Knee anatomy and injuries

The knee is made up of 3 bones, cartilage, ligaments & surrounding muscles.

The knee is hinge joint made up femur (above) and the tibia (below). The patella (knee cap) sits above this joint. The patella protects the font of the knee joint and also provides attachment of the quadriceps muscle to straighten/ extend the knee

Inside the hinge joint we have the meniscus which are 2 “C- shaped” cartilaginous structures. The role of the meniscus is to disperse the body weight and to deepen the groove where the femur fits on top of the tibia. This helps provides stability and reduce friction within the knee.

Inside the knee we have the anterior (front) cruciate ligament [ACL] and posterior (back) cruciate ligament [PCL]. The word cruciate comes from the Latin word cruci (as in crucifix) which means “cross” because these ligaments cross over each other inside the knee. The ACL provides stability to the front of the knee and prevents excessive forward/anterior movement of the tibia. The PCL provides stability at the back of the knee and prevents excessive back/posterior movement of the tibia

The other 2 ligaments are situated on the sides of the knee, medial collateral ligament[MCL] & lateral collateral ligament [LCL]. These ligaments provide stability on side to side movements of the knee.

Muscles which are crucial in the correct functioning of the knee are the quadriceps & hamstring muscles. Quadriceps straighten the knee and hamstrings bend the knee.

Types of knee injuries seen:

Meniscus injuries:

An injury to the meniscus can happen when too much pressure is put on the knee and then the knee is twisted e.g. being tackled in a football or basketball match while the knee is pivoting.

Meniscus injuries can also happen in day to life e.g. getting up from your haunches while pivoting/ twisting at the wrong angle or slipping on a wet floor while walking which causes a twist/pivot to the knee.

Ligament injuries:

Anterior cruciate ligament (ACL): An injury occurs when the ligament is overstretched causing a tear to the ligament. A tear may be partial or complete. A tear can occur when the lower bone (tibia) receives a sudden force to push it forward in in relation to the upper bone (femur). This can happen when getting hit hard on the side of the leg e.g. during a tackle, or when suddenly changing direction on the leg while running e.g. sidestep or when landing from a jump and turning e.g. basketball/ netball. In severe ACL injuries, there could also be damage to the MCL & medial meniscus.

Posterior cruciate ligament (PCL): this type of injury is less common but occurs when during sport e.g. football& rugby there impact from the front on the tibia (lower bone) in relation the femur (upper bone). This can happen during a front impact car accident where the dashboard of the car can push the tibia backwards.

Medial & lateral collateral ligament injuries (MCL & LCL): As these ligaments sit on the outside of the knee, sideways force would be needed to strain these ligaments. Impact from the inner part of the knee could cause the knee stretch open on the outside, therefore straining the LCL. Impact from the outside of the knee could cause the knee to stretch on the inside, therefore straining the MCL. The deeper fibres

of the MCL are very closely linked with the medial meniscus so strain to the MCL will often strain the medial meniscus.

Patellofemoral pain: Pain around the patella (kneecap) can occur when there is imbalance in the muscle tension around the kneecap. This imbalance can lead to friction of the knee cap in the groove of the femur. Tightness onto the outer border of the knee can lead to a condition like iliotibial band syndrome (ITB) Read more about the Iliotibial Band Syndrome (ITB)…

Other causes of pain around the knee cap can be:

• Tendinopathy (a type of inflammation) of the patellar tendon under the knee cap caused by excessive jumping, decelerating
• Fat pad impingement under the knee cap from excessive hyperextension of the knee causing pain under the knee cap

Assessment & treatment:

Assessment consists of testing degree of injury of the ligaments or meniscus or muscles/ tendons. The severity of injury needs to be determined to work out whether the injury can be treated conservatively or if the patient needs to be referred for surgical consultation. During the assessment, the physio will bend and twist the knee in various positions to test the integrity of the ligaments. The muscles/ tendons and superficial ligaments will be felt (palpated) to try determine where the injury is.

Physio treatment/ rehabilitation:

Treatment/ rehabilitation can start once the injury has been diagnosed and the physio has determined what structure is injured. Alternatively, if a patient has had surgery to e.g. the ACL then the physio will start the relevant rehabilitation program.

Physio treatment will consist of: soft tissue release, knee joint mobilisations, strapping, progressive knee and lower limb strengthening exercises.

If you have any queries, please don’t hesitate to call 011 064 5670 or enquire online.