Anatomic Anterior Cruciate Ligament Research Articles

Tibial spine volume is smaller in ACL-injured athletes compared to healthy athletes.

The aim of this study was to investigate whether the whole tibial spine volume and femoral intercondylar notch volume are risk factors for anterior cruciate ligament (ACL) injury. The hypothesis was that the whole tibial spine volume and femoral notch volume would be smaller in athletes who sustained ACL injury than in athletes with no history of ACL injury. Computed tomography scans of both knees were acquired and three-dimensionalbone models were created using Mimics to measure whole tibial spine volume and femoral notch volume. Tibial spine volume, femoral notch volumeand each of these volumes normalised by tibial plateau area were compared between the ACL-injured andthe ACL-intact group. Fifty-one athletes undergoing unilateral anatomical ACL reconstruction (17 female, 34 male: average age 22.0 ± 7.5) and 19 healthy collegiate athletes with no previous knee injury (eight female, 11 male: average age 20.1 ± 1.3) were included in this study. The whole tibial spine volume in the ACL-injured group(2.1 ± 0.5 cm3) was 20.7% smaller than in the ACL-intact group (2.7 ± 0.7 cm3) (p = 0.005). No differences were observed between the femoral notch volume in the ACL-injured group(9.5 ± 2.1 cm3) and the ACL-intact group (8.7 ± 2.7 cm3) (n.s.). The main finding of this study was that the whole tibial spine volume of the ACL-injured group was smaller than the ACL-intact group. A small tibial spine volume can be added to the list of anatomical risk factors that may predispose athletes to ACL injury. Level Ⅲ.

Femoral Tunnel Position in Anatomical Double-bundle ACL Reconstruction is not Affected by Blumensaat's Line Morphology.

The aim of this study was to reveal the influence of the morphological variations of the Blumensaat's line on anteromedial (AM) and posterolateral (PL) femoral tunnel position in anatomical double-bundle anterior cruciate ligament (ACL) reconstruction.Fifty-three subjects undergoing anatomical double-bundle ACL reconstruction were included (29 female, 24 male; median age 27.4 years; range: 14-50 years). Using an inside-out transportal technique, the PL tunnel position was made on a line drawn vertically from the bottommost point of the lateral condyle at 90 degrees of knee flexion, spanning a distance of 5 to 8 mm, to the edge of the joint cartilage. AM tunnel position was made 2 mm distal to the PL tunnel position. Following Iriuchishima's classification, the morphology of the Blumensaat's line was classified into straight and hill (large and small) types. Femoral tunnel position was determined using the quadrant method. A Mann-Whitney U test was performed to compare straight and hill type knees according to AM and PL femoral tunnel position.There were 18 straight and 35 hill type knees (13 small and 22 large hill). AM and PL femoral tunnel position in straight type knees were 21.7 ± 7.0 and 33.6 ± 10.5% in the shallow-deep direction, and 42.1 ± 11.1 and 72.1 ± 8.5% in the high-low direction, respectively. In hill type knees, AM and PL femoral tunnel position were 21.3 ± 5.8 and 36.9 ± 7.1% in the shallow-deep direction, and 44.6 ± 10.7 and 72.1 ± 9.7% in the high-low direction, respectively. No significant difference in AM or PL femoral tunnel position was detected between straight and hill type knees.AM and PL femoral tunnel position in anatomical double-bundle ACL reconstruction was not affected by the morphological variations of the Blumensaat's line. Surgeons do not need to consider Blumensaat's line morphology if AM and PL femoral tunnel position is targeted at the bottommost point of the lateral condyle. This was a level of evidence III study.

Anterior Cruciate Ligament Reconstruction: 3-Incision Technique With Allograft Quad Tendon ACL Reconstruction

Background: Anterior cruciate ligament (ACL) ruptures are becoming more common in younger and older athletes. Approximately 250,000 ACL injuries occur each year, requiring the need for an effective and reproducible surgical technique. Indications: The 3-incision outside-in technique utilizes the donor quadriceps tendon, an extraordinarily strong graft, without damage from autogenous harvesting of patellar tendon or hamstrings. While some data suggest higher re-rupture risk with donor tissue, this is counterbalanced by avoiding secondary surgical site damage. Technique Description: The ruptured ACL is removed and the intercondylar notch is cleaned to visualize the anatomical ACL insertion site. Using the 3-tunnel technique a gaff is passed through the intercondylar notch, through a puncture hole (incision 1) and a rear entry guide hooked to its tip. The guide point is pulled into the knee and placed in posterior aspect of the anatomic footprint of the native ACL. Through incision 2, a guide pin is drilled to this point and overdrilled with a 10-mm drill. The edges of the hole in the intercodylar notch are smoothed with a currette. The tibial footprint is cleared, a tibial aiming guide placed. Through incision 3, a guide pin is placed and over drilled with a 10-mm drill followed by a Gore-Tex reamer to ensure no impingement would inhibit graft passage. The proximal bone of a quadriceps tendon graft is sized through a 10-mm sizer and compacted. Two holes are drilled to hold sutures for the proximal aspect of the femoral graft. The quadriceps tendon graft is sized to fit through a 9-mm tunnel and the free end whipped with a stitch before being passed from outside-in through the smoothed tunnels. The femoral bone block is tapped to have a press fit initially and then is fixed with a Milagro screw. The knee is cycled ten times to remove slack and the interference fit guide pin is placed on the anterior aspect of the graft, and fixed with the knee at 15° to 30° of flexion. Stability is tested with confirmation of no impingement, and then an extra-articular reconstruction with a semitendinosus allograft is performed. The extra articular reconstruction is placed at the point between Gerdy's tubercle and the fibular head, passed under the skin and the iliotibial band, and then inserted just anterior and superior to the ACL femoral drill hole. Results: Patient outcomes in our initial experience are comparable to our autogenous bone-tendon-bone (BTB) procedures without anterior knee pain. Return to sport is similar with autogenous procedures, with a delay of 6 to 12 months. In addition, there is a possibility for acceleration of healing with the addition of platelet-rich plasma and hyaluronic acid between 1 and 3 months postsurgery. We have insufficient data so far to determine if the re-rupture rate will decline compared with reported outcomes. Conclusion: The 3-incision technique with allograft quadriceps tendon for ACL reconstruction is a reproducible surgical technique that avoids harvest from the patient's own body. Patient Consent Disclosure Statement: The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

Anterior Cruciate Ligament Reconstruction Using Hamstring Graft with and without Suture Augmentation: A Randomized Trial

Background: The anterior cruciate ligament (ACL) is a vital knee joint stabilizer with rising injury rates. Anatomic ACL reconstruction (ACLR) aims to restore the ACL to its original dimensions, collagen orientation, and insertion sites, but complete restoration may not be possible. Suture augmentation (SA) involves the use of autologous hamstring tendons with a braided ultrahigh molecular weight polyester or polyethylene (UHMWPE) suture or suture tape to act as a secondary stabilizer until complete integration. This study aimed to compare the outcomes of ACLR using hamstring grafts with and without SA.
 Methods: This trial was conducted at a tertiary-level health care center, with 50 patients divided randomly into two groups: 25 patients for standard ACLR (group A) and 25 patients for ACLR with SA (group B). Participants provided informed consent. Baseline clinical characteristics including range of motion (ROM), pain [Numeric Pain Rating Scale (NPRS)], and functional outcomes [Lysholm and International Knee Documentation Committee (IKDC) scores] were collected.
 Results: The mean age was 25.5 years, with 96% male and 4% female participants. A statistically significant improvement was found in both groups in ROM, NPRS scores, and functional outcomes at 1 and 6 months. There was no significant difference in both groups regarding the IKDC score. Lysholm’s score showed a remarkable improvement in both groups.
 Conclusion: SA could be an effective technique for ACLR, with comparable outcomes to standard ACLR.

Electroacupuncture improves cognitive function in a rat model of mild traumatic brain injury by regulating the SIRT-1/PGC-1α/mitochondrial pathway.

Mild traumatic brain injury (mTBI) is a common neurological trauma that can lead to cognitive impairment. The sirtuin-1 (SIRT-1)/peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α) pathway has been reported to have neuroprotective effects in rats with craniocerebral injury. We evaluated potential mechanisms underlying electroacupuncture-mediated recovery of cognitive function after mTBI, focusing on the SIRT-1/PGC-1α/mitochondrial pathway. We included forty 6-week-old male Sprague-Dawley rats in this study. Rats were randomly divided into four groups: controlled cortical impactor (CCI, n = 10), sham operation (sham, n = 10), electroacupuncture-treated CCI (CCI+EA, n = 10), and electroacupuncture-treated sham (sham+EA, n = 10) group. Randomization was performed by assigning a random number to each rat and using a random number table. The mTBI rat model was established using a controllable cortical impactor. Electroacupuncture therapy was performed on the back of rats, by inserting acupuncture needles to the specific acupoints and setting appropriate parameters for treatment. We evaluated spatial learning and memory functions with the Morris water maze test. We performed quantitative real-time polymerase chain reaction (qRT-PCR), western blotting, adenosine triphosphate (ATP) determination, and mitochondrial respiratory chain complex I (MRCC I) determination on rat hippocampal tissue. We analyzed SIRT-1/PGC-1α expression levels and the results of mitochondrial function assays, and compared differences between groups using bilateral Student's t -tests. Compared with the sham group, SIRT-1/PGC-1α expression was downregulated in the hippocampus of CCI group ( P <0.01). Although this expression was upregulated following electroacupuncture, it did not reach the levels observed in the sham group ( P <0.05). Compared with the sham group, MRCC I and ATP levels in the CCI group were significantly reduced, and increased after electroacupuncture ( P <0.01). In the Morris water maze, electroacupuncture reduced the incubation period of rats and increased average speed and number of crossing platforms ( P <0.05). Electroacupuncture may improve cognitive function in the mTBI rat model by regulating the SIRT-1/PGC-1α/mitochondrial pathway.

Incidence of Convergence Between Distally and Anteriorly Oriented ALL Femoral Tunnels and ACL Femoral Tunnels in Combined ACL and ALL Reconstruction: 3-Dimensional Computed Tomography Analysis of 227 Patients

Background: Adjusting the direction of the anterolateral ligament (ALL) femoral tunnel is suggested to avoid tunnel convergence during anterior cruciate ligament (ACL) reconstruction. Yet, there has been no in vivo clinical study reporting the effect of changing the direction of the ALL tunnel on the incidence of convergence with the ACL tunnel. Purpose: To report the incidence of convergence between the ACL femoral tunnel and a distally and anteriorly directed ALL femoral tunnel and to determine a safe distal angle and anterior angle. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A total of 227 patients undergoing concomitant ALL and anatomic single-bundle ACL reconstruction between January 2020 and December 2022 were retrospectively reviewed. The tunnel convergence rate, angular orientation of the tunnels, and distance between tunnels were obtained using postoperative computed tomography. The patients were grouped based on the direction of the ALL tunnel (transverse vs distal anterior) and the presence of tunnel convergence (convergence vs no convergence). Results: The overall tunnel convergence rate was 53.3% (121/227 patients). Tunnel convergence was observed less frequently in the distal anterior group (33.7%) than in the transverse group (65.2%) (P < .001). The no convergence group showed an ALL tunnel oriented more distally (20.2°± 11.1°) and anteriorly (19.5°± 10.2°) compared with the convergence group (8.7°± 6.5° and 6.9°± 5.3°, respectively) (P = .005 and P = .008, respectively). There were no cases of tunnel convergence for ALL tunnels >24.3° distally and >25.5° anteriorly. There was no difference in the angle of the ACL femoral tunnel between all groups. Conclusion: A distally and anteriorly directed ALL femoral tunnel reduced the incidence of convergence with the ACL femoral tunnel. A distal angle >24.3° and an anterior angle >25.5° of an ALL tunnel are suggested to safely avoid convergence with the ACL tunnel.

Number of intra-operative cyclic knee motion required to achieve stable graft tension in anterior cruciate ligament reconstruction; a prospective clinical study.

Applying pretension by cyclic knee motion immediately before graft fixation in anterior cruciate ligament (ACL) reconstruction surgery decreases graft elongation during the postoperative course. However, the expected change in graft tension caused by cyclic knee motion remains unclear. We measured graft tension changes caused by cyclic knee motion during double-bundle ACL reconstruction. We included 39 patients undergoing primary anatomical double-bundle ACL reconstruction with autologous hamstrings as graft sources, at multiple centers between February 2021 and August 2022. After securing the anteromedial (AM) and posterolateral (PL) bundle grafts to the femoral cortex, they were initially tensioned to 40 N per bundle. After 10 cycles of knee extension and flexion motion, ranging from 0 to 90-110°, tension was re-measured and re-tensioned to 40 N if the graft tension had decreased. This was repeated thrice for 10 cycles on each graft. Every 10 cycles, we recorded graft tension changes (ΔGT) and compared the mean ΔGT in the AM and PL bundles. Furthermore, we assessed relationships between total ΔGT in each bundle, age, sex, and graft diameter. Twenty-five women and 14 men with a mean age of 27.4 ± 12.4 years were included. The mean ΔGT in AM and PL bundles after every 10 cycles were 6.6 ± 3.7 N, 3.0 ± 2.3 N, 1.4 ± 1.5 N, and 9.9 ± 3.8 N, 4.9 ± 2.6 N, and 2.5 ± 1.9 N, respectively. There were significant differences in ΔGT in both bundles after every 10 cycles (p < 0.01). ΔGT in the AM bundle was significantly lower than in the PM bundle at the same number of cycles (p < 0.01). No correlation was observed between ΔGT in either bundle and age, sex, or graft diameter. The initially applied graft tension decreased by intra-operative cyclic knee movement, and the changes in graft tension decreased after retention and repeated cycles. Three sets of 10 cycles knee motion may avoid initial tension loss of the hamstring autograft in the early phase after double-bundle ACL reconstruction.

Morphometric Analysis of the Tibial Attachment Shape of the Anterior Cruciate Ligament and Its Relationship With the Location of the Anterior Horn of the Lateral Meniscus

Background: The success of anterior cruciate ligament (ACL) reconstruction relies on the accurate replication of the native ACL anatomy, including attachment shapes. The tibial attachment of the ACL exhibits significant shape variations with elliptical, C, and triangular shapes, highlighting the need for objective classification methods and additional information to identify individual anatomic variations. Hypothesis: The location of the attachment of the anterior horn of the lateral meniscus (AHLM) may determine the shape of the ACL attachment. Study Design: Cross-sectional study; Level of evidence, 3. Methods: The study used 25 knees from 17 Japanese cadavers for macroscopic anatomic examination and quantitative analysis. The shape of the ACL attachment was quantified using principal component analysis with elliptical Fourier descriptors, whereas the AHLM location was quantified by measuring its mediolateral and anteroposterior positions on the superior surface of the tibia. Reliability was assessed statistically. Results: The shape of the tibial attachment of the ACL varied among individuals and was classified as elliptical, C-shaped, or triangular. Scatterplots of the principal components of the ACL attachment shape showed overlapping regions of elliptical, C-shaped, and triangular ACL attachments, indicating that a C-shaped attachment is intermediate between elliptical and triangular attachments. The location of the AHLM attachment also varied, with areas in the anterolateral, anteromedial, or posteromedial region. The ACL shape and AHLM location were related, with elliptical, C-shaped, and triangular ACL attachments corresponding to anterolateral, anteromedial, and posteromedial AHLM attachments, respectively. Conclusion: The AHLM attachment location influences the shape of the ACL attachment. Information on the location of the AHLM attachment can aid in predicting the shape of the ACL attachment during ACL reconstruction, potentially improving footprint coverage.

Remnant-Sparing Anterior Cruciate Ligament Reconstruction Results in Similar Clinical, Functional, and Quality-of-Life Outcomes to Anatomic Single-Bundle Anterior Cruciate Ligament Reconstruction

To compare a large cohort of patients who underwent remnant-sparing anterior cruciate ligament reconstruction (rACLR) with a matched group of patients who underwent anatomic single-bundle anterior cruciate ligament reconstruction (ACLR) with respect to clinical laxity, patient-reported outcomes, and functional testing. Patients who underwent rACLR between January 2010 and December 2015 were matched according to age, sex, body mass index, and graft type to patients who underwent ACLR. The primary outcome measure was the ACL Quality of Life (ACL-QOL) score at final follow-up of 24 months. Secondary outcomes included functional tests and clinical laxity measurements at 6, 12, and 24 months postoperatively. Concurrent intra-articular pathology at the time of surgery and postoperative complications were also recorded. Statistical analyses included the dependent t test and the Wilcoxon signed rank test. A total of 210 rACLR patients were successfully matched to a corresponding cohort of 210 ACLR patients. There were no statistically significant differences in ACL Quality of Life (ACL-QOL) or functional testing results between the groups; however, scores in both groups showed a steady and statistically significant improvement over time. A statistically significant difference was noted with respect to the Lachman test findings, favoring the rACLR cohort (Z= -2.79, P= .005); no between-group difference was seen for the pivot-shift test (Z= -0.36, P= .72). The rACLR group had a significantly lower rate of concurrent meniscal and chondral injury. There was no difference in complications between the groups (Z= -0.49, P= .63). There was no difference in patient-reported or functional testing outcomes in patients undergoing remnant-sparing compared with anatomic single-bundle ACLR. There was, however, a significantly lower rate of positive Lachman test findings after rACLR. Furthermore, the rate of concurrent meniscal and chondral pathology was lower in the rACLR group. Level III, retrospective cohort study.

Effects of higher femoral tunnels on clinical outcomes, MRI, and second-look findings in double-bundle anterior cruciate ligament reconstruction with a minimal 5-year follow-up.

To perform anatomical anterior cruciate ligament reconstruction (ACLR), tunnels should be placed relatively higher in the femoral anterior cruciate ligament (ACL) footprint based on the findings of direct and indirect femoral insertion. But the clinical results of higher femoral tunnels (HFT) in double-bundle ACLR (DB-ACLR) remain unclear. The purpose was to investigate the clinical results of HFT and lower femoral tunnels (LFT) in DB-ACLR. From September 2014 to February 2016, 83 patients who underwent DB-ACLR and met the inclusion and exclusion criteria were divided into HFT-ACLR (group 1, n = 37) and LFT-ACLR (group 2, n = 46) according to the position of femoral tunnels. Preoperatively and at the final follow-up, clinical scores were evaluated with International Knee Documentation Committee (IKDC), Tegner activity, and Lysholm score. The stability of the knee was evaluated with KT-2000, Lachman test, and pivot-shift test. Cartilage degeneration grades of the International Cartilage Repair Society (ICRS) were evaluated on magnetic resonance imaging (MRI). Graft tension, continuity, and synovialization were evaluated by second-look arthroscopy. Return-to-sports was assessed at the final follow-up. Significantly better improvement were found for KT-2000, Lachman test, and pivot-shift test postoperatively in group 1 ( P >0.05). Posterolateral bundles (PL) showed significantly better results in second-look arthroscopy regarding graft tension, continuity, and synovialization ( P <0.05), but not in anteromedial bundles in group 1. At the final follow-up, cartilage worsening was observed in groups 1 and 2, but it did not reach a stastistically significant difference ( P >0.05). No statistically significant differences were found in IKDC subjective score, Tegner activity, and Lysholm score between the two groups. Higher return-to-sports rate was found in group 1 with 86.8% (32/37) vs. 65.2% (30/46) in group 2 ( P = 0.027). The HFT-ACLR group showed better stability results, better PL, and higher return-to-sports rate compared to the LFT-ACLR group.

Small Intercondylar Notch Size Is Not Associated with Poor Surgical Outcomes of Anatomical Single-Bundle Anterior Cruciate Ligament Reconstructions.

Although many studies have been conducted on the association between the intercondylar notch size and the risk of anterior cruciate ligament (ACL) injury, few studies have examined its relationship with the condition after surgical treatment. Therefore, this study aimed to investigate the surgical outcomes of anatomical single-bundle ACL reconstruction according to intercondylar notch volumes. Medical records of patients who underwent anatomical single-bundle ACL reconstruction using a tibialis anterior allograft between 2015 and 2019 were retrospectively reviewed. For each sex, eligible patients were classified into two groups based on their percentile of intercondylar notch volumes, which were measured using postoperative three-dimensional computed tomography images (group S, ≤ 50th percentile of included patients; group L, > 50th percentile of included patients). Additional grouping was performed based on the group's percentiles of normalized values of intercondylar notch volumes to body heights. Between-group comparative analyses were performed on the perioperative data and surgical outcomes in both objective and subjective aspects. One hundred patients were included in the study. For male patients, there were no differences in the overall surgical outcomes between groups, whereas group L showed a significantly greater knee anteroposterior (AP) laxity than group S at the final follow-up (p = 0.042 for the side-to-side differences [SSD] at the maximum manual force). Similarly, there were no differences in the female patients in the overall surgical results between the groups, whereas group L showed a significantly greater knee AP laxity at the final follow-up (p = 0.020 for the SSD at 134 N; p = 0.011 for the SSD at the maximum manual force). Additional analyses based on the normalized values of the intercondylar notch volume showed consistent results for male patients, and additional grouping for female patients was identical to the existing grouping. The surgical outcomes of anatomical single-bundle ACL reconstruction in patients with relatively small intercondylar notch volumes were comparable to those with large notch volumes, but rather showed favorable outcomes in postoperative knee AP laxity.

Modified Anatomical Anterior Cruciate Ligament Reconstruction with Flat Semitendinosus Graft and C-shaped Tibial Canal

Every year, approximately 400,000 patients undergo anterior cruciate ligament (ACL) reconstruction surgery in the United States, accounting for almost 50% of all knee surgeries in the country. Recent studies have demonstrated that the ACL is a ribbon-like structure with a C-shaped tibial insertion and a flat femoral origin. This article introduces a modification of an ACL reconstruction technique. The modification renders the procedure easily reproducible with standard surgical instruments. We will describe a surgical technique modification that goes beyond the standard round bone tunnels and adopts a more anatomical approach using a C-shaped tibial canal and a flat femoral canal using a flat semitendinosus (semi-T) graft. The use of a semi-T graft better reproduces the ribbon-like ACL anatomy. The semi-T graft, a flat femoral canal, and a C-shaped tibial canal provide increased bone-tendon contact surface area and decreased diffusion length, resulting in improved tendon-bone healing. The modification proposed by our team makes the anatomical ribbon-like ACL graft, C-shaped tibial canal, and the flat femoral canal technique feasible in every orthopaedic operating room and mitigates costly specialized instrument.

Effect of anteromedial portal location on femoral tunnel inclination, length, and location in hamstring autograft-based single-bundle anterior cruciate ligament reconstruction: a prospective study

BackgroundPortal positioning in arthroscopic anterior cruciate ligament reconstruction is critical in facilitating the drilling of the femoral tunnel. However, the traditional approach has limitations. A modified inferior anteromedial portal was developed. Therefore, this study aims to compare the modified and conventional far anteromedial portals for femoral tunnel drilling, assessing factors such as tunnel length, inclination, iatrogenic chondral injury risk, and blowout.Material and methodsPatients scheduled for hamstring autograft-based anatomical single-bundle arthroscopic anterior cruciate ligament reconstruction were divided into two groups: modified and far anteromedial groups. Primary outcomes include differences in femoral tunnel length intraoperatively, tunnel inclination on anteroposterior radiographs, and exit location on lateral radiographs. Secondary outcomes encompass tunnel-related complications and reconstruction failures. To identify potential risk factors for shorter tunnel lengths and posterior exits, regression analysis was conducted.ResultsTunnel parameters of 234 patients were analyzed. In the modified portal group, femoral tunnel length and inclination were significantly higher, with tunnels exhibiting a more anterior exit position (p < 0.05). A higher body mass index exerted a negative influence on tunnel length and inclination. However, obese patients in the modified portal group had longer tunnels, increased inclination, and a lower risk of posterior exit. Only a few tunnel-related complications were observed in the far anteromedial group.ConclusionThe modified portal allowed better control of tunnel length and inclination, ensuring a nonposterior femoral tunnel exit, making it beneficial for obese patients.

Race and Gender Differences in Anterior Cruciate Ligament Femoral Footprint Location and Orientation: A 3D-MRI Study.

The femoral tunnel position is crucial to anatomic single-bundle anterior cruciate ligament (ACL) reconstruction, but the ideal femoral footprint position are mostly based on small-sized cadaveric studies and elderly patients with a single ethnic background. This study aimed to identify potential race- or gender-specific differences in the ACL femoral footprint location and ACL orientation, determine the correlation between the ACL orientation and the femoral footprint location. Magnetic resonance images (MRIs) of 90 Caucasian participants and 90 matched Chinese subjects were used for reconstruction of three-dimensional (3D) femur and tibial models. ACL footprints were sketched by several experienced orthopedic surgeons on the MRI photographs. The anatomical coordinate system was applied to reflect the ACL footprint location and orientation of scanned samples. The femoral ACL footprint locations were represented by their distance from the origin in the anteroposterior (A/P) and distal-proximal (D/P) directions. The orientation of the ACL was described with the sagittal, coronal and transverse deviation angles. The ACL orientation and femoral footprint position were compared by the two-sided t-test. Multiple regression analysis was used to study the correlation between the orientation and femoral footprint position. The average femur footprint A/P position was -6.6 ± 1.6 mm in the Chinese group and -5.1 ± 2.3 mm in the Caucasian group, (p < 0.001). The average femur footprint D/P position was -2.8 ± 2.4 mm in Chinese and - 3.9 ± 2.0 mm in Caucasians, (p = 0.001). The Chinese group had a mean difference of a 1.5 mm (6.1%) more posterior and 1.1 mm (5.3%) more proximal in the position from the flexion-extension axis (FEA). And the males have a sagittal plane elevation about 4-5° higher than females in both racial groups. Furthermore, for every 1% (0.40 mm) increase in A/P and D/P values, the sagittal angle decreased by about 0.12° and 0.24°, respectively; the coronal angle decreased by about 0.10° and 0.30°, respectively. For every 1% (0.40 mm) increase in D/P value, the transverse angle increased by about 0.14°. The significant race- and gender-specific differences in the femoral footprint and orientation of the ACL should be taken in consideration during anatomic single-bundle ACL reconstruction. Furthermore, the quantitative relationship between the ACL orientation and the footprint location might provide some reference for surgeons to develop a surgical strategy in ACL single-bundle reconstruction and revision.

Reliability of the Tibial Spine Versus ACL Stump in Assisting Tibial Tunnel Positioning During ACL Reconstruction: Analysis Based on 3-Dimensional Computed Tomography Modeling

Background: Several techniques have been used by surgeons for anatomic tibial tunnel placement in anterior cruciate ligament (ACL) reconstruction, including the ACL stump positioning (ASP) technique and the tibial spine positioning (TSP) technique. Purpose/Hypothesis: The purpose of this study was to evaluate whether bony landmarks (medial and lateral tibial spine [MLTS]) can be a reliable reference for improving the accuracy of tibial tunnel placement in anatomic single-bundle ACL reconstruction compared with the ACL stump. It was hypothesized that the MLTS would not be a reliable bony landmark for tibial tunnel placement. Study Design: Cohort study; Level of evidence, 3. Methods: The 3-dimensional computed tomography images of 111 patients who underwent ACL reconstruction between 2020 and 2021 were included in this study. For tibial tunnel placement, the ASP technique was used in 49 patients, and the TSP technique was used in 62 patients. The 3-dimensional computed tomography images were reconstructed to enable measurements of the locations of the MLTS and tunnel center based on a grid method. Statistical analysis was conducted to compare the MLTS location and tibial tunnel position as well as the accuracy (mean distance of each actual location from the anatomic center) and precision (standard deviation of the accuracy, indicating the reproducibility of the tunnel position) of the tunnel position between the ASP and TSP groups. Results: Significant differences were observed between the ASP and TSP groups in terms of the tibial tunnel position on the mediolateral axis (46.7% ± 2.0% vs 45.9% ± 2.2%, respectively; P = .034), while no significant differences were found in terms of the accuracy (4.1% vs 4.6%, respectively; P = .259) or precision (2.1% vs 2.1%, respectively; P = .259) of tibial tunnel positioning between the 2 groups. Conclusion: In anatomic single-bundle ACL reconstruction, the use of the MLTS for tibial tunnel placement achieved comparable accuracy and precision compared with the use of ACL remnants, supporting its role as a reliable bony landmark in tibial tunnel positioning.

Postoperative quadriceps weakness and male sex are risk factors for patellofemoral articular cartilage lesions after anatomical anterior cruciate ligament reconstruction

PurposePatellofemoral (PF) compartment cartilage lesions are a frequent problem after anterior cruciate ligament (ACL) reconstruction. This study aimed to determine the factors that influence PF cartilage lesions after anatomical ACL reconstruction.MethodsThis study enrolled a total of 114 patients who did not manifest PF compartment cartilage lesions during anatomical ACL reconstruction and underwent second-look arthroscopy 18 months postoperatively. Arthroscopy using the International Cartilage Repair Society (ICRS) classification was used to assess cartilage lesions. The correlation between surgical findings, radiographic factors, and clinical factors and change of ICRS grade was analysed. Multivariate regression analysis was conducted to reveal the independent risk factors for PF cartilage lesions among patients’ demographic data and parameters that correlated with the change of ICRS grade in the correlation analyses.ResultsICRS grade changes in PF cartilage were significantly correlated with age, sex, quadriceps strength at 1 year postoperatively, hamstrings strength at pre- and 1 year postoperatively, and single leg hop test at 1 year postoperatively. However, no significant correlation was found between the time between injury and surgery, posterior tibial slope angle, pre- and postoperative Tegner activity scale, graft type, initial graft tension, meniscus injury, meniscus injury treatment, pre- and postoperative range of motion, anteroposterior laxity and preoperative quadriceps strength, and the change in ICRS grade. Multivariate regression analysis revealed male (P = 0.019) and quadriceps strength weakness at 1 year postoperatively (P = 0.009) as independent risk factors for PF cartilage lesions.ConclusionsQuadriceps strength weakness 1 year after ACL reconstruction and males were correlated with a new PF cartilage lesion after anatomical ACL reconstruction, with no significant correlation between bone-patellar tendon-bone autograft, initial graft tension, or extension deficit and new PF cartilage lesion. Rehabilitation that focuses on quadriceps strength after ACL reconstruction is recommended to prevent new PF cartilage lesions.Level of evidenceLevel IV.

Femoral Fixation Strength as a Function of Bone Plug Length in Anterior Cruciate Ligament Reconstruction Utilizing Interference Screws.

To determine femoral construct fixation strength as bone plug length decreases in anterior cruciate ligament reconstruction (ACLR). Sixty fresh-frozen bone-patellar tendon-bone allografts were utilized and divided into 20-, 15-, and 10-mm length bone plug groups, subdivided further so that half utilized the patella side (P) for testing and half used the tibial side (T). Ten mm diameter recipient tunnels were created within the anatomic anterior cruciate ligament footprint of 60 cadaveric femurs. All bone plugs were 10 mm in diameter; grafts were fixed using a 7 × 23 mm metal interference screw. An Instron was used to determine the load to failure of each group. A one-way multivariate analysis of variance (MANOVA) was conducted to test the hypothesis that there would be one or more mean differences in fixation stability between 20- or 15-mm plug lengths (P or T) versus 10 mm T plug lengths when cross-compared, with no association between other P or T subgroups. The mean load to failure of the 20 mm plugs (20 P + T) was 457 ± 66N, 15 mm plugs (15 P + T) was 437 ± 74N, and 10 mm plugs (10 P + T) was 407 ± 107N. There was no significant difference between P + T groups: 20-versus 15-mm (p = 1.000), 15-versus 10-mm (p = 0.798), and 20-versus 10-mm (p = 0.200); P + T MANOVA (p = 0.291). Within groups, there was no significant difference between patella and tibial bone plug subgroups with a pullout force range between 469 ± 56N and 374 ± 116N and p-value ranging from p = 1.000 for longer bone plugs to p = 0.194 for shorter bone plugs; P versus T MANOVA (p = 0.113). In this human time zero cadaver model, there was no significant difference in construct failure between 20-,15-, and 10-mm bone plugs when fixed with an interference screw within the femoral tunnel, although fixation strength did trend down when from 20- to 15- to 10-mm bone plugs. There is a balance between optimal bone plug length on the femoral side for achieving adequate fixation as well as minimizing donor site morbidity and facilitating graft passage in ACLR. This study reveals utilizing shorter plugs with interference screw fixation is potentially acceptable on the femoral side if shorter plugs are harvested.

[Research progress on bioactive strategies for promoting tendon graft healing after anterior cruciate ligament reconstruction].

To review the bioactive strategies that enhance tendon graft healing after anterior cruciate ligament reconstruction (ACLR), and to provide insights for improving the therapeutic outcomes of ACLR. The domestic and foreign literature related to the bioactive strategies for promoting the healing of tendon grafts after ACLR was extensively reviewed and summarized. At present, there are several kinds of bioactive materials related to tendon graft healing after ACLR: growth factors, cells, biodegradable implants/tissue derivatives. By constructing a complex interface simulating the matrix, environment, and regulatory factors required for the growth of native anterior cruciate ligament (ACL), the growth of transplanted tendons is regulated at different levels, thus promoting the healing of tendon grafts. Although the effectiveness of ACLR has been significantly improved in most studies, most of them are still limited to the early stage of animal experiments, and there is still a long way to go from the real clinical promotion. In addition, limited by the current preparation technology, the bionics of the interface still stays at the micron and millimeter level, and tends to be morphological bionics, and the research on the signal mechanism pathway is still insufficient. With the further study of ACL anatomy, development, and the improvement of preparation technology, the research of bioactive strategies to promote the healing of tendon grafts after ACLR is expected to be further promoted.

Femoral Tunnel Length in Anatomical Double-Bundle Anterior Cruciate Ligament Reconstruction Is Correlated with Body Size and Knee Morphology.

The purpose of this study was to reveal the correlation between anteromedial (AM) and posterolateral (PL) femoral tunnel lengths in anatomical double-bundle anterior cruciate ligament (ACL) reconstruction and body size and knee morphology. Thirty-four subjects undergoing anatomical double-bundle ACL reconstruction were included in this study. Preoperative body size (height, body weight, and body mass index) was measured. Using preoperative magnetic resonance imaging (MRI), quadriceps tendon thickness and the whole anterior-posterior length of the knee were measured. Using postoperative computed tomography (CT), axial and sagittal views of the femoral condyle were evaluated. The correlation between measured intraoperative AM and PL femoral tunnel lengths, and body size and knee morphology using preoperative MRI and postoperative CT parameters was statistically analyzed. Both AM and PL femoral tunnel lengths were significantly correlated with height, body weight, posterior condylar length, and Blumensaat's line length. These results suggest that the femoral ACL tunnel length created using a transportal technique can be estimated preoperatively by measuring the subject's body size and/or the knee morphology using MRI or CT. For clinical relevance, surgeons should be careful to create femoral tunnel of sufficient length when using a transportal technique, especially in knees of subjects with smaller body size and knee morphology. Level of evidence is III.

Introducing Skeletally-Mature Anterior Cruciate Ligament Reconstruction Technique Using Reinforcement (SATURN) With Iliotibial Band Autograft

Anterior cruciate ligament (ACL) injuries are increasingly common in the adolescent age group. Recent literature has endorsed combining ACL reconstruction with lateral extra-articular procedures to minimize residual rotatory knee instability and reduce the risk of reinjury in this age group. This technique describes a single-bundle combined anatomical ACL reconstruction and lateral extra-articular reinforcement performed with a single iliotibial band autograft. Also this technique allows for the ACL reconstruction and lateral extra-articular stabilization to be performed through a single surgical incision while obtaining autograft tissue without disruption of the extensor or hamstring mechanisms.