Femoral Tunnel Location Research Articles

Tunnel position following posterior cruciate ligament reconstruction: An in vivo computed tomography analysis

The success of posterior cruciate ligament (PCL) reconstruction is dependent on appropriate tunnel placement. Computed tomography (CT) provides detailed images of intra-articular osseous anatomy. The objective of this study was to analyze by CT the position of femoral and tibial tunnels relative to intra-operative goals following arthroscopic-assisted PCL reconstruction. Nineteen patients who underwent single-bundle PCL reconstruction were evaluated 16months post-operatively. Each underwent a CT scan and tunnel locations were identified in the coronal, sagittal, and axial planes. The coronal plane tibial tunnel location was within 5mm of the intra-operative goal (48% of the total tibial plateau width from the medial border of the plateau) in 16 patients (84%). The sagittal plane tibial tunnel location was within 5mm of the intra-operative goal (the middle of the posterior half of the retrospinal surface) in 14 patients (74%). In the sagittal plane, the femoral tunnel location was within 5mm of the intra-operative goal (10mm from in the distal articular margin of the medial femoral condyle) in 15 patients (79%). In the notch, the femoral tunnel was between 10:30 and 11:30 for left knees or between 12:30 and 1:30 for right knees (the intra-operative goal was 11 o'clock for left knees and 1 o'clock for right knees) in 18 patients (95%). Arthroscopic PCL reconstruction results in tunnel positions near intra-operative goals. Further work is necessary to define CT-specific criteria for the assessment of PCL tunnel position.

Anatomic Landmarks Utilized for Physeal-Sparing, Anatomic Anterior Cruciate Ligament Reconstruction: An MRI-Based Study (SS-68)

<h3>Introduction</h3> ACL injury and reconstruction are becoming more common in the skeletally immature. Damage to the femoral physes and concomitant growth disturbance is a fear for the surgeon, patient, and family. The use of an all-epiphyseal technique on the femoral side is gaining popularity, but is technically difficult, requires intraoperative X-ray, leads to variable femoral tunnel locations and is non-anatomic as currently described. The purpose of the study was to develop an easily reproducible, anatomic reconstructive technique using intra- and extra-articular landmarks, which can reliably produce a femoral tunnel of adequate length and diameter, while at the same time avoiding the femoral physis. <h3>Methods</h3> 188 MRI studies were evaluated for children aged 6 to 17. Multiple anatomic landmarks were examined to determine optimal landmarks for ACL reconstruction (reproducibility, physeal safety, ease of identification, etc.). The extra-articular landmarks were the femoral origin of the popliteus tendon and the lateral epicondyle. The intra-articular landmark was the central portion of the femoral ACL origin. Using multi-plane computer software, points were plotted at the three landmarks in all three planes. Lines, depicting potential femoral tunnels were then drawn connecting the ACL origin to the popliteal insertion and the lateral epicondyle. Distances were then calculated for lengths of these tunnels, the shortest distance from the physis to these tunnels, the width of the femoral notch, and the width and height of the femoral condyles. Statistical analysis was then performed, comparing distances between age groups and sexes. 3D MRI Physeal-reconstruction employed, confirmed that the chosen landmarks spared the physes after tunnel placement. <h3>Results</h3> Tunnel lengths from the ACL origin to the popliteus insertion, tunnel lengths from the ACL origin to the lateral epicondyle, total femoral widths, and notch widths significantly differed across all age groups and sexes (p<0.001), as did condylar heights (p<0.03). Average distance to the femoral physis from the tunnel, which was from the ACL origin to the popliteus were 12 mm, independent of sex or age (p<0.94), and the shortest distance was 8 mm. This tunnel length averaged 30.1 mm in males and 27.4 mm in females (p<0.001), with an average of 25.6 mm in 6-year-olds and 30.2 mm in 17-year-olds. Average distance to the femoral physis from the tunnel, which was from the ACL origin to the lateral epicondyle were 8.8 mm in males and 8.9 mm in females (p<0.55), and this tunnel's average length was 34.3 mm in males and 31.6 mm in females (p<0.001). <h3>Conclusion</h3> Advantages to sparing the femoral physis when drilling the femoral ACL tunnel are obvious, however the biomechanical advantages of anatomic ACL reconstruction are still being studied. A combination of the two techniques may be the preferred technique for skeletally immature patients in the future. Drilling from the ACL origin to the popliteal insertion will produce an average tunnel length of 27-30 mm for graft incorporation and safely allow at least an 8-10 mm diameter tunnel in a patient 6 to 17 years old. Using the easily identifiable landmarks discussed in this paper will allow safe, reproducible anatomic ACL reconstructions without the need for tedious x-ray utilization intra-operatively.

The study of graft offset in the anterior cruciate ligament reconstruction

Objective To investigate the impact of graft position shift on anterior cruciate ligament reconstruction induced by femoral fixation of interference screw. Methods Nineteen fresh cadaveric knees were used and assigned to three groups. 1） Study of graft position shift： 5 knees were randomly selected, interference screws of 7 mm, 8 mm and 9 mm were used in autologous tendon fixation, then the graft position shift were measured. 2） Study of isometry： 7 knees were randomly divided into the isometric reconstruction group （D group）. In the D group, Retrobutton, interference screw and interference screw in location-corrected bone tunnel were used respectively as fixation. The isometry of grafts was evaluated. 3） Study of tibia anterior translation： 7 knees were randomly divided into the anatomic reconstruction group （J group）. In the J group,the tibia anterior translation was measured in four different conditions in the same joint： intact knee joint,knee joint without ACL, ACL anatomic reconstruction by interference screw fixation, and ACL anatomic reconstruction by interference screw fixation with corrected bone tunnel location. Results 1） With 7 mm, 8mm and 9 mm interference screw fixation, graft position shift were （2.36±0.11） mm, （2.72±0.06） mm and （3.00±0.06） mm respectively. 2） Graft length change： graft length change in Retrobutton group and corrected bone tunnel group were less than 3 mm, while graft length change in those fixed with interference screw were stretched in more than 3 mm. 3） Study of tibia anterior translation： there was no difference among the intact group, the anatomic group and the corrected group at 0° and 15°. However, the difference was found between the intact group and other groups at 30°、60° and 90° of flexion, as well as between these two reconstructed methods at 20° joint flexion （P＜0.05）. Conclusion In both isometric and anatomic ACL reconstruction with interference screw, the graft is pushed tightly toward the femoral tunnel wall, which shifts the graft away from the desired position. In our study we find out that the corrected location of the femoral bone tunnel significantly improves the isometry of ACL reconstruction and anatomic reconstruction. Key words: Anterior cruciate ligament; Transplants; Exercise; Biomechanics

Inter- and intraobserver reliability of the clock face representation as used to describe the femoral intercondylar notch

To validate the use of the clock face reference as a reliable means of communicating femoral intercondylar notch position. A single red mark was made on ten identical left Sawbones femurs in the intercondylar notch at variable locations. Ten surgeons, who routinely perform ACL reconstructions, were presented the femurs in random order and asked to state the position of the mark to the nearest 30-min interval. Responses were recorded and then repeated 3 weeks later. The same 10 surgeons were presented with 30 actual arthroscopic photographs of the intercondylar notch, performed at 90° of knee flexion, with a probe pointing at various locations (10 knees; 3 photographs/knee) along the lateral aspect of the notch. The results were then analyzed with an ICC, Cronbach's alpha test, and descriptive statistics. For the Sawbones, the ICC was 0.996 while individual physician's Cronbach's alpha test ranged from 0.954 to 0.999, indicating a very high interobserver and intraobserver reliability. The mean range of responses among the 10 surgeons was 1.6 h, SD 0.6. For the photographs, the ICC was also high at 0.997. There was a mean range of 1.1 h, SD 0.4, among surgeons. The clock face method is commonly utilized for both placement of the femoral tunnel during ACL reconstruction as well as describing the location of the ACL femoral tunnel between communicating surgeons. Despite a high statistical interobserver correlation, there is significant range among different surgeons' responses. The present study questions the reliability of the clock face method for use between surgeons as a stand alone tool. Other methods also utilizing anatomic landmarks may be more accurate for describing intercondylar notch anatomy. III.

Revision Anterior Cruciate Ligament Reconstruction Using Two Anteromedial Portal Technique

There are numerous reasons for the failure of anterior cruciate ligament (ACL) reconstruction. Among them, surgical technical failure and wrong femoral tunnel location are the most common. The authors focused on the results of ACL revision using two anteromedial portals. Sixteen patients were selected with two anteromedial portals that were designed to decrease the femoral tunnel slope in sagittal plane. Clinical analysis was carried out based on Lysholm score, Tegner score and International Knee Documentation Committee (IKDC). For anterior stability test, Lachman test, KT-2000 arthrometer were used. pivot shift test was measured for rotatory stability test. Preoperative Lachman test and pivot shift test showed positive finding in all cases, however, postoperative Lachman with 10 cases (62.5%) and pivot shift test with 10 cases (62.5%) were negative. The difference of anterior displacement with the non-affected side using KT 2000 arthrometer showed 6.57 mm (range: 4.0-12.0 mm) preoperatively and 2.20 mm (range: 1.0-4.0 mm) postoperatively on average. Score of Tegner and Lysholm improved from 4.86 (range: 2.0-7.0), 46.14 (range: 33-52) preoperatively, to postoperative score of 8.14 (range: 7.0-9.0), 83.43 (range: 74-89) at the final follow up. IKDC result also showed improvement. ACL reconstruction method using two anteromedial tunnels that is desgined to decrease femoral tunnel slope at sagittal plane is an effective technigue for revision surgery after initial ACL reconstruction failure. This technigue allows superior femoral tunnel selection, firm fixation of grafts and also shows excellent clinical results with stability.

Anatomical and Non-anatomical Single bundle Anterior Cruciate Ligament Reconstruction: Effect of Femoral Tunnel Location on Knee Kinematics

Anatomical and Non-anatomical Single bundle Anterior Cruciate Ligament Reconstruction: Effect of Femoral Tunnel Location on Knee Kinematics

Anterior Cruciate Ligament Tunnel Position Measurement Reliability on 3-Dimensional Reconstructed Computed Tomography

The purpose of this study was to evaluate intraobserver and interobserver reliability of anterior cruciate ligament tunnel location measurement by use of 3-dimensional reconstructed computed tomography (CT). Three-dimensional reconstructed CT images of 31 cadaveric knees were used in this study. Twenty-one knees were operated on with a double-bundle technique, and ten knees were operated on with a single-bundle technique. Femoral tunnel location was measured with 3 methods on the medial-lateral view of the lateral femoral condyle in the strictly lateral position. Tibial tunnel location was measured in the top view of the proximal tibia. The images were evaluated independently by 2 orthopaedic surgeons. A second measurement was performed, by both testers, after a 4-week interval. The 3 methods of femoral tunnel location measurement had intraobserver intraclass correlation coefficients (ICCs) that ranged from 0.963 to 0.998 and interobserver ICCs that ranged from 0.993 to 0.999. Tibial tunnel measurement had intraobserver ICCs that varied between 0.957 and 0.998 and interobserver ICCs that varied between 0.993 and 0.996. The measurement of the anterior cruciate ligament tunnel location on 3-dimensional reconstructed CT provided excellent intraobserver and interobserver reliability. Three-dimensional reconstructed CT can be used for further studies to assess the effect of tunnel position on knee stability and patient outcomes.

The Ability of 3 Different Approaches to Restore the Anatomic Anteromedial Bundle Femoral Insertion Site During Anatomic Anterior Cruciate Ligament Reconstruction

The purpose of this study was to determine whether drilling the femoral tunnel when performing anterior cruciate ligament (ACL) reconstruction through the accessory medial portal, as opposed to drilling the tunnel transtibially, will lead to more frequent location of the anteromedial femoral tunnel within the anatomic anteromedial bundle insertion site. Primary anatomic double-bundle reconstruction was performed on 113 patients. Intraoperatively, we placed a guide pin through the anteromedial and posterolateral tibial tunnels and accessory medial portal, attempting to reach the center of the native femoral anteromedial bundle insertion. For each approach, the position of the guide pin was classified as (1) within the center of, (2) off-center within, or (3) outside of the femoral anteromedial insertion. There were significant differences in the ability of each approach to reach the center of the femoral anteromedial bundle insertion. Through the tibial anteromedial tunnel, the femoral anteromedial insertion center was reached in 4.4% of cases, whereas it was off-center within and outside of the femoral anteromedial insertion in 23.0% and 72.6%, respectively. Through the tibial posterolateral tunnel, the femoral anteromedial insertion center was reached in 60.2% of cases, whereas it was off-center within and outside of the femoral anteromedial insertion in 23.9% and 15.9% of cases, respectively. When approached from the accessory medial portal, the center of the femoral anteromedial insertion was reached in 100% of the cases. Ultimately, the femoral anteromedial tunnel was drilled through the tibial anteromedial tunnel in 0.9%, through the posterolateral tunnel in 62.8%, and through the accessory medial portal in 36.3% of cases. Drilling the femoral tunnel for the anteromedial graft through the accessory medial portal, as opposed to drilling the tunnel transtibially, leads to more frequent location of the anteromedial femoral tunnel within the anterior cruciate ligament anteromedial bundle anatomic footprint.

Evaluation of bone tunnel placement for suture augmentation of an injured anterior cruciate ligament: Effects on joint stability in a goat model

Use of novel tissue engineering approaches to heal an injured anterior cruciate ligament (ACL) requires suture repair and/or augmentation to provide joint stability. We evaluated the effects of the location of suture augmentation at the femur and tibia in terms of joint stability using a goat model. Eight goat stifle joints were tested with augmentation sutures placed in two femoral tunnel locations: (1) anterior to, or (2) through the ACL footprint, and two tibial tunnel locations: (1) medial to, or (2) medial and lateral to the footprint. Using a robotic/universal force-moment sensor testing system, the anterior tibial translation (ATT) and the corresponding in situ force carried by the sutures were obtained at 30°, 60°, and 90° of flexion in response to external loads. No significant differences were found between augmentation groups due to tunnel location in terms of ATT or the in situ forces carried by the sutures at all flexion angles tested. Similar results were found under 5 N m of varus-valgus torque. Under a 67 N anterior tibial load, the ATT was restored to within 3 mm of the intact joint following suture augmentation (p > 0.05). Suture augmentation, when placed close to the ACL insertion, could be helpful in providing initial joint stability to aid ACL healing in the goat model.

All-epiphyseal Semitendinosus PCL Reconstruction in a 10-year-old Child

Tears of the posterior cruciate ligament (PCL) in pediatric patients, especially avulsions from its tibial insertion, are not frequently encountered by physicians. However, with an increasing incidence of ligamentous injuries to the knee in skeletally immature patients, orthopaedic surgeons will more frequently need to decide how best to manage a PCL injury in children with open physes. A 10-year-old boy sustained an avulsion of the PCL from its tibial insertion site after a bicycle motocross racing accident. He required a PCL reconstruction after failed conservative treatment and an unsuccessful attempt at primary repair. This successful physeal sparing reconstruction was accomplished using a modified method of femoral tunnel placement in combination with the tibial inlay technique. A magnetic resonance imaging was acquired 2 years postoperatively when physical examination demonstrated both legs of equal length, no varus or valgus deformity, and a normal posterior drawer examination. Four years after the reconstruction, he continues to bicycle motocross race while experiencing no further symptoms and complete restoration to his prior quality of life. The use of the tibial inlay technique together with the modified femoral tunnel location prevented transphyseal drilling while attaining a favorable anatomic placement of the graft while avoiding the "killer" turn associated with the transtibial approach. Level IV (Therapeutic Study).

The Location of Femoral and Tibial Tunnels in Anatomic Double-Bundle Anterior Cruciate Ligament Reconstruction Analyzed by Three-Dimensional Computed Tomography Models

Characterization of the insertion site anatomy in anterior cruciate ligament reconstruction has recently received increased attention in the literature, coinciding with a growing interest in anatomic reconstruction. The purpose of this study was to visualize and quantify the position of anatomic anteromedial and posterolateral bone tunnels in anterior cruciate ligament reconstruction with use of novel methods applied to three-dimensional computed tomographic reconstruction images. Careful arthroscopic dissection and anatomic double-bundle anterior cruciate ligament tunnel drilling were performed with use of topographical landmarks in eight cadaver knees. Computed tomography scans were performed on each knee, and three-dimensional models were created and aligned into an anatomic coordinate system. Tibial tunnel aperture centers were measured in the anterior-to-posterior and medial-to-lateral directions on the tibial plateau. The femoral tunnel aperture centers were measured in anatomic posterior-to-anterior and proximal-to-distal directions and with the quadrant method (relative to the femoral notch). The centers of the tunnel apertures for the anteromedial and posterolateral tunnels were located at a mean (and standard deviation) of 25% +/- 2.8% and 46.4% +/- 3.7%, respectively, of the anterior-to-posterior tibial plateau depth and at a mean of 50.5% +/- 4.2% and 52.4% +/- 2.5% of the medial-to-lateral tibial plateau width. On the medial wall of the lateral femoral condyle in the anatomic posterior-to-anterior direction, the anteromedial and posterolateral tunnels were located at 23.1% +/- 6.1% and 15.3% +/- 4.8%, respectively. The proximal-to-distal locations were at 28.2% +/- 5.4% and 58.1 +/- 7.1%, respectively. With the quadrant method, anteromedial and posterolateral tunnels were measured at 21.7% +/- 2.5% and 35.1% +/- 3.5%, respectively, from the proximal condylar surface (parallel to the Blumensaat line), and at 33.2% +/- 5.6% and 55.3% +/- 5.3% from the notch roof (perpendicular to the Blumensaat line). Intraobserver and interobserver reliability was high, with small standard errors of measurement. This cadaver study provides reference data against which tunnel position in anterior cruciate ligament reconstruction can be compared in future clinical trials.

ACL mismatch reconstructions: influence of different tunnel placement strategies in single-bundle ACL reconstructions on the knee kinematics

To evaluate the influence of tibial and femoral tunnel position in ACL reconstruction on knee kinematics, we compared ACL reconstruction with a tibial and femoral tunnel in anteromedial (AM-AM reconstruction) and in posterolateral footprint (PL-PL reconstruction) with a reconstruction technique with tibial posterolateral and femoral anteromedial tunnel placement (PL-AM reconstruction). In 9 fresh-frozen human cadaveric knees, the knee kinematics under simulated Lachman (134N anterior tibial load) and a simulated pivot shift test (10N/m valgus and 4N/m internal tibial torque) were determined at 0°, 30°, 60°, and 90° of flexion. Kinematics were recorded for intact, ACL-deficient, and single-bundle ACL reconstructed knees using three different reconstruction strategies in randomized order: (1) PL-AM, (2) AM-AM and (3) PL-PL reconstructions. Under simulated Lachman test, single-bundle PL-AM reconstruction and PL-PL reconstructions both showed significantly increased anterior tibial translation (ATT) at 60° and 90° when compared to the intact knee. At all flexion angles, AM-AM reconstruction did not show any statistical significant differences in ATT compared to the intact knee. Under simulated pivot shift, PL-AM reconstruction resulted in significantly higher ATT at 0°, 30°, and 60° knee flexion and AM-AM reconstructions showed significantly higher ATT at 30° compared to the intact knee. PL-PL reconstructions did not show any significant differences to the intact knee. AM-AM reconstructions restore the intact knee kinematics more closely when compared to a PL-AM technique resembling a transtibial approach. PL-PL reconstructions showed increased ATT at higher flexion angles, however, secured the rotational stability at all flexion angles. Due to the independent tibial and femoral tunnel location, a medial portal technique may be superior to a transtibial approach.

Double-bundle ACL reconstruction: how big is the learning curve?

The study aim was to determine whether an experienced ACL surgeon could convert from a single-bundle to a double-bundle technique with relative accuracy. We also wanted to determine whether there was a significant learning curve. Ten double-bundle ACL reconstruction procedures were carried out on suitable individuals. Following the procedure, all patients underwent a CT scan of the relevant knee. Femoral and tibial tunnel locations were then measured and compared to reference anatomical locations previously described in the literature. The results were not known to the surgeon until all 10 cases were completed. The total percentage difference between the sum of all four study tunnel locations from their reference anatomical positions was calculated for each patient to assess overall accuracy in tunnel placement. Surgical time and all complications were recorded. There were no complications. The surgical time for patient 1 was 125 min and 65 min for patient 10. There was a tendency to place the anteromedial tunnel on the femur more distal than its anatomical location. The femoral posterolateral tunnel position was placed distal to its anatomical location in all cases. As a consequence, it was also slightly anterior compared to its anatomical location. Accurate tibial tunnel placement was achieved for both the AM and the PL tunnels. An improvement in tunnel placement was observed over the 10 cases. This present study shows that it is possible for an experienced ACL surgeon to convert from a transtibial single-bundle technique to a medial portal double-bundle reconstruction with relative accuracy.

Anatomical and Nonanatomical Double-Bundle Anterior Cruciate Ligament Reconstruction: Importance of Femoral Tunnel Location on Knee Kinematics

Anatomical and Nonanatomical Double-Bundle Anterior Cruciate Ligament Reconstruction: Importance of Femoral Tunnel Location on Knee Kinematics

Vertical Femoral Tunnel Placement Results in Rotational Knee Laxity After Anterior Cruciate Ligament Reconstruction

This retrospective study was performed to relate tunnel position as measured by plain radiographs and magnetic resonance imaging (MRI) to residual pivot shift and to determine its clinical relevance after anterior cruciate ligament reconstruction via central quadriceps tendon autograft. We reviewed 137 arthroscopic anterior cruciate ligament reconstructions via quadriceps tendon autograft with a minimum of 2 years' follow-up. Clinical results were evaluated by use of the Lachman test, pivot-shift test, Lysholm score, and Cybex dynamometer (Lumex, Ronkonkoma, NY). Anterior tibial translation was measured with the KT-1000 arthrometer (MEDmetric, San Diego, CA). Patients were classified into 3 groups based on postoperative pivot-shift and Lachman test findings: group I, both negative; group II, negative Lachman test and positive pivot shift; and group III, both positive. The radiographic analysis was performed via the angle between the tibial and femoral tunnels on plain anteroposterior radiographs, the angle between the tibial tunnel and anterior tibial cortex on the lateral view, and the femoral and tibial tunnel location by use of the ratio method. Postoperative knee MRI was performed, and the angle between the intercondylar anteroposterior axis and femoral tunnel on the axial view and the angle between the joint line and the graft on the oblique coronal and sagittal views were measured. There were 100 patients in group I, 13 in group II, and 24 in group III. Patients in group I showed the greatest improvement in Lysholm score among the groups, and patients in group III had the greatest side-to-side difference by KT-1000 arthrometer. Tunnel obliquity as measured by the angle between the anteroposterior axis of the femur and the femoral tunnel in the axial view on MRI was greater (P < .05) and the angle between the joint line and the graft on the oblique coronal view was less in group I. This study showed a significantly lower Lysholm score and more vertical orientation of the femoral tunnel in the group with residual pivot shift than in the group without pivot shift. Vertical orientation of the femoral tunnel in the axial plane is closely related to residual pivot shift without definite anteroposterior laxity. More oblique positioning of the graft may have advantages in rotational stability, which in turn increase subjective patient satisfaction. Level III, diagnostic study of nonconsecutive patients without consistently applied reference gold standard.

Biosteon Cross Pin Femoral Fixation and Tibial Interference Screw Fixation for Hamstring Anterior Cruciate Ligament Reconstruction

Summary: Advancements in surgical techniques for reconstruction of the anterior cruciate ligament (ACL) over the past decade have yielded increasingly favorable and reproducible outcomes. Numerous studies support the argument for hamstring tendon grafts as comparable in strength and stiffness to patellar tendon grafts. Most techniques now use fixation that maximizes initial strength and stiffness, and many also address the biologic factors involved in healing. These developments, along with the appeal of diminished harvest site morbidity associated with hamstring tendon grafts, have led to a sharp increase in the use of hamstring autografts. Femoral cross pin fixation for hamstring grafts has been shown to provide outstanding initial pullout strength, and this technique allows for a more anatomic femoral tunnel location, enhancing the biomechanical properties of the graft. The Biosteon femoral cross pin technique described in this article has the mechanical advantage of achieving “press-fit” graft fixation close to the knee joint and reproduces ACL anatomy by placing the graft in the native ACL footprint in the far posterolateral notch.

Residual pivot shift after anterior cruciate ligament reconstruction using quadriceps tendon autograft (SS-16)

This retrospective study was performed to determine the clinical significance and the causes of residual pivot shift after ACL reconstruction using central quadriceps tendon autograft. Methods: 93 knees of 92 patients who underwent an arthroscopic ACL reconstruction using quadriceps tendon autograft were reviewed with a minimum two years of follow-up. Clinical results were evaluated by Lysholm score and Cybex dynamometer. Anterior laxity was assessed using KT-2000 arthrometer. Patients were classified into three groups by postoperative pivot shift and Lachman test; Group 1 (all negative), Group 2 (negative in Lachman and positive pivot shift), Group 3 (all positive). The radiographic analysis was performed by 1) the angle between tibial and femoral tunnel on plain A-P image, 2) the angle between tibial tunnel and anterior tibial cortex on lateral image, 3) the femoral and tibial tunnel location using Aglietti method. Postoperative knee MRIs were obtained and 1) the angle between joint line and the graft on sagittal and oblique coronal view, 2) the angle between Leo’s line and femoral tunnel on axial view were measured. Results: The number of patients in each group was 75, 8, and 10 respectively. Patients in group 1 showed greatest improvement in Lysholm score among groups, and patients in group 3 experienced greatest side-to-side difference by KT-2000 arthrometer. Radiological study showed that the angle between Leo’s line and femoral tunnel in MRI axial view was greatest in group 1 (P ≤ .05) and the angle between joint line and the graft on oblique coronal view was greatest in group 3 (P ≤ .05). Conclusions: This study suggests that the postoperative symptoms are related to Pivot shift rather than the results of Lachman test, and the residual Pivot shift is related to the vertical placement of the reconstructed ligament in coronal plane.

Influence of the femoral tunnel location and angle on the contact pressure in the femoral tunnel in anterior cruciate ligament reconstruction.

The causes of bone tunnel enlargement after anterior cruciate ligament reconstruction have not been thoroughly investigated. A malpositioned femoral tunnel and an acute femoral tunnel angle may increase the mechanical stress in the femoral tunnel. Controlled laboratory study. Three femoral tunnels (normal, anterior, and acute) and the tibial tunnel were made in four fresh-frozen cadaveric knees. Aluminum cylinders containing pressure-sensitive conductive rubber sensors at the joint entrance were inserted into the femoral tunnels. Dynamic changes in the contact pressure of the graft in the femoral tunnel were measured. Peak contact pressures and dynamic changes in contact pressure for the normal and anterior femoral tunnels demonstrated no differences. Maximum contact pressure of the graft was observed at the anterior portion with the knee in full extension and at the posterior portion with deep knee flexion. Consistent contact pressure occurred at the anterior aspect of the acute femoral tunnel throughout the range of motion. Mean contact pressure at the anterior region of the acute femoral tunnel was significantly higher than that of the normal femoral tunnel at 60 degrees, 90 degrees, and 120 degrees of knee flexion. The consistent contact pressure in the anterior aspect of the acute femoral tunnel may erode the anterior portion of the femoral tunnel, resulting in bone tunnel enlargement. The femoral tunnel direction in anterior cruciate ligament reconstruction is an important factor in reducing femoral tunnel enlargement.

Magnetic Resonance Imaging of Tunnel Placement in Posterior Cruciate Ligament Reconstruction

Summary: The aim of this study was to define a reproducible method for evaluating posterior cruciate ligament (PCL) reconstructions using magnetic resonance imaging (MRI). A 2-fold investigation was performed. In part I, the “footprints” of an intact PCL were located on MRI and their coordinates were defined. Measurements were made on the images of 50 subjects using axial, coronal, and sagittal planes. Interobserver variability was calculated by averaging the measurements of the 2 reviewers and using the Kappa coefficient. Three points of reference were located: tibial attachment on the tibial axial plane, and two femoral attachments on the sagittal and coronal oblique planes. In part II, stability of 20 PCL reconstructions with a bone–patellar tendon–bone (BPTB) autograft were evaluated and scored using the IKDC evaluation form after a 2-year follow-up. Stability was evaluated clinically and instrumentally using a KT-2000 arthrometer at 89 N with the knee flexed at a neutral quadriceps knee angle of approximately 70°. Seven cases were graded A (0 to 2 mm), 11 graded B (3 to 5 mm), and 2 graded C (6 to 10 mm). All patients had an MRI after an average of 16 months (range, 12 to 24 months, 2 SD). The previous measurements from part I of the study were used to make a correlation between achieved stability and tunnel location. A 1-factor analysis of variance (ANOVA), nonparametric ANOVA, and the Fisher Exact test were used to determine if clinical outcome of the 3 groups was influenced by graft placement. At MRI evaluation, excessive deep placement was observed in 4 cases and a correlation between improper femoral tunnel location and stability was statistically significant ( P < .05). A correct placement of tibial tunnel was observed in all patients. In our analysis, proper location of the femoral tunnel seems to be more critical and difficult to achieve than tibial tunnel placement, probably because of the lack of specific anatomic landmarks during surgery. Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 15, No 7 (October), 1999: pp 733–740

Can an isometer predict the tensile behavior of a double-looped hamstring graft during anterior cruciate ligament reconstruction?

An isometer, a highly compliant spring-scale device for measuring suture displacement, has been used intraoperatively by surgeons to select the optimal placement of the femoral tunnel for an anterior cruciate ligament graft. The isometer measures the displacement of a suture centered in a tibial tunnel and attached to an intraarticular location on the femur before the femoral tunnel is drilled. Because the placement of the femoral tunnel strongly impacts the tensile behavior of an anterior cruciate ligament graft and because surgeons have used the amount of suture displacement to guide the placement of the femoral tunnel, the objective of this study was to determine the ability of an isometer to predict graft tension. In 14 patients undergoing reconstructive surgery of the anterior cruciate ligament, an isometer was used to measure suture displacement during passive knee motion for a provisional femoral tunnel location. An electrogoniometer recorded the flexion angle of the knee. The femoral tunnel was drilled. A double-looped semitendinosus and gracilis autograft was inserted around a post in the femoral tunnel, and the tension in the four limbs of the graft exiting the tibial tunnel was measured during passive knee motion. Graft-tension versus knee-flexion-angle curves revealed that each knee exhibited one of two distinct curve shapes: L-shaped, characterized by the maximum tension occurring at full extension and a nearly flat profile from 35 to 90 degrees of flexion, or U-shaped, with elevated tensions at 80-90 degrees of flexion (p < 0.001) reaching at least half of the tension in full extension. Because the shapes of the suture-displacement versus flexion-angle curves were more consistently L-shaped, the intraoperative measurement of suture displacement was not a useful predictor of either the increase in tension in the graft with flexion or the maximum tension in the graft.