Clinical tips: retrograde drilling of talar osteochondral defects.

Contemporary methods of bone grafting osteochondral defects, in which the remaining overlying cartilage is relatively well preserved, have inherent problems. The bony defects are often saucer-shaped and the cylindrical graft may not fill the void, leaving areas of cartilage with no underlying scaffold and obviating early weight bearing. Furthermore, to obtain a proper fill of the defect, tamping of the graft can cause excessive pressure and disruption of the overlying cartilage. In an effort to address these concerns, the authors propose the use of a biological viscous paste of calcium sulfate that hardens within 5 minutes when injected in a retrograde fashion into the talus. This confers a mechanical advantage of complete cystic fill of the cyst which allows early weight bearing. Calcium sulfate acts as an osteoconductive material that incorporates into host bone within 8 weeks. Donor site morbidity is eliminated using this system.