Technical Tip : A Simple Method for Proper Placement of an Intramedullary Nail Entry Point for Tibiotalocalcaneal or Tibiocalcaneal Arthrodesis

The purpose of this article is to report on a technical tip when performing tibiotalocalcaneal or tibiocalcaneal arthrodesis. Technical faults of this arthrodesis may include malpositioning of the IM nail that can potentiate complications such as nonunion, delayed union, malunion, screw fracture, painful hardware, fracture of the intramedullary nail, tibial fracture, wound healing complications, and nerve damage. This article will present important information to aid the surgeon in preventing malpositioning of an IM nail and will provide a simple clinical pearl for perioperative incisional planning using image intensification.

This manuscript reviews potential complications associated with intramedullary nailing, in particular to malpositioning of the retrograde nail.We present two cases that presented with continued pain upon ambulation after attempted tibiotalocalcaneal fusions.Their nonunion and failure of fixation was related in part due to malpositioning of the intramedullary nail.This article further reviews several authors' recommendations for determining the ideal entry point for the insertion of an intramedullary nail for tibiotalocalcaneal fusion.Many of these studies recommend a guide wire entry point based on anatomical landmarks and preoperative radiographic findings.
Lastly, this article will describe a simple method of perioperative incisional planning by using image intensification.

Potential complications
Potential complications associated with this type of procedure include: nonunion, delayed union, malunion, screw fracture, painful hardware, fracture of the intramedullary nail, tibial fracture, wound healing complications, and nerve damage. 4- 10

Recommendations for determining guide wire entry point
Accurate guide wire placement is critical prior to reaming and inserting a retrograde intramedullary nail for tibiotalocalcaneal or tibiocalcaneal fusion.The guide wire is typically placed into the central medial aspect of the calcaneus and centered in the medullary canal of the tibia.
Because the longitudinal bisection of the calcaneus is lateral relative to the alignment of the tibia in a normal anatomic structure, it is usually necessary to medially translate the talus and calcaneus.This will allow insertion of a straight nail from the calcaneus into the central portion of the tibia. 11e foot placement should be 90 degrees with respect to the lower leg, maintaining the heel in neutral position with 10-15 degrees of external rotation.Blunt dissection is carried down to the bone to avoid any neurovascular structures. 13A 3 cm longitudinal plantar incision is made anterior to subcalcaneal fat pad and lateral to the midline, especially in patients with preoperative valgus.The ideal position for the plantar calcaneal entry site is anterior to the weight-bearing surface of the calcaneal tuberosity and approximately 2 cm posterior to the articulation of the calcaneus with the transverse tarsal joint.

Mader (2003)
A 2.5 cm incision is made in the foot over the center of the tuberosity of the calcaneus, and blunt dissection is extended to its plantar surface.The neurovascular bundle is then protected with Langenbeck retractors.

DiDomenico & Adams (2005)
Approximately 3 cm distal to the plantar fascial insertion, in direct alignment with the medullary canal of the tibia.The guide wire should be placed into the central medial aspect of the calcaneus and centered in the medullary canal of the tibia.

Roukis (2006)
The guidewire should be first aligned with the lower leg soft tissue outline, which approximates the location of the calcaneocuboid joint , and then translated 2.0 cm posteriorly to increase the efficacy of properly seating the guide wire.This allows more efficient and accurate placement while decreasing dependency on intraoperative fluoroscopy.A number of authors have described the anatomical placement of the IM nail.Table 2 summarizes several author recommendations for determining the proper entry point.The surgical approach to placement of the IM nail is described in terms of measurement from specific landmarks and anatomical structures.
Our technique uses perioperative imaging to determine the placement of the IM nail.Using intraoperative C-arm visualization, the long axis of the tibia on lateral view is used to determine the tibial location along the plantar entry point of the foot.The IM nail is simply placed along the lateral leg just above the border of the fibula.A marking pen is then used to draw a horizontally placed line along the plantar aspect of the foot.This corresponds to the central tibial component for IM nail placement.
The IM nail should visually appear to go directly through the lateral process of the talus on lateral view.
The second vertical or longitudinal bisecting line is made with the calcaneal axial view perioperatively.The IM nail is placed directly against the plantar heel on axial view.The line corresponds to the valgus or varus rotation of the calcaneus.The marking pen is then used to draw a longitudinal bisecting line.The center of the bisecting line represents the ideal entry point for the IM nail.Here, no measurements are required, and the landmarks to determine the ideal entry point correspond to radiographic anatomical structures.Figures 4-7 show a stepwise approach for perioperative incisional planning.The entry point is based on lateral ankle and calcaneal axial views utilizing C-arm visualization.

Figure 4abc
Preoperatively, a line is made on the ankle which is consistent with a line that bisects the tibia and goes through the lateral talar process.

© The Foot & Ankle Journal, 2008
Figure 5 The mark on the lateral aspect of the ankle then continued transversely on the plantar surface of the foot.A guide-wire or metallic marker, in this case a threaded rod, is then placed against the plantar aspect of the foot along the center of the heel.
Volume 1, No. 9, September Using image intensification, a calcaneal axial view is taken and a line bisecting the calcaneus is then marked on the plantar skin.

Summary
In summary, ideal incisional placement permits accurate insertion, good screw purchase, and avoids neurovascular damage.(Fig. 8ab) Although fixed angled devices are being popularized as being able to purchase a greater amount of calcaneus and not having to medially translate the talus to align the tibia and calcaneus, clearly intraoperative errors can lead to postoperative complications as presented in this article.A simple, accurate, and reproducible method of determining the proper entry point as described in this article is invaluable to the foot and ankle surgeon performing tibiotalocalcaneal or tibiocalcaneal fusion with intramedullary devices.Currently there are retrograde devices approved for use that have a valgus orientation built into the nail.

Figure 1b Case 1 : 2 A
Figure 1b Case 1: Lateral ankle radiographs showing placement of intramedullary nail for the tibiotalocalcaneal arthrodesis.

Figure 2
Figure 2 Case 1: Calcaneal Axial radiograph demonstrating malpositioning of the IM nail through the hindfoot with the insertion site too medial.

© The Foot & Ankle Journal, 2008 Figure 3abc
Figure 3abc Case 2: AP (a), axial (b) and Lateral (c) radiographs of the ankle demonstrate an attempted tibiocalcaneal fusion with an intramedullary nail with broken calcaneal screw and distal migration of the nail.

Figure 7
Figure 7The center of the two intersecting lines is the ideal entry point.

Figure 8 ab
Figure 8 ab Lateral ankle (a), calcaneal axial (b) radiographs demonstrate a tibiotalocalcaneal fusion with a properly placed intramedullary nail.

Table 1
Reported complications of IM nailing.

Table 2 :
Recommendations for determining Entry Point Reference Recommendation

Table 2
Several recommendations for determining proper IM nail entry points.