MCQs – Lower Extremity 3

MCQs-LE 3
with Blount’s and a 30 degree femoral-tibial angle should have an osteotomy – probably closing wedge.
At this age, recurrence is high and the kid needs to be followed closely; may need repeat osteotomies down the road.

– in recurrent patellar dislocations, the starting point of treatment is lateral release, then a vastus medialis advancement (ie. proximal realignment).

– the Q angle is usually about 15 degrees. In males, the upper limit is about 17, in females it is about 20. Blumensatt’s line is seen at 30 degrees and the patella should go just above it. The Insall ratio compares the length of the patella and the length of the patellar tendon – the tendon should be no more than 1.2 times the length of the patella.

– genu valgum is not uncommon in young kids, especially between the ages of 2-6 (that’s where it peaks). There is no particularly good conservative treatment for it – just let the natural history take its course, because the natural history is usually good. It can lead to patellofemoral problems. Consider surgery if the child reaches the age of 10 (give them up to this age to grow out of it) with 10 cm inter-malleolar distance or greater than 15-20 degrees of valgus.

– be ready for the 9 year old that comes in with severe femoral anteversion and concomitant tibial external version (lateral tibial torsion) – should wait until the age of 10, but this will likely require double osteotomies (intertrochanteric and supramalleolar)

– do not consider supramalleolar osteotomy for internal tibial torsion until at least the age of eight to 10.

– how much internal tibial torsion is too much? Probably 10 degrees. Remember that most people have a thigh foot angle that is externally rotated about 10 degrees, so this represents 20 degrees of abnormal internal torsion.

– in a 14 year old with a stable OCD lesion – the age threshold is about 12, so he is in the worse category. You’d start with conservative, but if he doesn’t improve, you may take the opportunity to get on with it and go after his lesion. Remember that you might have trouble seeing it if the cartilage is intact. Probe to see where it is soft and drill it to induce bone growth.

– remember: age is key with OCD

– if you have an IT band contracture (seen with polio kids) there will be a flexion, abduction, external rotation deformity of the hip and a valgus, flexion, and external rotation of the knee. The hemipelvis will tilt down on that side. The spine will then curve away from that side (ie. the apex will be on that side.) So a right IT band contracture will show a right lumbar scoliosis (apex to the right).

– for head injured kids, severe equinus contractures often develop which should be splinted or casted (with well padded casts) if possible. It often maximizes at 2-3 months post injury. These are often correctable with serial casting. The spasticity often decreases over the ensuing couple years, and so you should not do heel-cord lengthening on them until at least 1 year or more after injury.

– pre-requisites for iliopsoas tendon transfer – good rectus femoris and sartorius and active flexion of hip.??

– in triplane fractures, you see a fracture of the epiphysis in the sagittal plane and in the coronal plane, and you see a fracture of the metaphysis in the coronal plane. This is a lateral rotation injury related to the fact that the posteromedial part of the physis has already closed; a significant number of these have a growth arrest which is clinically not significant as they are near skeletal maturity.

– the transmalleolar axis tends to externally rotate in young children as they grow (this is why they grow out of their intoing for internal tibial torsion).