Patient outcomes following bone–patellar tendon–bone ACL reconstruction: Influence of graft size relative to tendon width

Background: Understanding the role of graft size relative to patellar tendon size for bone-patellar tendon-bone (BTB) autografts may guide presurgical decision making for ACL reconstruction (ACLR). The purpose of this study was to determine the effect of BTB graft size on outcomes following ACLR. We hypothesized that patients with the smaller relative graft size would exhibit the highest strength and function. Methods: Overall, 135 participants approximately 6.8 months post-surgery completed strength testing via isokinetic dynamometer, hop testing, and patient reported outcomes (PROs). Two-year reinjury outcomes were also collected. Preoperative patellar tendon width was determined via MRI, and graft width was measured intraoperatively. Participants were divided based on graft size relative to patellar tendon width into a small percentage group (≤34 %) and large percentage group (>34 %). Results: There were differences in normalized knee extension and flexion at 90°/s (p = 0.02, p < 0.01) and 180°/s (p = 0.001, p = 0.01). When accounting for bilateral differences in strength within subjects, there were no differences in symmetry for strength, functional outcomes or PROs (p = 0.17–0.93). The overall graft rupture rate was 12.6 % and there was no difference in graft rupture rates by graft percentage group (p = 0.32). Conclusion: These findings indicate that the width of patellar tendon grafts relative to patella tendon size has limited effect on outcomes following ACLR. While the small percentage group had higher normalized strength in the involved limb, when accounting for the uninvolved limb via limb symmetry there were no differences in strength. In patients with grafts approximately 10.0–10.6 mm, strength and functional outcomes appear similar.