Anterior Cruciate Ligament Graft Placement Research Articles

The development of the anterior cruciate ligament in the paediatric population

The aim of this study was to retrospectively compile normative data on the anterior cruciate ligament (ACL) in the paediatric population with magnetic resonance imaging, emphasizing the differences between men and women. In this retrospective study, musculoskeletal radiologists evaluated length, area, coronal and sagittal inclination of the ACL and inclination of the intercondylar notch. A total of 253 MR examinations (130 males and 123 females between 6 and 18years of age) were included. The association between measurements, sex and age was considered. Linear and fractional polynomial regression models were used to evaluate the relationships between measurements. ACL length showed significant progressive growth (p < 0.001) with age in men and women, without characterization of growth peaks. ACL area in women showed more pronounced growth up to 11years, stabilized from 11 to 14years and then sustained a slight reduction. In men, ACL area showed more pronounced growth up to 12years, stabilized from 12 to 15years and then sustained slight reduction. Coronal and sagittal inclination of the ACL showed a significant progressive increase (p < 0.001) with age in both sexes, progressively verticalizing. The intercondylar roof inclination angle showed significant progressive reduction (p < 0.001) with age in both sexes. The area of the ACL does not accompany skeletal maturation, interrupting its growth around 11-12years. Progressive verticalization of the ACL as well as of the intercondylar notch roof in the evaluated ages was also observed. The clinical relevance of this study is that the ACL presents different angular and morphologic changes during growth in the paediatric population. Since ACL repair is now being performed on younger children, recognition of the normal developmental changes of the ACL is of utmost importance for successful ACL graft placement. III.

The influence of tibial slope on anterior cruciate ligament graft failure risk is dependent on graft positioning.

Increased lateral tibial posterior slope (LTPS) is associated with higher anterior cruciate ligament (ACL) reconstruction (ACLR) failure rate. Transportal central femoral footprint ACLR is associated with higher failure rate compared to transtibial high anteromedial footprint ACLR due to graft anisometry. The purpose of this study was to investigate whether the influence of tibial slope on ACL graft failure risk is dependent on graft positioning. Of the 1480 consecutive hamstring ACLRs, 30 transportal (central femoral tunnel placement) and 30 transtibial (high anteromedial tunnel placement) ACLR failures were evaluated and matched one-to-one with non-failure control participants by age, sex, graft and surgical technique. Lateral tibial slope was assessed on MRI. The risk of graft failure in the transportal group increased by 40.5% per degree of increasing LTPS (odds ratio 1.4; 95% confidence interval 1.05-1.87; p = 0.02). The transportal failure group showed a significantly higher mean tibial slope of 8.6° compared to both the transportal control group with 7.1° ( p = 0.03) and the transtibial failure group with 7.2° ( p = 0.04). Increased tibial slope was associated with shorter time to reconstruction failure ( p = 0.002). The difference between slopes in the transtibial failure group (7.2°) compared to the transtibial control group (7.1°) was not significant ( p = 0.56). Increased LTPS is associated with significantly increased risk of graft failure only in transportal ACLR, not in transtibial ACLR. Slope-related graft strain may be potentiated by anisometric ACL graft placement.

A study on associated injuries of anterior cruciate ligament tear

Introduction: Over the last decade, reconstruction of the anterior cruciate ligament (ACL) has evolved from a surgical technique in which the objectives were ‘isometric’ femoral tunnel placement and avoidance of inter-condylar notch roof impingement, towards an ‘anatomic’ surgical technique which attempts to restore the native ACL. Achieving the goals of isometric ACL graft placement and avoidance of roof impingement often resulted in the ACL femoral tunnel extending into the roof of the notch, outside of the native ACL femoral attachment site and the tibial tunnel being positioned in the posterior half of the native ACL tibial attachment site. Methodology: All patients admitted with clinico-radiological diagnosis of ACL tear with h/o injury (trauma) who met the inclusion criteria. This was a Prospective observational study with the minimum follow up 12 months. The sample size was 30. Results: A Total of 90% (27 cases) (n=27) patients had associated injuries usually the meniscal tear. Isolated medial meniscal tear were found in 33.3% (10 cases) (n=10) while isolated lateral meniscus tear were found in 33.3% (10 patients) (n=10) of cases. Combined medial and lateral meniscus tear were found in 23%% (7 cases) (n=7). Conclusion: Chondral changes were found in 30% (9 cases) (n=9) MCL, LCL and posterior cruciate ligament tear was found in none.

Effects of ACL graft placement on in vivo knee function and cartilage thickness distributions.

Injuries to the anterior cruciate ligament (ACL) frequently lead to early-onset osteoarthritis. Despite advancement in surgical techniques, ACL reconstruction has a limited ability to prevent these degenerative changes. While previous studies have investigated knee function after ACL reconstruction, in vivo investigations of the effects of graft placement on in vivo joint function and cartilage health are limited. This review presents a series of studies that used novel imaging and 3D modeling techniques to determine the in vivo placement of the ACL graft on the femur using two different ACL reconstruction techniques. These techniques resulted in two distinct graft placement groups: one where the ACL was placed anatomically near the center of the native ACL footprint and another where the graft was placed anteroproximally on the femur, centered outside the ACL footprint. We quantified the effects of graft placement on graft deformation during in vivo loading and how these variables affected knee motion. Finally, we quantified whether femoral placement of the graft affected cartilage thickness. Our results demonstrate that achieving anatomic graft placement on the femur is critical to restoring native ACL function and normal knee kinematics. Knees with grafts that more closely restored normal ACL function, and thus knee motion, experienced less focal cartilage thinning than did those that experienced abnormal knee motion. These results suggest that achieving anatomic graft placement is a critical factor in restoring normal knee motion and potentially slowing the development of degenerative changes after ACL reconstruction. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1160-1170, 2017.

Optimizing Graft Placement in Anterior Cruciate Ligament Reconstruction: A Finite Element Analysis.

Femoral anterior cruciate ligament (ACL) graft malposition may lead to clinical instability and graft failure. The purpose of this study was to evaluate the effect of ACL graft placement on global knee biomechanics using finite element (FE) analysis. An established nonlinear contact FE model was used to evaluate 25 distinct tunnel loci representing primary ACL reconstructions; knee flexion and a simulated Lachman maneuver was used to assess knee joint laxity, meniscal stress, in situ graft loading, and peak articular cartilage contact pressure for each of the tunnel positions. Increased anterior tibial translation during Lachman testing was observed when the femoral graft was moved from anterior, anterior/inferior, and posterior/inferior relative to the anatomic footprint. Cartilage contact pressure and meniscal stresses increased with anterior graft placement. Peak stresses in the ACL grafts increased with significant posterior and inferior placement (5-7.5 mm) from the anatomic location. Global joint biomechanics are lease favorable with anterior graft placement. Excessive posterior/inferior placement (> 5 mm) may subject grafts to increased pressures.

A Technique of Improved Medial Meniscus Visualization by Anterior Cruciate Ligament Graft Placement in Chronic Anterior Cruciate Deficient Knees

It is customary to perform medial meniscus repair before anterior cruciate ligament (ACL) graft placement when undertaken as a combined procedure. However, in chronic ACL-deficient knees, intraoperative anterior tibiofemoral translation can cause the medial meniscus repair to be more technically challenging. Intraoperative anterior tibiofemoral translation can both reduce the visualization of the medial meniscus and make its reduction unstable. An operative sequence alteration of ACL graft placement and tensioning before medial meniscal repair improves medial meniscus visualization in chronically ACL-deficient knees by using the ACL graft's ability to prevent anterior tibiofemoral translation. The technique sequence is as follows: (a) the medial meniscus is reduced, (b) ACL reconstruction is undertaken using a hamstring graft without final tibia fixation, (c) distal graft tension is manually applied to distal graft sutures by the surgeon to prevent tibiofemoral subluxation, (d) the medial meniscus is repaired while graft tension is applied, and (e) the graft is then fixed to the tibia using an interference screw or another device.

Computer-assisted Anterior Cruciate Ligament Reconstruction. Four Generations of Development and Usage

The purpose of this paper is to review the literature about the contribution of navigation in anterior cruciate ligament (ACL) reconstruction. The evolution of computer-assisted surgery (CAS) for ACL reconstruction has undergone several steps. These steps were divided into 4 subsequent developments: (1) positioning of ACL graft placement; (2) laxity measurement of ACL reconstruction (quality control); (3) kinematic evaluation during ACL reconstruction (navigated pivot shift); (4) case-specific individual ACL reconstruction with adjustments and additional reconstruction options. CAS has shown to improve femoral tunnel positioning, even if clinical outcomes do not improve results of manual techniques. CAS technology has helped researchers better understand the effects of different ACL reconstruction techniques and bundles replacements on joint laxity and to describe tunnel positioning in relation to native ACL insertion. CAS in ACL surgery can improve results at time zero and can improve knowledge in this field.

Pediatric ACL

Intrasubstance anterior cruciate ligament (ACL) tears in skeletally immature patients are being reported with increasing frequency. Children and adolescents often are noncompliant with conservative treatment and have higher demands for knee stability than their adult counterparts. Consequently, nonsurgical or delayed surgical management has been associated with poor outcomes, including recurrent instability, increased meniscal and chondral damage, and decreased return to athletic participation. Even so, physicians often are faced with a treatment dilemma because clinical and basic science studies have demonstrated risk of limb-length discrepancy and angular deformity with ACL reconstruction. Prior to undergoing ACL reconstruction, skeletal maturity and growth potential should be determined so patients can be risk-stratified and the appropriate surgical technique can be selected. Vertical transphyseal drill tunnels have been used to decrease physeal damage and minimize the chance of growth deformity; however, these techniques result in nonanatomic ACL graft placement. Physeal sparing techniques that avoid damage to the growth plate by drilling anatomic tunnels completely within the epiphysis and have been shown to be biomechanically superior to extraarticular and modified physeal sparing procedures. These all-epiphyseal reconstruction techniques can be used to effectively and safely treat patients with significant growth remaining. Patients nearing skeletal maturity can be treated with adult type transphyseal reconstruction techniques with quadrupled hamstring autografts. When performing transphyseal ACL reconstruction in patients nearing skeletal maturity, soft-tissue grafts should be placed across the physis to minimize the risk of growth deformity.

Medial portal technique for single-bundle anatomical Anterior Cruciate Ligament (ACL) reconstruction

The aim of the paper is to describe the medial portal technique for anatomical single-bundle anterior cruciate ligament (ACL) reconstruction. Placement of an ACL graft within the anatomical femoral and tibial attachment sites is critical to the success and clinical outcome of ACL reconstruction. Non-anatomical ACL graft placement is the most common technical error leading to recurrent instability following ACL reconstruction. ACL reconstruction has commonly been performed using a transtibial tunnel technique in which the ACL femoral tunnel is drilled through a tibial tunnel positioned in the posterior half of the native ACL tibial attachment site. ACL reconstruction performed using a transtibial tunnel technique often results in a vertical ACL graft, which may fail to control the combined motions of anterior tibial translation and internal tibial rotation which occur during the pivot-shift phenomenon. The inability of a vertically oriented ACL graft to control these combined motions may result in the patient experiencing continued symptoms of instability due to the pivot-shift phenomenon. The medial portal technique in which the ACL femoral tunnel is drilled through an anteromedial or accessory anteromedial portal allows consistent anatomical ACL tunnel placement. This paper describes the advantages of the medial portal technique, indications for the technique, patient positioning, proper portal placement, anatomical femoral and tibial tunnel placement, graft tensioning and fixation.

Update on new techniques for anatomic anterior cruciate ligament reconstruction

There has been a recent shift in anterior cruciate ligament (ACL) reconstruction surgery toward more “anatomic” graft positioning, particularly on the femoral side to avoid vertical graft placement. The impetus is driven by the belief that more optimal placement of an ACL graft should improve joint stability and perhaps minimize the risk of later osteoarthritis development seen with long-term follow-up of traditional transtibial reconstructions. This “anatomic” approach has gained attention in the recent literature, both relative to the limitations of traditional transtibial drilling and the advantage of lateral femoral graft positioning. This article reviews the most current literature on the subject and makes the case for independent drilling of the femur and tibia for ACL reconstruction. Clinical strategies to achieve optimal ACL graft placement also are discussed.

The Function of the Human Anterior Cruciate Ligament and Analysis of Single- and Double-Bundle Graft Reconstructions

Context:There exists controversy on the ability of a single or double anterior cruciate ligament graft technique to restore anterior cruciate ligament function. This article examines the published experimental and clinical data supporting these surgical procedures in the ability to restore knee stability.Evidence Acquisition:An analysis of anterior cruciate ligament function and single- and double-graft reconstructions defined by selected biomechanical, robotic, kinematic, anatomical, and clinical studies.Results:The anterior cruciate ligament resists the combined motions of anterior tibial translation and internal tibial rotation, which defines the concept of rotational stability. This function prevents anterior tibial subluxation of the lateral and medial tibiofemoral compartments that accounts for the pivot-shift phenomena. The placement of single anterior cruciate ligament grafts high and proximal at the femoral attachment and posterior at the tibial attachment results in a vertical graft orientation. This graft placement results in a limited ability to provide rotational stability and is inferior when compared to a double-bundle graft procedure. Studies show that a more oblique single-graft orientation, in the sagittal and coronal plane, achieved from a central anatomic femoral and tibial location provides rotational stability similar to a double-bundle anterior cruciate ligament graft.Conclusion:There exists insufficient experimental and clinical data to recommend the more complex double-bundle anterior cruciate ligament graft technique over a well-placed central anatomic single graft in terms of restoring knee rotational stability. Meticulous surgical technique for anterior cruciate ligament graft placement is necessary to avoid failure.

Checkpoints for Judging Tunnel and Anterior Cruciate Ligament Graft Placement

This article examines how the relationship between sagittal and coronal anatomy, anterior cruciate ligament (ACL) graft dimensions, and tibial and femoral tunnel placement affects the posterior cruciate ligament (PCL) and roof impingement, and their undesirable clinical consequences of motion loss and instability. Based on these interrelationships, a variety of checkpoints are defined that can be used intraoperatively to determine whether placement of the tibial tunnel guidewire avoids PCL and roof impingement, and whether placement of the femoral tunnel guidewire avoids PCL impingement with either transtibial or transportal techniques. A simple, 3-dimensional tibial drill guide that consistently places the tibial tunnel correctly without PCL and roof impingement so the femoral tunnel, when drilled through the tibial tunnel, restores the normal tension pattern in the ACL graft also is described. Arthroscopic and radiographic checkpoints that assess the final placement of the ACL graft and tibial and femoral tunnels are discussed.

Transitioning to Anatomic Anterior Cruciate Ligament Graft Placement

Anterior cruciate ligament (ACL) reconstruction techniques continue to improve. Recent biomechanical studies have found improved rotational stability as femoral tunnel placement becomes more horizontal and closer to the true ACL footprint. Clinical studies also correlate improved outcomes with these more anatomic reconstructions. This article reviews the transition from traditional to anatomic ACL reconstructions, as well as 3 techniques for achieving this: the modified transtibial technique, use of an accessory medial portal, and the retrograde drilling technique.

Sagittal Plane Imaging Parameters for Computer-Assisted Fluoroscopic Anterior Cruciate Ligament-Reconstruction

Reproducible graft placement in anterior cruciate ligament (ACL) reconstructions is considered to be a critical factor affecting the successful clinical outcome of the procedure. Many current ACL instrument systems rely on intra-articular landmarks to guide the ACL tunnel placement. However, most of these instrument systems use mobile soft tissues as landmarks. We hypothesize that consistently identifiable radiographic contour landmarks can be established that can be used to improve the reproducibility of graft tunnel placement in fluoroscopically and computerassisted ACL reconstructions. For the tibia, magnetic resonance imaging (MRI) scans showed the average ACL attachment site to be projected at 46% on a line extending from the anterior to the posterior cortices. Intraoperative fluoroscopic images were checked for the reproducibility of this line and its clinical use. For the femur, lateral radiographs demonstrated a consistent relationship between the intercondylar roof line (Blumensaat's line) and the nearly circular profile of the posterior and inferior contour of the lateral femoral condyle. The middle of this circular profile is consistently projected on Blumensaat's line at 66% of its anterior-to-posterior direction. Intraoperative images were used, which showed the aiming drill at the point of entering the lateral femoral condyle. Instead of determining the femoral attachment site relative to Blumensaat's line, we can thus determine its position relative to the center of the circle. Based on intraoperative x-rays, the proposed femoral ACL attachment site can be projected on a line parallel with the Blumensaat's line from the circle center in the posterior direction. Our results indicate that there are consistently identifiable radiographic features on the tibia and femur contours that can be used for fluoroscopic and computer-assisted guidance of ACL graft placement.

Sagittal plane imaging parameters for computer-assisted fluoroscopic anterior cruciate ligament reconstruction.

Reproducible graft placement in anterior cruciate ligament (ACL) reconstructions is considered to be a critical factor affecting the successful clinical outcome of the procedure. Many current ACL instrument systems rely on intra-articular landmarks to guide the ACL tunnel placement. However, most of these instrument systems use mobile soft tissues as landmarks. We hypothesize that consistently identifiable radiographic contour landmarks can be established that can be used to improve the reproducibility of graft tunnel placement in fluoroscopically and computer-assisted ACL reconstructions. For the tibia, magnetic resonance imaging (MRI) scans showed the average ACL attachment site to be projected at 46% on a line extending from the anterior to the posterior cortices. Intraoperative fluoroscopic images were checked for the reproducibility of this line and its clinical use. For the femur, lateral radiographs demonstrated a consistent relationship between the intercondylar roof line (Blumensaat's line) and the nearly circular profile of the posterior and inferior contour of the lateral femoral condyle. The middle of this circular profile is consistently projected on Blumensaat's line at 66% of its anterior-to-posterior direction. Intraoperative images were used, which showed the aiming drill at the point of entering the lateral femoral condyle. Instead of determining the femoral attachment site relative to Blumensaat's line, we can thus determine its position relative to the center of the circle. Based on intraoperative x-rays, the proposed femoral ACL attachment site can be projected on a line parallel with the Blumensaat's line from the circle center in the posterior direction. Our results indicate that there are consistently identifiable radiographic features on the tibia and femur contours that can be used for fluoroscopic and computer-assisted guidance of ACL graft placement.

Intraarticular anterior cruciate ligament graft placement on the average most isometric line on the femur. Does it reproducibly restore knee kinematics?

In the past, there has been a plausible hypothesis that anterior cruciate ligament graft placement at isometric sites, such that the tibial and femoral attachment sites remain equidistant from each other throughout knee range of motion, would increase the likelihood of a satisfactory outcome. For a given tibial placement we wanted to determine whether placing the graft on the average of the most isometric femoral line, a fixed distance from the outlet of the intercondylar notch, would return normal laxity to all knees. The three-dimensional kinematics of seven cadaveric knees were measured for angles from full extension to 90 degrees of flexion at 15 degrees increments. Physiologic levels of quadriceps muscle forces were applied to the intact knee, after transection of the anterior cruciate ligament, and after ligament reconstruction with a patellar tendon graft. On average, the reconstruction was found to return anterior-posterior translation, internal-external rotation, and varus-valgus rotation to levels not significantly different from those of the intact knee. However, the ranges of the translation and rotations were large. Placing the graft on the average most isometric femoral line did not restore knee laxity to normal in all knees. This supports the need to customize graft placement in each knee at the time of surgery.