– anatomically defined by a hallux valgus angle > 16, intermetatarsal angle > 9.
– usually family Hx positive; females > males
– may have slightly different patho-anatomy than adults. They definitely may have increased metatarsus primus varus, an oblique 1st TMT joint articulation, and a long first MT, in addition to generalized ligamentous laxity.
* in particular, note the metatarsus primus varus – if undertaking surgery, this must be corrected.
Things to consider:
– is the MTP congruent? Is the MTP passively correctable?
– what is the IMA?
– what is the hindfoot like? Any equinus too?
– what is the age of the patient and skeletal maturity – there is a high rate of recurrence if you operate before the closure of the growth plates (the other reason for recurrence is failure to deal with the metatarsal primus varus).
Soft tissue procedures
– medial capsular reefing and realignment of abductor hallucis so that it is not a deforming force
– lateral capsular release, adductor hallucis release from proximal phalanx and metatarsal head, division of transverse metacarpal ligament
– proximal phalangeal closing wedge osteotomy with medial eminence excision and medial capsule reefing (Akin)
– distal osteotomy (Chevron)
– diaphyseal osteotomy (Mitchell)
– 1st TMT fusion (Lapidus)
– make sure they have no Achilles tendon contracture, neuromuscular abnormalities, or spasticity
– look for ligamentous laxity, pes planus, hindfoot valgus, and other postural deformities
– try to temporize them as much as possible to get them to skeletal maturity
– be very wary about operating on one before growth plates close
– look very closely at their IMA and their first TMT – they often have an oblique first TMT which causes metatarsus primus varus – you need to correct this either with a first TMT fusion, or an opening wedge osteotomy of the cuneiform.
– look at their MTP joint – most adolescents the joint is incongruous and you can pull the proximal phalanx over with a soft tissue reefing medially.
My approach is going to be fairly simple. I will do a Lapidus, or modify the lapidus by doing an opening wedge osteotomy of the cuneiform.