Condition

Description/Presentation

Mechanism of Injury

Anterior Cruciate Ligament (ACL)Tear

Graded as I, II, III, or complete;

instabilty in knee, pain, swelling, difficulty with weight bearing

Sudden deceleration while pivoting on fixed foot

Combination of external rotation at femur; valgus stress and internal rotation of tibia

Influenced by strength, gender (more likely in females), general ligamentous laxity, Q angle, and anatomical differences in bone shape

MCL Injury

Graded as I, II, III, or complete

localized swelling and tenderness on medial side

Sudden valgus force while the leg is planted

Often accompanies an ACL injury

Meniscus Injury

Characterized by tenderness, clicking, catching, or locking with knee movement

Degenerative over time due to weight bearing forces

Associated wtih rotation on a fixed, flexed knee

Posterior Cruciate Ligament (PCL) Tear

Graded as I, II, III, or complete;

tibia may glide off femur posteriorly with any gravity load

MVA impact from tibia striking dashboard

Cross-walk or other pedestrian vs. car when there is sudden posterior force to tibia on a fixed foot

Forceful hyperflexion at knee

Patellofemoral Dysfunction Syndrome

Anterior and anteromedial and anteriolateral pain with knee bending, squatting, running, stairs

+Movie Sign (pain in anterior knee after sitting 20+ min)

Often has crepitus (sandy, grinding sensation with knee flexion)

Loss of patella articular cartilage

Abnormal tracking of patella due to muscle imbalance in quadriceps

Overuse of quadriceps

Tight lateral medial and lateral connective tissue

Insufficient hip stability resulting in excessive hip internal rotation

Osteoarthritis

May result in genu varus or genu valgus deformity, joint instability, stiffness, and pain due to distal femur wear, and painful limited gait

Degenerative joint condition; increased incidence in patients who are overweight, obese, or engage in high impact work activities

May result in genu varus or genu valgus deformity and joint instability and pain due to distal femur wear