Video

The AMI (Antero Medial Impingement) view is designed to disclose medially located osteophytes in the ankle joint. Medially located tibial and talar osteophytes go undetected on the standard AP and lateral X-ray. This 3D animation of the AMI view shows the correct production of the AMI view. It will help your radiologist with patient positioning and correct direction of the X-ray beam.

The animation has been kindly produced for ankleplatform by Stephan Wirth (Universitätsklinik Balgrist, Zurich)

Positioning

Anterior ankle arthroscopy is carried out as an outpatient procedure under general or spinal anaesthesia. The patient is placed in the supine position with slight elevation of the ipsilateral buttock. The heel of the affected ankle in placed at the very end of the operating table. This way, the surgeon can fully dorsiflex the ankle by leaning against the foot sole. Routine anterior portals used are the anteromedial and anterolateral portal. A soft-tissue distraction device can be used when indicated.

Instruments

A 4.0 mm arthroscope with 30° obliquity is used for removal of osteophytes. Normal saline, glycine or Ringer's lactate can be used of irrigation. When a 4 mm arthroscope is used, gravity inflow is usually adequate if the fluid is introduced through the arthroscope sheath.

We routinely use a 5.5 mm bonecutter shaver is used for removal of osteophytes, synovium and excessive soft tissue. The less experienced surgeon might start with a smaller diameter (4.0 mm) shaver. A 4 mm chisel and/or small periosteal elevator can be useful, an arthroscopic punch and small and large graspers.

A non-invasive distraction device can be useful at the end of the procedure to reach the inferior edge of an osteophyte of the anterior tiobial rim without damaging the opposite talar cartilage. However, overall the procedure is carried out in dorsiflexion because in this position the ankle capsule is not tensed giving the surgeon more space in the anterior compartment. 

Routinely used instruments for ankle arthroscopy

Instruments that can be used for endoscopic removal of an osteophyte (from left to right): surgical hammer, bonecutter shaver, probe, chisel (4mm), small periosteal elevator.

Portals

For removal of osteophytes through anterior arthroscopy, the standard anteromedial and- lateral portals are used. The technique is described in text & figures and in video.