J Knee Surg
DOI: 10.1055/s-0038-1626736
Original Article
Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Variability in the Clock Face View Description of Femoral Tunnel Placement in ACL Reconstruction Using MRI-Based Bony Models

Matthew J. Kraeutler
Department of Orthopaedics, Seton Hall-Hackensack Meridian School of Medicine, South Orange, New Jersey
,
Kushal V. Patel
Baylor Scott and White Orthopaedics at Garland, Garland, Texas
,
Ali Hosseini
Bioengineering Laboratory, Department of Orthopaedic Surgery, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
,
Guoan Li
Bioengineering Laboratory, Department of Orthopaedic Surgery, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts
,
Thomas J. Gill
Boston Sports Medicine and Research Institute, Dedham, Massachusetts
,
Jonathan T. Bravman
Department of Orthopedics, University of Colorado School of Medicine, Aurora, Colorado
› Author Affiliations
Further Information

Publication History

25 May 2017

23 December 2017

Publication Date:
08 February 2018 (eFirst)

Abstract

Though controversial, the “clock face view” of the intercondylar notch remains a way some surgeons communicate regarding placement of the femoral tunnel in anterior cruciate ligament reconstruction. The purpose of this study was to quantify the differences in angle measurement between several previous descriptions of the clock face view by using a new reference standard. Three-Tesla magnetic resonance imaging (MRI) was used to scan 10 human knees to create three-dimensional MRI-based bony models which were used for measurements. A standardized clock face view was developed with the knee flexed to 90° using the junction of the cartilage and cortex of the medial and lateral surfaces of medial and lateral femoral condyles as the 3 o'clock and 9 o'clock, respectively, with the 12 o'clock established as the midpoint of the roof of the intercondylar notch. With the knee viewed at 90° of flexion, an “idealized” femoral tunnel position was plotted on the medial wall of the lateral femoral condyle at 30° (corresponding to the 10 o'clock or 2 o'clock position). The clock faces as described by Edwards et al, Heming et al, and Mochizuki et al were each then overlaid on this same model and the difference in measurement calculated. The average angles measured when the previously described clock faces were projected onto the idealized clock face view comparing a mark made at 30° were 47.7°, 7.2°, and 49.8° for the methods described by Edwards et al, Heming et al, and Mochizuki et al, respectively (all p < 0.001). Significant variation exists between angle measurements in simulated femoral tunnel placement based on the varying descriptions of the intercondylar clock face.