Measurement of the graft angles for the anterior cruciate ligament reconstruction with transtibial technique using postoperative magnetic resonance imaging in comparative study

Abstract

The aims of this study were to quantify the angle and placement of an anterior cruciate ligament (ACL) grafted with a single incision ACL reconstruction technique using postoperative magnetic resonance imaging (MRI), and to compare the results with those with a native ACL. Between February 1996 and May 2004, 96 consecutive patients, who had undergone postoperative MRI of the knee followed by an arthroscopically assisted ACL reconstruction with either a hamstring tendon or bone-patellar tendon-bone (BTB) autograft, were enrolled in this study. The femoral tunnel was drilled using the transtibial technique. The patients were divided into two groups; the hamstring tendon graft group (group H; 50 patients) and the BTB graft group (group B; 46 patients). All the patients including both groups in this study underwent postoperative MRI and were followed up for a minimum of 2 years. The control group (group C) consisted of 50 patients whose meniscus tear had been operated on by arthroscopy and whose ACL was intact. The orientation of the ACL ligament or graft was measured using three different methods: the sagittal ACL angle, the ACL-Blumensaat line angle, and the coronal ACL angle. The mean sagittal ACL angle in group C (58.7 +/- 3.8 degrees ) was significantly lower than in groups H (64.6 +/- 4.2 degrees ) and B (71.3 +/- 6.0 degrees ). The mean ACL-Blumensaat line angle in group C (8.6 +/- 3.6 degrees ) was also significantly lower than in groups H (12.8 +/- 5.2 degrees ) and B (18.0 +/- 5.3 degrees ). The mean coronal ACL angle in group C (65.9 +/- 4.4 degrees ) was lower than that in groups H (73.5 +/- 2.4 degrees ) and B (75.2 +/- 2.9 degrees ). The grafted ACL of the hamstring tendon and BTB grafts on the postoperative MRI showed a significant vertical angle in the coronal and sagittal plane compared with the native ACL. In the sagittal plane, the hamstring tendon graft was positioned more obliquely than the BTB graft, which had a larger angle of the tibial tunnel, in an attempt to prevent a graft-tunnel mismatch. The postoperative MRI study showed that the more horizontally the angle of the tibial tunnel can be placed in a single incision ACL reconstruction, the more efficiently it can produce a graft closer to the native ACL.

Variations in the three‐dimensional location and orientation of the ACL in healthy subjects relative to patients after transtibial ACL reconstruction

“…Additionally, the orientation angles of the ACL reported in this study (Figs. 5 and 6) are in general agreement with the literature in which cadaveric and MRI-based studies have reported traditional transtibial ACL reconstruction to orient the graft at 65-718 in the sagittal plane and 73-788 in the coronal plane 19,20,40 compared to native ACL angles of 51-598 in the sagittal plane and 66-708 in the coronal plane. 19,20,40 It is important to note that the purpose of this study was not to determine whether it is possible to place the single-bundle ACL graft in the center of the native footprints using the transtibial surgical technique.…”

“…5 and 6) are in general agreement with the literature in which cadaveric and MRI-based studies have reported traditional transtibial ACL reconstruction to orient the graft at 65-718 in the sagittal plane and 73-788 in the coronal plane 19,20,40 compared to native ACL angles of 51-598 in the sagittal plane and 66-708 in the coronal plane. 19,20,40 It is important to note that the purpose of this study was not to determine whether it is possible to place the single-bundle ACL graft in the center of the native footprints using the transtibial surgical technique. The purpose of the study was to extend a recently developed measurement technique to characterize the 3D, in vivo differences in the side-to-side ACL footprint position in healthy subjects and then to apply this technique to retrospectively evaluate patient-specific graft position in both the tibia and femur of a cohort of patients with unilateral ACL reconstruction.…”

“…Nonetheless, recent studies suggest that placement of grafts in a nonanatomic position is a frequent problem, with grafts commonly placed in a relatively vertical orientation in both the sagittal and coronal planes. [19][20][21][22][23] Taken together, these findings have generated interest in surgical recommendations, both transtibial and independent femoral tunnel placement techniques, that emphasize placement of the graft in the center of the native ligament footprints. [24][25][26][27][28][29] Given that significant anatomic variation exists between patients, 30 there is a clear need to understand the interaction between ACL footprint position and orientation for the evaluation of anatomic graft placement on a patient-specific basis as more surgeons begin to adopt anatomic ''footprint'' techniques.…”

Does Anteromedial Portal Drilling Improve Footprint Placement in Anterior Cruciate Ligament Reconstruction?

“…Achieving an anatomic footprint is considered critical to achieving tibiofemoral stability after an ACL reconstruction [1,3,10,11,30,38,43], yet there is currently little agreement on the ideal footprint placement of a singlebundle ACL reconstruction. McConkey et al [30] showed that when 12 surgeons reviewed the femoral and tibial tunnels in 72 cadaveric knees, there was poor agreement (\5%) on what was considered the ideal tunnel placement, although 88% of the femoral tunnels and 78% of the tibial tunnels were created within the study criteria [4].…”

Effect of Femoral Tunnel Placement for Reconstruction of the Anterior Cruciate Ligament on Tibial Rotation

“…This type of reconstruction (i.e., more vertical positioning of the graft) may result in a functional graft that will not impinge on the roof, but it will not reproduce the actual anatomy of the native anterior cruciate ligament. Two recent magnetic resonance imaging studies have shown that contemporary anterior cruciate ligament grafts are more vertical than the native anterior cruciate ligament 38,39 . Therefore, we propose that a reconstruction of the anterior cruciate ligament should be performed with consideration of the three-dimensional positioning of the ligament within the knee.…”