Page 1 of 2: ortho - avascular necrosis

drprasu · Credits: 5755 My Scrapbook

avascular necrosis of head of femur is MC in

1) subcapital #
2) transcervical #
3) #intertrochantric
4) basal #

draditithegreat · Credits: 1248020 My Scrapbook

1) subcapital........#

drprasu · Credits: 5755 My Scrapbook

Transcervical #

Ya! I know every guide gives answer as subcapital.

Read these lines from apley 7/e p 656
" Transcervical fractures are, by definition, intracapsular. They have
a poor capacity for healing because by tearing the capsular vessels the injury deprives the head of its main blood supply ..."

They didn't mention about subcapital #

femoral head has got 3 vascular supply:

1) intramedullary vessels in the femoral neck which is always disrupted by the fracture.
2) ascending cervical vessels in the capsular retinaculum
3) vessels in round ligament (which is not much significant)

so in the # of neck, only blood supply which supports head perfusion
is the capsular vessels which are reflected from capsule onto the neck

and we know that capsule attaches on the neck somewhere around the middle area, not just below the head.

So, transcervical #, not the subcapital, will disrupt the capsule from
its attachment, thereby disrupting the main supply.

more proximal the fracture, more unstable it will be. So subcapital will
be more unstable than transcervical #. agreed

but avascular necrosis would be probably more in transcervical #

If anybody has got a better ref or explanation in favour of subcapital
please, do post it .

draditithegreat · Credits: 1248020 My Scrapbook

Intertrochanteric and extracapsular fractures of the femur rarely develop AVN.
Following hip dislocation, circulation is interrupted because of tears of the ligamentum teres, tearing the ALT(artery to lig teres).
Tearing of the joint capsule compromises the vessels within the capsular reflections.
AVN following subcapital fractures of the femur can develop as late as 10 years after fracture.

[/img]

draditithegreat · Credits: 1248020 My Scrapbook

draditithegreat · Credits: 1248020 My Scrapbook

Posterior view of the extraosseous blood supply to the femoral head.

draditithegreat · Credits: 1248020 My Scrapbook

Garden fracture classification

bhavu · Credits: 9491 My Scrapbook

it is sub capital

drprasu · Credits: 5755 My Scrapbook

draditi you said "Tearing of the joint capsule compromises the vessels within the capsular reflections."

So fracture occuring at/near the site of capsular attachment to neck
would tear the capsule and that is transcervical.

and we know that capsule attaches on the neck somewhere around the middle area, not just below the head(subcapital).

Subcapital will not tear the capsule, because Subcapital# occurs just below the head where capsule is not attached. it is attached somewhere on neck.

there seems to be confusion, but do read apley 7/e p656I had already quoted the main part in my previous post. HERE it is again
" Transcervical fractures are, by definition, intracapsular. They have
a poor capacity for healing because by tearing the capsular vessels the injury deprives the head of its main blood supply ..."

Moreover the question is not that AVN occurs in which fracture,
but it is that AVN occurs most commonly in which fracture.
I agree that AVN does occur in subcapital, but the question has MC
word in it.

DO REPLY

bhavu · Credits: 9491 My Scrapbook

see rockwood fracture for adults 5th edi page 1592 has to say " with more distal fracture due to typical proximal displacement and lateral rotation of the shaft tend to spare the vessels by pealing them off the neck, allowing displacements upto 1/2 the diameter of the head involved without putting tension on the neck critical vessels"

so answer is subcapital.
rockwood is the standard text book for pg in orthopaedics along with chapman. i am having it becoz my brother is an orthopaedics surgeon. he and above line from books confirms that answr is subcapital.. i hope your doubts are clear dr prasu.

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