OrthoNet

Difficult femur
Pitfalls in the Difficult Femur

Congenital Hip Disloctaion
- coxa valga or vara, short neck, proximal displacement of the whole thing, posterior trochanteric rotation, gracile femoral cortex, narrow femoral canal, dramatic femoral anteversion
- consider osteotomy for exposure (trochanteric or trochanteric slide, or subtrochanteric osteotomy)
- choose a small straight stem - preferably porous coated; watch out for the anteversion; if you cannot choose the anteversion (S-ROM) then you might have to cut the neck abit lower so you can put the stem in exactly as you want it.

Rheumatoids - Juvenile and Adult
- considerable osteoporosis - watch out for fracture when dislocating
- may have protrusio
- may be on steroids - increased infection
- watch out for joint contractures (rectus and adductors - need releasing!), increased femoral anteversion in JRA, and an adherent capsule

Ank Spond
- soft tissue contractures; beware trying to dislocate the head without totally skeletonizing the proximal femur (you may break the femur trying to force the head out) - be ready to osteotomize in situ
- heterotopic bone
- loss of lumbar lordosis - makes it harder to position the patient right and get the anteversion correct

Previous Trauma
- leave all hardware in until you dislocate (reduces risk of fracture)
- beware significant soft tissue contractures
- beware angular deformities of the stem

Pagets
- bowed femur, hard, brittle bone, enlarged proximal femur
- may need wide exposure and osteotomy
- watch out for bleeding - be prepared pre-op!

Conversion of an Arthrodesis
- make sure you know what hardware is in there and how to get it out
- use the ASIS, teardrop, and ischium as landmarks intraoperatively
- drill through the medial wall and measure this to guide you with the depth of reaming (stop with 1 cm to go)
- use intraoperative xray!
- be ready for XRT postop to reduce the risk of HO

Conversion of a Girdlestone
- make sure you rule out infection, both preop and postop
- consider using antibiotics in the cement
- consider using a constrained cup if abductors are abit weak and you aren�t sure about the dislocation risk