No Superior Bone Union Outcomes with Allografts Compared to No Grafts and Autografts Following Medial Opening Wedge High Tibial Osteotomy: A Retrospective Cohort Study

Objective: There has been long-standing debate about whether a medial opening wedge high tibial osteotomy (MOWHTO) gap should be filled with autologous bone graft or any other filler to expedite the healing process. The main purpose of this study was to compare the clinical and radiological outcomes of MOWHTO with an opening gap >= 10 mm, utilizing autograft, allograft, or no graft at 1 year postoperatively. Methods: A total of 68 patients were included in this retrospective study and divided into three treatment groups: Group A (no bone graft), Group B (autologous iliac crest graft), and Group C (allogenous tibia plateau graft). At postoperative 1-year follow-up, the area of callus filling in the most medial side of the knee was measured using anteroposterior radiographs, and a modified van Hemert scoring system was used to evaluate bone union outcomes in five mediolaterally divided zones. Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores and relevant complications were assessed. The correlations between the gap width and bone union scores were evaluated. Results: Patients in the autograft group demonstrated better bone union progression (p = 0.031) and higher bone union scores (p < 0.01) compared to patients in the allograft or no graft groups. There were no significant differences in terms of postoperative WOMAC scores and incidence of complications among the three groups. No discernible linear relationships between the width of the opening gap and the bone union score were found. Conclusion: For MOWHTOs with an average gap opening width of 12.1 mm, autografts resulted in superior bone union outcomes compared to allografts and no graft at 1 year postoperatively. However, no bone graft achieved similar outcomes to allografts, suggesting that routine use of allografts should not be recommended.