A Retrospective Comparison of Union Rates After Open Wedge High Tibial Osteotomies With and Without Synthetic Bone Grafts (Hydroxyapatite and β-tricalciumphosphate) at 2 Years

Abstract

To evaluate the clinical and radiological results of no bone graft (NBG) after opening wedge high tibial osteotomy (OWHTO) with a locking plate and to compare the bone union rate between the synthetic bone graft (SBG) group and the NBG group after OWHTO using serial radiographs. From 2012 to 2015, OWHTOs were performed with SBG or without bone graft using long locking plates. Inclusion criteria were: (1) OWHTO for disease of the medial compartment with varus deformity, and (2) minimum 2-year follow-up and radiographs taken serially to 2years. Exclusion criteria were: (1) follow-up period <2years (n= 8) or (2) absence of at least 1 radiograph taken at each follow-up point (n= 14). We retrospectively reviewed radiographs taken preoperatively and at 6weeks, 3months, 6months, 1year, and 2years postoperatively. Groups comprised those filled with a synthetic bone [hydroxyapatite (HA) and β-tricalciumphosphate (TCP), n=33, SBG group] or without a bone graft (n= 38, NBG group). We compared bone union rate between the 2 groups by measuring the union zone from zone 1 to zone 5 in serial radiographs using Fisher's exact test. OWHTO was performed in a total of 93 knees and 71 knees were included in this study. Both groups showed good clinical and radiological results without correction loss at 2years. The entire NBG group and 93.9% of the SBG group showed union over zone 3 at 2years. However, the NBG group showed significantly more incorporation than the SBG group at 6months (P= .006), 1year (P= .0003), and 2years (P= .0003). Union without correction loss was obtained after OWHTO without bone graft. The NBG group showed significantly more incorporation than the SBG group (HA and β-TCP) within 2years. Level IV, case series.