Tibial Footprint Research Articles

Anterior Cruciate Ligament Reconstruction

Introduction:The most recent advances in ACL reconstruction try to reproduce the anatomic femoral and tibial footprints as close as possible. Creating independent tunnels would allow an optimal of the entry point and the femoral tunnel obliquity, and together with an adequate reamer diameter they wouldreproduce with greater certainty the anatomy.Objective:To compare the radiographic parameters of the femoral and tibial tunnel positions in two groups of patients, one operated with a transtibial and other with transportal anatomic techniques.Materials and Methods:From December 2012 to December 2013, 59 patients with a primary ACL reconstruction divided in two groups, a trans tibial technique (TT), 19 patients, and an transportal one (TP) with 40 patients were prospectively evaluated with AP and lateral X-rays. The femoral tunnel angle, the insertion site with respect of the Blumensaat line, the trans osseous distance, the tibial tunnel position as a percentage of the tibial plateau in the AP and lateral views. And finally the tibial tunnel angle in the AP and Lateral views.Results:The femoral tunnel angle was in the TP group of 45,92º and in the TT one 24,53º, p 0,002. The insertion site percentage of the Blumensaat line was of 20,96 in TP and 20,74 in the TT, p 0,681.Trans osseous distance was in the TP of 3,43 cm and in the TT of 4,79 cm, p <0,000. The tibial tunnel position as a percentage in the AP tibial plateau was of 44,35 in TP and of 40,80 TT with a p of 0,076. The tibial tunnel position as a percentage of the lateral tibial plateau was of 28,70 in TP and 34,53 in TT with a p 0,367. Tibial tunnel angle in the AP was of 73,48º in TP and 62,81 in TT with a p of 0,002, and in the lateral plateau of 114,69º in TP and 112,79º in TT with a p of 0,427.Conclusion:It is possible to create tibial and femoral tunnel in optimal positions but not equal between both groups. Creating independent tunnels allow a more anterior and vertical tibial tunnel allowing a better coverage of the tibial footprint. A transportal femoral tunnel would allow a better inclination angle and a lesser trans-osseous distance, technical details that would allow a better coverage of the femoral footprint.

Consequences of Tibial Tunnel Reaming on the Meniscal Roots During Cruciate Ligament Reconstruction in a Cadaveric Model, Part 1

Background: The current standard for treating complete tears of the anterior cruciate ligament (ACL) is reconstruction, which requires reaming a tibial tunnel. Based on recent anatomic and biomechanical studies, this reconstruction tunnel may cause injuries to the anterior meniscal root attachments. Purpose/Hypothesis: The purpose was to determine if injuries occurred to the anteromedial (AM) and anterolateral (AL) meniscal root attachments because of reaming a tibial reconstruction tunnel in the anatomic center of the ACL footprint. It was hypothesized that tibial tunnel reaming for ACL reconstruction would result in significant decreases in the attachment area and in ultimate failure strength for the AL root. Study Design: Controlled laboratory study. Methods: Twelve matched pairs of human cadaveric knees were tested. One knee from each pair remained intact, while the contralateral knee was reamed with a tibial tunnel for an anatomic ACL reconstruction. The attachment areas of the anterior meniscal roots were measured with a coordinate measuring device before and after tunnel reaming. The anterior meniscal roots were then pulled to failure with a dynamic tensile testing machine. Results: There was a significant mean decrease in the attachment area for the AL root (%Δ, 38%; 95% CI, 25-51) after ACL tunnel reaming compared with the intact state (P = .003). The mean ultimate failure strength of the native AL root (mean, 610 N; 95% CI, 470-751) was significantly stronger (P = .015) than that of the AL root with a reamed ACL reconstruction tunnel (mean, 506 N; 95% CI, 353-659). Tunnel reaming did not significantly affect the AM root attachment area or ultimate failure strength. Conclusion: Tibial tunnel reaming during anatomic single-bundle ACL reconstruction significantly decreased the AL meniscal root attachment area and ultimate failure strength. The AM root was not significantly affected by reaming of the ACL reconstruction tunnel. Future studies should investigate the clinical importance of these iatrogenic injuries to the AL root. Clinical Relevance: The ACL reconstruction tunnels reamed in the center of the ACL tibial footprint caused a significant decrease in the attachment area and ultimate strength of the AL meniscal root attachment. Clinically, repositioning guide pins placed in the lateral aspect of the ACL attachment before tibial tunnel reaming may minimize iatrogenic injuries to the AL meniscal root attachment.

Preservation of the PCL when performing cruciate-retaining TKA: Is the tibial tuberosity a reliable predictor of the PCL footprint location?

Reconstruction of the joint line is crucial in total knee arthroplasty (TKA). A routine height of tibial cut to maintain the natural joint line may compromise the preservation of the PCL. Since the PCL footprint is not accessible prior to tibial osteotomy, it seems beneficial to identify a reliable extraarticular anatomic landmark for predicting the PCL footprint and being visible within standard TKA approach. The fibula head predicts reliably the location of PCL footprint; however, it is not accessible during TKA. The aim of this study now was to analyze whether the tibial tuberosity can serve as a reliable referencing landmark to estimate the PCL footprint height prior to tibial cut. The first consecutive case series included 216 CR TKA. Standing postoperative lateral view radiographs were utilized to measure the vertical distance between tibial tuberosity and tibial osteotomy plane. In the second case series, 223 knee MRIs were consecutively analyzed to measure the vertical distance between tibial tuberosity and PCL footprint. The probability of partial or total PCL removal was calculated for different vertical distances between tibial tuberosity and tibial cutting surface. The vertical distance between the tibial tuberosity and tibial cut averaged 24.7 ± 4 mm. The average vertical distance from tibial tuberosity to proximal and to distal PCL footprint was found to be 22 ± 4.4 and 16 ± 4.4 mm, respectively. Five knees were considered at 50% risk of an entire PCL removal after CR TKA. Current surgical techniques of tibial preparation may result in partial or total PCL damage. Tibial tuberosity is a useful anatomical landmark to locate the PCL footprint and to predict the probability of its detachment pre-, intra-, and postoperatively. This knowledge might be useful to predict and avoid instability, consecutive pain, and dissatisfaction after TKA related to PCL insufficiency. III.

The Segond Fracture: A Bony Injury of the Anterolateral Ligament of the Knee

The purpose of this study was to investigate the relation of the Segond fracture with the anterolateral ligament (ALL) of the knee. To identify the soft-tissue structure causative for the Segond fracture, a study was set up to compare anatomic details of the tibial insertion of the recently characterized ALL in cadaveric knees (n = 30) with radiologic data obtained from patients (n = 29) with a possible Segond fracture based on an imaging protocol search. The spatial relation of the ALL footprint with well-identifiable anatomic landmarks at the lateral aspect of the knee was determined, and this was repeated for the Segond fracture bed. In all of the included cadaveric knees, a well-defined ALL was found as a distinct ligamentous structure connecting the lateral femoral epicondyle with the anterolateral proximal tibia. The mean distance of the center of the tibial ALL footprint to the center of the Gerdy tubercle (GT-ALL distance) measured 22.0 ± 4.0 mm. The imaging database search identified 26 patients diagnosed with a Segond fracture. The mean GT-Segond distance measured 22.4 ± 2.6 mm. The observed difference of 0.4 mm (95% confidence interval, -1.5 to 2.2 mm) between the GT-ALL distance and GT-Segond distance was neither statistically significant (P = .70) nor clinically relevant. The results of this study confirmed the hypothesis that the ALL inserts in the region on the proximal tibia from where Segond fractures consistently avulse, thus suggesting that the Segond fracture is actually a bony avulsion of the ALL. Although the Segond fracture remains a useful radiographic clue for indirect detection of anterior cruciate ligament injuries, the Segond fracture should be considered a frank ligamentous avulsion itself.

Proportional evaluation of anterior cruciate ligament footprint size and knee bony morphology.

The purpose of this study was to reveal the correlation in size between the native anterior cruciate ligament (ACL) footprint and the femoral intercondylar notch and the tibia plateau, and to calculate the proportion in size between the ACL footprint and knee bony morphology. Twenty-six non-paired human cadaver knees were used. All soft tissues around the knee were resected except the ACL. The ACL was cut in the middle, and the femoral bone was cut at the most proximal point of the femoral notch. The ACL was carefully dissected, and the periphery of the ACL insertion site was outlined on both the femoral and tibial sides. An accurate lateral view of the femoral condyle and an axial view of the tibial plateau were photographed with a digital camera, and the images were downloaded to a personal computer. The size of the femoral and tibial ACL footprints and the area of the lateral wall of the intercondylar notch and the tibia plateau were measured with Image J software (National Institution of Health). The sizes of the native femoral and tibial ACL footprints were 69.8 ± 25 and 133.8 ± 31.3 mm(2), respectively. The areas of the lateral wall of the intercondylar notch and the tibia plateau were 390.5 ± 70.5 and 2,281.7 ± 377.3 mm(2), respectively. The femoral ACL footprint area and the area of the lateral wall of the femoral intercondylar notch (Pearson's correlation coefficient = 0.603, p = 0.001), and the tibial ACL footprint area and the area of the tibia plateau (Pearson's correlation coefficient = 0.452, p = 0.02) both showed significant correlation. The femoral ACL footprint was 17.8 ± 4.9 %, the size of the lateral wall of the femoral intercondylar notch, and the tibial ACL footprint was 5.9 ± 1.3 %, the size of the tibia plateau. For clinical relevance, the femoral ACL footprint is approximately 18 %, the size of the intercondylar notch, and the tibial ACL footprint is approximately 6 %, the size of the tibia plateau. It might be possible to predict the size of the ACL measuring these parameters preoperatively.

Tibial Tunnel Placement Accuracy During Anterior Cruciate Ligament Reconstruction: Independent Femoral Versus Transtibial Femoral Tunnel Drilling Techniques

This study aimed to compare the accuracy of tibial tunnel placement using independent femoral (IF) versus transtibial (TT) techniques. Ten matched pairs of cadaveric knees were randomized so that one knee in the pair underwent arthroscopic TT drilling of the femoral tunnel and the other underwent IF drilling through an accessory medial portal. For both techniques, an attempt was made to place the femoral and tibial tunnels as close to the center of the respective anterior cruciate ligament (ACL) footprints as possible. Preoperative and postoperative computed tomography using a technique optimized for ligament evaluation allowed comparison of the anatomic ACL tibial footprint to the tibial tunnel aperture. The percentage of tunnel aperture contained within the native footprint, as well as the distance from the center of the tunnel aperture to the center of the footprint, was measured. Additionally, graft obliquity relative to the tibial plateau was evaluated in the sagittal plane. The percentage of tibial tunnel aperture contained within the native footprint averaged 71.6% ± 17.2% versus 52.1% ± 23.4% (P = .04) in the IF and TT groups, respectively. The distance from the center of the footprint to the center of the tibial tunnel aperture was 3.50 ± 1.6 mm and 4.40 ± 1.7 mm (P = .27) in the IF and TT groups, respectively. TT drilling placed 6 of 10 tunnels posterior to the center of the footprint versus 3 of 10 tunnels in IF drilling. The graft obliquity angles were 54.8° in TT specimens and 47.5° in IF specimens (P = .09). This study adds to the literature suggesting that TT drilling with an 8-mm reamer has deleterious effects on tibial tunnel aperture and position. IF drilling, which does not involve repeated reaming of the tibial tunnel, is associated with the placement of a higher percentage of the tunnel aperture within the native tibial footprint. There was not a significant difference between the IF and TT techniques in their ability to place the center of the tibial aperture near the center of the footprint or in graft obliquity. ACL reconstruction has continued to evolve in an attempt to restore the functional anatomy and biomechanical behavior of the knee. Tibial tunnel characteristics-such as location, aperture topography, and tunnel obliquity-are important factors to consider in ACL reconstruction. This study compares tibial tunnels after IF and TT techniques.

Flat midsubstance of the anterior cruciate ligament with tibial "C"-shaped insertion site.

Purpose This anatomical cadaver study was performed to investigate the flat appearance of the midsubstance shape of the anterior cruciate ligament (ACL) and its tibial “C”-shaped insertion site.MethodsThe ACL midsubstance and the tibial ACL insertion were dissected in 20 cadaveric knees (n = 6 fresh frozen and n = 14 paraffined). Magnifying spectacles were used for all dissections. Morphometric measurements were performed using callipers and on digital photographs.ResultsIn all specimens, the midsubstance of the ACL was flat with a mean width of 9.9 mm, thickness of 3.9 mm and cross-sectional area of 38.7 mm2. The “direct” “C”-shaped tibial insertion runs from along the medial tibial spine to the anterior aspect of the lateral meniscus. The mean width (length) of the “C” was 12.6 mm, its thickness 3.3 mm and area 31.4 mm2. The centre of the “C” was the bony insertion of the anterior root of the lateral meniscus overlayed by fat and crossed by the ACL. No posterolateral (PL) inserting ACL fibres were found. Together with the larger “indirect” part (area 79.6 mm2), the “direct” one formed a “duck-foot”-shaped footprint.ConclusionThe tibial ACL midsubstance and tibial “C”-shaped insertion are flat and are resembling a “ribbon”. The centre of the “C” is the bony insertion of the anterior root of the lateral meniscus. There are no central or PL inserting ACL fibres. Anatomical ACL reconstruction may therefore require a flat graft and a “C”-shaped tibial footprint reconstruction with an anteromedial bone tunnel for single bundle and an additional posteromedial bone tunnel for double bundle.

Anatomical dissection and CT imaging of the posterior cruciate and lateral collateral ligaments in skeletally immature cadaver knees.

Understanding the relationship of the posterior cruciate ligament (PCL) and the lateral collateral ligament (LCL) to the femoral and tibial physes is important to reducing the risk of physeal injury during surgical reconstruction. The purpose of this study was to identify the location of the attachments of the PCL and LCL in skeletally immature cadaveric knee specimens and to determine their position relative to the physes. Seven skeletally immature cadaveric knee specimens were examined through gross dissection. These specimens were divided into two groups: infants (an age at death of one month for one specimen and eleven months for two specimens) and children (an age at death of eight years for one specimen, ten years for one specimen, and eleven years for two specimens). Metallic markers were placed at the femoral origins of the PCL and LCL and at the tibial insertion of the PCL. Computed tomography (CT) scans were made for each specimen and analyzed with the use of OsiriX imaging software. The width of the PCL tibial insertion footprint and the height of the PCL femoral origin footprint, the distance from the midpoints of the PCL and LCL femoral origin to the distal femoral physis, and the distance from the PCL insertion footprint midpoint to the proximal tibial physis were measured. The mean distance from the midpoint of the femoral origin footprint of the PCL to the femoral physis was 11.1 mm (range, 10.6 to 11.7 mm) and 18.8 mm (range, 18.2 to 19.2 mm) distal to the physis for infants and children, respectively. The mean distance from the midpoint of the tibial insertion footprint of the PCL to the tibial physis was 3.1 mm (range, 0.0 to 5.7 mm) and 5.8 mm (range, 2.5 to 8.9 mm) proximal to the physis for infants and children, respectively. The mean width of the tibial insertion of the PCL was 5.5 mm (range, 1.1 to 8.3 mm) for infants and 10.2 mm (range, 8.4 to 11.9 mm) for children. The mean distance from the midpoint of the femoral origin of the LCL to the femoral physis was 6.3 mm (range, 3.9 to 7.7 mm) and 5.9 mm (range, 0.0 to 10.0 mm) distal to the physis for infants and children, respectively. The relationship of the PCL and LCL attachments to physeal structures has not been well described. We found the midpoints of the PCL and LCL femoral origins at or distal to, and the midpoint of the PCL tibial insertion at or proximal to, the respective physis in all specimens. This study with CT-scan correlation provides unique information on the location of ligament attachments in relation to the physes. A better understanding of the spatial relationship between the PCL and LCL attachments and their respective physes may help guide drill-hole placement during ligament reconstructions and reduce the risk for iatrogenic physeal injury in skeletally immature patients.

Bony Landmarks of the Anterior Cruciate Ligament Tibial Footprint

Background: Although the importance of tibial tunnel position for achieving stability after anterior cruciate ligament (ACL) reconstruction was recently recognized, there are fewer detailed reports of the anatomy of the tibial topographic footprint compared with the femoral side. Hypothesis: The ACL tibial footprint has a relationship to bony prominences and surrounding bony landmarks. Study Design: Descriptive laboratory study. Methods: This study consisted of 2 anatomic procedures for the identification of bony prominences that correspond to the ACL tibial footprint and 3 surrounding landmarks: the anterior ridge, lateral groove, and intertubercular fossa. In the first procedure, after computed tomography (CT) was performed on 12 paired, embalmed cadaveric knees, 12 knees were visually observed, while their contralateral knees were histologically observed. Comparisons were made between macroscopic and microscopic findings and 3-dimensional (3D) CT images of these bony landmarks. In the second procedure, the shape of the bony prominence and incidence of their bony landmarks were evaluated from the preoperative CT data of 60 knee joints. Results: In the first procedure, we were able to confirm a bony prominence and all 3 surrounding landmarks by CT in all cases. Visual evaluation confirmed a small bony eminence at the anterior boundary of the ACL. The lateral groove was not confirmed macroscopically. The ACL was not attached to the lateral intercondylar tubercle, ACL tibial ridge, and intertubercular space at the posterior boundary. Histological evaluation confirmed that the anterior ridge and lateral groove were positioned at the anterior and lateral boundaries, respectively. There was no ligament tissue on the intercondylar space corresponding to the intercondylar fossa. In the second investigation, the bony prominence showed 2 morphological patterns: an oval type (58.3%) and a triangular type (41.6%). The 3 bony landmarks, including the anterior ridge, lateral groove, and intertubercular fossa, existed in 96.6%, 100.0%, and 96.6% of the cases, respectively. Conclusion: There is a bony prominence corresponding to the ACL footprint and bony landmarks on the anterior, posterior, and lateral boundaries. Clinical Relevance: The study results may help create an accurate and reproducible tunnel, which is essential for successful ACL reconstruction surgery.

A Surgical Trick for Adjusting an Inaccurate Guide Pin to the Center of the Tibial Footprint in Anatomic Single-Bundle Anterior Cruciate Ligament Reconstruction

Anatomic positioning of the graft in anatomic anterior cruciate ligament reconstruction is the key to improved knee stability, restoration of normal knee kinematics, and the prevention of long-term joint degeneration. We have developed a technique for adjusting inaccurate drill guide placement to the center of the tibial footprint in anatomic single-bundle anterior cruciate ligament reconstruction. This technique can solve the inaccurate drill guide placement problems that may be encountered during this surgical procedure.

Size correlation between the tibial anterior cruciate ligament footprint and the tibia plateau

The purpose of this study was to reveal the correlation between the size of the native anterior cruciate ligament (ACL) footprint and the size of the tibia plateau. Twenty-four non-paired human cadaver knees were used. All soft tissues around the knee were resected except the ACL. The ACL was cut in the middle, and the femoral bone was cut at the most proximal point of the femoral notch. The ACL was carefully dissected, and the periphery of the ACL insertion site was outlined on both the femoral and tibial sides. An accurate lateral view of the femoral condyle and the tibial plateau was photographed with a digital camera, and the images were downloaded to a personal computer. The size of the femoral and tibial ACL footprints, and anterior-posterior (AP) and medial-lateral (ML), lengths of the tibia plateau and area of tibia plateau were measured with Image J software (National Institution of Health). The sizes of the native femoral and tibial ACL footprints were 72.3±24.4 and 134.1±32.4mm(2), respectively. The AP lengths of the whole, medial and lateral facet of the tibia plateau were as follows: 44.5±4.1, 40.8±4.1 and 36.8±4mm, respectively. The ML length of the tibia plateau was 68.3±5.5mm. Total area of tibia plateau was 2,282.9±378.7mm(2). The AP length of the lateral facet of the tibia plateau (Pearson's correlation coefficient=0.508, p=0.011) and the total area of tibia plateau (Pearson's correlation coefficient=0.442, p=0.031) were significantly correlated with the size of the tibial ACL footprint. For clinical relevance, the AP length of lateral facet of the tibia plateau and total area of tibia plateau are significantly correlated with the size of the tibial ACL footprint. It might be possible to predict the size of the ACL measuring these parameters.

Iatrogenic Meniscus Posterior Root Injury Following Reconstruction of the Posterior Cruciate Ligament: A Report of Three Cases.

Kennedy, Nicholas I. BS1; Michalski, Max P. MSc1; Engebretsen, Lars MD, PhD2; LaPrade, Robert F. MD, PhD1 Author Information

Transtibial Tunnel Placement in Posterior Cruciate Ligament Reconstruction: How It Relates to the Anatomic Footprint.

Background:It is common to place the posterior cruciate ligament (PCL) tibial tunnel with a transtibial technique using a guide that attempts to place the center of the tunnel 1 to 1.5 cm distal to the tibiofemoral joint. It is unknown how well this technique will re-create the native tibial footprint of the PCL.Purpose:To evaluate the accuracy of tibial tunnel placement using a transtibial technique.Study Design:Controlled laboratory study.Methods:Ten cadaveric knees from 10 donors underwent arthroscopic transtibial drilling of the tibial tunnel with use of a posteromedial portal for visualization. The transtibial guide was rested flush against the tibial spines to allow for the guide to be as distal as possible, which was between 1 and 1.5 cm distal to the tibiofemoral joint line. Using this technique, an attempt was made to place the tibial tunnels as close to the center of the PCL footprint as possible. All knees underwent computed tomography both pre- and postoperatively with a previously reported technique optimized for ligament evaluation. This allowed comparison of the anatomic PCL tibial footprint to the tibial tunnel aperture. The percentage of tunnel aperture contained within the native footprint as well as the distance from the center of the tunnel aperture to the center of the footprint was measured.Results:The percentage of tunnel aperture contained within the native footprint was 45.9% ± 23.1%. The distance from the center of the tibial tunnel aperture to the center of the tibial PCL footprint was 6.4 ± 2.3 mm. The tunnels were almost always (9/10) distal (or inferior) to the native footprint and either slightly lateral (5/10) or centered (5/10) in a medial to lateral direction.Conclusion:This study demonstrates that using the transtibial drilling technique in the tibia for PCL reconstruction places approximately half of the tibial tunnel aperture within the tibial footprint. Generally, the tunnel is distal to the footprint.Clinical Relevance:Consideration should be given to the fact that, using this transtibial technique, the tibial tunnel aperture is generally not placed in the center of the footprint. This may not be a negative issue, however, since there are other potential advantages from distal tunnel placement.

Isolierter Bündelersatz bei Partialruptur des vorderen Kreuzbandes

Partial augmentation of isolated tears of the anteromedial and posterolateral bundle of the anterior cruciate ligament (ACL) with autologous hamstring tendons. The intact fibers of the ACL are preserved. Symptomatic isolated tear of the anteromedial or posteromedial bundle of the ACL or rotational instability after ACL reconstruction with malplaced tunnels (e.g., high femoral position) In revision cases: loss of motion due to malplaced ACL and excessive tunnel widening of the present tunnels with the risk of tunnel confluence. Examination of anterior-posterior translation and rotational instability under anesthesia. Diagnostic arthroscopy, repetition of the clinical examination under direct visualization of the ACL, meticulous probing of the functional bundles. Resection of ligament remnants, preparation/preservation of the femoral and tibial footprint. Harvesting one of the hamstring tendons, graft preparation. Positioning of a 2.4 mm K-wire in the anatomic center of the femoral anteromedial/posterolateral bundle insertion, cannulated drilling according to the graft diameter. Positioning of a 2.4 mm K-wire balanced according to the femoral tunnel at the tibia, cannulated drilling. Insertion of the graft and fixation. Analogous to that for ACL reconstruction.

The Use of the 70° Arthroscope for Anatomic Femoral and Tibial Tunnel Placement and Tunnel Viewing in Anterior Cruciate Ligament Reconstruction

The use of the 70° arthroscope in knee surgery is not a new concept, and it is frequently used in posterior cruciate ligament reconstruction. There are previous reports of its use in anterior cruciate ligament surgery, but it has not achieved routine use. With the move toward anatomic anterior cruciate ligament reconstruction, it is recognized that accurate tunnel placement is vital for a good clinical outcome. Visualization of the femoral and tibial footprints can be variable with the use of only an anterolateral viewing portal, and it may be necessary to create accessory anteromedial portals, which can cause problems with instrument crowding. Overall, the 70° arthroscope provides an excellent view of the femoral and tibial footprints and a view of the full length of the femoral and tibial tunnels through a single anterolateral viewing portal.

Three-dimensional computed tomography evaluation of anterior cruciate ligament footprint for anatomic single-bundle reconstruction

Femoral and tibial footprint coordinates have been well studied in double-bundle anterior cruciate ligament (ACL) reconstruction. However, in a single-bundle reconstruction approach, the central coordinate of femoral and tibial footprints have not been determined. The purpose of this study was to describe the central point locations of the ACL footprints visualized by three-dimensional computed tomography (3D CT) images and analysed by the quadrant method. Eight cadaveric knees were dissected, and the central points of ACL femoral and tibial footprints were marked and analysed using 3D CT images. In the present study, the means (and standard deviation) of ACL femoral footprint dimensions were in the ventral-dorsal plane and in the cranial-caudal plane 9.4 ± 0.8 and 15.6 ± 0.9 mm, respectively. In the tibial side, the means of ACL footprint dimensions were in the anterior-posterior and in the medial-lateral 18.5 ± 1.9 and 15.5 ± 1.0 mm, respectively. In the tomographic analyses, the means of femoral central location coordinates in the ventral-dorsal (y) and in the cranial-caudal (x) axes were 35.3 ± 4.5 and 30.0 ± 1.6 %, respectively. The means of tibial central location coordinates were in the anterior-posterior (y) and in the medial-lateral (x) axes, respectively: 40.5 ± 5.3 and 50.2 ± 1.3 %, respectively. These computed tomographic coordinates might help future studies as a reference on ACL single-bundle anatomic reconstruction, with respect to the management of ACL revision surgery or in symptomatic patients after ACL reconstruction. Improvements in three-dimensional image acquisition could facilitate its intraoperative applicability in the coming years.

TransMedial All-Inside Posterior Cruciate Ligament Reconstruction Using a Reinforced Tibial Inlay Graft

Surgical reconstruction of the posterior cruciate ligament (PCL) is technically demanding. Potential challenges include visualization of the tibial footprint and drilling of the tibial tunnel without damaging posterior neurovascular structures, as well as graft selection, deployment, tensioning, and fixation. We present a novel TransMedial all-inside arthroscopic technique (technique designed by A. J. Wilson with support from Arthrex) using a single hamstring tendon graft, fixed with adjustable cortical suspensory devices. The technique simplifies the difficult steps encountered during PCL reconstruction and is safe and reproducible. All arthroscopic viewing is accomplished from the lateral portal, and femoral socket preparation is performed from the medial side with specially contoured instruments, which allow accurate marking, measuring, and anatomic positioning of the graft. The quadrupled semitendinosus graft can be augmented with composite polymer tape for increased strength and initial stability. We use outside-in drilling to create retrograde femoral and tibial sockets. Cortical suspensory fixation on the tibial side can be supplemented with anchor fixation. We use an arthroscopic tibial inlay technique that better approximates native knee anatomy. This also avoids the “killer turn,” a problem seen in transtibial PCL reconstruction techniques, which theoretically induces graft laxity due to abrasion with cyclic loading. This technique can be further adapted to allow a modified double-bundle or TriLink graft (technique designed by A. J. Wilson with support from Arthrex.).

Effect of Medial-Lateral Position of the Tibial Anteromedial Bundle Tunnel on Knee Biomechanics

Effect of Medial-Lateral Position of the Tibial Anteromedial Bundle Tunnel on Knee Biomechanics

Anatomic ACL reconstruction produces greater graft length change during knee range-of-motion than transtibial technique

Because distance between the knee ACL femoral and tibial footprint centrums changes during knee range-of-motion, surgeons must understand the effect of ACL socket position on graft length, in order to avoid graft rupture which may occur when tensioning and fixation is performed at the incorrect knee flexion angle. The purpose of this study is to evaluate change in intra-articular length of a reconstructed ACL during knee range-of-motion comparing anatomic versus transtibial techniques. After power analysis, seven matched pair cadaveric knees were tested. The ACL was debrided, and femoral and tibial footprint centrums for anatomic versus transtibial techniques were identified and marked. Asuture anchor was placed at the femoral centrum and a custom, cannulated suture-centring device at the tibial centrum, and excursion of the suture, representing length change of an ACL graft during knee range-of-motion, was measured in millimeters and recorded using a digital transducer. Mean increase in length as the knee was ranged 120°–0° (full extension) was 4.5 mm (±2.0 mm) for transtibial versus 6.7 mm (±0.9 mm) for anatomic ACL technique. A significant difference in length change occurs during knee range-of-motion both within groups and between the two groups. Change in length of the ACL intra-articular distance during knee range-of-motion is greater for anatomic socket position compared to transtibial position. Surgeons performing anatomic single-bundle ACL reconstruction may tension and fix grafts with the knee in full extension to minimize risk of graft stretch or rupture or knee capture during full extension. This technique may also result in knee anterior–posterior laxity in knee flexion.

Commonly used ACL autograft areas do not correlate with the size of the ACL footprint or the femoral condyle

The purpose of this study was to reveal the correlation between the size of the native anterior cruciate ligament (ACL) footprint and the area of commonly used autografts using cadaveric knees. Twenty-Four non-paired human cadaver knees were used. The size of the femoral and tibial ACL footprints, length of Blumensaat's line, and the height and area of the lateral wall of the femoral intercondylar notch were photographed and measured with Image J software (National Institution of Health). Simulating an semitendinosus tendon (ST) graft, the ST was cut in half. The bigger half was regarded as the antero-medial (AM) bundle, and the remaining half was regarded as the postero-lateral (PL) bundle. Simulating an semitendinosus and gracilis (ST-G) graft, the bigger half of the ST and G was regarded as the AM bundle, and the smaller half of the ST was regarded as the PL bundle. Each graft diameter was measured, and the graft area was calculated. Simulating a bone-patella tendon-bone (BPTB) graft, a 10-mm wide BPTB graft was harvested and the area calculated. The sizes of the native femoral and tibial ACL footprints were 72.3 ± 24.4 and 134.1 ± 32.4 mm(2), respectively. The length of Blumensaat's line, and the height and area of the lateral wall of the femoral intercondylar notch were 29.5 ± 2.5 mm, 17.7 ± 2.3 mm, and 400.9 ± 62.6 mm(2), respectively. The average areas of the ST, ST-G, and BPTB graft were 52.7 ± 6.3, 64.7 ± 7.6, and 37.1 ± 7.5 mm(2). Both the height and the area of the lateral wall of the femoral intercondylar notch were significantly correlated with the femoral size of the ACL footprint (p = 0.007 and 0.008, respectively). However, no significant correlation was observed between ACL footprint size and autograft size. No significant correlation was observed between autograft size and the size of the lateral wall of the femoral intercondylar notch. In ACL reconstruction, if the reconstructed ACL size is determined by the harvested autograft size alone, native ACL size and anatomy are unlikely to be reproduced.