Relationship of the Intercondylar Roof and the Tibial Footprint of the ACL Implications for ACL Reconstruction

Department of Orthopaedics, University of Utah, Salt Lake City, Utah.
The American Journal of Sports Medicine (Impact Factor: 4.36). 12/2012; 41(2). DOI: 10.1177/0363546512467955
Source: PubMed


BACKGROUND:Debate exists on the proper relation of the anterior cruciate ligament (ACL) footprint with the intercondylar notch in anatomic ACL reconstructions. Patient-specific graft placement based on the inclination of the intercondylar roof has been proposed. The relationship between the intercondylar roof and native ACL footprint on the tibia has not previously been quantified. HYPOTHESIS:No statistical relationship exists between the intercondylar roof angle and the location of the native footprint of the ACL on the tibia. STUDY DESIGN:Case series; Level of evidence, 4. METHODS:Knees from 138 patients with both lateral radiographs and MRI, without a history of ligamentous injury or fracture, were reviewed to measure the intercondylar roof angle of the femur. Roof angles were measured on lateral radiographs. The MRI data of the same knees were analyzed to measure the position of the central tibial footprint of the ACL (cACL). The roof angle and tibial footprint were evaluated to determine if statistical relationships existed. RESULTS:Patients had a mean ± SD age of 40 ± 16 years. Average roof angle was 34.7° ± 5.2° (range, 23°-48°; 95% CI, 33.9°-35.5°), and it differed by sex but not by side (right/left). The cACL was 44.1% ± 3.4% (range, 36.1%-51.9%; 95% CI, 43.2%-45.0%) of the anteroposterior length of the tibia. There was only a weak correlation between the intercondylar roof angle and the cACL (R = 0.106). No significant differences arose between subpopulations of sex or side. CONCLUSION:The tibial footprint of the ACL is located in a position on the tibia that is consistent and does not vary according to intercondylar roof angle. The cACL is consistently located between 43.2% and 45.0% of the anteroposterior length of the tibia. Intercondylar roof-based guidance may not predictably place a tibial tunnel in the native ACL footprint. Use of a generic ACL footprint to place a tibial tunnel during ACL reconstruction may be reliable in up to 95% of patients.

Download full-text


Available from: Heath B Henninger, Oct 07, 2015
30 Reads
  • [Show abstract] [Hide abstract]
    ABSTRACT: Objective: This study evaluated the ability of routine 1.5-T MRI scans to visualize the anterolateral ligament (ALL) and describe its path and anatomic relations with lateral knee structures. Materials and methods: Thirty-nine 1.5-T MRI scans of the knee were evaluated. The scans included an MRI knee protocol with T1-weighted sequences, T2-weighted sequences with fat saturation, and proton density (PD)-weighted fast spin-echo sequences. Two radiologists separately reviewed all MRI scans to evaluate interobserver reliability. The ALL was divided into three portions for analyses: femoral, meniscal, and tibial. The path of the ALL was evaluated with regard to known structural parameters previously studied in this region. Results: At least a portion of the ALL was visualized in 38 (97.8%) cases. The meniscal portion was most visualized (94.8%), followed by the femoral (89.7%) and the tibial (79.4%) portions. The three portions of the ALL were visualized in 28 (71.7%) patients. The ALL was characterized with greater clarity on the coronal plane and was visualized as a thin, linear structure. The T1-weighted sequences showed a statistically inferior ligament visibility frequency. With regard to the T2 and PD evaluations, although the visualization frequency in PD was higher for the three portions of the ligament, only the femoral portion showed significant values. Conclusion: The ALL can be visualized in routine 1.5-T MRI scans. Although some of the ligament could be depicted in nearly all of the scans (97.4%), it could only be observed in its entirety in about 71.7% of the tests.
    Skeletal Radiology 08/2014; 43(10). DOI:10.1007/s00256-014-1966-7 · 1.51 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Recent anatomic studies have confirmed the presence of a true ligament structure, the anterolateral ligament (ALL), in the anterolateral region of the knee. This structure is involved in the rotatory instability of the knee and might explain why some isolated reconstructions of the anterior cruciate ligament result in a residual pivot shift. Therefore, when considering the least invasive method for reconstruction of this structure, it is important to identify the corresponding bony landmarks on radiographic images.
    The American Journal of Sports Medicine 08/2014; 42(10). DOI:10.1177/0363546514543770 · 4.36 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Objective To evaluated the presence of the anterolateral ligament (ALL) of the knee in magnetic resonance imaging (MRI) examinations. Methods Thirty‐three MRI examinations on patients’ knees that were done because of indications unrelated to ligament instability or trauma were evaluated. T1‐weighted images in the sagittal plane and T2‐weighted images with fat saturation in the axial, sagittal and coronal planes were obtained. The images were evaluated by two radiologists with experience of musculoskeletal pathological conditions. In assessing ligament visibility, we divided the analysis into three portions of the ligament: from its origin in the femur to its point of bifurcation; from the bifurcation to the meniscal insertion; and from the bifurcation to the tibial insertion. The capacity to view the ligament in each of its portions and overall was taken to be a dichotomous categorical variable (yes or no). Results The ALL was viewed with signal characteristics similar to those of the other ligament structures of the knee, with T2 hyposignal with fat saturation. The main plane in which the ligament was viewed was the coronal plane. Some portion of the ligament was viewed clearly in 27 knees (81.8%). The meniscal portion was evident in 25 knees (75.7%), the femoral portion in 23 (69.6%) and the tibial portion in 13 (39.3%). The three portions were viewed together in 11 knees (33.3%). Conclusion The anterolateral ligament of the knee is best viewed in sequences in the coronal plane. The ligament was completely characterized in 33.3% of the cases. The meniscal portion was the part most easily identified and the tibial portion was the part least encountered.
    Revista Brasileira de Ortopedia 09/2014; 50(2). DOI:10.1016/j.rbo.2014.03.006
Show more