scholarly journals Predictors of Healing Ligament Size and Magnetic Resonance Signal Intensity at 6 Months After Bridge-Enhanced Anterior Cruciate Ligament Repair

2019 ◽  
Vol 47 (6) ◽  
pp. 1361-1369 ◽  
Author(s):  
Martha M. Murray ◽  
Ata M. Kiapour ◽  
Leslie A. Kalish ◽  
Kirsten Ecklund ◽  
Christina Freiberger ◽  
...  
Keyword(s):  
Anterior Cruciate Ligament ◽  
Magnetic Resonance ◽  
Signal Intensity ◽  
Cruciate Ligament ◽  
Quadriceps Strength ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Acl Repair ◽  
Cross Sectional ◽  
Anterior Cruciate

Background: Primary repair of the anterior cruciate ligament (ACL) augmented with a tissue engineered scaffold to facilitate ligament healing is a technique under development for patients with ACL injuries. The size (the amount of tissue) and signal intensity (the quality of tissue) of the healing ligament as visualized on magnetic resonance imaging (MRI) have been shown to be related to its strength in large animal models. Hypothesis: Both modifiable and nonmodifiable risk factors could influence the size and signal intensity of the repaired ligament in patients at 6 months after surgery. Study Design: Case series; Level of evidence, 4. Methods: 62 patients (mean age, 19.4 years; range, 14-35 years) underwent MRI of the knee 6 months after ACL repair augmented with an extracellular matrix scaffold. The signal intensity (normalized to cortical bone) and average cross-sectional area of the healing ligament were measured from the MRI stack obtained by use of a gradient echo sequence. Associations between these 2 measures and patient characteristics, which included demographic, clinical, and anatomic features, were determined by use of multivariable regression analysis. Results: A larger cross-sectional area of the repaired ligament at 6 months was associated with male sex, older age, and the performance of a larger notchplasty ( P < .05 for all associations). A lower signal intensity at 6 months, indicating greater similarity to normal ligament, was associated with a smaller tibial slope and greater side-to-side difference in quadriceps strength 3 months after surgery. Other factors, including preoperative body mass index, mechanism of injury, tibial stump length, and Marx activity score, were not significantly associated with either MRI parameter at 6 months. Conclusion: Modifiable factors, including surgical notchplasty and slower recovery of quadriceps strength at 3 months, were associated with a larger cross-sectional area and improved signal intensity of the healing ACL after bridge-enhanced ACL repair in this preliminary study. Further studies to determine the optimal size of the notchplasty and the most effective postoperative rehabilitation strategy after ACL repair augmented by a scaffold are justified. Registration: NCT02664545 (ClinicalTrials.gov identifier).

Morphological Evaluation of the Quadriceps Tendon Using Preoperative Ultrasound in Anterior Cruciate Ligament Reconstruction

2021 ◽  
pp. 036354652110540
Author(s):  
Satoshi Takeuchi ◽  
Kevin J. Byrne ◽  
Ryo Kanto ◽  
Kentaro Onishi ◽  
Freddie H. Fu
Keyword(s):  
Anterior Cruciate Ligament ◽  
Acl Reconstruction ◽  
Cruciate Ligament ◽  
Quadriceps Tendon ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Preoperative Ultrasound ◽  
Anterior Cruciate ◽  
Superior Pole

Background: An evaluation of quadriceps tendon (QT) morphology preoperatively is an important step when selecting an individually appropriate autograft for anterior cruciate ligament (ACL) reconstruction. However, to our knowledge, there are no studies that have assessed the morphology of the entire QT in an ACL-injured knee preoperatively using ultrasound. Purpose: We aimed to investigate the morphological characteristics of the QT using preoperative ultrasound in ACL-injured knees. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A total of 33 patients (mean age, 26.0 ± 11.5 years) with a diagnosed ACL tear undergoing primary ACL reconstruction were prospectively included. Using ultrasound, short-axis images of the QT were acquired in 10-mm increments from 30 to 100 mm proximal to the superior pole of the patella. The length of the QT was determined by 2 contiguous images that did and did not contain the rectus femoris muscle belly. The width of the superficial and narrowest parts of the QT, the thickness of the central and thickest parts of the QT, and the cross-sectional area at the central 10 mm of the superficial QT width were measured at each assessment location. The estimated intraoperative diameter of the QT autograft was calculated using a formula provided in a previous study. Results: There were no significant relationships between QT morphology and any of the demographic data collected. The length of the QT was less than 70 mm in 45.5% of patients (15/33). The width, thickness, cross-sectional area, and estimated intraoperative diameter of the QT autograft were significantly greater at 30 mm than at 70 mm proximal to the superior pole of the patella. Conclusion: Preoperative ultrasound may identify a QT that is too small for an all–soft tissue autograft in ACL reconstruction. Furthermore, harvesting a QT with a fixed width may result in autografts that are smaller proximally than they are distally. Assessing the morphology of the QT preoperatively using ultrasound may help surgeons to adequately reconstruct the native length and diameter of the ACL with a QT autograft.

scholarly journals Higher Physiologic Platelet Counts in Whole Blood Are Not Associated With Improved ACL Cross-sectional Area or Signal Intensity 6 Months After Bridge-Enhanced ACL Repair

2020 ◽  
Vol 8 (7) ◽  
pp. 232596712092765 ◽  
Author(s):  
Christina Freiberger ◽  
Ata M. Kiapour ◽  
Shanshan Liu ◽  
Rachael N. Henderson ◽  
Samuel Barnett ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Magnetic Resonance ◽  
Blood Cell ◽  
Signal Intensity ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Acl Repair ◽  
Cross Sectional ◽  
Platelet Concentration ◽  
Male Sex

Background: A bridge-enhanced anterior cruciate ligament (ACL) repair (BEAR) procedure places an extracellular matrix implant, combined with autologous whole blood, in the gap between the torn ends of the ligament at the time of suture repair to stimulate healing. Prior studies have suggested that white blood cell (WBC) and platelet concentrations significantly affect the healing of other musculoskeletal tissues. Purpose/Hypothesis: The purpose of this study was to determine whether concentrations of various blood cell types placed into a bridging extracellular matrix implant at the time of ACL repair would have a significant effect on the healing ligament cross-sectional area or tissue organization (as measured by signal intensity). We hypothesized that patients with higher physiologic platelet and lower WBC counts would have improved healing of the ACL on magnetic resonance imaging (MRI) (higher cross-sectional area and/or lower signal intensity) 6 months after surgery. Study Design: Cohort study; Level of evidence, 2. Methods: A total of 61 patients underwent MRI at 6 months after bridge-enhanced ACL repair as part of the BEAR II trial. The normalized signal intensity and average cross-sectional area of the healing ligament were measured from a magnetic resonance stack obtained using a gradient echo sequence. The results were stratified by sex, and univariate and multivariate regression analyses determined significant correlations between blood cell concentrations on these 2 magnetic resonance parameters. Results: In unadjusted analyses, older age and male sex were associated with greater healing ligament cross-sectional area ( P < .04) but not signal intensity ( P > .15). Adjusted multivariable analyses indicated that in female patients, a higher monocyte concentration correlated with a higher ACL cross-sectional area (β = 1.01; P = .049). All other factors measured, including the physiologic concentration of platelets, neutrophils, lymphocytes, basophils, and immunoglobulin against bovine gelatin, were not significantly associated with either magnetic resonance parameter in either sex ( P > .05 for all). Conclusion: Although older age, male sex, and monocyte concentration in female patients were associated with greater healing ligament cross-sectional area, signal intensity of the healing ligament was independent of these factors. Physiologic platelet concentration did not have any significant effect on cross-sectional area or signal intensity of the healing ACL at 6 months after bridge-enhanced ACL repair in this cohort. Given these findings, factors other than the physiologic platelet concentration and total WBC concentration may be more important in the rate and amount of ACL healing after bridge-enhanced ACL repair.

scholarly journals Sex-Specific Function and Morphology of the Anterior Cruciate Ligament During Skeletal Growth in a Porcine Model

2021 ◽  
Author(s):  
Danielle Howe ◽  
Stephanie G. Cone ◽  
Jorge A. Piedrahita ◽  
Bruce Collins ◽  
Lynn A. Fordham ◽  
...  
Keyword(s):  
Anterior Cruciate Ligament ◽  
Porcine Model ◽  
Cruciate Ligament ◽  
Joint Laxity ◽  
Cross Sectional Area ◽  
Skeletal Growth ◽  
Sectional Area ◽  
Anteromedial Bundle ◽  
Cross Sectional ◽  
Anterior Cruciate

Pediatric anterior cruciate ligament (ACL) injuries are on the rise, and females experience higher ACL injury risk than males during adolescence. Studies in skeletally immature patients indicate differences in ACL size and joint laxity between males and females after the onset of adolescence. However, functional data regarding the ACL and its anteromedial and posterolateral bundles in the pediatric population remain rare. Therefore, this study uses a porcine model to investigate the sex-specific morphology and function of the ACL and its bundles throughout skeletal growth. Hind limbs from male and female Yorkshire pigs aged early youth to late adolescence were imaged using magnetic resonance imaging to measure the size and orientation of the ACL and its bundles, then biomechanically tested under anterior-posterior drawer using a robotic testing system. Joint laxity decreased (p<0.001) while joint stiffness increased (p<0.001) throughout skeletal growth in both sexes. The ACL was the primary stabilizer against anterior tibial loading in all specimens, while the functional role of the anteromedial bundle increased with age (p<0.001), with an earlier shift in males. ACL and posterolateral bundle cross-sectional area and ACL and anteromedial bundle length were larger in males than females during adolescence (p<0.01 for all), while ACL and bundle sagittal angle remained similar between sexes. Additionally, in situ ACL stiffness correlated with cross-sectional area across skeletal growth (r2=0.75, p<0.001 in males and r2=0.64, p<0.001 in females), but not within age groups. This study has implications for age and sex-specific surgical intervention strategies and suggests the need for human studies.

scholarly journals Changes in Cross-sectional Area and Signal Intensity of Healing Anterior Cruciate Ligaments and Grafts in the First 2 Years After Surgery

2019 ◽  
Vol 47 (8) ◽  
pp. 1831-1843 ◽  
Author(s):  
Ata M. Kiapour ◽  
Kirsten Ecklund ◽  
Martha M. Murray ◽  
Brett Flutie ◽  
Christina Freiberger ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Signal Intensity ◽  
Tibial Slope ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Resonance Imaging ◽  
Cross Sectional ◽  
Anterior Cruciate ◽  
Sagittal Orientation

Background: The quality of a repaired anterior cruciate ligament (ACL) or reconstructed graft is typically quantified in clinical studies by evaluating knee, lower extremity, or patient performance. However, magnetic resonance imaging of the healing ACL or graft may provide a more direct measure of tissue quality (ie, signal intensity) and quantity (ie, cross-sectional area). Hypotheses: (1) Average cross-sectional area or signal intensity of a healing ACL after bridge-enhanced ACL repair (BEAR) or a hamstring autograft (ACL reconstruction) will change postoperatively from 3 to 24 months. (2) The average cross-sectional area and signal intensity of the healing ligament or graft will correlate with anatomic features of the knee associated with ACL injury. Study Design: Cohort study; Level of evidence, 2. Methods: Patients with a complete midsubstance ACL tear who were treated with either BEAR (n = 10) or ACL reconstruction (n = 10) underwent magnetic resonance imaging at 3, 6, 12, and 24 months after surgery. Images were analyzed to determine the average cross-sectional area and signal intensity of the ACL or graft at each time point. ACL orientation, stump length, and bony anatomy were also assessed. Results: Mean cross-sectional area of the grafts was 48% to 98% larger than the contralateral intact ACLs at all time points ( P < .01). The BEAR ACLs were 23% to 28% greater in cross-sectional area than the contralateral intact ACLs at 3 and 6 months ( P < .02) but similar at 12 and 24 months. The BEAR ACLs were similar in sagittal orientation to the contralateral ACLs, while the grafts were 6.5° more vertical ( P = .005). For the BEAR ACLs, a bigger notch correlated with a bigger cross-sectional area, while a shorter ACL femoral stump, steeper lateral tibial slope, and shallower medial tibial depth were associated with higher signal intensity ( R2 > .40, P < .05). Performance of notchplasty resulted in an increased ACL cross-sectional area after the BEAR procedure ( P = .007). No anatomic features were correlated with ACL graft size or signal intensity. Conclusion: Hamstring autografts were larger in cross-sectional area and more vertically oriented than the native ACLs at 24 months after surgery. BEAR ACLs had a cross-sectional area, signal intensity, and sagittal orientation similar to the contralateral ACLs at 24 months. The early signal intensity and cross-sectional area of the repaired ACL may be affected by specific anatomic features, including lateral tibial slope and notch width—observations that deserve further study in a larger cohort of patients. Registration: NCT02292004 (ClinicalTrials.gov identifier)

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