Anterior cruciate ligament reconstruction with bone-patellar tendon-bone grafts: a prospective comparative study of femoral cortical suspensory fixation and interference screw fixation

Abstract

Background: We prospectively compared the clinical outcome between suspensory fixation and conventional interference screw fixation of bone-patellar tendon-bone (BPTB) grafts in patients who underwent anterior cruciate ligament (ACL) reconstruction. Methods: We enrolled 32 patients who underwent primary ACL reconstruction with BPTB grafts. The minimum followup period was 24 months. We categorized subjects into two groups based on treatment: 14 patients into the interference screw fixation group and 12 patients into the suspensory fixation group. The patients were also analyzed in terms of patellar tendon length. We assessed clinical outcome with the Lachman test and the pivot shift test and anterior translation with a KT-2000 arthrometer. We assessed functional outcome in terms of the Lysholm score, the International Knee Documentation Committee subjective score, and objective grades. In the suspensory group, we measured the length from the outer cortical aperture to the femoral grafted bone and the degree of axial rotation of the grafted bone by using computed tomography (CT) scans taken immediately and 3 months postoperatively. Results: We did not observe a statistically significant difference in anterior translation between the two groups (P = 0.934). We found that the patients who underwent suspensory fixation had an average difference in length between the graft bone and the cortex bone of 0.06 mm (range, –0.34 to 0.46 mm; P = 0.755) and axial rotation of 0.57° (range, –0.76° to 1.89°; P = 0.366). Conclusion: In sum, we found that the degree of postoperative anterior translation in patients who received femoral suspensory fixation was comparable to those who underwent interference screw fixation. In addition, we did not observe early loosening of the graft-bone block upon CT analysis. Therefore, we conclude that suspensory fixation could be an alternative to the conventional interference screw fixation technique that can eliminate the graft-tunnel mismatch observed in BPTB grafting in ACL reconstruction.