Lower limb (2) pathologies

Question 1

Describe a fracture of the femoral shaft (different fragments, causes)

Answer 1

High-velocity trauma in healthy young, low-velocity trauma in osteoporotic bones & patients with bone lesions
Proximal fragment is often abducted due to pull of gluteus medius and minimus and flexed due to iliopsoas
Distal fragment is adducted into a varus deformity due to adductor muscles and extended due to pull of gastrocnemius
Tense, swollen thigh & treated with surgical fixation

Question 2

Describe distal femoral fractures

Answer 2

High-energy sporting injury in young, fall in elderly
Popliteal artery may be involved if significant displacement (neurovascular structures should be carefully assessed throughout)

Question 3

Describe tibial plateau fractures

Answer 3

High-energy injuries (axial loading with varus or valgus angulation of the knee)
Articular cartilage is always damaged
Most patients will develop post-traumatic osteoarthritis in the affected joint

Question 4

Describe patellar fractures

Answer 4

Caused by direct impact injury or eccentric contraction of quadriceps muscle
Patient will be unable to perform a straight leg raise
Displaced = surgery fixation & reduction, undisplaced = protected while healing takes place eg. crutches, splinting therefore surgery not required

Question 5

Describe patella dislocation

Answer 5

Patella is completely displaced out of its normal alignment
Most common to dislocate laterally, common cause trauma
Predisposing factors: weakness of quads, previous dislocations, generalised ligamentous laxity

Question 6

Describe meniscal injuries

Answer 6

Most common knee injury -> occur during a sudden twisting motion of a weight-bearing knee in a high degree of flexion
Intermittent pain localised to joint line, knee clicking
Swelling is a delayed symptom
Acute treated with surgery, chronic treated with conservative management

Question 7

Describe collateral ligament injuries

Answer 7

Common sporting injury (acute varus or valgus angulation of the knee)
Valgus strain = medial collateral ligament, varus strain = lateral collateral ligament
MCL more commonly injured, but a torn LCL causes more instability

Question 8

Describe an anterior cruciate ligament injury

Answer 8

Result of quick deceleration, hyperextension or rotational injury = non-contact injury
Feel popping sensation with immediate swelling & knee gives way (anterolateral rotatory instability)
Surgical reconstruction
Lachman’s test used to detect ACL injuries

Question 9

Describe a posterior cruciate ligament injury

Answer 9

‘dashboard injury’ = knee is flexed and a large force is applied to the upper tibia (can be torn in football)
Dial test used to detect PCL injuries

Question 10

What is the unhappy triad?

Answer 10

Injury to the:

1) Anterior cruciate ligament
2) Medial collateral ligament
3) Medial meniscus

Question 11

Describe dislocations of the knee joint

Answer 11

Uncommon injury & high-energy trauma
Three of MCL, LCL, ACL and PCL must be ruptured
Associated artery injury is common (popliteal)

Question 12

Describe prepatellar bursitis (‘housemaids knee’)

Answer 12

Knee pain, swelling

Difficult to walk and can’t kneel on affected side (repetitive trauma to the bursa)

Question 13

Describe superficial infrapatellar bursitis (‘clergyman’s knee’)

Answer 13

Occurs due to repeated microtrauma caused by activities involving kneeling

Question 14

Describe suprapatellar bursitis (knee effusion)

Answer 14

Usually a sign of significant pathology in the knee joint

Causes of a knee effusion: osteoarthritis, infection, gout

Question 15

Describe semimembranosus bursitis (popliteal cyst)

Answer 15

Indirect consequence of swelling within the knee joint

Effusion -> fluid can force its way through the narrow communication into the semimembranosus bursa

Question 16

Describe Osgood-Schlatter’s disease

Answer 16

Inflammation of the apophysis of the patellar ligament into the tibial tuberosity
Occurs in teenagers in who play sport & causes localised pain and swelling
Resolves with rest and ice

Question 17

Describe septic arthritis

Answer 17

Invasion of the joint space by microbes
Most common pathogen = staph aureus
Prosthetic joints are particularly at risk
Major consequence = damage to the articular cartilage due to bacterial invasion
Aspiration of joint should be carried out immediately

Question 18

Describe osteoarthritis of the knee

Answer 18

Knee pain, stiffness and swelling
Deformity is common eg. varus/valgus deformity
Increased friction can be felt as crepitus (grating sound on movement of the joint)
Surgery ultimately required