MSK Lower Limb Clinical

Question 1

Fractures of the pelvis (2)

Answer 1

Fracture of the pubic rami or avulsion fracture of the ischial tuberosity (hamstring muscles tear off a piece of the ischial tuberosity- rapid contraction/relaxation sports like sprinting)

Question 2

Intracapsular fracture of the femur
Description
Causes
Presentation

Answer 2

Fracture within capsule of hip joint (fracture of the neck of femur/ broken hip)
Causes: elderly women post menopausal osteoporosis, minor trip/stumble
Presentation: distal fragment pulled upwards and laterally (shortened leg, laterally rotated)
Damage to medial femoral circumflex artery leads to avascular necrosis

Question 3

Extracapsular fracture of the femur
Description and types
Causes
Presentation
Treatment

Answer 3

Description: fracture of the femur, outside of the joint capsule.
Trochanteric fracture, subtrochanteric fracture (fracture of femur below lesser trochanter), intercondylar fracture (damage to popliteal artery and misalignment of knee joint)
Causes: high energy road traffic accident
Presentation: blood supply to head of femur remains intact (no AVN), leg shortened and laterally rotated due to distal fragment being pulled upwards and laterally
treatment: dynamic hip screw

Question 4

Surgical hip replacement

Answer 4

Plastic socket replaces acetabulum
Stainless steel femoral stem and head replaces femur
1/3 of people die within a year of hip replacement

Question 5

Medial malleolus fracture

Answer 5

Spiral fracture.
Causes: twisting/rotating ankle, tripping/falling, car accident, over inversion
Presentation: if fibula is not fractured it supports the tibia -> minimal displacement

Question 6

Tibial shaft fractures

Answer 6

Shaft is narrowest at junction between middle and inferior third (little blood supply -> poor healing)
If nutrient artery is damaged: predisposes patient to non union of bone fragments
Transverse stress fracture: indirect force applied to tibial shaft with bone turns with a fixed foot during a fall
Diagonal fracture: high speed forward fall. Limb shortens due to overriding bone fragments

Question 7

Lateral malleolus fracture

Answer 7

Causes: twisting/rotating ankle, tripping/falling, car accident, over eversion (transverse fracture), external rotation of ankle (spiral fracture)

Question 8

Talus fracture

Answer 8

Neck is fractured during dorsiflexion (neck pushed into tibia)
Body is fractured when jumping from height
The malleoli hold the fragments together -> minimal displacement
Avascular necrosis due to poor blood supply

Question 9

Calcaneal fracture

Answer 9

Jumping from height, large force on heel.
Talus driven into calcaneus -> crushes it -> comminuted fracture
Presentation: disabling as it disrupts talocalcaneal joint

Question 10

Metatarsal fractures

Answer 10

Blow to foot (drop heavy object on foot), stress fracture (athletes), excessive inversion (fibularis brevis causes an avulsion fracture of the base of metatarsal 5)
Presentation: usually 2nd, 3rd, or 4th metatarsal. Pain and swelling

Question 11

Congenital dislocation of hip joint

Answer 11

8x more common in girls (1.5/100 births)
Femoral head not placed correctly within acetabulum during development-> dislocated joint
Presentation: inability to abduct, affected leg is shorter, positive trendelenburg sign due to superior gluteal nerve damage

Question 12

Acquired dislocation of femoral head

Answer 12

Posterior more common than anterior as it is the weakest part of the joint capsule (less ligaments)
Posterior: traumatic accidents. Femoral head forced posteriorly through inferior and posterior parts of joint capsule. Leg is shorter and medially rotated. Potential damage to sciatic nerve -> paralysis of hamstrings/all muscles distal to knee (and sensory loss)
Anterior: caused by extension, abduction and lateral rotation in traumatic accidents. Femoral head ends up anterior and inferior to acetabulum and pulls acetabulum labrum with it.

Question 13

Palpation of femoral artery

Answer 13

Continuation of external iliac artery (becomes femoral after passing under inguinal ligament). Branches into profunda femoris in femoral triangle (profunda femoris supplies most of thigh)

Femoral pulse can be palpated at the midinguinal point (halfway between pubic symphysis and ASIS)

Question 14

Pulled groin (pulled adductor muscle)

Answer 14

Muscle strain in the medial compartment of the thigh
Cause: sports that require explosive movements/extreme stretching
Proximal part of muscle usually most vulnerable. Tears near the origin

Question 15

Hamstring strain

Answer 15

Strain- excessive stretching or tearing of muscle fibres
cause: athlets (running, kicking sports)
Causes damage to muscle fibres and may rupture surrounding blood vessels -> forms a haematoma but remains contained by overlying fascia lata

Question 16

Saphenous vein

Answer 16

Great saphenous vein graph (reversed due to valves) used for coronary artery bypass grafting

Stripping of the saphenous vein- procedure done if varicose veins are particularly bad. Prevents stasis of blood and formation of venous ulcers, typically near the medial malleolus.
May damage saphenous nerve in procedure. Pain/paraesthesia.complete loss of sensation in medial lower leg

Question 17

Trendelenberg sign

Answer 17

Superior gluteal nerve damage/lesion -> paralysis of gluteus medius and gluteus minimus, so when contralateral leg si raised, the pelvis becomes unsupported and drops.
Ie. With SG nerve damage on your right side, if you lift your left leg your right glut med/min wont be able to contract as they are paralysed so your left pelvis drops

Question 18

Intramuscular injection in the gluteal region

Answer 18

Divide one buttock into 4
Injection should be given in the upper outer quadrant
High risk of hitting sciatic nerve, blood vessel or bone

Question 19

Ligament injuries of the knee

Answer 19

Presentation:
Swelling, pain and instability over site of damage. PCL and ACL damage causes difficulty walking
Assess:
Medial and lateral collateral ligament damage is assessed by passively rotating the a flexed lower limb. Pain on medial rotation- medial damage. Pain on lateral damage- lateral damage.
Anterior and posterior cruciate ligament damage is assessed by anterior/posterior drawer test (pull tibia forward- ACL damage, push tibia posteriorly- PCL damage)
Causes:
MCL- force applied to lateral side of knee when foot is fixed on ground
LCL- force applied to medial side of knee when foot is fixed on ground
ACL- force applied to back of knee when joint is partially flexed
PCL- dashboard injury (force applied to shins when knee is flexed, tibia pushed posteriorly) or hyperextension

Question 20

Medial meniscus tear

Answer 20

Medial collateral ligament is firmly attached to medial meniscus
If one gets damage, its likely to cause damage to the other

Question 21

Unhappy triad

Answer 21

Blow to lateral side of knee or lateral twisting of a flexed knee
Causes ACL damage as ACL is taut during flexion-> medial shift of unstable femur -> MCL tear -> medial meniscus tear

Question 22

Housemaids knee

Answer 22

Prepatellar bursitis (swelling on the anterior side of knee)
Due to friction between skin and patella

Question 23

Clergymans knee

Answer 23

Infrapatellar bursitis due to friction between skin and tibia

Question 24

Coronary angiography

Answer 24

Catheterise femoral artery within femoral triangle (midinguinal point)
Tube is navigated up external iliac artery, common iliac artery, aorta and into coronary vessels
Dye used to identify coronary occlusions

Question 25

Femoral hernia

Answer 25

Part of bowel displaced and pushed into femoral canal under the inguinal ligament-> produces a lump
Hernial sac compresses femoral canal contents (lymphatics) and distends the wall of the canal
Can pass inferiorly through the saphenous opening into the subcutaneous tissue of the thigh
Strangulation of the femoral hernia may occur because of the rigid boundaries of the femoral ring. Causes necrosis of the herniated intestine.

Question 26

Bakers cyst

Answer 26

Inflammation and swelling of the semimembranosus bursa
Arises in conjunction with osteoarthritis/rheumatoid arthritis of the knee
Usually resolved but can rupture -> similar symptoms to DVT

Question 27

Popliteal aneurysm

Answer 27

Dilation of popliteal artery, greater than 50% of normal diameter
Popliteal fascia is tough/nonextensible-> aneurysm compresses the tibial nerve (loss of sensation/motor function of lower leg)
Detected by obviously palpable pulsation in popliteal fossa