Objectives

The aim of this study was to investigate the biomechanical effect of the anterolateral ligament (ALL), anterior cruciate ligament (ACL), or both ALL and ACL on kinematics under dynamic loading conditions using dynamic simulation subject-specific knee models.

Objectives

CT-based three-column classification (TCC) has been widely used in the treatment of tibial plateau fractures (TPFs). In its updated version (updated three-column concept, uTCC), a fracture morphology-based injury mechanism was proposed for effective treatment guidance. In this study, the injury mechanism of TPFs is further explained, and its inter- and intraobserver reliability is evaluated to perfect the uTCC.

There have been differing descriptions of the anterolateral structures of the knee, and not all have been named or described clearly. The aim of this study was to provide a clear anatomical interpretation of these structures. We dissected 40 fresh-frozen cadaveric knees to view the relevant anatomy and identified a consistent structure in 33 knees (83%); we termed this the anterolateral ligament of the knee. This structure passes antero-distally from an attachment proximal and posterior to the lateral femoral epicondyle to the margin of the lateral tibial plateau, approximately midway between Gerdy’s tubercle and the head of the fibula. The ligament is superficial to the lateral (fibular) collateral ligament proximally, from which it is distinct, and separate from the capsule of the knee. In the eight knees in which it was measured, we observed that the ligament was isometric from 0° to 60° of flexion of the knee, then slackened when the knee flexed further to 90° and was lengthened by imposing tibial internal rotation.

Cite this article: Bone Joint J 2014;96-B:325–31.

Introduction. The Segond's fracture is described as a cortical avulsion of the lateral tibial plateau at the site of insertion of the middle third of the lateral capsular ligament. The Segond's fracture is usually associated with a tear of the Anterior Cruciate Ligament (ACL) and it is considered as an indirect radiological sign of complete rupture of the ACL. However there are no studies investigating the effect of a Segond's fracture on the kinematic of the knee especially on the rotatory instability and Pivot Shift (PS) phenomenon. The purpose of this study is to investigate the effect of a Segond's fracture on the kinematic of the knee with the use of navigation and the PS test. Methods. Ten whole fresh-frozen cadavers were used. A navigator (2.0 Orthopilot Navigation System, BBraun Aesculap, Tuttlingen, Germany) was used to measure maximum manual Anterior Tibial Translation (ATT) at 30°, 60° and 90° of flexion, maximum manual Internal Rotation (IR) and maximum manual External Rotation (ER) at 0°, 15°, 30°, 45° and 90° of flexion. All procedures were performed three times and the mean value taken as the final result in each case. Moreover a PS test was performed by the senior, most experienced, surgeon, and graded as mild (gliding), moderate (jerk) and severe (subluxation). Navigation measurements and PS tests were performed in each knee with ACL intact, after arthroscopic cutting of the entire ACL and after a Segond's fracure was produced by exposing the antero lateral compartment of the knee underneath the ileo-tibial tract. Statistical analysis was performed using ANOVA 1-way and MANOVA tests and value for statistical analysis was set at p<0.05. Results. Navigation procedure: Cutting the whole ACL resulted in a significant increase of ATT at 30° and 60° of flexion, with no significant effect on IR and ER. Producing the Segond's fracure resulted in a significant increase of ATT at 60° and 90° of flexion, in a significant increase of IR at 30°, 45° and 60° of flexion with no significant effect on ER. PS: The PS was clinically undetectable in all knees with ACL intact. After cutting the ACL it continued to be undetectable in two cases, mild positive in six cases and moderate in two. The addition of the Segond's fracture resulted in an increase of the PS in all cases with a moderate grade detected in three and severe in seven. Conclusions. Despite the limitations of this study, which include manual loads applied to the knee during navigation measurements and subjective evaluation of the PS, the results of this cadaver study indicate that the Segond's fracture has a significant effect on knee stability especially on rotational stability, which is functionally the most important in case of ACL tear. Therefore, in case of an acute ACL tear, when a Segond's fracture is radiologically detected and an ACL reconstruction is performed, an inspection of the lateral compartment with repair of capsule and fixation of the fracture could be advisable in order to better restore knee stability