No difference in anterior knee pain after anterior cruciate ligament reconstruction: A randomised controlled trial comparing autograft, calcium phosphate cement and demineralised bone matrix for patellar defect filling

Purpose Although bone‐patellar tendon‐bone autograft is widely used for anterior cruciate ligament reconstruction, it is often associated with anterior knee pain resulting from the residual patellar bone defect. Various materials have been proposed to fill this void, yet no consensus exists regarding the optimal choice. This study compared three commonly used patellar harvest site bone void fillers and assessed their impact on the frequency and severity of anterior knee pain. We hypothesised that calcium phosphate cement would result in lower postoperative anterior knee pain compared with autologous bone graft and demineralised bone matrix (DBM) due to its compressive modulus approximating cancellous bone. Methods Skeletally mature patients undergoing primary anterior cruciate ligament reconstruction with a bone‐patellar tendon‐bone autograft were enrolled. Exclusion criteria included age under 18, prior anterior cruciate ligament reconstruction, multiligament knee injury, coronal malalignment exceeding three degrees of varus or valgus, or less than 1 year of follow‐up. Participants were randomly assigned to one of three groups: (1) autologous bone graft, (2) calcium phosphate cement or (3) DBM. Patient‐reported outcomes were collected preoperatively and at 1 week, 6 weeks, 3 months, 6 months, 9 months and 12 months postoperatively. Analysis of variance and chi‐square tests were used for statistical analysis. Results After applying exclusion criteria, 148 patients were included in the final analysis. No significant differences in visual analog scale pain scores were observed between cohorts at any postoperative interval (12‐month, p = 0.598). Similarly, Kujala and Knee injury and Osteoarthritis Outcome scores did not differ significantly among the three cohorts at any time point (12‐month, p = 0.878, p = 0.366). Conclusions Filling the patellar harvest site defect with autologous bone graft, calcium phosphate cement, or DBM resulted in similar postoperative anterior knee pain following anterior cruciate ligament reconstruction with bone‐patellar tendon‐bone autograft. Level of Evidence Level I.