Preoperative Estimated Width of the Patellar Tendon for Anterior Cruciate Ligament Reconstruction

This study aims to compare the actual patellar tendon width with the skin and magnetic resonance imaging (MRI) measurements and to describe a more accurate method to predict the actual patellar tendon width before anterior cruciate ligament reconstruction (ACLR).Thirty-nine patients undergoing primary ACLR were identified. Patients with patellar tendon width of less than 30 mm by skin or MRI measurements were excluded from the study. The actual patellar tendon width was measured as an intraoperative reading taken after surgical exposure. Mean difference between the skin and actual measurement and mean difference between the MRI and actual measurement was calculated. Paired t-test was run to determine any significant differences. A difference was also calculated between the actual measurement and the average sum of skin and MRI measurements for each patient. Skin thickness was compared to Δ (Δ = preincision skin measurement of patellar tendon width minus postincision actual measurement) by Spearman's correlation test. Mean difference between skin and actual measurements was 2.5 mm, with p = 0.001. Mean difference between MRI and actual measurement was -2.7 mm with p = 0.001. However, the mean difference between the actual and the average sum of skin and MRI measurements was 0.13 mm with p = 0.76. The Pearson's correlation coefficient, r _s, between average sum of skin and MRI measurements and the actual measurement was 0.6 with p = 0.001. There was no correlation found between the skin thickness and Δ∙. This study indicates that there is a significant difference between the actual patellar tendon width and the measurement of the tendon taken using a ruler on the skin or using MRI image software. However, the average sum of skin and MRI measurements, which is not significantly different from the actual width, can accurately predict the actual patellar tendon width before ACLR. The study reflects level IV evidence.