Assessment of Femoral Tunnel Placement in ACL Reconstruction

Tunnel Placement in ACL Reconstruction:
Can Plain Radiographs Accurately Assess
Tunnel Position and Reaming Method
Jeremy M. Burnham, MD
UK Orthopaedic Surgery and Sports Medicine
Senior Author: Mary Lloyd Ireland, MD
UK Orthopaedic Surgery and Sports Medicine

OrthopaedicSurgeryandSportsMedicine
Background:
• ACL injury 1 in 3000
• More than 100,000 reconstructions each year
• Failure rate as high as 10-15%
• This rate is holding fairly constant despite improvements in the
understanding of the ACL anatomy and its biomechanics

Background:
• Continued focus on more closely restoring normal anatomy during ACL
reconstruction
• Tunnel placement is an important factor in the success of a reconstructed ACL
• Reaming methods: anteromedial (AM) vs. transtibial (TT)
• Many times X-rays are shown and failure of the graft is blamed on the non-anatomic
position of the tunnels and/or the reaming method

Background:
• Ideally, estimating tunnel position would be simple to perform using common clinical
imaging
• Currently, most accurate method for assessing tunnel position is 3D CT
• Plain radiographs have been suggested as a quicker and less expensive solution
• Limited research about our ability to determine reaming method by assessing plain
films

Literature:
• Can we assess tunnel position reliably with radiographs?

Pinczewski, L. A., Salmon, L. J., Jackson, W. F. M., von Bormann, R. P. B., Haslam, P. G., & Tashiro, S. (2008).
Radiological landmarks for placement of the tunnels in single-bundle reconstruction of the anterior cruciate
ligament. Journal of Bone and Joint Surgery-British Volume, 90B(2), 172-179

Warme, B. A., et al. (2012). Reliability of Early Postoperative Radiographic Assessment of Tunnel Placement After
Anterior Cruciate Ligament Reconstruction. Arthroscopy-the Journal of Arthroscopic and Related Surgery, 28(7)

Cole, J., Brand, J. C., Jr., Caborn, D. N., & Johnson, D. L. (2000). Radiographic analysis of femoral tunnel position in
anterior cruciate ligament reconstruction. Am J Knee Surg, 13(4), 218-222.

Illingworth, KD, et. Al., Fu, “A Simple Evaluation of Anterior Cruciate Ligament Femoral Tunnel Position: The
Inclination Angle and Femoral Tunnel Angle,” Am. J. Sports Med 39:12 (December, 2011), pp. 2611-2618.

Literature:
• Radiographic assessment of tunnels
• Reaming methods

Harner, C. D., Honkamp, N. J., & Ranawat, A. S. (2008). Anteromedial portal technique for creating the anterior
cruciate ligament femoral tunnel. Arthroscopy, 24(1), 113-115.

Ahn, J. H., et al (2013). 3-D reconstruction computed tomography evaluation of tunnel location during single-
bundle anterior cruciate ligament reconstruction: a comparison of TT and 2-incision TTI techniques. Clin
Orthop Surg, 5(1), 26-35.

Piasecki, D. P., Bach, B. R., Orias, A. A. E., & Verma, N. N. (2011). Anterior Cruciate Ligament Reconstruction Can
Anatomic Femoral Placement Be Achieved With a Transtibial Technique? AJSM, 39(6), 1306-1315

Research Questions:
• Can the reaming method be predicted by postop x-rays
• Is one actual reaming method associated with more favorable
assessments of tunnel placement on plain films
• Is one assumed reaming method associated with more favorable

Methods
• Operative reports of ACL reconstructions performed by the senior author
from a four-year period (2006 – 2010) were reviewed
• 119 transtibial (TT), 101 anteromedial (AM) reaming
• 40 of these were randomly chosen
• Randomized into 2 groups of 20 each:
AM or TT reaming

Surgical Technique
• Usual degree of knee flexion 120°
• Not measured with goniometer
• No intraoperative radiographs

Postop X-rays

Methods
• 15 reviewers
• 5 attendings, 6 fellows, 4 senior residents
• Research survey was sent as an excel file
• Radiographs were embedded in the file
• Reviewers were blinded

Worksheet Sample

Results - Assessment of Reaming Method
Rater
Reaming Method judged
correctly
95% CI P Training Level
1 30/40 (75.0%) 61.6%, 88.4% 0.0016 Attending
2 28/40 (70.0%) 55.8%, 84.2% 0.0114 Attending
3 25/40 (62.5%) 47.5%, 77.5% 0.1138 Fellow
4 29/40 (72.5%) 58.7%, 86.3% 0.0044 Resident
5 21/40 (52.5%) 37.0%, 68.0% 0.7518 Fellow
6 26/40 (65.0%) 50.2%, 79.8% 0.0578 Fellow
7 20/40 (50.0%) 34.5%, 65.5% 1.0000 Resident
8 34/40 (85.0%) 73.9%, 96.1% 0.0000 Attending
9 24/40 (60.0%) 44.8%, 75.2% 0.2059 Fellow
10 21/40 (52.5%) 37.0%, 68.0% 0.7518 Attending
11 22/40 (55.0%) 39.6%, 70.4% 0.5271 Attending
12 22/40 (55.0%) 39.6%, 70.4% 0.5271 Fellow
13 25/40 (62.5%) 47.5%, 77.5% 0.1138 Resident
14 33/40 (82.5%) 70.7%, 94.3% 0.0000 Fellow
15 18/40 (45.0%) 29.6%, 60.4% 0.5271 Resident

Results – Assessment of Reaming Method
Training Level Percent
of Total
Frequency
Average
Percent
judged Correct
Standard
Deviation
Attending 5 67.50 13.69
Fellow 6 62.92 10.66
Resident 4 57.50 12.42
• Overall, the reaming method was correctly identified 64% of the time
• 57% for AM and 71% for TT
• Range 45-85%

Rater
Correctly Judged
AM
Correctly
Judged TT
Kappa 95% CI P-value Training
1 12/20 (60.0%) 18/20 (90.0%) 0.50000 0.2440, 0.7560 0.00092 Attending
2 14/20 (70.0%) 14/20 (70.0%) 0.40000 0.1160, 0.6840 0.01141 Attending
3 11/20 (55.0%) 14/20 (70.0%) 0.25000 -0.0467, 0.5467 0.10977 Fellow
4 14/20 (70.0%) 15/20 (75.0%) 0.45000 0.1736, 0.7264 0.00438 Resident
5 4/20 (20.0%) 17/20 (85.0%) 0.05000 -0.1852, 0.2852 0.67732 Fellow
6 11/20 (55.0%) 15/20 (75.0%) 0.30000 0.0103, 0.5897 0.05281 Fellow
7 17/19 (89.5%) 3/20 (15.0%) 0.04387 -0.1610, 0.2488 0.67617 Resident
8 17/20 (85.0%) 17/20 (85.0%) 0.70000 0.4787, 0.9213 0.00001 Attending
9 12/20 (60.0%) 12/20 (60.0%) 0.20000 -0.1036, 0.5036 0.20590 Fellow
10 11/18 (61.1%) 10/17 (58.8%) 0.19935 -0.1254, 0.5241 0.23826 Attending
11 9/19 (47.4%) 13/20 (65.0%) 0.12417 -0.1838, 0.4322 0.43251 Attending
12 4/20 (20.0%) 18/20 (90.0%) 0.10000 -0.1202, 0.3202 0.37583 Fellow
13 8/20 (40.0%) 17/20 (85.0%) 0.25000 -0.0180, 0.5180 0.07664 Resident
14 14/20 (70.0%) 19/20 (95.0%) 0.65000 0.4220, 0.8780 0.00002 Fellow
15 9/19 (47.4%) 9/20 (45.0%) -0.07622 -0.3888, 0.2363 0.63365 Resident

0
1
2
3
4
5
6
7
Slight Fair Moderate Substantial Perfect
Kappa

0
2
4
6
8
10
12
Better Worse
33%
66%
Compared to Chance

Conclusions
• Reaming method was properly identified 64% of the time
• Precision was suboptimal
• Only 33% of the reviewers were able to accurately identify the reaming
method more often than would be expected by pure chance

Pending Analysis
• Is one actual reaming method associated with more favorable
• Is one assumed reaming method associated with more favorable
• Clockface analysis

Future Questions
• How does postoperative x-ray assessment correlate with tunnel
position on 3D CT scan

Assessment of Femoral Tunnel Placement in ACL Reconstruction

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