No bone tunnel enlargement in patients with open growth plates after transphyseal ACL reconstruction

Bone tunnel enlargement after ACL reconstruction has been described extensively in adults. However, little is known about this phenomenon in patients with open growth plates. Thus, the goals of the current study were to evaluate changes in bone tunnel size in patients with open growth plates after transphyseal ACL reconstruction with suspensory fixation and to correlate tunnel size with clinical outcome after medium-term follow-up. Fourteen patients with open growth plates were included that underwent primary transphyseal ACL reconstruction using hamstrings autografts and suspensory fixation. Mean follow-up time was 7 years. At the time of follow-up, MRIs of the operated knee were performed, and outcome was assessed using KOS-ADLS, Lysholm score, IKDC Subjective Knee Form score, Knee Examination Form score, and KT-1000 measurements. On MRI, the cross-sectional area of the bone tunnels was assessed using special axial cuts perpendicular to the axes of the tunnels. Two orthopaedic surgeons and two radiologists analysed the MRIs. Change in bone tunnel size from surgery to follow-up was calculated. No significant changes in bone tunnel size from surgery to follow-up were found. Regarding outcome measures, KOS-ADLS averaged 95%, Lysholm Score averaged 96 points, IKDC Subjective Knee Form averaged 95%, IKDC Knee Examination Form scores were 8A, 5B, 1C, and KT-1000 measurements averaged 1.8 ± 1.4 mm. No significant correlations were found between tunnel size at follow-up and outcome measures. Based on our study, bone tunnel enlargement does not occur in patients who have open growth plates and undergo ACL reconstruction using suspensory fixation.