- tuberosity fragment tilts into varus and is pulled proximally by the Achilles tendon; However, the sinus tarsi approach has limited exposure to the lateral wall, which. 6. Clin Orthop Relat Res. (2):CD001161. 12. The classification of extraarticular fractures has been less controversial and makes use of anatomic landmarks on the calcaneus to divide the bone into anterior, middle, and posterior areas. Lateral impingement syndromes,