro trauma when upright kneeling = Clergyman's knee

Question 32

Suprapatellar bursitis

Answer 32

Is extension of synovial cavity = fluid there Causes: - OA - RA - Infection - Gout - Repetitive microtrauma as a result of running on soft/uneven surface

Question 33

Semimembranous bursitis

Answer 33

Swelling in the popliteal fossa | Popliteal cyst or baker's cyst

Question 34

Osgood-Schlatter's disease

Answer 34

Inflammation of site of insertion of patellar ligament into tibial tuberosity Localised pain and swell Patients - intense knee pain when active Treatment - rest and ice

Question 35

OA of knee

Answer 35

Knee pain that comes and goes when bending, kneeling etc, morning stiffness and swelling Varus or Valgus deformity of knee joint Crepitus Buckling knee

Question 36

Varus

Answer 36

Away from midline

Question 37

Valgus

Answer 37

Towards midline

Question 38

Septic arthritis

Answer 38

Invasion of joint space by micro-organisms, knee most common joint affected Staph aureus most common Damage to articular cartilage

Question 39

Risk factors of septic arthritis

Answer 39

- Extremes of age - DM - RA - Immunosuppression - IV drug use - Prosthetic joints - infection years can be after initial operation

Question 40

Symptoms and signs of septic arthritis

Answer 40

- Fever - Pain - Reduced range of motion - Erythema - Swelling - Warmth - Tenderness - Limitation of active and passive range of motion

Question 41

Investigations of septic arthritis

Answer 41

Aspiration of joint and aspirate sent for urgent microscopy, culture and sensitivities

Question 42

Outcome of septic arthritis

Answer 42

High morbidity and if survive often decreased range of motion and chronic pain