Chapter 35

### INTRODUCTION

The thing is I have no ACL. So unless I get surgery, there’s nothing really magical that I can do that’s going to make it better. I just can get my leg stronger, my muscle stronger and try and support it a little more. But that has a small impact. My knee is loose and it’s not stable and that’s the way it’s going to be from here on out.

Lindsey Vonn, Olympic gold medal skier

For many athletes, the most fearful injury is that of the acute knee—it can spell the end of a professional career. Even for recreational athletes, an acute knee injury may be the catalyst for early arthritis. Acute knee injuries are common in all sports that require twisting movements and sudden changes of direction, especially the various types of football, basketball, netball and alpine skiing.

### FUNCTIONAL ANATOMY

The knee joint can be divided into two parts: the tibiofemoral joint with its associated collateral ligaments, cruciate ligaments and menisci; and the patellofemoral joint, which obtains stability from the medial and lateral retinaculum and the large extensor mechanism tendons (quadriceps and patella tendons) which encase the patella distally before its insertion on the proximal tibia. Most commonly we refer to the tibiofemoral joint as the knee joint. The anatomy of the knee joint is shown in Figure 35.1.

###### Figure 35.1

Anatomy of the knee joint (a) The knee joint (anterior view) (b) The knee joint (posterior view)

The two cruciate (‘cross’) ligaments, anterior and posterior, are often referred to as the ‘crucial’ ligaments, because of their importance in providing knee stability. They are named anterior and posterior in relation to their attachment to the tibia. The anterior cruciate ligament (ACL) prevents forward movement of the tibia in relation to the femur and controls rotational movement of the tibia under the femur. The posterior cruciate ligament (PCL) prevents the femur from sliding forwards off the tibial plateau.

The ACL is essential for control in pivoting movements. If the ACL is not functional, the tibia may rotate under the femur in an anterior–lateral direction such as when an athlete attempts to land from a jump, pivot or stop suddenly. The PCL stabilises the body (femur) above the tibia. In its absence, the femur wants to shift forwards on the tibia. This shift forwards is accentuated when one tries to run down an incline plane or down stairs.

The two collateral ligaments, the medial and lateral, provide medial and lateral stability to the knee joint. The superficial medial (or tibial) collateral ligament (MCL) is extracapsular. The deep layer, or coronal ligaments, attaches to the joint margins and has an attachment from its deep layer to the medial meniscus. The MCL prevents excessive medial opening (i.e. valgus) ...

Sign in to your MyAccess profile while you are actively authenticated on this site via your institution (you will be able to verify this by looking at the top right corner of the screen - if you see your institution's name, you are authenticated). Once logged in to your MyAccess profile, you will be able to access your institution's subscription for 90 days from any location. You must be logged in while authenticated at least once every 90 days to maintain this remote access.

Ok

## Subscription Options

### Clinical Sports Medicine Collection Full Site: One-Year Subscription

Connect to one of the most renowned references in sports medicine and explore all aspects of diagnosis and management of sports-related injuries and physical activity. Subscription includes access to a library of sports medicine videos.