Lateral posterior tibial slope and length of the tendon within the tibial tunnel are independent factors to predict tibial tunnel widening following anatomic anterior cruciate ligament reconstruction

Abstract

Purpose This study aimed to conduct a multivariate analysis to identify independent factors that predict tibial tunnel widening (TW) after anatomical anterior cruciate ligament (ACL) reconstruction using bone-patellar tendon-bone (BPTB) grafts. Methods In total, 103 patients who underwent ACL reconstructions using BPTB grafts were included. Tunnel aperture area was measured using three-dimensional computed tomography 1 week and 1 year postoperatively, and the tibial TW was calculated. The patients were divided into group S comprising 58 patients who had tibial TW < 30% and group L comprising 45 patients who had tibial TW > 30%, retrospectively. Using univariate analyses, age, gender, body mass index, Tegner activity scale, the time between injury and surgery, tibial tunnel location, tibial tunnel angle, medial posterior tibial slope, lateral posterior tibial slope, and length of the tendon in the tibial tunnel were compared between two groups. Multivariate regression analysis was conducted to reveal the independent risk factors for the tibial TW among preoperative demographic factors and radiographic parameters that correlated with the tibial TW in the univariate analyses. Results Compared with those at 1 week postoperatively, mean tibial tunnel aperture areas were increased by 30.3% ± 26.8% when measured at 1 year postoperatively. The lateral posterior tibial slope was signiicantly larger (p < 0.001), and the length of the tendon within the tibial tunnel was signiicantly longer in group L than that in group S (p = 0.03) in the univariate analyses. Multivariate regression analysis showed that the increase in lateral posterior tibial slope (p = 0.001) and the length of the tendon within the tibial tunnel (p = 0.03) were predictors of the tibial TW. Conclusions This study showed that increased lateral posterior tibial slope and a longer tendinous portion within the tibial tunnel were independent factors that predicted the tibial TW following anatomical ACL reconstruction with a BPTB graft. Level of evidence III.

Lateral posterior tibial slope does not affect femoral but does affect tibial tunnel widening following anatomic anterior cruciate ligament reconstruction using a Bone–Patellar Tendon–Bone graft

“…The medial and lateral PTS were measured using CT according to the previously reported method. 7 , 9 , 21 To determine the longitudinal axis of the tibia, the central sagittal CT slice with the following criteria was used: (1) the anterior and posterior proximal tibial cortices be seen in concave shape and (2) intercondylar eminence and its PCL attachment. A circle was fitted to the proximal tibia, tangential to the cortexes, and a second circle was fitted distally with its center placed on the border of the first circle.…”

“…In recent years, it has been noted that posterior tibial slope (PTS) affects several types of outcomes after ACL reconstruction, such as static anterior tibial translation, 5 graft failure rate, 6 and TW. 7 The influence of lateral PTS is found to be particularly significant. Several studies have found that increased lateral PTS results in greater TW after ACL reconstruction.…”

“…Several studies have found that increased lateral PTS results in greater TW after ACL reconstruction. 7 , 8 , 9 …”

“…In addition, there are few published papers studying TW after anatomical ACL reconstruction using BTB grafts, and many of these previous studies treated femoral and tibial TW individually as separate events. 7 , 11 , 12 , 13 Therefore, the correlation between femoral and tibial TW after anatomical ACL reconstruction using BTB grafts has not been fully understood. Even among the papers that studied the relationship between PTS and TW, most examined only the effects on the tibial side of TW, 7 , 8 , 9 and the effects on the femoral side of TW have rarely been investigated.…”

“… 7 , 11 , 12 , 13 Therefore, the correlation between femoral and tibial TW after anatomical ACL reconstruction using BTB grafts has not been fully understood. Even among the papers that studied the relationship between PTS and TW, most examined only the effects on the tibial side of TW, 7 , 8 , 9 and the effects on the femoral side of TW have rarely been investigated.…”