Medial Knee Injury: Part 1, Static Function of the Individual Components of the Main Medial Knee Structures

Abstract

Interpretation of clinical knee motion testing following medial knee injuries will improve with the information in this study. Significant increases in external rotation at 30 degrees of knee flexion were found with all medial knee structures sectioned, which indicates that a positive dial test may be found not only for posterolateral knee injuries but also for medial knee injuries.

Surgical Technique: Development of an Anatomic Medial Knee Reconstruction

“…The posterior oblique ligament and the distal division of the superficial medial collateral ligament were also important primary internal rotation stabilizers. In addition, we found there was as much external rotation at 30°of knee flexion with the medial knee structures sectioned as had been reported with a posterolateral corner injury [4]. In addition, we found an increased amount of external rotation was present at 90°for an isolated medial knee injury.…”

“…Thus, we found important new knowledge about the individual biomechanical function and load sharing between these important medial knee structures. Importantly, we found the superficial medial collateral ligament was essentially comprised of two separate divisions, with the proximal division being more important to valgus stability and the distal division more important to providing external rotation stability to the knee [4,5,13].…”

“…Concurrent with this force measurement study, we also performed a static sectioning study of the posterior oblique ligament, proximal and distal divisions of the superficial medial collateral ligament, and meniscofemoral and meniscotibial divisions of the deep medial collateral ligament in 24 cadaveric knees [4]. The cadavers were divided into three separate groups with unique cutting sequences.…”

“…Thus, we established a collaborative project with the University of Oslo to develop an anatomic medial knee reconstruction technique to better restore the static function and overall stability to these patients and to allow immediate postoperative knee motion to decrease the risk of the postoperative stiffness issues commonly seen with medial knee surgeries [11]. This involved detailed quantitative anatomic studies [9], static biomechanical sectioning studies [5], assessment of forces in the native medial knee structures to applied loads [4,15], and the development and biomechanical validation of an anatomic medial knee reconstruction technique [3].…”

“…These three structures work together to provide both primary and secondary static stabilization roles for valgus, external rotation, and internal rotation stability to the knee. As part of the development and optimization of an anatomic medial knee reconstruction technique, we performed biomechanical studies that included static sectioning studies of the posterior oblique ligament, proximal and distal divisions of the superficial medial collateral ligament, and meniscofemoral and meniscotibial divisions of the deep medial collateral ligament [4] and measurement of the forces present on the proximal and distal divisions of the superficial medial collateral ligament and the posterior oblique ligament to applied loads in both the intact [5] and sectioned states [14]. The anatomic information was utilized to develop the locations of the medial knee reconstruction grafts and to place them into anatomic locations, while the biomechanical studies provided important information about the static stability and loadsharing functions of each individual component of the medial knee structures.…”