Correlation of graft position, knee laxity and clinical outcome: comparison with native anterior cruciate ligament using magnetic resonance imaging study.

OBJECTIVE: To compare the sagittal obliquity of anterior cruciate ligament graft with normal native anterior cruciate ligament in contralateral knee, to determine the effect of sagittal obliquity and axial femoral tunnel graft placement on stability and functional knee score (Lysholm), and to measure size of graft after complete ligamentization. MATERIAL AND METHOD: Seventy single tunnel quadruple hamstring anterior cruciate reconstructed knee in unilateral ACL injury patients were evaluated at 18 months after surgery. At follow up, patients were evaluated including measurement of knee laxity by using side to side different on KT 1000 arthromeres and clinical outcome by completed Lysholm functional knee questionnaires. Sagittal T1 weighted magnetic resonance image with complete dimension of graft from origin to insertion on each side of knee were depicted to compare the obliquity by measuring the intersection angle of the graft line with the tibial plateau plane. The axial femoral tunnel was determined by angle between anteroposterior axis of distal femur and long axis of femoral tunnel. The diameter of graft was also measured. RESULTS: Graft obliquity was average 58 degrees with range between 41 degrees and 69 degrees. In contralateral native ACL obliquity was average 50 degrees with range between 33 degrees and 63 degrees. The difference between the two groups was statistically significant (p < 0.0001). Average axial femoral tunnel was 36 degrees with range between 10 degrees and 56 degrees. Knee laxity (KT-1 000 arthrometer; average pre-op = 6, post-op = 3) and Lysholm knee scores (average score; pre-op 55, post-op score 89) were significantly improved after surgery (p < 0.01). There was no correlation between degree of sagittal obliquity and axial femoral tunnel with knee laxity and functional score in this series. Graft size was increased in average 8% after 18 months post-operatively. CONCLUSION: ACL grafts in patients with appropriate tibial tunnel placement were more vertical than native ACL. There was no significant effect of degree of sagittal obliquity and axial femoral tunnel to antero-postero stability and knee score. ACL graft size was increased in diameter during post-operative period. Graft-notch distance should be considered during operation.

Pattern of angular change of the anterior cruciate ligament across the range of knee flexion and the related anatomical dimensions.

Improper femoral and/or tibial tunnel placements are major causes of failure in anterior cruciate ligament (ACL) reconstruction. The 52 embalmed cadaveric knees were measured the dimensions of the surgical related structures using vernier caliper and goniometer. The intercondylar notch width was 17.4 +/- 2.3 mm and slope of the roof was 31.3 +/- 3.4 degrees. The average length of ACL was 21.6 +/- 2.5 mm. The relation of tibial attachment was 47.98% of the width of the lateral tibial plateau and 49.8% anteriorly, when it was measured through ACL attachment. Angle of ACL in sagittal plane was decreased during knee flexion. On the contrary, angle of ACL in coronal plane was increased during knee flexion. According to this study), The expected femoral tunnel at 10.00 am to 10.30 am could be performed by arthroscopic transtibial technique using the 48% of tibial width anteriorly for intraartricular tibial-tunnel drill-guide placement and aiming for sagittal and coronal plane of 52.0+/-4.6 / 20.9+/-3.9, 46.2+/-5.1 / 26.8+/-4.6 degrees, and 41.6+/-5.1 / 32.0+/-4.3 degrees while knee flexion degree were as 60, 90, and 120 degrees, respectively.