Impact of Partial and complete rupture of anterior cruciate ligament on medial meniscus: A cadavaric study

Abstract

Background: The clinical relationship between medial meniscus tear and anterior cruciate ligament (ACL) rupture has been well documented. However, the mechanism of this clinical phenomenon is not exactly explained. Our aim is to investigate the biomechanical impact of partial and complete ACL rupture on different parts of medial meniscus.

Materials and methods: TWELVE FRESH HUMAN CADAVERIC KNEE SPECIMENS WERE DIVIDED INTO FOUR GROUPS: ACL intact (ACL-I), anteromedial bundle transection (AMB-T), posterolateral bundle transection (PLB-T), and ACL complete transection (ACL-T) group. Strain on the anterior horn, body part, and posterior horn of medial meniscus were measured under 200 N axial compressive tibial load at 0°, 30°, 60°, and 90° of knee flexion, respectively.

Results: Compared with the control group (ACL-I), the ACL-T group had a higher strain on whole medial meniscus at 0°, 60°, and 90° of flexion. But at 30°, it had a higher strain on posterior horn of meniscus only. As to PLB-T group, strain on whole meniscus increased at full extension, while strain increased on posterior horn at 30° and on body of meniscus at 60°. However, AMB-T only brought about higher strain at 60° of flexion on body and posterior horn of meniscus.

Conclusions: Similar to complete rupture, partial rupture of ACL can also trigger strain concentration on medial meniscus, especially posterior horn, which may be a more critical reason for meniscus injury associated with chronic ACL deficiency.

Keywords: Anterior cruciate ligament; anterior cruciate ligament rupture; biomechanics; medial meniscal tear.

Figure 1

(a) Biomechanical test instrumentation setup and (b) transducer strain gauges fixed in different parts of medial meniscus

Figure 2

Strain value on medial meniscus at 0° of flexion. Both complete rupture and PLB rupture cause higher strain than intact group in all parts of medial meniscus. No increase has been noted in AMB-T group yet (με, microstrain; *, P < 0.05 compared to ACL-I; Δ, P < 0.05 compared to AMBT; ◊, P < 0.05 compared to PLB-T)

Figure 3

Strain value on medial meniscus at 30° of flexion. ACL-T and PLB-T groups had a higher strain compared to the ACL-I in posterior horn only (με, microstrain; *, P < 0.05 compared to ACL-I; Δ, P < 0.05 compared to AMBT; ◊, P < 0.05 compared to PLB-T)

Figure 4

Strain value on medial meniscus at 60° of flexion. Compared to the control, strain value increased significantly on whole meniscus in ACL-T group, on body part in PLB-T group, and on both body and posterior horn in AMB-T group (με, microstrain; *, P < 0.05 compared to ACL-I; ◊, P < 0.05 compared to AMB-T; Δ, P < 0.05 compared to PLB-T)

Figure 5

Strain value on medial meniscus at 90° of flexion. Significant higher strain value on whole meniscus was found in ACL-T group compared with the other three groups. But no significant difference was noted among ACL-I, AMB-T, and PLB-T groups (με, microstrain; *, P < 0.05 compared to ACL-I; Δ, P < 0.05 compared to AMB-T; ◊, P < 0.05 compared to PLB-T)