P&C (6) Knee Injuries

What is in the knee?

• Bones:

  • Femur, patella, tibia, fibula

• Joints:

  • Tibio-femoral

    • Modified hinge synovial joint between the distal femur and the proximal tibia

  • Patello-femoral

    • Where the back of your patella (kneecap) and femur (thigh bone) meet at the front of your knee.

• Ligaments:

  • Medial & Lateral Collateral Ligaments

    • Located medially and laterally to the knee

  • Anterior and Posterior Cruciate Ligaments

    • Located within the knee, anteriorly and posteriorly

  • Coronary

• Meniscus:

  • Medial is C-shaped

  • Lateral is O-shaped

  • Both are disc-like structures with a high on the outer edge

  • Allows for grabbing/holding tension, like the surface of water grabbing the inside of the water glass.

  • Function:

    • Deepens tibial surface, increasing joint stability.

    • Spreads out load bearing force on the joint

    • Helps control rotational/gliding motion at the tibio-femoral joint

    • Helps circulate synovial fluid through joint

Which muscles act on the knee?

• Quadriceps

• Hamstrings

• Gastrocnemius

• Popliteus

• Tensor Fascia Latae & Iliotibial Band (ITB)

• Pes Anserine Complex

  • Gracilis, semitendinosus, sartorius

What is the general biomechanics of the knee?

• Flexion to Extension: 0 Degrees

• Extension to Flexion: 135 Degrees

• Specific Elements of Motion, such as Rocking, Gliding, and Rotation:

  • 0 Degrees - tibia is externally rotated and in the locked home position

  • From 0 to 20, rocking action takes place as the tibia internally rotates

  • From 20 to onwards, gliding action takes place on the femur and some rotation begins

  • Increasing amounts of rotation results in up to 40 degrees as the knee is flexed to 90 degrees

What are the common knee injuries?

• Lateral to Medial Force (Valgus)

  • MCL damage occurs (MCL stress test)

    • Deep and Superficial Layers of the Ligament have Complications

  • One part attached to the meniscus therefore tearing of the meniscus may also occur (McMurry Test)

  • Joint is stressed far enough, stretching of the ACL (Lachmans)

  • MCL, McMurray, Lachmans positive test = O’Donoghue’s Unhappy Triad

• Medial to Lateral Force (Varus)

  • LCL is damaged (Varus stress test is positive)

• Anterior to Posterior (Hyperextension)

  • Femur goes posterior, tibia goes anterior.

  • Injured Structures Include:

    • Hamstring Strain

    • Posterior Capsule Strain

    • ACL Tear

    • Osteochondral Bruising of Femoral/Tibial Condyles

• Rotational

  • Same features as Valgus (Lateral to Medial)

  • Complications include the O’Donaghue’s Triad (MCL, McMurray, and Lachmans)

What are the different severities of knee injuries?

• Loud popping sound often associated with 3rd degree sprains of any knee ligaments

• In all injuries, severity is dependant on how the foot is planted

  • EX) In hockey, the foot is more mobile than a planted food in football thus injuries are less severe

• 1st Degree - Mild

  • Simple stretching

    • No tearing, no laxity, very little swelling, few limitations

  • Treatment:

    • Rest from Sport 7-10 Days

    • Use of PIER

    • Heat Modalities

      • Joint is hot = no heat

    • ROM and Strength Exercises

      • Restoring flexion and full extension

    • Proprioception Exercises

      • Restoring balance

    • Maintain Cardiovascular System

      • Should be maintained throughout ALL injury

      • For the knee, it shouldn’t be jogging or running. Maybe like an exercise bike, or swimming.

    • Psychological Support as needed

      • Helping the person try and do the activity

    • Tape Support or Appropriate Brace

• 2nd Degree - Moderate

  • Partial tearing, partial laxity is evident

    • May feel solid on stress tests, like the ligament stopping you from going any further.

    • Increased swelling, more pain

  • Treatment:

    • Use of PIER

    • Rest from sport 2-6 weeks

    • Cast/brace up to six weeks

    • Use EMS to prevent atrophy and re-educating the muscle how to work

      • Electrical Muscle Stimulation

    • Follow up with treatment as above

      • 1st Degree

• 3rd Degree - Rupture

  • Ligament is ‘hanging on by strands’

    • It is torn, no end feel.

    • Intense pain initially, after there is no pain until increased pressure from swelling.

    • Surgery is the ‘big question mark’

      • Usually treatment is to immobilize it, unless if the severity is horrible

    • In most cases, only casting or bracing is done

    • Follow up treatment as in 1st degree

Explain Meniscal Injuries

• The Medial Meniscus is most injured, less mobility and attached to the MCL.

• Creates instability in the joint structure when not in tact

• 1. Peripheral Tears

  • Front, back.

• 2. Longitudinal

  • Along the meniscus

  • Can lead to ‘bucket-handle’ tears

• 3. Horizontal Cleavage Tear

  • Imagine butterflying the chicken breast

How can a Meniscal Injury happen?

• 1. Can be torn by MCL with valgus (lateral) force

• 2. Deep squats or Duck Walking

  • Great for strengthening quads, but insane amount of pressure in the meniscus

• 3. Abnormal shear forces in an unstable knee

  • Joint moves too much, especially after an ACL tear.

• 4. Crushed when the knee is twisted while weight bearing

  • Jumping, landing, and turning the joint all in one fluid motion

• * Zone of tearing is important with respect to healing. There is only blood supply to the outer third of the meniscus

What are the signs and symptoms of a meniscal injury?

• 1. Joint line pain on the side of injury

• 2. Intra-articular pain localized to the side of injury

  • Pain is there, but it is deep inside and cannot be touched

• 3. Feeling of uncertainty or actual giving way

  • After the pain goes away, the person feels like the knee is still wrong

• 4. Clicking or popping heard occasionally

• 5. The sensation of ‘something blocking the joint’ when trying to achieve extension

  • Flexion are generally better tolerated

• 6. Locked individual will walk on toes to release pressure in the joint

• 7. May present with joint effusion

  • Swelling that occurs when there is a buildup of synovial fluid

• 8. In cases of long standing injuries, may show quads atrophy especially the VMO.

How is surgery considered in a meniscal injury?

• Remove or Repair?

  • Torn tissues on the inner aspect of the meniscus are often removed, this is usually the avascular zone.

  • Newly torn tissue on the outer edge of the meniscus can often be repaired. Tissue gets enough blood to heal properly.

  • Age is often the consideration on what is to be done

    • Younger the athlete, the more likely that a repair is attempted no matter where it is torn.

  • Could be repaired with sutures/tacks.

What are some acute patellar injuries? What are its functions?

• Patellar Dislocation

• Subluxed Patella

• Patellar Fraction

Main Functions:

• Increases lever arm of quads mechanism

  • Increases the force of knee extension

• Protection of femoral condyles from direct blows

• Patella glides in the intercondylar groove during flexion and extension to decrease the friction on the patellar tendon

What is a patellar dislocation?

• Most commonly seen in females

• How can it happen?

  • Forced quad contraction when the knee is about 45 degrees in flexion and in valgus

  • Genetic predisposition due to the shape of the patella

  • Increased Q angle is over 10 degrees (males) or over 16 degrees (females)

• Resulting Trauma from Dislocation

  • Medial Retinaculum (controls medial/lateral movement of the patella) get stretched

  • Vastus Medialis Obliques or other parts of quad complex are strained

  • Patella or Femoral Condyles Fractures

• Treatment

  • Do not attempt to put it back

  • Immobilize, ice, transport to medical care

  • First time dislocation are treated conservatively

    • Reduced, then use of ‘control’ devices to stabilize patella

  • Immobilized in straight leg position for 4-6 weeks

  • Knee brace with patellar stabilizer is worn for all activities thereafter

  • Full Treatment after Immobilization:

    • ROM Exercise

    • Strengthening Surrounding Muscle

    • Correcting any biomechanical problems

    • Proprioception exercises

What is a Subluxed Patella?

• Acute total or partial dislocation and subsequent relocation where the athlete is uncertain of what happened except that something is wrong

• Most often signs and symptoms are similar to ACL/Meniscal Tears, this is what it is:

  • Popping Sound

  • Intense Pain

  • Knee gives way

  • Rapid Onset Haemarthrosis

    • Joint bleeding

  • Describes as “Knee Joint has shifted”

• Treatment:

  • PIER (Pressure, Ice, Elevate, Rest)

  • Immobilization for a few days

  • Patellar Stabilization Brace

  • Ongoing treatment as in a first time dislocation

What is a Patellar Fracture?

• Common Causes can be:

  • Direct Trauma

  • Indirect Trauma

    • As in a severe forced contraction of the quads when the knee is in flexion

• Treatment:

  • If un-displaced: Immobilization for 4-6 weeks

  • If comminuted: Surgery with a wire/screw fixation

  • Post immobilization treatment is same as a dislocation

How can an ACL injury happen?

• Mechanisms of Injuries:

  • 90% of injures, the foot is planted and immobile

  • Hyperextension

  • Internal rotation of the leg with external rotation of the body

  • External rotation with valgus force at the knee as in a cutting motion

  • Sudden deceleration, causing hyperextension or rotational forces

  • Anteriorly directed force to the tibia when the knee is at 90 degrees

What are the sign and symptoms of an ACL injury?

• Loud audible Pop/Crack is heard

• Sudden giving way of the knee and an inability to bear weight

• Rapid joint swelling (reaches peak within first 24-48 hours)

• Medical diagnostics using aspiration will reveal frank blood in the joint

• Positive Lachmans Test

• MRI will often be used to confirm clinical findings

How can you treat an ACL injury?

• Acute:

  • 1. Rule out Fracture

  • 2. PIER

  • 3. Immobilize and Refer to Doctor

• In the athlete, surgical repair is often the only option in restoring stability to an ACL deficient knee

How are Female Athletes and ACL Injuries associated?

• Since athlete are getting bigger, stronger, and faster, there is an increased aggressiveness in how the sport is played. Consequently, an increase in ACL injuries are noted.

• Studies have shown that female athletes are between 3 to 5 times more likely to suffer an isolated ACL injury compared to men, but how?

  • 1. Hormonal Influence

    • Presence of estrogen and menstrual cycle stages have been studied at great length to suggest that the ligament is more elastic at certain times of the cycle and more vulnerable to tearing

  • 2. Anatomical

    • Women have a smaller ACL than men, as well as a smaller intercondylar notch

  • 3. Neuromuscular Risk Factors

    • Core stability, strength, proprioception or intermuscular coordination, and rate of firing

  • 4. Biomechanical Factors

    • Females tend to place more emphasis on the quads compared to men

    • Females decelerate (cutting, pivoting, and landing) in a straighter knee position

    • Tend to exhibit excessive valgus stress on the knees (knocking inward)

How can a PCL injury happen? Signs and Symptoms?

• Occurs when there is an anterior to posterior force to the tibia at the tibial tuberosity

  • Force drives the knee backwards

• May occur with Hyperextension/flexion

• Signs and Symptoms:

  • Similar to ACL, but less swelling and very little instability

  • Posterior drawer test is positive

  • Sag sign is present

What is Prepatellar Bursitis?

aka Housemaid’s Knee, Carpenter or Carpet Layer Knee

• Bursa located between the skin and patella

• Called Housemaid’s (and what not) because when we go on our knees to do a task, we generally lay on our tibia unless we move forward

• Injury can happen from single contusion force or repeated compression/shearing forces together

What is Deep Infra-Patellar Bursitis?

• Located inferiorly to the patella between the patellar tendon and the tibia

• Becomes inflamed with direct trauma or with repeated rubbing of the patellar tendon

• Often called the Jumpers Knee

What is Pes Anserine Bursitis?

• Located between the tendons of sartorious, gracilis, and semitendinosus muscles and the upper medial aspect of the tibia, just medial to the tibial tubercle

• Caused by;

  • Overuse

    • Kicking a ball repeatedly

  • Repeated pivoting from a deep knee bend

  • Direct blow to the area

  • Genu Valgum or Knocked Knees

What is Iliotibial Band (ITB) Friction Syndrome?

• Found in cycling, sports that have cutting (basketball?)

• Observed in people who vigorously exercise vigorously

• When the knee flexes, ITB moves posteriorly along the layeral femoral epicondyle

• Contact against the condyle is highest between 20 to 30 degrees, average 21.

• When the band is too tight or overused, it rubs more vigorously

What is Patellar Tendonitis?

• Most common overuse problems referred to as the Jumpers Knee, pain in more than one regions;

  • Inferior pole of the patella

  • Mid Tendon Region

  • Insertion at Tibial Tuberosity

• Etiology of Patellar Tendonitis

  • Intense Running

  • Jumping

  • Starts and Stops

  • Squatting

  • Kneeling

What is Quadriceps Tendonitis?

• Another set of problems called Jumpers Knee

• Etiology is same as the Patellar Tendonitis except pain comes at the superior pole or the patella were the quads inserts

What is Patellofemoral Arthralgia (PFA)

• Onset of pain in the peri-patellar region of the knee usually due to mal tracking of the patella on the femur

• Common in running and jumping athletes 

• Pain increases with going up/down the stairs

• Positive Theater Sign

  • Pain increase and difficulty getting when sitting for long periods

• Positive Clarke's Sign

  • Pushing down on the top of the knee and asking the patient to contract their quads?

• Contributors to PFA:

  • Chronic mal-tracking of the patella in the trochlear groove

  • Secondary to inappropriate treatment or improper rest after a deep contusion

  • Biomechanical issues such as over pronation

What is Chondromalacia Patella?

Specific degenerative changes of the articular hyaline cartilage in the patella

What is the treatment of general overuse injuries?

• Controlled rest is key

• Ice and heat as required to help pain symptoms

• Correcting biomechanical issues and muscle imbalances

• Improving all knee muscle flexibility

• Using support and patellar stabilizing brace

What is the Osgoode-Schlatter disease?

• An avulsion injury of the patellar tendon from the apophysis at the tibial tuberosity

• Seen often in highly active adolescents (10 to 15)

  • Most prevalent in 12 to 15 yr old males

• Etiology:

  • Muscle does not respond to growth fast enough, coupled with strenous activity resulting in increasing traction to come out as avulsion

  • Direct contulsion to tibial tuberosity may cause similar problems with inflammatory changes over the tibial tuberosity

What is the Larsen-Johansson Syndrome?

Another adolescent apophysis injury that involves the patellar tendon at the attachment of the inferior pole

What is Osteochondritis?

• Area underneath cartilage surface is injured, leading to blood vessels damaged in the bone.

  • Leads to avascular necrosis and the bone dies

  • Can be seen on an X-ray and is sometimes referred to as “osteochondritis lesion”

• If the hyaline cartilage breaks off then we have osteochondritis dessicans

How do we assess and rehab the knee?

• Immediate injury assessment is essential and must be done within the first 10-20 minutes before pain, swelling, and muscle spasm mask over the injury

  • 1. Rule out potential fracture 

  • 2. Look for Laxity

  • 3. Assess full to rule out inert vs contractile tissue

• Follow up Diagnosis by sports medicine physician or orthopedic surgeon

  • X-ray

    • Will show anything related to a torn ACL

  • Arthrogram

    • Usage of dye to identify things

  • CAT scan

    • ‘Slices’ of X-rays that scan the entire body

  • Arthroscopy

  • MRI

What is the acute treatment for a knee injury?

• PIER

• Rest

• Immobilization

What is the rehab/reconditioning process of the knee?

• Restoring Range of Motion

• Maintaining Cardiovascular System

• Strengthen surrounding muscles, as long as there is no excess stress on the joint

• Specific Muscle Strength

• Proprioception

  • Balance control, if you injure something it will be much harder to balance it.

What is the General Treatment Plan of the Knee?

• 1. Range of Motion, active flexion/extension within pain-free range.

  • Hold and Relax?

• 2. Whirlpool-heat, buoyancy of water may work for strength (water is a true isokinetic exerciser)

  • Takes gravity off of the leg, think of raising your leg with and without gravity, gravity weighs it down but water doesn’t

• 3. Massaging to facilitate blood flow, loosening soft tissue

• 4. Strengthening exercises for the hamstrings, quads, abductors, adductors, and calves.

  • Make exercises ‘closed kinetic chain’ such as squats or step ups, closed chain meaning the distal segment (foot) is not moving freely

    • Open chain: Distal segment of whatever you're moving is free

• 5. Proprioception, these activities must be started ASAP.

Guidelines of returning to participation?

• Person should:

  • have full and pain-free range of motion

  • have equal strength oh both legs, shouldn’t vary more than 10-15%

  • have equal muscle girth, which is ideal.

  • have proprioception better than the non-injured side

  • not involve games which can be a psychologically be a problem

    • Athlete feels comfortable about the duress of the activity

• Extrinsic support may be required but should not be permanent

  • Some sort of taping and what not