Common Injuries to the Knee

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Common Injuries to the Knee

Learning Target: I can identify common injuries of the knee based on mechanism of injury and signs and symptoms.

Medial Collateral Ligament Sprain

• Mechanism of Injury:

  • Direct blow from the lateral side (valgus force)

  • External rotation of the tibia

• More common than lateral collateral ligament sprains

MCL: Signs and Symptoms

• Depends on severity of sprain

  • Remember there are 3 grades!

• Grade 1

  • Mild pain over MCL, minor stiffness, stable knee

• Grade 2

  • Moderate swelling, loss of ROM, mild instability

• Grade 3

  • Moderate swelling, immediate pain, loss of stability

Lateral Collateral Ligament Sprain

• Mechanism of Injury:

  • Direct blow from the medial side (varus force) and the tibia is internally rotated

• Can be accompanied by a avulsion fracture of the femur or tibia

LCL: Signs and Symptoms

• Pain and tenderness over LCL

• Swelling over the LCL

• Some joint laxity

• The greatest pain is with grade 1 and grade 2 sprains

Posterior Cruciate Ligament Sprain

• Mechanism of Injury

  • A fall with the full weight on anterior aspect of the the bent knee with the ankle in plantar flexion

• Known as dashboard injury

PCL: Signs and Symptoms

• Feeling a “pop” in the back of the knee

• Tenderness in the back of the knee

• Laxity during posterior sag test

• Instability during weight bearing

Positive Posterior Sag Test

Patella

Tibia

Femur

Anterior Cruciate Ligament Tear

• Generally considered the most serious ligament injury in the knee

• Mechanism of Injury:

  • External rotation of the tibia with the knee in a valgus position

  • “Cutting in the same direction as a planted foot”

ACL Tear: Signs and Symptoms

• Feeling and hearing a “pop”

• Immediate pain

• Immediate laxity/disability

• Rapid swelling

• Feeling unstable

Meniscus Tear

• Medial meniscus is more likely to be injured than lateral meniscus

• Mechanism of Injury:

  • Rotation while weight bearing

  • “Cutting while running”

Meniscus Tear Signs and Symptoms

• Moderate/mild swelling

• Pain along the joint line

• Intermittent locking and giving away of the knee

• Pain when squatting

• Pain when going up or down stairs

Knee Plica Syndrome

• Plica: fold/s in the synovial joint capsule that did not close during development

  • Occurs in approx. 20% of the population

• The mediopatellar plica is the most subject to injury

  • The plica becomes thick and fibrous

• Commonly associated with chondromalacia and other knee injuries

Knee Plica Syndrome Signs and Symptoms

• Patient usually has a history of knee trauma

• Episodes of painful pseudolocking (patient feels like the knee is locked/“needs to pop”) after sitting for long periods of time

• Knee snapping may be felt or heard during knee flexion

• Pain going up or down stairs

• *NO SWELLING OR LAXITY*

Osteochondritis Dissecans

• Painful condition involving partial or complete separation of a piece of articular cartilage and bone

• Referred to as loose bodies or “joint mice”

• Cause is unknown and has a slow onset (chronic)

OCD: Signs and Symptoms

• Knee “aches”

• Recurrent swelling

• Knee may occasionally catch or lock

Patella Subluxation/Dislocation

• Subluxation: partial displacement

• Dislocation: total displacement

• Occurs when the patella slides out of the femoral groove

• Most commonly, the patella is displaced laterally

Patella Subluxation/Dislocation Signs & Symptoms

1. Dislocation:

• Obvious deformity

  • Loss of function

  • Pain

1. Subluxation:

• Pain and swelling

  • Tenderness over medial border

  • Instability

Chondromalacia Patella

• Softening and deterioration of the articular cartilage on the backside of the patella

• Exact cause is unknown

• Chronic injury

Chondromalacia Signs and Symptoms

• Pain in the anterior knee during weight bearing

• Recurrent swelling around the patella

• Grating sensation when flexing and extending the knee

Osgood-Schlatter Disease

• Apophysitis of the tibial tuberosity

  • Inflammation at the attachment of the patella tendon to the tibial tuberosity

• Caused by tension placed on the tibial tuberosity from the patella tendon

• Occurs in adolescence--usually resolves by age 18

Osgood-Schlatter Signs and Symptoms

• Enlargement of the tibial tuberosity

• Severe pain when kneeling, jumping, and running

• Point tenderness over the tibial tuberosity

Jumper’s Knee

• Inflammation of the patella tendon

• Chronic/overuse injury

  • Jumping

  • Kicking

  • Running

Jumper’s Knee Signs and Symptoms

• Multiple Stages of Pain

  • Stage 1: pain after activity

  • Stage 2: pain during and after activity (the patient is still able to perform at the appropriate level)

  • Stage 3: pain during activity and prolonged after activity (performance is hampered)

Runner’s Knee

• Aka: Iliotibial Band Friction Syndrome

• Chronic/overuse injury

• Irritation develops at the insertion of the IT band

  • Friction is created over the lateral femoral condyle

  • Caused by “tight” IT Band

• Usually found in runners and cyclist who have genu varum and pronated feet

Runner’s Knee Signs and Symptoms

• Pain over the lateral femoral condyle during activity