The Knee

ANATOMY

The Knee Bones (4) Femur Tibia Fibula Patella

Patella Sesamoid bone – sits inside the quadriceps/patellar tendon Patellar tendon attaches to the tibial tuberosity Patella rides in a groove on the femur

The Knee Joints (2) Femur and tibia Patellofemoral Motions: flexion and extension Patellofemoral Patella sits on the femur in quadriceps tendon

Ligaments Cruciates (2) Short, strong ligaments inside the knee joint Cross each other and form an ‘x’ Cruciate means cross Named for where they attach on the tibia Functions Provide anterior and posterior stability Prevent rotation at knee

Ligaments Cruciates Anterior Cruciate Ligament (ACL) Prevents anterior movement of tibia on femur

Ligaments Cruciates Posterior Cruciate Ligament (PCL) Twice as strong as the ACL Prevents posterior movement of the tibia on the femur

Ligaments Collaterals On sides of knee Give side to side stability

Ligaments Collaterals Medial Collateral Ligament (MCL) Goes from the femur to the tibia Prevents valgus stress Valgus stress: pushing knee from outside in

Ligaments Collaterals Lateral Collateral Ligament (LCL) Goes from femur to the head of the fibula Prevents varus stress Varus Stress: Knee pushed from inside out

Meniscus “Cartilage” of the knee Sit on the tibia Functions: Deepens socket for the femur Gives stability to the knee Shock absorption

Meniscus Medial Lateral Larger and ‘c’ shaped More firmly fixed to the tibia Attached to tibia, MCL, and joint capsule Lateral Oval shaped More freely movable

Muscles Quadriceps femoris (Quad) Four muscles on the anterior thigh Rectus Femoris Vastus Medialis Vastus Intermedius Vastus Lateralis Function is to straighten/extend the knee Patella sits inside the tendon that is formed by these muscles Attach to tibia by way of patellar tendon

Muscles Hamstrings Three muscles on the posterior thigh Biceps Femoris Semitendinosus Semimembranosus Function is to flex/bend the knee Also function to extend the hip

INJURIES

MCL Sprain Cause Signs and Symptoms Treatment Blow to the lateral side of the knee Rotation to knee Signs and Symptoms MCL is tender to touch Hurts to have knee totally straight Positive Valgus stress test Will “give out” if 2nd or 3rd degree Treatment RICE immediately Immobilizer/brace for 2-6 weeks

LCL Sprain Cause Signs and Symptoms Treatment Injured by a blow to the medial side of the knee Not a very common injury Signs and Symptoms Pain and tenderness over LCL Positive Varus Stress test Treatment RICE immediately Immobilizer/brace for 2-6 weeks

PCL Sprain Injured by: Signs and Symptoms Care Blow forcing tibia back Leg is bent and it is hit on tibial tuberosity Hyperextension Signs and Symptoms Feel and hear pop in the back of the knee Positive Posterior Drawer Test Care RICE immediately and rehab Some athletes can participate without a PCL

ACL Sprain Causes Signs and Symptoms Treatment Plant and cut in opposite direction Hyperextension Blow to the lateral side Signs and Symptoms Feel and hear a pop Immediate swelling Major pain and then pain can subside Positive Lachman’s and Anterior Drawer Test Feels like it will give out if standing on it Treatment RICE immediately, Crutches Needs surgery to repair – out 6 months

Meniscus Injured when they get trapped/pinched between the bones Medial Meniscus injured more often than Lateral Mensicus Cause Planting foot and cutting in opposite direction, knee is flexed Sign and Symptoms Symptoms can come about 48-72 hours later Swelling, giving out, knee locks up, clicking Pain with squatting Treatment RICE If locked, to MD right away Needs Arthroscopic surgery

The Unhappy Triad Injury to the ACL, MCL and Medial Meniscus Injured all at once Cause: planting foot and cutting/twisting

Patellar Tendinitis Also known as Jumper’s Knee Cause Running and jumping sports Poor flexibility Signs and Symptoms Sorest at warm-up and cool down May have crepitus Tender over patellar tendon Treatment Rest – decrease pounding activity Anti-inflammatory meds Ice/Ice Massage Heat Patellar Tendon Strap

Osgood-Schlatter Insertion of the patellar tendon on the tibial tuberosity gets stressed and pulls away from its insertion site Cause From repeated jumping Common in adolescents Signs and Symptoms Pain will be right on the tibial tuberosity Tibial tuberosity will become much more prominent Treatment Much the same as patellar tendonitis

Dislocation/Subluxation of Patella Dislocated patella Goes out and stays out Victim will be found with knee bent – patella will be on lateral side of knee Extending the knee will reduce the patella Subluxed patella Dislocates and reduces itself quickly More common Signs: History of patella problems, sore over the medial aspect of the patella

Dislocation/Subluxation of Patella Cause Due to quad contracting and/or twisting of the knee Once it happens, it is more likely to happen again More prone if you are Female Have a weak vastus medialis Treatment Referral to MD RICE immediately Will usually require rehab and immobilization

Patellofemoral Syndrome/ Chondromalacia Cause Degenerative process where the articular cartilage under the patella softens and then wears away Patella may not track well in the groove Poor flexibility Signs and Symptoms Pain and grinding sensation under the patella Aching pain after activity Treatment Ice Increase flexibility of leg muscles May have to decrease activity while inflamed.

Pre-Patellar Bursitis Cause Direct hit to knee Kneeling Signs and Symptoms Increased swelling right on top of knee Treatment Ice Compression Eliminate the cause