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Posterior Ankle Arthroscopic Reduction With Internal Fixation

Open AccessPublished:November 07, 2016DOI:https://doi.org/10.1016/j.eats.2016.07.015

      Abstract

      Current surgical techniques in ankle fracture management now include arthroscopic-assisted reduction and internal fixation. The need for minimally invasive fracture reduction techniques, which preserve soft tissue envelops and assists in overall anatomic reduction, can be refined and improved. The ankle is an ideal anatomic location for arthroscopic-assisted reduction and internal fixation due to the high incidence of intra-articular pathology and the poor long-term sequela of nonanatomic reduction. Thus, we propose using prone posterior ankle arthroscopic reduction internal fixation for posterior ankle fracture variants.

      Technique Video

      See video under supplementary data.

      Ankle fractures are among the most commonly treated fractures, but surgeons have been slow to accept arthroscopic assistance in treating these fractures. The thin rigid articular surfaces of the tibiotalar joint and the high incidence of traumatic osteochondral lesions produce small fragments and often loose bodies that are difficult to assess with standard open techniques. Standard anterior ankle arthroscopy is ideal for anterior pathology and syndesmosis reduction, but puts posterior pathology out of reach.
      • Bonasia D.E.
      • Rossi R.
      • Saltzman C.L.
      • Amendola A.
      The role of arthroscopy in the management of fracture about the ankle.
      Posterior ankle arthroscopy puts the posterior malleolus and pilon variants and their associated pathology within reach, making loose body removal and direct visualization of fracture reduction possible, while avoiding extensive posterior lateral dissection. Thus, we purpose using prone posterior arthroscopic reduction and internal fixation for posterior ankle fracture variants.

      Surgical Technique

      Preoperative Setup

      The patient is positioned prone taking care to prevent hyperextension of the cervical spine and padding all bony prominences. We also recommend placing a thigh tourniquet before rolling the patient into the prone position ensuring that the feet are off the end of the bed. An external positioning arm (Trimano; Arthrex, Naples, FL) is applied to the ipsilateral side on the most distal end of the operating table rail. The operative leg is then prepped and draped in the standard fashion. We then apply a standard padded ankle distraction strap positioned around the end of the external position arm with gentle traction applied. The gentle traction serves 2 purposes: helps with reduction and holds the ankle in place as we operate. The anatomic landmarks (medial/lateral malleolus, Achilles tendon, and sural nerve) are marked and identified.

      Portal Placement

      We use the tip of the lateral malleolus to gauge the location of the posterior portals, which are established tangential to the Achilles tendon. The posteromedial portal is initially established using the nick-and-spread technique. Then a Stryker (Kalamazoo, MI) 4.0-mm 30° arthroscope is introduced. The posterolateral portal is then established in the same manner using a straight hemostat to create a working space and help with triangulation.

      Hematoma Evacuation and Loose Body Removal

      A Stryker 4.0-mm Tomcat shaver is then introduced. Before addressing pathology, it is paramount to visualize and stay lateral to the flexor hallucis longus (FHL), which helps prevent injury to the medial neurovascular bundle. After the FHL is identified, the posterior capsule is taken down and the tibiotalar joint is identified. A small c-arm fluoroscopy is useful to help identify landmarks and with the aforementioned patient positioning access should be unimpeded and easily accessible. Evacuate the hematoma and begin identifying the fracture characteristics (Fig 1). If a loose body is identified, we turn off the inflow before grasping the fragment to prevent propulsion of the fragment into the anterior ankle.
      Fig 1
      Fig 1Images obtained from the posterior medial portal using a Stryker 4-mm 30° arthroscope. They were taken after the fracture hematoma has been evacuated so that the fracture line can adequately be identified (which is shown by the blue arrows) before the reduction. In the images a fracture step off can be noted. The fracture is on the tibial plafond; the images show that the start, end, and amount of disruption can all be accurately identified. The most inferior bone (talus) can be seen and no injury is identified.

      Reduction and Fixation

      We then begin our reduction by establishing an accessory posterior lateral portal approximately 2 to 3 cm proximal to the standard posterolateral portal using the previously mentioned nick-and-spread technique. This technique mitigates iatrogenic damage to the sural nerve. A bone pusher or elevator is introduced into the newly created portal to reduce the posterior fragment. C-arm and direct arthroscopic visualization are used concomitantly. After anatomic reduction, which can be seen and confirmed both arthroscopically and via the use of fluoroscopy, a cannulated guidewire is introduced through the standard posterior lateral portal (Fig 2). We then place our arthroscope into the standard posterolateral portal, and place a second guidewire through the posterior medial portal. A third guidewire is placed in the accessory portal at an oblique angle creating an axilla preventing proximal migration of the fragment (Fig 3). Depending on the fragment size 1-3, Synthes (Trimano; Arthrex) 3.5-mm cannulated titanium screws are placed using standard techniques (see Table 1). Screws are tightened sequentially, whereas visualization of the maintained reduction is achieved arthroscopically to ensure that the fragment does not migrate proximal (Fig 4).
      Fig 2
      Fig 2After the fracture is identified, it must be reduced. A third portal is created approximately 2-3 cm proximal to that of the posterior lateral portal; the portal must be established using the nick-and-spread technique to prevent injury to the sural nerve. A bone pusher or elevator may be used for the reduction (which is just superior to the blue arrow). Then a 1.25-mm cannulated guidewire is introduced through the posterior lateral portal; the position and angle are checked arthroscopically (indicated by the red arrow) and with fluoroscopy as seen above. This also shows the positioning of the arthroscope in the posteriormedial portal and guidewires through the posterior lateral portal before reduction. Blue arrow = posterior malleolus of tibia. Red arrow = arthroscope in joint space from posterior arthroscopy.
      Fig 3
      Fig 3Arthroscopic image from the posterior medical portal using a Stryker 4-mm 30° arthroscope showing direct visualization of the 2 cannulated guidewires after inserting into the posterior fragment before screw fixation. During this step, spacing is checked along with fracture alignment using fluoroscopy. The screws are then placed on the guidewires and direct visualization of insertion is observed.
      Table 1Recommended Equipment and Procedural Tips
      Positioning• Ensure that ulnar nerves, chest, knees, and anterior ankle are well padded (we prefer gel pads)

      • Foot is off the end of the bed, neutral

      • External positioning arm that provides distraction and position
      Fluoroscopy• Mini c-arm reduces exposure
      Portals• Level of the lateral malleolus

      • Adjacent to Achilles
      Arthroscopy• Stryker 4.0 mm 30°

      • Fluid gravity up to 30 mm Hg

      • Stryker 4.0-mm Tomcat shaver

      • Smith & Nephew small joint arthroscopic instruments
      Reduction• Proximal posterior lateral portal allows bone pusher or elevator reduction
      Wire fixation• Preliminary reduction with 1.25-mm cannulated guidewires

      • Number of wires depends on the size of the fragment

      • Larger fragments need a perpendicular pin to create an axilla, stopping proximal migration
      Screws• Synthes 3.5-mm cannulated titanium screws, washers depending on bone quality
      Postoperative protocol• Splint for 2 wk

      • Boot with range of motion for 4 wk

      • Progressive weight bearing starting at 6 wk
      Fig 4
      Fig 4Arthroscopic images from the posterior medical portal using a Stryker 4-mm 30° arthroscope showing the postreduction fracture line. Moving inferiorly in the images, it can been seen that the tibial plafond only has slight plastic deformation after the reduction (this is indicated by the blue arrows). Joint space preservations remain and the talus remains uninjured.

      Discussion

      Prone posterior ankle arthroscopic reduction and internal fixation is ideal for posterior hindfoot pathology. It provides access to loose bodies and allows direct visualization of the fracture reduction. Our technique described above also allows for safe placement of internal fixation by using established portals within anatomic safe locations
      • Sitler D.F.
      • Amendola A.
      • Bailey C.S.
      • Thain L.M.
      • Spouge A.
      Posterior ankle arthroscopy: An anatomic study.
      with a low rate of major complications.
      • Nickisch F.
      • Barg A.
      • Saltzman C.L.
      • et al.
      Postoperative complications of posterior ankle and hindfoot arthroscopy.
      This technique provides several advantages over standard open reduction internal fixation. The primary advantage is the limited soft tissue disruption. The standard posterolateral approach requires the FHL to be stripped from the syndesmosis and retracted allowing for care to protect the posterior inferior tibiofibular ligament. The posterolateral approach requires extensive dissection and retraction while only providing a limited view of the reduction and articular surface. Preserving the posterior inferior tibiofibular ligament with posterior malleolus fixation restores 70% of syndesmotic stiffness compared with 40% with syndesmotic screw fixation in a cadaveric model.
      • Gardner M.J.
      • Brodsky A.
      • Briggs S.M.
      • Nielson J.H.
      • Lorich D.G.
      Fixation of posterior malleolar fractures provides greater syndesmotic stability.
      Our approach also maximizes the biomechanical advantage of partially threaded cannulated screws, compared with anterior-to-posterior directed screws. Our technique also avoids plates and screws that can lead to impingement with the FHL tendon. Posterior arthroscopic-assisted reduction and internal fixation (ARIF) provides a clear advantage due to direct visualization of the reduction and removal of loose bodies with no retraction and minimal dissection. The arthroscopic lavage also evacuates the hematoma and helps reduce inflammatory cytokines and matrix metalloproteinase that contribute to cartilage damage and synovitis
      • Adams S.B.
      • Selton L.A.
      • Bell R.D.
      • et al.
      Inflammatory cytokines and matrix metalloproteinases in the synovial fluid after intra-articular ankle fracture.
      (see Table 2).
      Table 2Tips, Advantages, and Pitfalls
      TipsAdvantagesPitfalls
      Pad all boney prominences in the prone positionLimited soft tissue capsule disruptionIncreases surgical time because of patient setup in the prone position
      Use a low pump pressure <30 mm HgDirect visualization of fracture or injuryFracture hematoma decreases visualization and makes landmarks more difficult to find
      Find your landmarks before starting surgery—locate the flexor hallucis longus (FHL) and stay inside (lateral)Direct visualization of reduction during and after fixationFracture reduction time may be increased
      Have mini c-arm draped and ready to help locate and confirm positionFHL remains intact and not disrupted from syndesmosis
      Plates and screws no longer have to be used
      Preservation of the posterior inferior tibiofibular ligament

      Limitations

      The most notable risk or limitation of this technique is surgeon experience and comfort with posterior ankle arthroscopy. The surgeon should be comfortable with posterior ankle arthroscopy before attempting ARIF, because the fracture hematoma and fracture fragments can make visualization difficult. Prone arthroscopy is a difficult surgical setup that requires the anesthesia provider to be familiar and comfortable with prone positioning. This positioning increases surgical times because of the difficulty of setup and the need to flip and maneuver the patient from a supine to prone position from the transport bed to the operating table. Ensuring that all bony prominences are well padded is also paramount to prevent nerve compression in the prone position. Soft tissue fluid extravasation is an additional risk that the surgeon should continually monitor and mitigate with low pump pressure and short arthroscopy times (see Table 3).
      Table 3Key Points, Indications, Contraindication, and Risks
      Key PointsIndicationsContraindicationsRisks
      Surgeon must be comfortable with posterior ankle arthroscopyPosterior hindfoot pathologiesSevere soft tissue swelling caused by fractureSoft tissue extravasation
      Find your landmarks before starting reduction to decrease iatrogenic damagePilon fractures/Pilon-variant-type fracturesInfection where portal sites need to be placedUnable to locate fracture because of surgeons' ability
      Partially threaded cannulated screws can be used giving biomechanical advantagePosterior malleolus fracture
      Loose body removal

      Conclusions

      Prone posterior ankle arthroscopic reduction and internal fixation allows for direct visualization of fracture reduction and allows the surgeon to simultaneously address intra-articular pathology. Posterior ankle ARIF uses safe proven portals for fixation, while avoiding large extensive soft tissue disruption from a standard posterolateral approach (see Video 1).

      Supplementary Data

      References

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