2. MSK p155-163 (Trauma/Acquired - Lower Limbs)

Question 1

Femoral neck fractures - trivia (anatomy) (2)

Answer 1

Medial is classic stress fracture location.
Lateral is classic bisphosphonate fracture location.

Question 2

Hip dislocation (3)

Answer 2

Commonly associated with dashboard injuries.
Posterior dislocation much more common than anterior.
Posterior dislocation usually associated with fracture.

Question 3

Anterior & posterior column of the hip (3)

Answer 3

Acetabulum supported by 2 columns of bone, which come together to form an inverted Y.
Iliopectineal line = anterior column, Ilioischial line = posterior column.
Both column fractures divide the ilium proximal to hip joint, meaning no articular surface of the hip attached to the axial skeleton, which is a problem.

Question 4

Corona mortis (2)

Answer 4

Anastamosis of inferior epigastric and obturator vessels sometiems lies on the superior pubic ramus.
This can be injured during lateral dissection, sometimes used to repair hip.

Question 5

Hip fracture and AVN (2)

Answer 5

Displaced intracapsular fracture increases risk of AVN (vascular supply comes from circumflex femorals).
Degree of displacement corresponds with degree of AVN risk.

Question 6

Avulsion injury - trivia (2)

Answer 6

Seen more in kids than adults (because tendons are stronger than bones in kids).
Isolated lesser trochanter avulsion - suspect pathologic fracture.

Question 7

Avulsion at iliac crest caused by

Answer 7

Abdominal muscles

Question 8

Avulsion at ASIS caused by

Answer 8

Sartorius

Question 9

Avulsion at AIIS caused by

Answer 9

Rectus femoris

Question 10

Avulsion at Greater Trochanter caused by

Answer 10

Gluteal muscles

Question 11

Avulsion at ischial tuberosity caused by

Answer 11

Hamstrings

Question 12

Avulsion at pubic symphysis caused by

Answer 12

Adductor group

Question 13

Snapping hip syndrome (4)

Answer 13

Clinical sensation of snapping or clicking on hip flexion and extension
3 types:
External (most common) - Iliotibial band over greater trochanter
Internal - iliopsoas over iliopectineal eminence or femoral head
Intra-articular - labral tears/joint bodies

Question 14

Femoroacetabular impingement (FAI) (3)

Answer 14

Painful hip movement, caused by deformities of the hip/femoral head.
2 types - pincer impingement and cam impingement
Commonest location for acetabular labral tear = anterior superior.

Question 15

Pincer type FAI (3)

Answer 15

Over-coverage of the femoral head by the acetabulum
Seen in middle aged women
Cross over sign - anterior acetabular rim crossing over the posterior rim

Question 16

Cam type FAI (3)

Answer 16

Bony protrusion on the antero-superior femoral head-neck junction.
Seen in young men.
Pistol grip deformity of the femur.

Question 17

Sacral insufficiency fracture - causes (6)

Answer 17

Commonest: postmenopausal osteoporosis.
Also seen in:
- Renal failure
- RA
- Radiation
- Mechanical changes post hip arthroplasty
- Long term steroid use

Question 18

Sacral insufficiency fractures - imaging (2)

Answer 18

Often occult on plain film.
Honda sign (H shaped increased uptake) on bone scan

Question 19

Segond fracture (3)

Answer 19

Lateral tibial plateau fracture.
Associated with ACL tear.
Occurs with internal rotation.

Question 20

Reverse segond fracture (4)

Answer 20

Medial tibial plateau fracture.
Associated with PCL tear.
Occurs in external rotation.
Associated with medial meniscus injury.

Question 21

Arcuate sign (2)

Answer 21

Avulsion of proximal fibula (insertion of arcuate ligament complex).
90% associated with cruciate ligament injury (usually PCL).

Question 22

Deep intercondylar notch sign (2)

Answer 22

Depression of lateral femoral condyle (terminal sulcus), secondary to impaction injury.
Associated with ACL tears.

Question 23

Patella dislocation (3)

Answer 23

Almost always lateral, medial patello-femoral ligament is injured.
Characteristic appearance on MRI:
- Classic contusion pattern.

Question 24

Patella Alta - causes (7)

Answer 24

Patella tendon rupture leads to unopposed upward pull from quads tendon, causing patella alta.
Classically associated with SLE.
Also seen in:
- elderly
- trauma
- athletics
- RA
“Bilateral patellar tendon rupture” = Chronic steroids

Question 25

Patella Baja (2)

Answer 25

Quads tendon rupture leads to unopposed downward pull, leading to Patella Baja.

Question 26

Tibial plateau fractures (3)

Answer 26

Most commonly due to axial loading.
Lateral way more common than medial (Medial is usually seen WITH lateral too).
Schatzker type 2 (split, depressed lateral fracture) is commonest.

Question 27

Pilon fracture (4)

Answer 27

a.k.a. tibial plafond fracture.
Commonly due to axial loading, talus driven into tibial plafond.
Comminution and articular impaction.
75% also get distal fibula fractures

Question 28

Tibial shaft fracture (2)

Answer 28

Commonest long bone fracture.
Many ways to repair it surgically.

Question 29

Tillaux fracture

Answer 29

Salter Harris 3 through the anterolateral aspect of the distal tibial epiphysis.

Question 30

Triplane fracture

Answer 30

Salter Harris 4, vertical component through epiphysis, horizontal through physis, oblique through metaphysis.

Question 31

Maisonneuve fracture - definition/pathology/trivia (3)

Answer 31

Unstable fracture involving medial malleolus and/or disruption of the distal talofibular syndesmosis.
Forces begin distally (tibiotalar joint) and ride up syndesmosis to proximal fibula.
Does NOT extend into the hindfoot.

Question 32

Maisonneuve fracture - imaging (2)

Answer 32

Ankle with widened mortis on XR.
Look further up for proximal fibular shaft fracture.

Question 33

Cassanova fracture (3)

Answer 33

Bilateral calcaneal fractures - look for compression or burst fractures of the spine.
Occur due to axial loading.
Peroneal tendons can become entrapped within lateral calcaneal fractures.

Question 34

Bohler’s angle (2)

Answer 34

Line drawn between anterior and posterior borders of calcaneus on lateral view.
Normal >20 degrees. <20 concerning for fracture.

Question 35

Jones fracture (3)

Answer 35

Fracture of base of 5th metatarsal, 1.5cm distal to tuberosity.
Rx: Non-wt bearing cast
may need internal fixation due to risk of non-union.

Question 36

Avulsion fracture of 5th MT

Answer 36

More common than Jones #.
Classically dancer with lateral foot pain.
Can be 2ndary to tug from lateral cord of plantar aponeurosis or peroneus brevis.

Question 37

Stress fracture of 5th MT

Answer 37

High risk fracture, hard to heal

Question 38

Lisfranc injury (5)

Answer 38

Commonest dislocation of the foot.
Lisfranc joint is the articulation of the tarsals and metatarsal heads.
Lisfranc ligament connects medial cuneiform to the 2nd metatarsal base on the plantar aspect.
Rupture of ligament results in one of 2 parrrerns:
- Homo-lateral: Every MT moves lateral
- Divergent: 1st MT moves medial, others move lateral.

Question 39

Lisfranc injury - trivia (3)

Answer 39

Cannot exclude on non-wt bearing film.
Associated fractures most common at base of 2nd MT (Fleck sign - bony fragment in the LisFranc space between 1st MT and 2nd MT, associated with avulsion of LisFranc ligament).
Fracture non-union and post traumatic arthritis are complications of missed fractures.

Question 40

Stress fracture vs insufficiency fracture

Answer 40

Stress fracture = abnormal stress on normal bone
Insufficiency fracture = normal stress on abnormal bone

Question 41

Compressive side vs tensile side (5)

Answer 41

Relates to femoral neck and tibia.
Compressive side fractures are constantly being pushed together, hence they do well as they heal well.
Tensile side fractures are constantly being pulled apart, hence they do poorly.
Femoral neck: tensile = lateral.
Tibia: tensile = anterior

Question 42

Femoral stress fracture (3)

Answer 42

Compressive (medial) more common
usually seen in younger people along inferior femoral neck.
Tensile (lateral) more common in old people

Question 43

Tibial stress fracture (5)

Answer 43

Commonest site of stress fracture in young athletes.
Most common on compressive side (posterior medial)
Most common in proximal or distal third.
Less common on tensile side (these favor mid shaft).
“Dreaded black lines” as they often don’t heal.

Question 44

SONK (5)

Answer 44

Spontaneous osteonecrosis of the knee.
Type of insufficiency fracture.
Classically old ladies, sudden pain after rising from seated.
Can be seen in younger people, after meniscal surgery.
Favours medial femoral condyle (area of max weight bearing).

Question 45

Navicular stress fracture (2)

Answer 45

Runners on hard surfaces.
Navicular is high risk of AVN.

Question 46

March fractures

Answer 46

Metatarsal stress fracture, classically seen in military recruits.

Question 47

Calcaneal stress fracture (3)

Answer 47

Calcaneus is most fractured tarsal bone.
Usually intra-articular (75%).
Stress fracture with fracture line perpendicular to trabecular lines.

Question 48

High risk stress fractures (7)

Answer 48

low likelihood of uncomplicated healing with conservative management.
Femoral neck (tensile)
Transverse patella
Anterior tibial fracture (midshaft)
5th metatarsal
Talus
Tarsal navicular
Sesamoid great toe

Question 49

Low risk stress fractures (5)

Answer 49

High likelihood of uncomplicated healing with conservative Rx
Femoral neck (compressive),
Longitudinal patella
Posteriomedial tibial fracture
2nd and 3rd metatarsal
Calcaneus