2017 ISAKOS Biennial Congress ePoster #1129

 

Is There A Correlation Between The Orientation Of The Femoral Tunnel And Clinical Outcome? A Clinical And Radiological Follow-Up Of Patients 16 Years After ACL Reconstruction

David S. Sundemo, MD, Stenungsund, Västra Götaland SWEDEN
Julia Mårtensson, Medical Student, Gothenburg, Västra Götaland SWEDEN
Jon Karlsson, Prof., Mölndal SWEDEN
Jüri T. Kartus, MD, PhD, Trollhättan SWEDEN
Ninni Sernert, PhD, RPT, Trollhättan SWEDEN
Kristian Samuelsson, MD, PhD, MSc, Prof., Mölndal SWEDEN

Sahlgrenska Academy, University of Gothenburg, Gothenburg, Västra Götaland, SWEDEN

FDA Status Not Applicable

Summary

A clinical study investigating the correlation between the orientation of the femoral tunnel and clinical outcome using radiography, laxity measurements and subjective outcome.

Abstract

Background

Correct positions and drilling angles of the tunnels in anterior cruciate ligament (ACL) reconstruction is paramount. In recent years tunnels have developed from predominantly isometric positions to a more anatomical placement. A crucial difference between the two techniques is the angle and position of the femoral tunnel.

Hypothesis

Tunnels with orientation more similar to the native ACL anatomy will render superior clinical and subjective results at follow-up.

Purpose

To determine the influence of the orientation of the femoral tunnel on clinical and subjective outcomes in patients subjected to ACL reconstruction.

Study design: Retrospective cohort study

Methods

The study was based on two cohorts comprising 193 patients who were subjected to unilateral non-anatomical ACL reconstruction using either hamstring-tendon or patellar-tendon autograft. Reconstructions were performed between September 1995 and January 2000. Clinical assessments involved the Lachman test, the pivot-shift test, the KT-1000 and the one-leg hop test. Subjective outcome was evaluated with the IKDC 2000 form. Radiographs with postero-anterior and lateral projections were obtained in order to determine the angle of the femoral tunnel in the coronal plane and the position in the coronal and sagittal planes. The position in the coronal plane is calculated as a percentage of the distance between the femoral condyles, measuring from lateral to medial. The position of the tunnel in the sagittal plane was determined using Bernard’s quadrant method and is expressed as a percentage from the posterior border to the anterior border of the femoral condyle. Radiographic signs of osteoarthritis were determined using the Kellgren-Lawrence score.

Results

A total of 147 (76%) patients were examined at a mean follow-up time of 196 (±15) months and 119 (62%) had radiographs eligible for the present study. Twenty-nine patients were reconstructed using a medial portal and 71 patients were reconstructed using single-incision transtibial technique. The femoral tunnel angle and the position of the tunnels in the coronal and sagittal planes were at a mean of 9.6° (±9.4), 42.9 % (±3.5) and 45.7 % (±7.7) respectively. Intra- and interrater reliability of all radiographic measurements was determined using ICC and were considered good to excellent (ICC 0.58-0.97). Using multivariate logistic regression analysis femoral tunnel angle was not considered a predictor for outcome of the pivot shift test (p=0.11), the IKDC 2000 (p=0.14), osteoarthritis (p=0.61) or other tests measuring knee laxity, however it was significantly correlated to the performance of the one-leg hop test (p=0.036). The position of the femoral tunnel in the frontal and sagittal planes showed no significant correlation with investigated outcome variables. Further, analysis showed that tunnels drilled trough a medial portal were significantly closer to the posterior condyle (43%, p=0.027) than tunnels drilled using the transtibial method (47%).

Conclusion

At long-term follow-up, the femoral tunnel angle was a significant predictor for knee function evaluated using the one-leg hop test. Moreover, the medial-portal technique resulted in tunnels with a slightly more anatomic orientation.