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Knee and Ankle Injuries

This lecture explains knee and ankle injuries, along with types, mechanisms involved and management.

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Overview of Lecture

Knee and ankle injuries

Knee is the lower extremity joint connecting the femur and the tibia.

The knee is a complex, compound, condyloid variety of a synovial joint.

The human knee joint

Since in humans the knee supports nearly the entire weight of the body, it is the joint most vulnerable both to acute injury and to the development of osteoarthritis.

The knee accepts and transfer biomechanical loads between the femur, tibia, patella, and fibula.

The movements at the knee are:

flexion, extension.

Slight medial and lateral rotation.

Special locking and unlocking mechanisms, related to movement by the femoral condyles on the tibial plateau.

The ligaments and menisci, along with the muscles which traverse the joint, prevent movement beyond the knee’s intended range of motion.

It is also classified as a hinge joint.

Assessment And Management Of The Knee Injury

Knee injuries

Overuse knee injuries

Acute knee injuries

Overuse knee injuries

iliotibial band friction syndrome

popliteus tendinitis

patellofemoral joint pain syndrome

patellofemoral synovial plica

infrapatellar fat pad syndrome

patellar tendinitis(jumper’s knee)

pes anserinus bursitis

And in addition

Knee problems not to be missed

Baker’s Cyst


Septic Arthritis


Referred pain

House maids knee

Clergyman’s knee



Anterior cruciate ligament rupture (acl)

Posterior cruciate ligament rupture (pcl)

Medial collateral ligament tear (mcl)

lateral collateral ligament tear (lcl)

injuries to the menisci

osteochondral problems

patellofemoral instability


Mechanism of injury is vitally important.


Forced flexion/Hyperextension

Falls/Direct Blow

Knee Examination


Wasting, swelling, deformity

redness, scars



Temp, Effusion, crepitus



Passive, Active

Resting position, SLR, Extension, flexion, collateral ligaments, cruciates menisci


When to X-ray?

X-rays are required if any of the following is present.

Isolated bony tenderness of the patella.

Bony tenderness of the fibula head.

Patient cannot flex knee to 90°

Patient cannot bear weight (4 steps) after injury.

Fractures of lower femur/ upper tibia ?


Tibia Plateau Fracture

Tibia Plateau fracture

Proximal tibia examination reveals tenderness.

Swelling, haemarthrosis, ligament damage.


Patella Facture

Patella Fracture

Direct blow,

Fall, Violent flexion, Quadriceps contraction.

Pain/Swelling, Crepitus, Pain on extension

Straight leg raise.





Dislocation of the Knee


Serious ligamentous and   soft tissue damage.

Vascular and Nerve damage.


Acute haemarthrosis


Onset of swelling following injury

Warm, tense, painful


Cruciate ligament damage

tibial avulsions


Cruciate Ligament Rupture


ACL Rupture

PCL Rupture
(tibial sag)

Meniscal Injury

Usually ‘twisting” injury

History crucial

McMurray’s Test

Collateral Ligament Injury


Grade I

Local tenderness+ slight or no laxity

Grade II

Local tenderness+ laxity

Complete rupture

Soft Tissue Injuries

Ruptured Quadriceps

Unable to straight leg raise

Possible palpable defect.

Surgical repair

Ruptured Patellar Tendon

Unable to straight leg raise

Possible palpable defect. Displaced patella

Avulsion of tibial tuberosity

Surgical repair.

Ankle Injuries


Anatomical Structures




Ankle Ligaments

There are three lateral ligaments predominantly responsible for the support and maintenance of bone apposition (best possible fit).  These ligaments prevent inversion of the foot.

These ligaments are:

Anterior talofibular ligament

Calcaneofibular ligament

Posterior talofibular ligament

The deltoid ligament

This is located on the medial aspect of the foot.  It is the largest ligament but is actually comprised of several sections all fused together.  This ligament prevents (eversion) of the ankle.  The deltoid ligament is triangular in shape and has superficial and deep layers.  It is the most difficult ligament in the foot to sprain.

Specific Injuries

Ankle Injuries: Sprains

Single most common injury in athletics caused by sudden inversion or eversion moments

GRADE 1 ( Mild ) SPRAINS (Ligament is affected)

GRADE 2 (Moderate) SPRAINS (Ligament is torn)

GRADE 3 ( Severe ) SPRAINS (Uncommon severe injuries, associated with fractures)

Inversion Sprains

Most common and result in injury to the lateral ligaments

Anterior talofibular ligament is injured with inversion, plantar flexion and internal rotation

Occasionally the force is great enough for an avulsion fracture to occur w/ the lateral malleolus



Inversion ankle sprains

Inversion ankle sprain injures the lateral ligaments of the ankle.

About 90% of all ankle sprains are inversion sprains.


Eversion sprain

Ankle dislocation

An injury to the ankle so that the bones are displaced and are no longer in the correct alignment.

Ankle dislocations are almost always associated with sprains and fractures.

Ankle dislocation


Ankle dislocation

Patient Evaluation



Time since injury

Associated injuries





Alcoholism / drug abuse

Physical Exam

Note obvious deformities

Neurovascular exam

Pain to palpation of malleoli and ligaments

Palpate along the entire fibula

Pain at the ankle with compression

syndesmotic injury

Examine the hindfoot and forefoot for associated injuries

X-ray Evaluation

AP, Lateral and Mortise views of the ankle

AP and lateral of tibia

Foot series if tender

Fifth metatarsal

Calcaneus fracture

Mortise View

AP view of ankle with foot internally rotated

Abnormal findings:

medial joint space widening

tibia/fibula overlap <1mm

Types of fractures


Conservative if stability present

Closed reduction

Compression dressing, splint, and elevation

Pain control

Surgery if stability compromised





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