THA – Difficult Femur

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