ARTHROSCOPY OF THE ANKLE - A NEW POSTERO- MEDICAL POSTAL

Introduction The development of the indications in the arthroscopic su rgery of the ankle and the narrowness of this joint impose perfectly a dapted portals. Several posterior portals which allow to access to the postero medial corner of the joint have been already described, but a re not satisfying. We describe, here, a new postero-medial portal whic h allows a safe and easy access to the posterior part of the joint. Me thods The arthroscopy is performed with a standard arthroscope (30 deg rees, 4,5 mm in diameter) and a lateral ankle distractor. The landmark for this portal is the posterior crest of the medial malleolus. Above the posterior tip of the medial malleolus, this crest is directed up and back, then its direction becomes strictly vertical. The new portal is situated there, 5 millimeters behind the crest (generally 2 centim eters above the posterior tip of the medial malleolus). A needle vizua lised by the anterior portal is helpfull to show the right direction f or the portal. After skin incision, a forceps is used to widen the por tal. Then the instruments or the arthroscope can be introduced. Poster ior tibial artery and nerve are protected by the tendons of tibialis p osterior and flexor digitorum longus. Material We have used this porta l (instrumentation and arthroscope) in four patients (3 osteochondriti s dissecans of the medial part of the talus, 1 loose body) without pro blem. Results This portal is safe; it does not intersect the direction of posterior tibial artery and nerve as in the postero-medial portal described by Parisien and avoids in most cases the approach described by Guhl. Discussion Because the medial malleolus is more anterior than the lateral malleolus, it allows a larger approach to the posterior p art of the joint than the postero-lateral portal. We recommend it for the arthroscopic treatment of all the lesions of the postero-medial pa rt of the joint.