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, MDUK Orthopaedic Surgery and Sports Medicine

Senior Author: Mary Lloyd Ireland, MDUK Orthopaedic Surgery and Sports Medicine

Orthopaedic Surgery and Sports Medicine

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 assessments of tunnel placement on plain films


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

RaterReaming Method

judgedcorrectly

95% CI P Training Level

1 30/40 (75.0%) 61.6%, 88.4% 0.0016 Attending2 28/40 (70.0%) 55.8%, 84.2% 0.0114 Attending3 25/40 (62.5%) 47.5%, 77.5% 0.1138 Fellow4 29/40 (72.5%) 58.7%, 86.3% 0.0044 Resident5 21/40 (52.5%) 37.0%, 68.0% 0.7518 Fellow6 26/40 (65.0%) 50.2%, 79.8% 0.0578 Fellow7 20/40 (50.0%) 34.5%, 65.5% 1.0000 Resident8 34/40 (85.0%) 73.9%, 96.1% 0.0000 Attending9 24/40 (60.0%) 44.8%, 75.2% 0.2059 Fellow10 21/40 (52.5%) 37.0%, 68.0% 0.7518 Attending11 22/40 (55.0%) 39.6%, 70.4% 0.5271 Attending12 22/40 (55.0%) 39.6%, 70.4% 0.5271 Fellow13 25/40 (62.5%) 47.5%, 77.5% 0.1138 Resident14 33/40 (82.5%) 70.7%, 94.3% 0.0000 Fellow15 18/40 (45.0%) 29.6%, 60.4% 0.5271 Resident


Results – Assessment of Reaming Method

Training Level

Percentof TotalFrequency

Average Percentjudged Correct

Standard Deviation

Attending 5 67.50 13.69Fellow 6 62.92 10.66Resident 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 Attending2 14/20 (70.0%) 14/20 (70.0%) 0.40000 0.1160, 0.6840 0.01141 Attending3 11/20 (55.0%) 14/20 (70.0%) 0.25000 -0.0467, 0.5467 0.10977 Fellow4 14/20 (70.0%) 15/20 (75.0%) 0.45000 0.1736, 0.7264 0.00438 Resident5 4/20 (20.0%) 17/20 (85.0%) 0.05000 -0.1852, 0.2852 0.67732 Fellow6 11/20 (55.0%) 15/20 (75.0%) 0.30000 0.0103, 0.5897 0.05281 Fellow7 17/19 (89.5%) 3/20 (15.0%) 0.04387 -0.1610, 0.2488 0.67617 Resident8 17/20 (85.0%) 17/20 (85.0%) 0.70000 0.4787, 0.9213 0.00001 Attending9 12/20 (60.0%) 12/20 (60.0%) 0.20000 -0.1036, 0.5036 0.20590 Fellow10 11/18 (61.1%) 10/17 (58.8%) 0.19935 -0.1254, 0.5241 0.23826 Attending11 9/19 (47.4%) 13/20 (65.0%) 0.12417 -0.1838, 0.4322 0.43251 Attending12 4/20 (20.0%) 18/20 (90.0%) 0.10000 -0.1202, 0.3202 0.37583 Fellow13 8/20 (40.0%) 17/20 (85.0%) 0.25000 -0.0180, 0.5180 0.07664 Resident14 14/20 (70.0%) 19/20 (95.0%) 0.65000 0.4220, 0.8780 0.00002 Fellow15 9/19 (47.4%) 9/20 (45.0%) -0.07622 -0.3888, 0.2363 0.63365 Resident



Slight Fair Moderate Substantial Perfect0

1

2

3

4

5

6

7Kappa


Results - Assessment of Reaming Method

RaterReaming Method

judgedcorrectly

95% CI P Training Level

1 30/40 (75.0%) 61.6%, 88.4% 0.0016 Attending2 28/40 (70.0%) 55.8%, 84.2% 0.0114 Attending3 25/40 (62.5%) 47.5%, 77.5% 0.1138 Fellow4 29/40 (72.5%) 58.7%, 86.3% 0.0044 Resident5 21/40 (52.5%) 37.0%, 68.0% 0.7518 Fellow6 26/40 (65.0%) 50.2%, 79.8% 0.0578 Fellow7 20/40 (50.0%) 34.5%, 65.5% 1.0000 Resident8 34/40 (85.0%) 73.9%, 96.1% 0.0000 Attending9 24/40 (60.0%) 44.8%, 75.2% 0.2059 Fellow10 21/40 (52.5%) 37.0%, 68.0% 0.7518 Attending11 22/40 (55.0%) 39.6%, 70.4% 0.5271 Attending12 22/40 (55.0%) 39.6%, 70.4% 0.5271 Fellow13 25/40 (62.5%) 47.5%, 77.5% 0.1138 Resident14 33/40 (82.5%) 70.7%, 94.3% 0.0000 Fellow15 18/40 (45.0%) 29.6%, 60.4% 0.5271 Resident



Better Worse0

2

4

6

8

10

12

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 assessments of tunnel placement on plain films

• Is one assumed reaming method associated with more favorable assessments of tunnel placement on plain films

• 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

Health & Medicine

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