The dorsomedial approach to the navicular can be used for comminuted, displaced, intraarticular fractures. The talo-navicular joint is very important. Loss of the talo-navicular joint can result in loss of 90% or greater of complex hindfoot motion/circumduction. If fracture care requires a more extensile approach, the advantages of better reduction are balanced against wider dissection causing stripping/loss of blood supply which may impede healing. If the dorsomedial approach is required, care should be taken to minimize dissection. The approach can be extended onto the distal talus. A small distractor can be used. This allows visualization and palpation of the concavity of the navicular to assure anatomical reduction.
The dorsomedial approach to the navicular is made between the tibialis anterior tendon and extensor hallucis longus (EHL) tendon. The approach should be made straight down from skin to periosteum without raising flaps or any unnecessary dissection.
A small distractor can be used to aid in medial column alignment/length and to allow visualization and palpation of the talonavicular joint. Once reconstruction, bone grafting (if needed) and provisional fixation are accomplished, a dorsal plate can be applied. If needed, the navicular reconstruction can include bridge plating and screw fixation into the cuneiforms.
3. Skin incision
The incision uses the interval between the tibialis anterior and the EHL, roughly directly over the fracture.
The incision can be extended distally if incorporation of the cuneiforms into the construct is needed. The incision can be extended proximally to allow inspection and palpation of the talonavicular joint.
4. Deep dissection
Once down to the periosteum/joint capsule, the tibialis anterior can be retracted medially and the EHL can be retracted laterally. This will expose the dorsum of the navicular.
5. Visualization of the joint
In a high-energy injury, the comminution may be severe. Care should be taken not to strip the periosteum or joint capsule from any small pieces. If a piece is attached to a proximal piece of joint capsule, then the best course of action may be to flip it proximally so as not to disrupt its soft-tissue attachments. Once the joint is reconstructed, this “trap-door” piece can be reduced and fixed.
6. Additional medial incision
In some cases additional fixation (screws) can be inserted from the medial side. For the medial approach to the navicular, the area along the medial utility incision over the navicular is used. The incision can be extended proximally to allow access to the talonavicular joint, or distally for access to the cuneiforms, first metatarsal base and naviculo-cuneiform and intertarsal joints.
For more details about the medial utility incision click here.
7. Wound closure
In general wounds must be closed without any tension on the skin edges. Since there is not much soft tissue in the midfoot, the deep layer closure may consist of closing the capsule/periosteum in order to take off tension from the overlying skin. The next layer is the subcutaneous layer which is loosely reapproximated using 2-0 vicryl (absorbable braided). The skin is closed without tension using an appropriate running everting suture (absorbable) or staples (less reactive but can last longer). In the case of multiple adjacent incisions (double dorsal Lisfranc approach) nylon can be used. The knots are placed outside the skin bridge.