The knee is made up from muscles, bones and ligaments and is also the biggest synovial joint in the body, it is made up from the distal femur and proximal tibia which is called the tibiofemoral joint, the knee is a hinge joint allowing flexion + extension with slight medial + lateral rotation.

Main Bone Anatomy -:

Patella

Tibia/fibula

Femur

Lateral + Medial condyle

Head of fibula

Tibial Tuberosity

Pes anserius atatatchment

Soleal line

Medial and lateral malleoi

Tibial plateau

Adductor tubercle

Knee Cap

The patella is also known as the knee cap, it is a circular/triangular bone that articulates with the femur, it covers and protects the anterior articular surface of the knee joint. It is also the most common and largest sesamoid bone in the body, attaching to the rectus femoris which in contracting causing extension at the knee. The vastus intermediallias attaches to the posterior part of the pattella, the vastus lateralis attaches to the lateral border of the patella and the vastus mediallis are attached to the medial border of the patella, therefore the patella’s main purpose is to aid in extension.

Muscles that act upon the Knee or have an indirect effect upon the knee:

MAJOR MUSCLE ORIGIN INSERTION ACTION
Rectus femoris AIIS Tibial Tuberosity extends kneeflexes hip 
Vastus lateralis greater trochanterlateral lip of linea asperalateral intermuscular septum

 

 

common quadriceps tendon into patellatibial tuberosity via patellar ligament  extends kneecan abnormally displace patella 
Vastus intermedius anterior lateral aspect of the femoral shaft common quadriceps tendon into patellatibial tuberosity via patellar ligament  extends knee
Vastus medialis intertrochanteric line of femurmedial aspect of linea aspera  common quadriceps tendon into patellatibial tuberosity via patellar ligament  extends knee
Gluteus Medius Gluteal Surface of the Ilium Greater Trochanter anterior and lateral fibers abduct and medially rotate the thighposterior fibers may laterally rotate thighstabilizes the pelvis and prevents free limb from sagging during gait

 

 

Gluteus Minimus Gluteal Surface of the Ilium Greater Trochanter abduct and medially rotate the thighstabilizes the pelvis and prevents free limb from sagging during gait 
Tensor fascia Late ASIS Fibres of the iliotibial Tract hip flexionmedially rotate & abduct a flexed thightenses IT tract to support femur on the tibia during standing

 

 

Sartoris ASIS Medial shaft of tibia flexes hip and kneelaterally rotates thigh if flexed at the hip 
Psoas Major Lumbar vertebrae Lesser Trochanter hip flexionlateral rotation 
Iliacus Iliac fossa Lesser Trochanter powerful hip flexionlateral rotation 
Bicep Femoris Ischial tuberosity + Lateral lip of linae aspera Head of Fibula flexor at the knee (mainly short head)laterally rotates thigh if flexed at the kneeextends hip (long head)

 

 

Semmitendonosus Ischial tuberosity Proximal medial shaft of the tibia extends hipflexes kneemedially rotates tibia

 

 

Semimembronosis Ischial Tuberosity Medial Condoyle of tibia flexes kneeextends hipmedially rotates tibia

 

pulls medial meniscus posterior during flexion

 

Gluteus Maximus Coccyx, iliac crest Gluteal tuberosity powerful extensor of hiplaterally rotates thighupper fibers aid in abduction of thigh

 

fibers of IT band stabilize a fully extended knee

 

Gluteus Medius Gluteal surface of Ilium Greater trochanter
Adductor Magnus Inferior ramus of pubis, ramus of ischium Medial Lip of Linae Aspera +adductor tubercle. adducts the thighposterior fibers also extend and laterally rotate thigh 
Adductor Longus Pubic tubercle Medial lip of linae aspera adducts thighflexes thighmay laterally rotate thigh at the hip

 

 

Gracillias Inferior ramus of ilium Proximal medial shaft of tibia
Piriformis Anterior part of the sacrum + the greater sciatic notch. Greater Trochanter lateral rotation of extended thighabducts a flexed thigh 
Gastrocnemius medial head: just above medial condyle of femurlateral head: just above lateral condyle of femur  calcaneus via lateral portion of calcaneal tendon plantarflex the ankleknee flexion (when not weight bearing)stabilizes ankle & knee when standing

 

 

 

Soleus upper fibulasoleal line of tibia  calcaneus via medial portion of calcaneal tendon plantarflex the foot
Tibialis posterior posterior, proximal tibiainterosseous membranemedial surface of fibula

 

 

navicular tuberosity (principle)all 3 cuneiforms (plantar surface)bases of 2nd-4th metatarsals

 

cuboid

sustentaculum tali of calcaneus

 

stabilizes ankleinversion & adduction of footprevents hyperpronation while in gait

 

weak plantarflexion of ankle

 

Tibialis Anterior lateral tibial condyleproximal 2/3 of anteriolateral surface of tibiainterosseous membrane

 

anterior intermuscular septum & crural fascia

 

medial & plantar surface of base of 1st metatarsalmedial & plantar surface of the cuneiform  strongest dorsiflexorinverts & adducts the foot 
Extensor digitorum longus lateral condyle of the tibiaupper anterior surface of fibulainterosseous membrane

 

crural fascia

 

dorsal surface of the bases of the middle & distal phalanxes of the 2nd-5th rays extends the lateral 4 toesweak dorsiflexor & everts foot 

 

Ligaments of the Knee:

Medial collateral ligament

Lateral collateral ligament

Anterior cruciate ligament

Posterior cruciate ligament

Menisci

The menisci is the articular disks in the knee joint, two disks in total consisting of the medial meniscus and lateral meniscus and involves of widespread collagen fibres consisting of pseudo cartilage cells and connective tissue. Fibres run along the menisci to allow for attachments, flat over the centre of the knee joint itself, fused with the synovial membrane laterally and moves over the tibial surface. The menisci exist to protect the bone ends from rubbing, act as shock absorbers and therefore come in very handy especially those involved with exercise and sports.

Ok so now we understand the knee a bit better, we will go into the injuries and how you can help:

ACL injury/tears

The ACL or anterior cruciate ligament is one of the 4 main knee ligaments and prevents excessive movement of the knee joint.

Injuries to the ACL are the most common ligamentous injury to the knee joint and can be very debilitating. Tearing and rupture due to excessive movement is the common cause of ACL tears with contact ACL injuries only accounting for 20%. Sports show the highest incidence of ACL injuries within society, with football, martial arts, gymnastics and skiing being sports with particular high risks factors. Female athletes and those over 40 also show higher incidence of ACL injuries.

Symptoms

A pop or bang when the injury occurs (this is the ACL tearing or rupturing)

Swelling around the knee joint

Pain (can be severe)

Instability on the affected leg

Diagnosis

The clinical tests shown here are highly accurate and performed by a trained professional but a ruptured ACL is commonly confirmed by an MRI examination.

Anterior Draw test

This test is used to search for laxity within the ligament and must be performed on both sides to compare differences.

With the client positioned in a lying supine position flex the knee to 45degrees and the knee to 90degrees. Sit on the client’s foot whilst finding the joint line placing the thumbs on either side of the patellar tendon, whilst using index fingers to palpate for hamstring tendons which need to be relaxed for the test to be accurate. Draw the tibia forward towards yourself (anterior), do this on both side, if the tibia comes forward excessively in comparison to the unaffected side then you have a positive test for an ACL injury.

 

Lachman test

Another great test to help diagnose an ACL injury, flex the knee to 30 degrees with the client in a supine position. Pull on the effected knee anteriorly, if the tibia has an increased forward laxity compared with the unaffected limb than this is a positive test for an ACL injury.

The Lachman test has been reported to be a superior test for ACL rupture compared with the anterior draw test.

Prevention

A great way to prevent ACL injuries occurring (non-contact) is to work on proprioception muscular strength activities. It is essential that those performing in sports at high risk of ACL injury perform proprioception exercises to help prevent injuries occurring during training and play.

Examples:

Wobble board work

Biodex Stability System

Bosu

Piston Squats

Agility Exercises (rapid changing turns) – only used in functional stage of rehab.

Meniscal Cartilage Tear

Commonly injured in sports such as football and skiing, the meniscus can become torn by a sudden and/or forceful movement of the knee during weight bearing. Mechanisms of injury are very similar to that of an ACL injury, such as a footballer changing direction whilst the foot is planted in the ground or when a tennis player goes for a strong forearm but fails to move the foot with the rotation of the body. The amount of meniscus tearing and the site of tearing represents how bad the injury will be.

Whilst the most common reason for meniscus tearing is a forceful movement it can come about due to repetitive damage occurring at the meniscal site and can be a caused by muscular imbalances or other soft tissue/bone/joint injuries. The major problem with the meniscus is that it has a bad supply of blood and therefore does not heal well when injured, the central area of the meniscus has no direct blood supply, which indicates that a tear through the centre in general will not heal.

Symptoms

The usual symptoms would be suspected such as pain and swelling, these are made worse by weight bearing and especially during weight bearing movement (e.g. running). It is not uncommon for the knee to lock or seize up during movement especially at full extension, and like an ACL injury there is usually a sense of giving way and/or instability with the knee.

Diagnosis

McMurray test

This rotational test is performed to search or tears in the meniscus, the test is performed by the trainer/therapist taking hold of the knee along the joint line with the knee in flexion, with the other hand placed on the sole of the client, adding a valgus stress will identify a valgus deformity, rotating the leg in an external movement whilst putting the knee into extension. This can be reversed with internal rotation.

If there is pain and/or clicking involved within the knee then this would be a positive test for a meniscal tear. The most recent study showed that the McMurray test had a 97% specificity for finding meniscal tears.

Apley grind test

Another test for meniscus tearing of the knee, with the client laying prone the trainer/therapist places their knee upon the clients affected thigh, with the hand placed upon the sole the tibia is compressed against the knee joint with external rotation force placed throughout, if the client complains of pain then this would indicate a positive test for meniscal damage.

Cooper’s sign

If the client complains of joint pain within the knee when trying to sleep especially when turning over in bed it is a possible sign of meniscal damage. Ultrasound and MRI along with the other tests mentioned above will help diagnose a meniscal tear.

Prevention

A very common injury in sports as we have already mentioned, the menisci holds up to 50% of our torso weight, however there are methods to help prevent tears from occurring.

Footwear

Choosing the correct footwear for the sports that you are taking part in, football is a prime example of where studs are better than blades, blades have a tendency to become stuck within the ground in moments of high rotational agility which leads to over twisting of the knee joint. Those involved with Olympic lifting may want to consider flat soled high grip shoes/trainers, trainers which are designed for running are not going to offer the stability required in snatches/clean & jerk movements, and this is also applicable in all weight lifting from squats to leg press.

Stretching & Strengthening

Major leg muscles such as the hamstring/quad and calf muscle groups require stretching and strengthening to help prevent injuries occurring. Stretching before dynamic activities is paramount in preventing meniscal tears for occurring. When strengthening muscles it is essential that correct technique is used, squats cause a great deal of stress to be placed throughout the knee joint and it is essential this is done correctly.


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