2. MSK p155-163 (Trauma/Acquired - Lower Limbs) Flashcards
Femoral neck fractures - trivia (anatomy) (2)
Medial is classic stress fracture location.
Lateral is classic bisphosphonate fracture location.
Hip dislocation (3)
Commonly associated with dashboard injuries.
Posterior dislocation much more common than anterior.
Posterior dislocation usually associated with fracture.
Anterior & posterior column of the hip (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.
Corona mortis (2)
Anastamosis of inferior epigastric and obturator vessels sometimes lies on the superior pubic ramus.
This can be injured during lateral dissection, sometimes used to repair hip.
Hip fracture and AVN (2)
Displaced intracapsular fracture increases risk of AVN (vascular supply comes from circumflex femorals).
Degree of displacement corresponds with degree of AVN risk.
Avulsion injury - trivia (2)
Seen more in kids than adults (because tendons are stronger than bones in kids).
Isolated lesser trochanter avulsion - suspect pathologic fracture.
Avulsion at iliac crest caused by
Abdominal muscles
Avulsion at ASIS caused by
Sartorius
Avulsion at AIIS caused by
Rectus femoris
Avulsion at Greater Trochanter caused by
Gluteal muscles
Avulsion at ischial tuberosity caused by
Hamstrings
Avulsion at pubic symphysis caused by
Adductor group
Snapping hip syndrome (4)
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
Femoroacetabular impingement (FAI) (3)
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.
Pincer type FAI (3)
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
Cam type FAI (3)
Bony protrusion on the antero-superior femoral head-neck junction.
Seen in young men.
Pistol grip deformity of the femur.
Sacral insufficiency fracture - causes (6)
Commonest: postmenopausal osteoporosis.
Also seen in:
- Renal failure
- RA
- Radiation
- Mechanical changes post hip arthroplasty
- Long term steroid use
Sacral insufficiency fractures - imaging (2)
Often occult on plain film.
Honda sign (H shaped increased uptake) on bone scan
Segond fracture (3)
Lateral tibial plateau fracture.
Associated with ACL tear.
Occurs with internal rotation.
Reverse segond fracture (4)
Medial tibial plateau fracture.
Associated with PCL tear.
Occurs in external rotation.
Associated with medial meniscus injury.
Arcuate sign (2)
Avulsion of proximal fibula (insertion of arcuate ligament complex).
90% associated with cruciate ligament injury (usually PCL).
Deep intercondylar notch sign (2)
Depression of lateral femoral condyle (terminal sulcus), secondary to impaction injury.
Associated with ACL tears.
Patella dislocation (3)
Almost always lateral, medial patello-femoral ligament is injured.
Characteristic appearance on MRI:
- Classic contusion pattern.
Patella Alta - causes (7)
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
Patella Baja (2)
Quads tendon rupture leads to unopposed downward pull, leading to Patella Baja.
Tibial plateau fractures (3)
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.
Pilon fracture (4)
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
Tibial shaft fracture (2)
Commonest long bone fracture.
Many ways to repair it surgically.
Tillaux fracture
Salter Harris 3 through the anterolateral aspect of the distal tibial epiphysis.
Triplane fracture
Salter Harris 4, vertical component through epiphysis, horizontal through physis, oblique through metaphysis.
Maisonneuve fracture - definition/pathology/trivia (3)
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.
Maisonneuve fracture - imaging (2)
Ankle with widened mortis on XR.
Look further up for proximal fibular shaft fracture.
Cassanova fracture (3)
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.
Bohler’s angle (2)
Line drawn between anterior and posterior borders of calcaneus on lateral view.
Normal >20 degrees. <20 concerning for fracture.
Jones fracture (3)
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.
Avulsion fracture of 5th MT
More common than Jones #.
Classically dancer with lateral foot pain.
Can be 2ndary to tug from lateral cord of plantar aponeurosis or peroneus brevis.
Stress fracture of 5th MT
High risk fracture, hard to heal
Lisfranc injury (5)
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.
Lisfranc injury - trivia (3)
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.
Stress fracture vs insufficiency fracture
Stress fracture = abnormal stress on normal bone
Insufficiency fracture = normal stress on abnormal bone
Compressive side vs tensile side (5)
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
Femoral stress fracture (3)
Compressive (medial) more common
usually seen in younger people along inferior femoral neck.
Tensile (lateral) more common in old people
Tibial stress fracture (5)
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.
SONK (5)
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).
Navicular stress fracture (2)
Runners on hard surfaces.
Navicular is high risk of AVN.
March fractures
Metatarsal stress fracture, classically seen in military recruits.
Calcaneal stress fracture (3)
Calcaneus is most fractured tarsal bone.
Usually intra-articular (75%).
Stress fracture with fracture line perpendicular to trabecular lines.
High risk stress fractures (7)
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
Low risk stress fractures (5)
High likelihood of uncomplicated healing with conservative Rx
Femoral neck (compressive),
Longitudinal patella
Posteriomedial tibial fracture
2nd and 3rd metatarsal
Calcaneus
