Summary
With the new tibial guide, no tibial tunnel coalition was found and tibial tunnels were located more anteriorly.
Abstract
Introduction
Tunnel coalition is one of the surgical complications due to technical error after anatomic double-bundle ACL reconstruction. Tibial tunnel coalition after double-bundle ACL reconstruction was more frequently than femoral tunnel coalition and once it happens on the tibial side, the rotatory knee laxity would not be controlled as expected. So, we have developed a new device that tibial tunnel coalition can be avoided. The purpose of this study is to compare the frequency of tibial tunnel coalition and the tibial tunnel position after anatomic double-bundle ACL reconstruction by using a new tibial guide “Anatomic Tibial Double Bundle 2-in-1 Guide System” and the conventional method.
Methods
Subjects were 47 unilateral ACL injured patients (24 males, 23 females, average age 28 ± 12 yo) who underwent anatomic double-bundle ACL reconstruction. 20 patients (Group N: 14 males, 6 females) underwent initial ACL reconstruction using a new tibial guide that tunnel positions can be simultaneously determined and two tibial tunnels can be created as they are. 27 patients (Group C: 10 males, 17 females) underwent using the conventional method in which the position of each tunnel was determined separately and created sequentially. 3DCT of the affected knees were taken at two weeks after the surgery. The tibial tunnels were extracted by 3D image analysis using Mimics (Materialise inc., Leuven, Belgium), and the presence or absence of coalition and the tibial tunnel positions were evaluated.
Results
No tibial tunnel coalition was observed in Group N. In Group C, 12/27 (44.4%) patients had tibial tunnel coalition, and significantly less tunnel coalition was observed in Group N (p<0.01). In Group N, on the tibial side, the mean thickness of the bone bridge at the level of the joint line was 2.7 ± 0.9 mm. The anteromedial (AM) and posterolateral (PL) tunnels were located significantly more anteriorly in Group N than in Group C. (AM: Group N 21.2±5.1%, Group C 33.6±6.7%, p<0.01) (PL: Group N 34.5±6.5%, Group C 48.0±6.5%, p<0.01)
Discussion
With the new tibial guide, tibial tunnel coalition can be avoided immediately after surgery, and good knee stability was expected. It has been reported that the bone bridge fracture is less likely to occur if the thickness of the bone bridge is more than 2 mm, and stable tunnel condition can be expected in cases where a tibial guide was used. And, it has been reported that clinical outcomes and rotatory knee laxity were worsened by posterior placement of the tibial tunnel. In Group N, both the AM and PL tunnels were able to be placed more anteriorly, which may also contribute to good knee stability. With the conventional method, even if the surgeon was careful, the bone tunnel can be overlapped and the AM tunnel can be placed posteriorly. However, by using the new guide, no coalition and better tunnel positions and better knee stability could be achieved.