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Ankle Arthroscopy

Discussion

  • indicated for symptomatic soft tissue impingement, synovitis:
  • specific lesions amenable to arthroscopic debridement include:
    • osteochondral lesions;
    • meniscoid lesion in anterolateral gutter;
      • mass of fibrocartilagenous tissue arising from the tibio-fibular joint will protrude into the joint;
      • patients will note anterolateral ankle pain, popping, and giving way;
    • anterior impingement snydrome of the ankle
      • thickening of antero-inferior tibiofibular ligament;
    • arthrofibrosis following ankle fracture;

Technical Considerations

  • use 30 deg wide angle - 2.7 mm arthroscope (if not available, then use 4 mm scope);
  • consider use of a pump set for a pressure of 50 mm;
  • use 3.5 mm shaver;

Mechanical Distraction

  • some sort of mechanical distraction device is useful;
  • typically the kit will contain sterile straps which are applied to a sterile metal bar after the leg is prepped;
  • usually a sterile strap is wrapped over the dorsum of the foot and heel;
  • usually about 25 lbs of distraction force is required, which gives between 1 to 1.5 mm of distraction;

Cautions

  • distraction of more than 30 lbs for more than 1 hour is associated with reversible nerve conduction changes;
  • excssive use of force for prolonged periods of time may cause bothersome paresthesias in the superficial peroneal nerve;

Position

  • patient is supine with leg placed in a arthroscopic leg holder (as for knee scopes);
  • leg hangs free so that knee is flexed to about 90 deg;
  • a sterile kerlex cloth band is wraped in figure of 8 fashio around the foot and ankle, with the free end tied into a loop which is then positioned just above the floor;

Portals

  • use a 15 blade to carefully incise thru skin only;

Anteromedial

  • initial arthroscopy is performed with the scope in the anteromedial portal, but for the majority of case, this portal will be used for instrumentation;
  • located at the level of the ankle joint, just medial to the tibialis anterior tendon, and located about 5 mm proximal to the medial malleolus;
  • 18 gauge syringe is used to infuse saline into the joint;
  • greater saphenous nerve and vein are at risk w/ this portal, lying 7-9 mm medial to the portal;

Anterolateral

  • once joint is distended w/ saline, use 18 gauge needle to mark location of anterolateral  portal which should lie just lateral to peroneus tertius tendon;
    • staying lateral to the peroneus tertius, helps avoid injury to the dorsal lateral branch of the peroneal nerve;
  • use the scope to transilluminate the anterolateral skin, inorder to look for underlying cutaneous nerves;
  • scope can then be driven forward (elevating the synovium and skin) which further assists with placement of this portal;
  • make small incision and then spread w/ hemostat;
  • be aware that the intermediate branch of the superficial peroneal nerve is about 5-6 mm from this portal;
  • reference Anatomic relations between ankle arthroscopic portal sites and the superficial peroneal and saphenous nerves.

Sequential Examination

  • visualization from the anteromedial portal:
    • deltoid ligament;
    • medial malleolus;
    • medial gutter (medial talomalleolar joint);
    • talar dome (osteochondral lesions)
    • anterior gutter;
    • tibiofibular joint:
      • synovitis, fibrocartilagenous protrusion;
      • posterior tib-fib ligament;
      • anterior tib-fib ligament;
      • anterior talofibular ligament (arising from the tip of the fibula)

References