Posterior cruciate ligament and coupled posterolateral instability of the knee - A cadaver study

Wang, CJ Chen, CYC Chen, LM Yeh, WL

Cj. Wang et al., Posterior cruciate ligament and coupled posterolateral instability of the knee - A cadaver study, ARCH ORTHOP, 120(9), 2000, pp. 525-528

12

INGLESE

Article

Ortopedics, Rehabilitation & Sport Medicine

ARCHIVES OF ORTHOPAEDIC AND TRAUMA SURGERY

0936-8051 → ACNP

120

9

2000

525 - 528

ISI

0936-8051(200008)120:9<525:PCLACP>2.0.ZU;2-4

We wanted to investigate the role of the posterior cruciate ligament (PCL) in the knee's posterolateral stability and the magnitude of the coupled pos terolateral instability with the knee examined at 90 degrees of flexion. Th e coupled posterolateral instability of the knee was studied by selective l igament cutting in cadaver knees set at 90 degrees. The coupled posterolate ral displacement after cutting the PCL was 173% of the intact knee. With an intact PCL, the coupled posterolateral displacement after cutting the popl iteus tendon and lateral collateral ligament with the knee at 90 degrees of flexion was 299% of the intact knee. When the PCL was cut together with th e popliteus tendon and lateral collateral ligament, the coupled posterolate ral displacement was 367%. The PCL plays an important role in the posterola teral stability of the knee, and its injury may cause mild (< 5 mm) to mode rate (5-10 mm) posterolateral instability. Thus, in a knee with posterolate ral instability, injury of the PCL must be considered. With an intact PCL, the posterolateral instability was very recognizable with the knee at 90 de grees of flexion, and injury to the PCL further increased the posterolatera l instability and caused posterior translation of the knee. Therefore, exam ination for posterolateral instability of the knee should also be performed with the knee at 90 degrees of flexion, which is much easier to perform in a clinical setting. A positive posterior translation rather than posterola teral instability at different knee positions differentiates knees with com bined PCL and posterolateral instability from knees with isolated posterola teral instability.