Wan F, Chen T, Ge Y, Zhang P, Chen S. Effect of Nearly Isometric ACL Reconstruction on Graft-Tunnel Motion: A Quantitative Clinical Study.
Orthop J Sports Med 2020;
7:2325967119890382. [PMID:
32656282 PMCID:
PMC7333503 DOI:
10.1177/2325967119890382]
[Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Background:
In anterior cruciate ligament (ACL) reconstruction, minimizing the
graft-tunnel motion (GTM) will promote graft-to-bone healing and avoid graft
loosening or tearing as well as potential bone tunnel enlargement. A nearly
isometric state of the graft can be achieved by placing the tunnel properly
to theoretically gain better graft-to-bone healing. However, little clinical
evidence is available to quantify the relation between GTM and tunnel
position.
Purpose:
To find the proper zones for the femoral and tibial tunnel apertures that
minimize the GTM, referred to as the “nearly isometric zone,” through use of
intraoperative GTM measurement and 3-dimensional computed tomography
(3D-CT).
Study Design:
Cross-sectional study; Level of evidence, 3.
Methods:
A total of 100 patients were enrolled in this study. Nearly isometric ACL
reconstruction was performed, and an intra-articular GTM measuring device
was designed to measure and record the amplitude of GTM while the knee was
flexed from 0° to 120°. Postoperatively, the patients underwent multislice
CT, and the images were used to create 3D-CT models. After tibial aperture
examination, 5 patients were excluded due to the divergence of tibial
aperture, and therefore 95 patients remained in the study. Patients were
divided into 2 groups according to whether the lateral intercondylar ridge
was absent or present. The Bernard-Hertel grid coordinates (h,
t) of the femoral tunnel were then quantified.
Results:
The maximal GTM (mGTM) was a mean ± SD of 1.06 ± 0.66 mm (range, 0.0-3.0 mm).
The mGTM in patients with a lateral intercondylar ridge was significantly
lower than that in patients without a lateral intercondylar ridge (0.81 ±
0.39 vs 1.59 ± 0.73 mm, respectively; P < .0001). The
average h and t were 0.227 ± 0.079 and
0.429 ± 0.770, respectively. Notably, in 1 patient, the mGTM was 0 mm
whereas the coordinates (h, t) of the femoral tunnel were
0.250 and 0.255. The overall GTM slowly increased before 90° but increased
significantly after the knee was bent 105° (P = .010).
Correlation analysis showed that the t coordiinate had
significant correlation with mGTM (R = 0.581;
P < .001). A gradient pattern was created to show
the nearly isometric blue zone (mGTM <0.5 mm), which was found to overlap
with the IDEAL (isometric, direct insertion, eccentric, anatomic, low
tension-flexion pattern) position.
Conclusion:
A method of measuring intraoperative GTM and quantifying femoral tunnel
position on postoperative 3D-CT was successfully developed. The presence of
a lateral condylar ridge can significantly reduce mGTM. A nearly isometric
zone was described that was consistent with the IDEAL concept.
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