Safety and efficacy of talonavicular arthroscopy in arthroscopic triple arthrodesis. A cadaveric study.

This is a cadaveric study on the safety and efficacy of talonavicular arthroscopy in arthroscopic triple arthrodesis. Talonavicular arthroscopy was performed in 18 feet of 9 fresh frozen cadavers. The specimens were divided into 3 groups (6 feet in each group). The articular cartilage of the talar and navicular facet was abraded with a hemostat through the dorsolateral portal in group 1 specimens. The cartilage was abraded through the dorsomedial portal in group 2 specimens and through the medial portal in group 3 specimens. The area of cartilage abrasion represented the working area of the corresponding portal. The working area of individual portal and the relationship of individual portal to the adjacent neurovascular structure were studied. The medial portal averaged 12 mm medial to the long saphenous vein and saphenous nerve. The dorsomedial portal was 1 mm lateral to the intermediate cutaneous branch of superficial peroneal nerve and 5 mm lateral to the extensor hallucis longus tendon. It was 4 mm lateral to the deep peroneal nerve. The dorsolateral portal was 4 mm medial to the lateral branch of superficial peroneal nerve. In group 1, the working area of the dorsolateral portal averaged 60 +/- 4% for the talar facet and 66 +/- 12% for the navicular facet. In group 2, the working area of the dorsomedial portal averaged 56 +/- 3% for the talar facet and 64 +/- 8% for the navicular facet. In group 3, the working area of the medial portal averaged 40 +/- 4% for the talar facet and 55 +/- 11% for the navicular facet. Most of the talar and navicular surfaces can be prepared for fusion without the need of excessive bone removal during arthroscopic triple arthrodesis. This study confirmed the efficacy of the arthroscopic triple arthrodesis and arouses the surgeon about the risk of neural damage especially at the dorsomedial portal.