Recon (355-423) & Review Flashcards
Acetabular dysplasia classical definitions: CE angle, Anterior CE angle and Acetabular Index
CE Angle 5 degrees
Acetabular dysplasia classically lacks what coverage?
Anterolateral
Acetabular retroversion - two signs?
Crossover, ischial spine
Acetabular overcoverage for dysplasia?
Excess anterolateral coverage, downsloping aceetabular index >5 degrees downward
Proximal femoral dysplasia - two types?
- Head-neck dysplasia - alpha angle 40 degrees or less 2. Altered neck version - excess ante or retroversion
FAI - where is the abnormal impingement occuring?
Anterosuperior zone of acetabulum
FAI can be caused by pincer and cam. Whats the difference?
Pincer - anatomic aberration between retroverted socket and normal femoral neck creates a mechanical block, pinches acetabular labrum Cam - Raised proximal femoral neck, slips under labrum and impinges articular surface, chondral acetabulum gets damaged
Surgical Treatment of FAI?
- PAO
- Anterior hip decomopression
- Proximal hip osteotomy
PAO?
Corrects tilt and version
Allows for medialization
Correct AI to 0
Head coverage to lateral CE <20
No crossover sign
Advantages:
No abductor, no posterior colum, early WB, low complication rate
Anterior hip decompression as treatment for FAI?
Will not correct shallow socket
Femoral neck, acetabular osteoplasty
Repair soft tissue tears, labrum, chondral flap
Trochanteric slide (vastus and medis attached)
Anterior dislocation
Z capsulotomy
When do you use a proximal hip osteotomy for FAI?
Correction of proximal femoral retroversion or excessive anteversion
Significant coxa valga with decreased lateral offset
4 Non-op hip arthritis treatment
- Activity modification
- NSAID
- Joint injetions
- Assist device (can in OPPOSITE hand)
Hip arthroscopy, 3 most common nerve injuries?
- Pudendal
- LFCN
- Femoral
Hip fusion salient points?
Young male, unilateral
You get adjacent joint OA
Position, 20 flex, neutral add/ab, 0-10 ER
Indication for fusion take down? Ipsilateral knee pain, back pain, contralateral hip pain
Do the abductors work? EMG, If not constrained THA
If no abductors your get a lurch gait
4 indication for THA for hip fracture
- High activity level
- Age greater than 70
- Supcapital or high neck fracture
- No risk factors for dislocation
Osteonecrosis of hip. What vessels are affected?
May be result of hypercoagulable state in idiopathic cases.
Juxtaarticular sinusoids
What percentage of hip osteonecrosis cases are bilateral?
50% so image both hips
What staging system do we use for osteonecrosis of the hip?
Ficat.
0-4 MRI and Bone scan positive only
0-1 Xray neg, 2 positive no crescent, 3 crescent, 4- collapse, DJD
Asymptomatic in only stage 0
Treatment for osteonecrosis of hip?
- Non-op - Bisphosphonates
- Surgical - start before crescent
Prognostic features?
Head collapse, young age, irreversible etiology, extent of head involvement (volume)
Head involvement % on ap x % on lateral
Therefore:
- Young with crescent - THA
- Young no crescent - Core decompression, vascularized fibular strut, curretage and bone grafting
What coating allows for bone ingrowth? Ongrowth?
Porous - Ingrowth
Grit - Ongrowth
Successful cemeting technique requires 5 steps
- Porosity reduction - vaccum
- Pressurization
- Pulsatile lavage
- Stem centralization - avoid mantle defect
- Stiff stem
Biologic fication of bone ingrowth require pore size (um) and porosity of %? Can you think of other factors?
Between 50 and 150 um
Porosity of 40-50%
Pore depth
Minimize distance between prosthesis and bone <50um
Minimal micromotion
Cortical contact
Viable bone
Two techniques of rigid fixation of cementless implants.
What are they, where do fractures occur?
Line to line, press fit
Line to line relies on extensive porous coating and frictional “scratch fit”
Line to line - distal
Press fit - proximal
What is the role of hydroxyapetite?
Osteoblasts adhere to HA and grow toward bone shortening time to biologic fixation
