This study compared bone union progression using highly porous (80% porosity) β-tricalcium phosphate (β-TCP) granules or allogeneic bone chips in the gap created by medial opening-wedge high tibial osteotomy (MOWHTO).
The study population consisted of 54 patients who received MOWHTO with locking plate fixation: 27 patients using highly porous β-TCP granules, and 27 age- and sex-matched patients using allogeneic bone chips. Bone union progression was evaluated 1, 3, 6, and 12 months postoperatively. The presence of radiographic sclerosis at the osteotomy margin was also assessed.
Among all patients, the highest degree of bone union observed 12 months postoperatively was grade 4. As postoperative time passed, bone union progression of highly porous β-TCP granules increased linearly and was statistically significant compared with that of cancellous allogeneic bone chips (P = 0.014). The presence of radiographic sclerosis at the osteotomy margin was significantly less common in the β-TCP group than in the allograft group (P = 0.003) and was the strongest predictor of delayed progress of bone union (odds ratio = 6.16, P = 0.006).
Patients who underwent MOWHTO using highly porous β-TCP granules had faster new bone remodeling, less radiographic sclerosis at the osteotomy margin, and no inferior clinical outcome compared with allogeneic bone chips, as determined at the 1-year follow up. The presence of radiographic sclerosis at the osteotomy margin in patients undergoing MOWHTO using allogeneic bone or synthetic bone substitute may indicate delayed progress of bone union.