The Knee ANATOMY The Knee n Bones 4
The Knee
ANATOMY
The Knee n Bones (4) n n Femur Tibia Fibula Patella
Patella n n n 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 n Joints (2) n Femur and tibia n n Motions: flexion and extension Patellofemoral n Patella sits on the femur in quadriceps tendon
Ligaments n Cruciates (2) n n Short, strong ligaments inside the knee joint Cross each other and form an ‘x’ n n n Cruciate means cross Named for where they attach on the tibia Functions n n Provide anterior and posterior stability Prevent rotation at knee
Ligaments n Cruciates n Anterior Cruciate Ligament (ACL) n Prevents anterior movement of tibia on femur
Ligaments n Cruciates n Posterior Cruciate Ligament (PCL) n n Twice as strong as the ACL Prevents posterior movement of the tibia on the femur
Ligaments n Collaterals n n On sides of knee Give side to side stability
Ligaments n Collaterals n Medial Collateral Ligament (MCL) n n Goes from the femur to the tibia Prevents valgus stress n Valgus stress: pushing knee from outside in
Ligaments n Collaterals n Lateral Collateral Ligament (LCL) n n Goes from femur to the head of the fibula Prevents varus stress n Varus Stress: Knee pushed from inside out
Meniscus n n n “Cartilage” of the knee Sit on the tibia Functions: n n n Deepens socket for the femur Gives stability to the knee Shock absorption
Meniscus n Medial n n Larger and ‘c’ shaped More firmly fixed to the tibia Attached to tibia, MCL, and joint capsule Lateral n n Oval shaped More freely movable
Muscles n Quadriceps femoris (Quad) n Four muscles on the anterior thigh n n n 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
Muscles n Hamstrings n Three muscles on the posterior thigh n n n Biceps Femoris Semitendinosus Semimembranosus Function is to flex/bend the knee Also function to extend the hip
INJURIES
MCL Sprain n Cause n n n Signs and Symptoms n n n Blow to the lateral side of the knee Rotation to knee MCL is tender to touch Hurts to have knee totally straight Positive Valgus stress test Will “give out” if 2 nd or 3 rd degree Treatment n n RICE immediately Immobilizer/brace for 2 -6 weeks
LCL Sprain n Cause n n n Signs and Symptoms n n n Injured by a blow to the medial side of the knee Not a very common injury Pain and tenderness over LCL Positive Varus Stress test Treatment n n RICE immediately Immobilizer/brace for 2 -6 weeks
PCL Sprain n Injured by: n n Signs and Symptoms n n n Blow forcing tibia back Leg is bent and it is hit on tibial tuberosity Hyperextension Feel and hear pop in the back of the knee Positive Posterior Drawer Test Care n n RICE immediately and rehab Some athletes can participate without a PCL
ACL Sprain n Causes n n Signs and Symptoms n n n Plant and cut in opposite direction Hyperextension Blow to the lateral side Feel and hear a pop Immediate swelling Significant pain and then pain can subside Positive Lachman’s and Anterior Drawer Test Feels like it will give out if standing on it Treatment n n RICE immediately, Crutches Needs surgery to repair – out 6 months
Meniscus Tear n n n Injured when they get trapped/pinched between the bones Medial Meniscus injured more often than Lateral Mensicus Cause n n Sign and Symptoms n n Planting foot and cutting in opposite direction, knee is flexed Symptoms can come about 48 -72 hours later Swelling, giving out, knee locks up, clicking Pain with squatting Treatment n n n RICE If locked, to MD right away Needs Arthroscopic surgery
The Unhappy Triad n n n Injury to the ACL, MCL and Medial Meniscus Injured all at once Cause: planting foot and cutting/twisting
Patellar Tendinitis n n Also known as Jumper’s Knee Cause n n n Signs and Symptoms n n Running and jumping sports Poor flexibility Sorest at warm-up and cool down May have crepitus Tender over patellar tendon Treatment n n n Rest – decrease pounding activity Anti-inflammatory meds Ice/Ice Massage Heat Patellar Tendon Strap
Osgood-Schlatter n n Insertion of the patellar tendon on the tibial tuberosity gets stressed and pulls away from its insertion site Cause n n n Signs and Symptoms n n n From repeated jumping Common in adolescents due to growth spurt and inflexibility Pain will be right on the tibial tuberosity Tibial tuberosity will become much more prominent Treatment n n Much the same as patellar tendonitis Modify activity as pain persists
Dislocation/Subluxation of Patella n Dislocated patella n n 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 n n n Dislocates and reduces itself quickly More common Signs: History of patella problems, sore over the medial aspect of the patella
Dislocation/Subluxation of Patella n Cause n n n Due to quad contracting and/or twisting of the knee Once it happens, it is more likely to happen again More likely to happen if you are n n n Female Have a weak vastus medialis Treatment n n n Referral to doctor/ER RICE immediately Will usually require rehab, surgery and/or immobilization
Chondromalacia n Cause n n n Signs and Symptoms n n n Degenerative process where the articular cartilage under the patella softens and then wears away Patella may not track well in the groove Poor flexibility Squatting activities Pain and grinding sensation under the patella Aching pain after activity Treatment n n n Ice Increase flexibility of leg muscles May have to decrease activity while inflamed.
Pre-Patellar Bursitis n Cause n n n Signs and Symptoms n n Direct hit to knee Kneeling Increased swelling right on top of knee Treatment n n n Ice Compression Eliminate the cause
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