Despite being flagged as a terrorist at LHR and LAX then they didn't spot my not entirely original ankle, so you should be OK.
Alternatively, should you wish to smuggle in titanium as I'm sure it's sold at an inflated price in the local Pak N Save and Mitre 10 then I would advise fashioning it into parts which can be inserted into your lower appendages to get past MAF and Customs.
You guys are hilarious.
Speaking of thwarting airport security, nowadays I'd be afraid of going through with even crutches, they'd probably be paranoid about things stuffed down the tubing and dissect the damn things.
I'm hoping to get some quality rehab in NZ without breaking the bank. I had my ankle nearly snapped during a football/soccer match four years ago and could not even get rehab as school insurance didn't allow it. I had to fight for 9 months to get them to pay my $800 ER x-ray!!!