It is imperative that the open wedge is healed and repopulated by new bone, to strengthen the tibia and allow full recovery following HTO. Regeneration will take place naturally, although some surgeons apply aids to promote bone healing, such as the ChronOS β-tricalcium phosphate wedge. However, research into this aspect of filling the wedge has shown that there is no advantage to using the filler - both in terms of stability and bone healing time of the wedge . Although fixed systems like Tomofix facilitate early weight-bearing of the affected joint, the complete closure and consolidation of the wedge takes considerably longer. In one study, 23 /27 (85%) osteotomies were fully healed twelve months after procedure . Histologically, there is variability in the degree of healing and indeed maturation of bone regeneration achieved in the tibial wedge. With current fixed plate devices, even two years post-procedure, a minor subset of patients will not have significant signs of regeneration in the surgical site. In the majority of patients, partial bone regeneration with fibrocartilaginous tissue takes place and in some patients by new regenerated fibrocartilage or hyaline-like cartilage will appear .