MCQs – Lower Extremity 2

MCQs-LE 2
tibial torsion to do something.
– Kids with “miserable malalignment” can have severe femoral anteversion and a compensatory external tibial torsion in which case you might have to do double osteotomies – to externally rotate the femur and internally rotate the tibia. Patellar tracking can become a major problem in these kids.

– in a Salter 4 medial malleolar fracture of the ankle, you pin the epiphysis to epiphysis. You may have to excise the little metaphyseal part of the fragment to prevent get it reduced perfectly and to prevent bony bar formation to tether the ankle medially.

– Tillaux fractures are external rotation injuries that occur around the time the growth plate is closing (12-15 year olds), and can be treated with closed reduction and casting (long leg) or by ORIF if articular surface incongruent.

– the interval for the anterior approach to the hip is sartorius (fem nerve) vs tensor fascia lata (superior gluteal nerve) superficially, and gluteus medius (superior gluteal nerve) vs rectus femoris (femoral nerve) deep.

– deciding what to do about femoral fracture malunion can be difficult, starting with deciding what actually constitutes a malunion. Obviously, more can be accepted as a neonate than as a child nearing skeletal maturity. Suffice to say that in a child 11 years old or up, accept 5 of varus/valgus, 10 of flex/ext, and 10 mm of shortening. In a child less than 5, you can probably accept up to 15 of varus/valgus, 20 of flex/ext, and 15 to 20 of shortening.

– with the femur fracture that is 5 weeks out with unacceptable alignment, you can try to do a remanipulation in the OR, or you can do drill osteoclasis and remanipulate it. It kinda depends on how much you think it’s healed at 5 weeks.

– 8 y/o with 8 week old femur fracture in 30 of valgus – drill osteoclasis
– 5 year old with 5 week old femur fracture in 20 of varus – maybe able to remanipulate it. Hard to say; just know that you might have to do drill osteoclasis

– shortening is an interesting thing to consider in femur fractures – you can accept up to 1-1.5 cm of shortening and anticipate that overgrowth will look after the rest. If more than 3 cm short initially, then the kid needs traction before going into a spica – the spica will not control length! If the thing has healed short (say, 6 cm) it may be worthwhile to wait for the overgrowth to occur (usually in the first 12 months) then decide what to do after that. Because you cannot be totally sure how much overgrowth will happen, you are better off to wait.

– in general, overgrowth happens most rapidly for the first 2 years, then tapers off, although in some patients the increased growth rate in that bone continues until they are skeletally mature. So if after 18 months there is a two cm difference in length in an 8 year old, you can expect that the discrepancy will probably decrease, albeit slowly.

– 90-90 traction is good for subtrochanteric fractures, supracondylar fractures, and femur fractures that are not compound. Avoid traction in head injured patients. I question the use of traction in the supracondylar fracture – the knee must remain flexed, making it difficult to assess varus/valgus.

– tibial eminence fractures probably deserve a try at closed reduction in extension – if this doesn’t work (unreduced by 2 mm) then ORIF. If it does reduce, you want to make sure it is stable in a few degrees of flexion, because you will cast them in a few degrees of flexion.

– remember the classification of tibial eminence fractures –
– I – undisplaced
– II – complete fracture that is hinged at the back – the anterior horn of the medial meniscus may block \ reduction
– III – complete separation and displacement

– for the proximal tibial fracture – long leg cast in extension

– for proximal tibial fracture – beware valgus deformity down the road. Numerous theories about why this happens – asymmetric stimulation of the growth plate, soft tissue (periosteal, pes, MCL) interposition, tethering of the fibula.

– a 5 year old

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