Abstract:BackgroundRevision anterior cruciate ligament (ACL) reconstruction requires a precise evaluation of previous tunnel locations and diameters. Enlargement of the tunnels, despite not usually affecting primary reconstruction outcomes, plays an important role in revision ACL management. Three dimensional (3D) computed tomography (CT) models are reported to be the most accurate method for identifying the tunnel position and possible conflicts with a revision tunnel placement. However, the ability of 3D CT to measur… Show more
“…Best-fit cylinder measurements (Fig. 3): A cylinder was fit to the tunnel using a best-fit algorithm within the software, and the diameter and cross-sectional area of the cylinder were recorded [5, 24]. They were compared to the measurements at 1-year follow-up, and the percentage widening was determined.Fig.…”
Section: Imagingmentioning
confidence: 99%
“…A best-fit cylinder was generated semi-automatically by the software ( b ), and the cylinder diameter was measured ( c ) [5]…”
PurposeThe consequence of tunnel widening after ACL reconstructions is foremost of importance in case of revision surgery. Tunnel expansion leads to bone loss close to the joint, and additional surgery with bone grafting prior to revision surgery might be necessary. The purpose of the study was to measure widening of the tunnels in single-bundle (SB) and double-bundle (DB) ACL reconstructed knees during the first year after surgery, detected by a novel, semi-automated 3D CT imaging modality. Our hypothesis was that there would be a difference between the initial tunnel size and the size measured one year post-operatively due to the tunnel widening process. Further, the purpose was to evaluate whether there were any differences in the amount of tunnel widening between the two surgical techniques.MethodsTwenty patients who underwent DB ACL reconstruction, and 22 patients who underwent SB ACL reconstruction, performed a CT scan of the bony tunnels, during their first days after surgery and one year post-operatively. The CT scans were transformed into 3D CT reconstructions, and the tunnels were measured with the “best-fit cylinder” method, measurements at the level of tunnel aperture and 10.0 mm from the joint line.ResultsAll tunnels in the DB and SB ACL reconstructed knees exhibited widening during the first year after the operation (p < 0.001). The SB femoral tunnels showed more widening compared to the DB femoral AM tunnels (1.4 ± 0.9 vs. 0.5 ± 0.6 mm) (p < 0.001), and the SB tibial tunnels widened more compared to the DB tibial PL tunnels (1.0 ± 1.0 vs. 0.5 ± 0.6) (p < 0.043).ConclusionAll tunnels widened during the first year after the ACL reconstruction with a larger amount of widening in the SB tunnels compared to the DB femoral AM tunnels and the DB tibial PL tunnels. This is the first study to detect tunnel widening in DB reconstructed knees through a semi-automated 3D CT imaging modality.Level of evidenceProspective cohort study, Level III.
“…Best-fit cylinder measurements (Fig. 3): A cylinder was fit to the tunnel using a best-fit algorithm within the software, and the diameter and cross-sectional area of the cylinder were recorded [5, 24]. They were compared to the measurements at 1-year follow-up, and the percentage widening was determined.Fig.…”
Section: Imagingmentioning
confidence: 99%
“…A best-fit cylinder was generated semi-automatically by the software ( b ), and the cylinder diameter was measured ( c ) [5]…”
PurposeThe consequence of tunnel widening after ACL reconstructions is foremost of importance in case of revision surgery. Tunnel expansion leads to bone loss close to the joint, and additional surgery with bone grafting prior to revision surgery might be necessary. The purpose of the study was to measure widening of the tunnels in single-bundle (SB) and double-bundle (DB) ACL reconstructed knees during the first year after surgery, detected by a novel, semi-automated 3D CT imaging modality. Our hypothesis was that there would be a difference between the initial tunnel size and the size measured one year post-operatively due to the tunnel widening process. Further, the purpose was to evaluate whether there were any differences in the amount of tunnel widening between the two surgical techniques.MethodsTwenty patients who underwent DB ACL reconstruction, and 22 patients who underwent SB ACL reconstruction, performed a CT scan of the bony tunnels, during their first days after surgery and one year post-operatively. The CT scans were transformed into 3D CT reconstructions, and the tunnels were measured with the “best-fit cylinder” method, measurements at the level of tunnel aperture and 10.0 mm from the joint line.ResultsAll tunnels in the DB and SB ACL reconstructed knees exhibited widening during the first year after the operation (p < 0.001). The SB femoral tunnels showed more widening compared to the DB femoral AM tunnels (1.4 ± 0.9 vs. 0.5 ± 0.6 mm) (p < 0.001), and the SB tibial tunnels widened more compared to the DB tibial PL tunnels (1.0 ± 1.0 vs. 0.5 ± 0.6) (p < 0.043).ConclusionAll tunnels widened during the first year after the ACL reconstruction with a larger amount of widening in the SB tunnels compared to the DB femoral AM tunnels and the DB tibial PL tunnels. This is the first study to detect tunnel widening in DB reconstructed knees through a semi-automated 3D CT imaging modality.Level of evidenceProspective cohort study, Level III.
“…Femoral and tibial bone tunnel enlargement was assessed by CT scanning (mean time from ACL reconstruction to CT tunnel measurement ¼ 40.8 months) using the traditional two-dimensional (2D) CT method. 30 The transosseus diameter of femoral and tibial tunnels was measured at each tunnel midpoint in coronal, sagittal, and axial CT image planes using a linear measuring tool (►Fig. 1).…”
Section: Ct Assessmentmentioning
confidence: 99%
“…Two-dimensional (2D) computed tomography (CT) measuring method 30. Bone tunnels are assessed in coronal, sagittal, and axial CT image planes.…”
Bone tunnel enlargement is a well-established phenomenon following anterior cruciate ligament (ACL) reconstruction, and is related to soft tissue grafts, suspension fixation devices, and absorbable implants. Severe tunnel enlargement can lead to reconstruction failure. The correlation between bone tunnel enlargement following ACL reconstruction and original bone tunnel diameter has not been elucidated. To determine whether bone tunnel enlargement after ACL reconstruction with hamstring autograft is dependent on original tunnel diameter established during primary ACL reconstruction. A retrospective review was conducted on 56 patients scheduled for ACL revision surgery who had undergone computed tomography (CT) scanning as part of their preoperative evaluation. All patients had undergone previous hamstring ACL reconstruction. Original femoral and tibial bone tunnel diameters were extracted from operative reports, and femoral and tibial bone tunnel enlargement was assessed on CT serial sections. The correlation between original tunnel diameter and bone tunnel enlargement was investigated using regression analysis. Mean tibial bone tunnel enlargement was significantly and inversely dependent on the original tibial bone tunnel diameter with a correlation coefficient of -0.55 per unit (7 mm = +1.93 mm, 8 mm = +1.43 mm, 9 mm = 0.83 mm, = 0.007). Thus, every additional increase (mm) in diameter of the original tibial bone tunnel reduces the extend of tunnel widening by 0.55 mm. The results of this study indicate that tibial bone tunnel enlargement following ACL reconstruction is dependent on original tibial bone tunnel diameter with smaller diameter tunnels developing more tunnel enlargement than larger tunnels. The contributing factors remain unclear and need to be further investigated.
“…4). [23][24][25][26] In the knee, 3D assessment of the femur and tibia has been implemented to aid in surgical planning for anterior cruciate ligament (ACL) reconstruction, as well as to assess for tunnel remodeling as a complication of ACL repair. 27…”
Magnetic resonance imaging (MRI) is widely used in the clinical setting as well as for research applications. Since its inception, technical development has broadly progressed as a response to challenges in both the clinical and research settings. Higher magnetic field strength and advances in hardware and software have revolutionized the diagnostic potential of MRI and moved well beyond diagnosis to characterization of tissue metabolism, biochemistry, disease pathogenesis, and material property, to name a few. This article focuses on state-of-the-art clinical and cutting-edge novel pulse sequences applied to knee MRI.
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