Hip

Question 1

2 commonest causes of hip OA?

Answer 1

Bony deformities that cause misalignment!
1. Femoroacetabular impingement
2. Dysplasia

Question 2

Ficat classification for NOF fracture AVN?

Answer 2

Pre-radiographic = edema on MRI
Pre-collapse = mixed sclerosis + subchondral cysts on XR, edema on MRI
Collapse = bone necrosis on MRI
Advanced arthritis = advanced DJD on XR

Question 3

Causes of positive Trendelenburg test?

Answer 3

Weak abductors
Nervous = Superior Gluteal nerve / L5
Fulcrum = OA, AVN, sublux/dislocation
Femoral neck issues

Question 4

Common causes of LLD?

Leg length discrepancy

Answer 4

Congenital = DDH, dysplasia, unilateral clubfoot
Paralytic disorder = Cerebral palsy
Physis disruption = Infection, trauma, tumour

Question 5

Conditions associated with LLD?

Answer 5

OA
Back pain
Functional scoliosis
Inefficient gait
Equinus contracture of ankle

Lower coverage of femoral head on long leg causes OA 84% of time

Question 6

RF for NOF fracture AVN?

Answer 6

Steroids, TCM
Post-trauma
Radiation, Alcohol, obesity
Hematologic diseases - Leukemia, lymphoma etc
Diving - Decompression (nitrogen intoxication)

Question 7

How to differentiate AVN from OA?

Answer 7

OA affects 1 joint.
Non-traumatic OA is usu bilateral

Question 8

3 subdivisions of femoral neck?

Proximal -> distal

Answer 8

Subcapital
Transcervical
Basi-cervical

Question 9

Between Neck and introchanters, which is intra/extra-capsular?

Answer 9

Neck is intracapsular -> risk of AVN
IT, Subtrochanteric, GT/LT are extracapsular

Question 10

How good is healing potential of NOF frac? Why?

Answer 10

• Femoral neck is intracapsular, bathed in synovial fluid.
• Lacks periosteal layer
• Callus formation limited, which affects healing

Question 11

Main vascular supply to NOF?

Answer 11

Lateral retinacular arteries from medial circumflex from profunda femoris

Question 12

How does Garden’s classification guide Mx?

Answer 12

1/2 = ORIF
3/4 = Hip replacement (hemi/total arthroplasty)

Question 13

Unipolar vs Bipolar hemi-arthroplasty?

Answer 13

Unipolar = only one block is put in to move against native acetabulum
Bipolar = Includes shell which the head articulates with.

Bipolar is mostly done recently

Question 14

Compare effectiveness of Hemi vs Full arthroplasty?

Answer 14

Hemi is more stable, but THR gives better function.
Hence Hemi better for younger patients,
THR better for elderlies

BUT ofc ORIF is better for young pts. Hence NOF Frac is emergency for young pts. Old people wont go play tennis and all

Question 15

Can u do hip arthroplasty for Inter-Trochanteric frac?

Answer 15

no. always nail fixation due to low AVN risk

Question 16

Cemented vs Uncemented hip implants?

Answer 16

Cemented implants held in place with bone cement.
Uncemented implants allow new bone to grow into the implant, securing it in place.

Cemented usu done for elderly with lower demand and less physical activity

Question 17

Normally IT Frac is alw fixation. When do u do arthroplasty?

Answer 17

Severely comminuted, severe arthritis

Question 18

Anatomical landmark for subtrochanteric frac?

Answer 18

Frac within 5cm distal to LT

Question 19

Best Mx for femoral shaft frac?

Answer 19

Adults = immobilize with thomas splint, M&R + intramedullary nail
Kids = Traction 3-4 weeks -> Spica 4-6 weeks

Question 20

Urgent thing to do in Hip dislocation?

Answer 20

Reduction - to minimize risk of AVN

Question 21

Common mechanism of Hip dislocation?

Answer 21

Posterior dislocation 90%.
Axial load through flexed knee (dashboard injury)