Category:Ankle Arthritis; Ankle
Introduction/Purpose:Aim of this study is to identify reliable anatomical landmarks of the
posterior tibial neurovascular bundle during Total Ankle Replacement (TAR)
to minimise the risk of iatrogenic injury. Secondary aim is to identify if
there is associated translation of the bundle when anterior translation of
the talus is present.
Methods:A radiological landmark protocol was devised to create a consistent method
for measuring the relations of the bundle to the tibia, talus and medial
gutter line when measured at levels mimicking those of resection undertaken
in TAR. Analysis between patients with and without anterior subluxation was
undertaken.
Results:Total of 42 ankles were reviewed with 38% patient having anterior translation
of the talus. At the tibiotalar joint, the bundle lies less than 5mm lateral
to the medial gutter line and less than 8mm posterior to the posterior
tibia. The same measurements at 10mm superior to the tibiotalar joint are
less than 8mm and less than 6.5mm respectively. At 5mm distal to the dome of
the talus, the bundle is less than 4mm lateral to the medial gutter line and
between 8.4-16.0mm posterior to the posterior talus. The bundle to posterior
tibia distance does not increase in the sagittal plane for patients with
anterior subluxation of the talus.
Conclusion:This study provides relevant guidance for surgeons to use intraoperatively
when undertaking tibial and talus resections in TAR to identify their
relations to the vulnerable neurovascular structures. The measurements of
this study indicate for the first time that there is not an increased risk
of iatrogenic injury during bone resection at the tibia in patients with
anterior subluxation of the talus.